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Sample records for sound pressure measurements

  1. Sound field separation with sound pressure and particle velocity measurements

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren; Jacobsen, Finn; Leclère, Quentin

    2012-01-01

    separation techniques make it possible to distinguish between outgoing and incoming waves from the two sides, and thus NAH can be applied. In this paper, a separation method based on the measurement of the particle velocity in two layers and another method based on the measurement of the pressure...... and the velocity in a single layer are proposed. The two methods use an equivalent source formulation with separate transfer matrices for the outgoing and incoming waves, so that the sound from the two sides of the array can be modeled independently. A weighting scheme is proposed to account for the distance......In conventional near-field acoustic holography (NAH) it is not possible to distinguish between sound from the two sides of the array, thus, it is a requirement that all the sources are confined to only one side and radiate into a free field. When this requirement cannot be fulfilled, sound field...

  2. A note on measurement of sound pressure with intensity probes

    DEFF Research Database (Denmark)

    Juhl, Peter; Jacobsen, Finn

    2004-01-01

    be improved under a variety of realistic sound field conditions by applying a different weighting of the two pressure signals from the probe. The improved intensity probe can measure the sound pressure more accurately at high frequencies than an ordinary sound intensity probe or an ordinary sound level meter......The effect of scattering and diffraction on measurement of sound pressure with "two-microphone" sound intensity probes is examined using an axisymmetric boundary element model of the probe. Whereas it has been shown a few years ago that the sound intensity estimated with a two-microphone probe...... is reliable up to 10 kHz when using 0.5 in. microphones in the usual face-to-face arrangement separated by a 12 mm spacer, the sound pressure measured with the same instrument will typically be underestimated at high frequencies. It is shown in this paper that the estimate of the sound pressure can...

  3. Differential Intracochlear Sound Pressure Measurements in Normal Human Temporal Bones

    Science.gov (United States)

    Nakajima, Hideko Heidi; Dong, Wei; Olson, Elizabeth S.; Merchant, Saumil N.; Ravicz, Michael E.; Rosowski, John J.

    2009-02-01

    We present the first simultaneous sound pressure measurements in scala vestibuli and scala tympani of the cochlea in human cadaveric temporal bones. Micro-scale fiberoptic pressure sensors enabled the study of differential sound pressure at the cochlear base. This differential pressure is the input to the cochlear partition, driving cochlear waves and auditory transduction. Results showed that: pressure of scala vestibuli was much greater than scala tympani except at low and high frequencies where scala tympani pressure affects the input to the cochlea; the differential pressure proved to be an excellent measure of normal ossicular transduction of sound (shown to decrease 30-50 dB with ossicular disarticulation, whereas the individual scala pressures were significantly affected by non-ossicular conduction of sound at high frequencies); the middle-ear gain and differential pressure were generally bandpass in frequency dependence; and the middle-ear delay in the human was over twice that of the gerbil. Concurrent stapes velocity measurements allowed determination of the differential impedance across the partition and round-window impedance. The differential impedance was generally resistive, while the round-window impedance was consistent with a compliance in conjunction with distributed inertia and damping. Our techniques can be used to study inner-ear conductive pathologies (e.g., semicircular dehiscence), as well as non-ossicular cochlear stimulation (e.g., round-window stimulation) - situations that cannot be completely quantified by measurements of stapes velocity or scala-vestibuli pressure by themselves.

  4. Differential Intracochlear Sound Pressure Measurements in Human Temporal Bones with an Off-the-Shelf Sensor

    Directory of Open Access Journals (Sweden)

    Martin Grossöhmichen

    2016-01-01

    Full Text Available The standard method to determine the output level of acoustic and mechanical stimulation to the inner ear is measurement of vibration response of the stapes in human cadaveric temporal bones (TBs by laser Doppler vibrometry. However, this method is reliable only if the intact ossicular chain is stimulated. For other stimulation modes an alternative method is needed. The differential intracochlear sound pressure between scala vestibuli (SV and scala tympani (ST is assumed to correlate with excitation. Using a custom-made pressure sensor it has been successfully measured and used to determine the output level of acoustic and mechanical stimulation. To make this method generally accessible, an off-the-shelf pressure sensor (Samba Preclin 420 LP, Samba Sensors was tested here for intracochlear sound pressure measurements. During acoustic stimulation, intracochlear sound pressures were simultaneously measurable in SV and ST between 0.1 and 8 kHz with sufficient signal-to-noise ratios with this sensor. The pressure differences were comparable to results obtained with custom-made sensors. Our results demonstrated that the pressure sensor Samba Preclin 420 LP is usable for measurements of intracochlear sound pressures in SV and ST and for the determination of differential intracochlear sound pressures.

  5. Near-field acoustic holography with sound pressure and particle velocity measurements

    DEFF Research Database (Denmark)

    Fernandez Grande, Efren

    of the particle velocity has notable potential in NAH, and furthermore, combined measurement of sound pressure and particle velocity opens a new range of possibilities that are examined in this study. On this basis, sound field separation methods have been studied, and a new measurement principle based on double...... layer measurements of the particle velocity has been proposed. Also, the relation between near-field and far-field radiation from sound sources has been examined using the concept of the supersonic intensity. The calculation of this quantity has been extended to other holographic methods, and studied...

  6. Tutorial and Guidelines on Measurement of Sound Pressure Level in Voice and Speech

    Science.gov (United States)

    Švec, Jan G.; Granqvist, Svante

    2018-01-01

    Purpose: Sound pressure level (SPL) measurement of voice and speech is often considered a trivial matter, but the measured levels are often reported incorrectly or incompletely, making them difficult to compare among various studies. This article aims at explaining the fundamental principles behind these measurements and providing guidelines to…

  7. Pressure sound level measurements at an educational environment in Goiania, Goias, Brazil

    International Nuclear Information System (INIS)

    Costa, Jhonatha J.L.; Nascimento, Eriberto O. do; Oliveira, Lucas N. de; Caldas, Linda V. E.

    2017-01-01

    In this work, twenty five points located on the ground floor of the Federal Institute of Education, Science and Technology of Goias - IFG - Campus Goiania, were analyzed in morning periods of two Saturdays. The pressure sound levels were measured at internal and external environments during routine activities seeking to perform an environmental monitoring at this institution. The initial hypothesis was that an amusement park (Mutirama Park) was responsible for originating noise pollution in the institution, but the results showed, within the campus environment, sound pressure levels in accordance with the Municipal legislation of Goiania for all points. (author)

  8. Pressure sound level measurements at an educational environment in Goiania, Goias, Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Jhonatha J.L.; Nascimento, Eriberto O. do; Oliveira, Lucas N. de [Instituto Federal de Educação, Ciência e Tecnologia de Goiás (IFG), Goiânia, GO (Brazil); Caldas, Linda V. E., E-mail: lcaldas@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    In this work, twenty five points located on the ground floor of the Federal Institute of Education, Science and Technology of Goias - IFG - Campus Goiania, were analyzed in morning periods of two Saturdays. The pressure sound levels were measured at internal and external environments during routine activities seeking to perform an environmental monitoring at this institution. The initial hypothesis was that an amusement park (Mutirama Park) was responsible for originating noise pollution in the institution, but the results showed, within the campus environment, sound pressure levels in accordance with the Municipal legislation of Goiania for all points. (author)

  9. Variation of the Korotkoff Stethoscope Sounds During Blood Pressure Measurement: Analysis Using a Convolutional Neural Network.

    Science.gov (United States)

    Pan, Fan; He, Peiyu; Liu, Chengyu; Li, Taiyong; Murray, Alan; Zheng, Dingchang

    2017-11-01

    Korotkoff sounds are known to change their characteristics during blood pressure (BP) measurement, resulting in some uncertainties for systolic and diastolic pressure (SBP and DBP) determinations. The aim of this study was to assess the variation of Korotkoff sounds during BP measurement by examining all stethoscope sounds associated with each heartbeat from above systole to below diastole during linear cuff deflation. Three repeat BP measurements were taken from 140 healthy subjects (age 21 to 73 years; 62 female and 78 male) by a trained observer, giving 420 measurements. During the BP measurements, the cuff pressure and stethoscope signals were simultaneously recorded digitally to a computer for subsequent analysis. Heartbeats were identified from the oscillometric cuff pressure pulses. The presence of each beat was used to create a time window (1 s, 2000 samples) centered on the oscillometric pulse peak for extracting beat-by-beat stethoscope sounds. A time-frequency two-dimensional matrix was obtained for the stethoscope sounds associated with each beat, and all beats between the manually determined SBPs and DBPs were labeled as "Korotkoff." A convolutional neural network was then used to analyze consistency in sound patterns that were associated with Korotkoff sounds. A 10-fold cross-validation strategy was applied to the stethoscope sounds from all 140 subjects, with the data from ten groups of 14 subjects being analyzed separately, allowing consistency to be evaluated between groups. Next, within-subject variation of the Korotkoff sounds analyzed from the three repeats was quantified, separately for each stethoscope sound beat. There was consistency between folds with no significant differences between groups of 14 subjects (P = 0.09 to P = 0.62). Our results showed that 80.7% beats at SBP and 69.5% at DBP were analyzed as Korotkoff sounds, with significant differences between adjacent beats at systole (13.1%, P = 0.001) and diastole (17.4%, P < 0

  10. Sound velocity and equation-of-state measurements in high pressure fluid and solid helium

    International Nuclear Information System (INIS)

    Liebenberg, D.H.; Mills, R.L.; Bronson, J.C.

    1979-01-01

    A piston--cylinder apparatus was used to obtain P, V, T, and simultaneous values of longitudinal sound velocity in helium fluid throughout the ranges 75 to 300 0 K and 3 to 20 kbar. Some 670 data sets were obtained for the fluid and used in a double-process least-squares fit to an equation of state of the Benedict type. Additional measurements extended across the melting line into the solid phase at pressures up to 18 kbar. Measurements of the compressibility are compared with those obtained by Stewart along the 4 0 K isotherm up to 20 kbar. We discuss the use of helium as a pressure medium in high-pressure diamond anvil cells. Essentially no data are given

  11. Pressure sound level measurements at an educational environment in Goiânia, Goiás, Brazil

    Science.gov (United States)

    Costa, J. J. L.; do Nascimento, E. O.; de Oliveira, L. N.; Caldas, L. V. E.

    2018-03-01

    In this work, 25 points located on the ground floor of the Federal Institute of Education, Science and Technology of Goias - IFG - Campus Goiânia, were analyzed in morning periods of two Saturdays. The pressure sound levels were measured at internal and external environments during routine activities seeking to perform an environmental monitoring at this institution. The initial hypothesis was that an amusement park (Mutirama Park) was responsible for originating noise pollution in the institute, but the results showed, within the campus environment, sound pressure levels in accordance with the Municipal legislation of Goiânia for all points.

  12. Joint reconstruction of the initial pressure and speed of sound distributions from combined photoacoustic and ultrasound tomography measurements

    Science.gov (United States)

    Matthews, Thomas P.; Anastasio, Mark A.

    2017-12-01

    The initial pressure and speed of sound (SOS) distributions cannot both be stably recovered from photoacoustic computed tomography (PACT) measurements alone. Adjunct ultrasound computed tomography (USCT) measurements can be employed to estimate the SOS distribution. Under the conventional image reconstruction approach for combined PACT/USCT systems, the SOS is estimated from the USCT measurements alone and the initial pressure is estimated from the PACT measurements by use of the previously estimated SOS. This approach ignores the acoustic information in the PACT measurements and may require many USCT measurements to accurately reconstruct the SOS. In this work, a joint reconstruction method where the SOS and initial pressure distributions are simultaneously estimated from combined PACT/USCT measurements is proposed. This approach allows accurate estimation of both the initial pressure distribution and the SOS distribution while requiring few USCT measurements.

  13. Towards direct realisation of the SI unit of sound pressure in the audible hearing range based on optical free-field acoustic particle measurements

    Energy Technology Data Exchange (ETDEWEB)

    Koukoulas, Triantafillos, E-mail: triantafillos.koukoulas@npl.co.uk; Piper, Ben [Acoustics Group, National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW (United Kingdom)

    2015-04-20

    Since the introduction of the International System of Units (the SI system) in 1960, weights, measures, standardised approaches, procedures, and protocols have been introduced, adapted, and extensively used. A major international effort and activity concentrate on the definition and traceability of the seven base SI units in terms of fundamental constants, and consequently those units that are derived from the base units. In airborne acoustical metrology and for the audible range of frequencies up to 20 kHz, the SI unit of sound pressure, the pascal, is realised indirectly and without any knowledge or measurement of the sound field. Though the principle of reciprocity was originally formulated by Lord Rayleigh nearly two centuries ago, it was devised in the 1940s and eventually became a calibration standard in the 1960s; however, it can only accommodate a limited number of acoustic sensors of specific types and dimensions. International standards determine the device sensitivity either through coupler or through free-field reciprocity but rely on the continuous availability of specific acoustical artefacts. Here, we show an optical method based on gated photon correlation spectroscopy that can measure sound pressures directly and absolutely in fully anechoic conditions, remotely, and without disturbing the propagating sound field. It neither relies on the availability or performance of any measurement artefact nor makes any assumptions of the device geometry and sound field characteristics. Most importantly, the required units of sound pressure and microphone sensitivity may now be experimentally realised, thus providing direct traceability to SI base units.

  14. Laboratory measurement of elastic anisotropy on spherical rock samples by longitudinal and transverse sounding under confining pressure

    Czech Academy of Sciences Publication Activity Database

    Lokajíček, Tomáš; Svitek, Tomáš

    2015-01-01

    Roč. 56, February 2015 (2015), s. 294-302 ISSN 0041-624X R&D Projects: GA MŠk LH13102; GA ČR GAP104/12/0915; GA ČR GA13-13967S Institutional support: RVO:67985831 Keywords : elastic anisotropy * hydrostatic pressure * ultrasonic sounding * high pressure * longitudinal and shear waves Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.954, year: 2015

  15. Measuring the 'complexity' of sound

    Indian Academy of Sciences (India)

    cate that specialized regions of the brain analyse different types of sounds [1]. Music, ... The left panel of figure 1 shows examples of sound–pressure waveforms from the nat- ... which is shown in the right panels in the spectrographic representation using a 45 Hz .... Plot of SFM(t) vs. time for different environmental sounds.

  16. A Comparative Study of Sound Speed in Air at Room Temperature between a Pressure Sensor and a Sound Sensor

    Science.gov (United States)

    Amrani, D.

    2013-01-01

    This paper deals with the comparison of sound speed measurements in air using two types of sensor that are widely employed in physics and engineering education, namely a pressure sensor and a sound sensor. A computer-based laboratory with pressure and sound sensors was used to carry out measurements of air through a 60 ml syringe. The fast Fourier…

  17. Microflown based monopole sound sources for reciprocal measurements

    NARCIS (Netherlands)

    Bree, H.E. de; Basten, T.G.H.

    2008-01-01

    Monopole sound sources (i.e. omni directional sound sources with a known volume velocity) are essential for reciprocal measurements used in vehicle interior panel noise contribution analysis. Until recently, these monopole sound sources use a sound pressure transducer sensor as a reference sensor. A

  18. Sound field separation with cross measurement surfaces.

    Directory of Open Access Journals (Sweden)

    Jin Mao

    Full Text Available With conventional near-field acoustical holography, it is impossible to identify sound pressure when the coherent sound sources are located on the same side of the array. This paper proposes a solution, using cross measurement surfaces to separate the sources based on the equivalent source method. Each equivalent source surface is built in the center of the corresponding original source with a spherical surface. According to the different transfer matrices between equivalent sources and points on holographic surfaces, the weighting of each equivalent source from coherent sources can be obtained. Numerical and experimental studies have been performed to test the method. For the sound pressure including noise after separation in the experiment, the calculation accuracy can be improved by reconstructing the pressure with Tikhonov regularization and the L-curve method. On the whole, a single source can be effectively separated from coherent sources using cross measurement.

  19. Analysis of sound pressure levels emitted by children's toys.

    Science.gov (United States)

    Sleifer, Pricila; Gonçalves, Maiara Santos; Tomasi, Marinês; Gomes, Erissandra

    2013-06-01

    To verify the levels of sound pressure emitted by non-certified children's toys. Cross-sectional study of sound toys available at popular retail stores of the so-called informal sector. Electronic, mechanical, and musical toys were analyzed. The measurement of each product was carried out by an acoustic engineer in an acoustically isolated booth, by a decibel meter. To obtain the sound parameters of intensity and frequency, the toys were set to produce sounds at a distance of 10 and 50cm from the researcher's ear. The intensity of sound pressure [dB(A)] and the frequency in hertz (Hz) were measured. 48 toys were evaluated. The mean sound pressure 10cm from the ear was 102±10 dB(A), and at 50cm, 94±8 dB(A), with ptoys was above 85dB(A). The frequency ranged from 413 to 6,635Hz, with 56.3% of toys emitting frequency higher than 2,000Hz. The majority of toys assessed in this research emitted a high level of sound pressure.

  20. Sound pressure distribution in a long, narrow hallway: Measurements versus results from a computer model with scattering from surface roughness and diffraction

    DEFF Research Database (Denmark)

    Wang, Lily M.; Rathsam, Jonathan; Christensen, Claus Lynge

    2005-01-01

    The sound pressure level distributrion down a long, narrow hallway due to a sound source at one end does not decrease linearly along the length of the hall. This characteristic may be due to the changing behaviour of scattering that occurs down the length of the hallway, which is distance...

  1. Sound intensity and its measurement

    DEFF Research Database (Denmark)

    Jacobsen, Finn

    1997-01-01

    The paper summarises the basic theory of sound intensity and its measurement and gives an overview of the state of the art with particular emphasis on recent developments in the field. Eighty references are given, most of which to literature published in the past two years. The paper describes...

  2. Thermoelastic properties of liquid Fe-C revealed by sound velocity and density measurements at high pressure

    Science.gov (United States)

    Shimoyama, Yuta; Terasaki, Hidenori; Urakawa, Satoru; Takubo, Yusaku; Kuwabara, Soma; Kishimoto, Shunpachi; Watanuki, Tetsu; Machida, Akihiko; Katayama, Yoshinori; Kondo, Tadashi

    2016-11-01

    Carbon is one of the possible light elements in the cores of the terrestrial planets. The P wave velocity (VP) and density (ρ) are important factors for estimating the chemical composition and physical properties of the core. We simultaneously measured the VP and ρ of Fe-3.5 wt % C up to 3.4 GPa and 1850 K by using ultrasonic pulse-echo method and X-ray absorption methods. The VP of liquid Fe-3.5 wt % C decreased linearly with increasing temperature at constant pressure. The addition of carbon decreased the VP of liquid Fe by about 2% at 3 GPa and 1700 K and decreased the Fe density by about 2% at 2 GPa and 1700 K. The bulk modulus of liquid Fe-C and its pressure (P) and temperature (T) effects were precisely determined from directly measured ρ and VP data to be K0,1700 K = 83.9 GPa, dKT/dP = 5.9(2), and dKT/dT = -0.063 GPa/K. The addition of carbon did not affect the isothermal bulk modulus (KT) of liquid Fe, but it decreased the dK/dT of liquid Fe. In the ρ-VP relationship, VP increases linearly with ρ and can be approximated as VP (m/s) = -6786(506) + 1537(71) × ρ (g/cm3), suggesting that Birch's law is valid for liquid Fe-C at the present P-T conditions. Our results imply that at the conditions of the lunar core, the elastic properties of an Fe-C core are more affected by temperature than those of Fe-S core.

  3. Measurement of incident sound power using near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2009-01-01

    ; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using ‘statistically optimised near field acoustic holography’ (SONAH...

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

    DEFF Research Database (Denmark)

    Christensen, Christian Bech; Christensen-Dalsgaard, Jakob; Brandt, Christian

    2012-01-01

    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...

  5. Wind turbine sound pressure level calculations at dwellings.

    Science.gov (United States)

    Keith, Stephen E; Feder, Katya; Voicescu, Sonia A; Soukhovtsev, Victor; Denning, Allison; Tsang, Jason; Broner, Norm; Leroux, Tony; Richarz, Werner; van den Berg, Frits

    2016-03-01

    This paper provides calculations of outdoor sound pressure levels (SPLs) at dwellings for 10 wind turbine models, to support Health Canada's Community Noise and Health Study. Manufacturer supplied and measured wind turbine sound power levels were used to calculate outdoor SPL at 1238 dwellings using ISO [(1996). ISO 9613-2-Acoustics] and a Swedish noise propagation method. Both methods yielded statistically equivalent results. The A- and C-weighted results were highly correlated over the 1238 dwellings (Pearson's linear correlation coefficient r > 0.8). Calculated wind turbine SPLs were compared to ambient SPLs from other sources, estimated using guidance documents from the United States and Alberta, Canada.

  6. Measuring the 'complexity'of sound

    Indian Academy of Sciences (India)

    Sounds in the natural environment form an important class of biologically relevant nonstationary signals. We propose a dynamic spectral measure to characterize the spectral dynamics of such non-stationary sound signals and classify them based on rate of change of spectral dynamics. We categorize sounds with slowly ...

  7. Sound source measurement by using a passive sound insulation and a statistical approach

    Science.gov (United States)

    Dragonetti, Raffaele; Di Filippo, Sabato; Mercogliano, Francesco; Romano, Rosario A.

    2015-10-01

    This paper describes a measurement technique developed by the authors that allows carrying out acoustic measurements inside noisy environments reducing background noise effects. The proposed method is based on the integration of a traditional passive noise insulation system with a statistical approach. The latter is applied to signals picked up by usual sensors (microphones and accelerometers) equipping the passive sound insulation system. The statistical approach allows improving of the sound insulation given only by the passive sound insulation system at low frequency. The developed measurement technique has been validated by means of numerical simulations and measurements carried out inside a real noisy environment. For the case-studies here reported, an average improvement of about 10 dB has been obtained in a frequency range up to about 250 Hz. Considerations on the lower sound pressure level that can be measured by applying the proposed method and the measurement error related to its application are reported as well.

  8. Temperature/pressure and water vapor sounding with microwave spectroscopy

    Science.gov (United States)

    Muhleman, D. O.; Janssen, M. A.; Clancy, R. T.; Gulkis, S.; Mccleese, D. J.; Zurek, R.; Haberle, R. M.; Frerking, M.

    1992-01-01

    Two intense microwave spectra lines exist in the martian atmosphere that allow unique sounding capabilities: water vapor at 183 GHz and the (2-1) rotational line of CO at 230 GHz. Microwave spectra line sounding is a well-developed technique for the Earth's atmosphere for sounding from above from spacecraft and airplanes, and from below from fixed surface sites. Two simple instruments for temperature sounding on Mars (the CO line) and water vapor measurements are described. The surface sounder proposed for the MESUR sites is designed to study the boundary layer water vapor distribution and the temperature/pressure profiles with vertical resolution of 0.25 km up to 1 km with reduced resolution above approaching a scale height. The water channel will be sensitive to a few tenths of a micrometer of water and the temperature profile will be retrieved to an accuracy between 1 and 2 K. The latter is routinely done on the Earth using oxygen lines near 60 GHz. The measurements are done with a single-channel heterodyne receiver looking into a 10-cm mirror that is canned through a range of elevation angles plus a target load. The frequency of the receiver is sweep across the water and CO lines generating the two spectra at about 1-hr intervals throughout the mission. The mass and power for the proposed instrument are 2 kg and 5-8 W continuously. The measurements are completely immune to the atmospheric dust and ice particle loads. It was felt that these measurements are the ultimate ones to properly study the martian boundary layer from the surface to a few kilometers. Sounding from above requires an orbiting spacecraft with multichannel microwave spectrometers such as the instrument proposed for MO by a subset of the authors, a putative MESUR orbiter, and a proposed Discovery mission called MOES. Such an instrument can be built with less than 10 kg and use less than 15 W. The obvious advantage of this approach is that the entire atmosphere can be sounded for temperature and

  9. Sound exposure measurements using hearing-aid technology

    DEFF Research Database (Denmark)

    Jensen, Simon Boelt; Drastrup, Mads; Morales, Esteban Chávez

    2016-01-01

    scenarios. The purpose of this work is to document the use of a modified behind-the-ear (BTE) hearing-aid as a portable sound pressure level (SPL) meter. In order to obtain sound level measurements with a BTE device comparable to sound field values that can be used with existing risk assessment strategies...... levels of sound exposures are experienced in modern society in many different situations such as attending concerts, sport events and others. This leads to an interest in measurement devices which are discreet and simple to use, in order to assess sound exposures encountered in typical daily life......, differences due to microphone positions and the presence of a person in the measurement must be taken into account. The present study presents measurements carried out to document the characteristics of the BTE device, using the same framework presented in the ISO 11904 standard series. The responses...

  10. Characterization of the natural ambient sound environment : Measurements in open agricultural grassland

    NARCIS (Netherlands)

    Boersma, HF

    The audibility of manmade sound in a natural environment is affected because of masking by ambient sound. In this report results are presented of measurements of the level and spectral composition of natural ambient sound. The statistical L-95 level was determined, i.e., the sound pressure level

  11. Sound pressure distribution within natural and artificial human ear canals: forward stimulation.

    Science.gov (United States)

    Ravicz, Michael E; Tao Cheng, Jeffrey; Rosowski, John J

    2014-12-01

    This work is part of a study of the interaction of sound pressure in the ear canal (EC) with tympanic membrane (TM) surface displacement. Sound pressures were measured with 0.5-2 mm spacing at three locations within the shortened natural EC or an artificial EC in human temporal bones: near the TM surface, within the tympanic ring plane, and in a plane transverse to the long axis of the EC. Sound pressure was also measured at 2-mm intervals along the long EC axis. The sound field is described well by the size and direction of planar sound pressure gradients, the location and orientation of standing-wave nodal lines, and the location of longitudinal standing waves along the EC axis. Standing-wave nodal lines perpendicular to the long EC axis are present on the TM surface >11-16 kHz in the natural or artificial EC. The range of sound pressures was larger in the tympanic ring plane than at the TM surface or in the transverse EC plane. Longitudinal standing-wave patterns were stretched. The tympanic-ring sound field is a useful approximation of the TM sound field, and the artificial EC approximates the natural EC.

  12. Comprehensive measures of sound exposures in cinemas using smart phones.

    Science.gov (United States)

    Huth, Markus E; Popelka, Gerald R; Blevins, Nikolas H

    2014-01-01

    Sensorineural hearing loss from sound overexposure has a considerable prevalence. Identification of sound hazards is crucial, as prevention, due to a lack of definitive therapies, is the sole alternative to hearing aids. One subjectively loud, yet little studied, potential sound hazard is movie theaters. This study uses smart phones to evaluate their applicability as a widely available, validated sound pressure level (SPL) meter. Therefore, this study measures sound levels in movie theaters to determine whether sound levels exceed safe occupational noise exposure limits and whether sound levels in movie theaters differ as a function of movie, movie theater, presentation time, and seat location within the theater. Six smart phones with an SPL meter software application were calibrated with a precision SPL meter and validated as an SPL meter. Additionally, three different smart phone generations were measured in comparison to an integrating SPL meter. Two different movies, an action movie and a children's movie, were measured six times each in 10 different venues (n = 117). To maximize representativeness, movies were selected focusing on large release productions with probable high attendance. Movie theaters were selected in the San Francisco, CA, area based on whether they screened both chosen movies and to represent the largest variety of theater proprietors. Measurements were analyzed in regard to differences between theaters, location within the theater, movie, as well as presentation time and day as indirect indicator of film attendance. The smart phone measurements demonstrated high accuracy and reliability. Overall, sound levels in movie theaters do not exceed safe exposure limits by occupational standards. Sound levels vary significantly across theaters and demonstrated statistically significant higher sound levels and exposures in the action movie compared to the children's movie. Sound levels decrease with distance from the screen. However, no influence on

  13. Sound pressure gain produced by the human middle ear.

    Science.gov (United States)

    Kurokawa, H; Goode, R L

    1995-10-01

    The acoustic function of the middle ear is to match sound passing from the low impedance of air to the high impedance of cochlear fluid. Little information is available on the actual middle ear pressure gain in human beings. This article describes experiments on middle ear pressure gain in six fresh human temporal bones. Stapes footplate displacement and phase were measured with a laser Doppler vibrometer before and after removal of the tympanic membrane, malleus, and incus. Acoustic insulation of the round window with clay was performed. Umbo displacement was also measured before tympanic membrane removal to assess baseline tympanic membrane function. The middle ear has its major gain in the lower frequencies, with a peak near 0.9 kHz. The mean gain was 23.0 dB below 1.0 kHz, the resonant frequency of the middle ear; the mean peak gain was 26.6 dB. Above 1.0 kHz, the second pressure gain decreased at a rate of -8.6 dB/octave, with a mean gain of 6.5 dB at 4.0 kHz. Only a small amount of gain was present above 7.0 kHz. Significant individual differences in pressure gain were found between ears that appeared related to variations in tympanic membrane function and not to variations in cochlear impedance.

  14. Indoor measurements of sound at low frequencies

    DEFF Research Database (Denmark)

    Pedersen, Steffen; Møller, Henrik; Persson-Waye, Kerstin

    2006-01-01

    Due to standing waves, the sound pressure level within a room may vary as much as 20-30 dB with low-frequency tonal noise, somewhat less with noise bands. For assessment of annoyance from low-frequency noise it is relevant to measure a level close to the highest level of the room, rather than a r...

  15. Corrigendum to "A semi-empirical airfoil stall noise model based on surface pressure measurements" [J. Sound Vib. 387 (2017) 127-162

    Science.gov (United States)

    Bertagnolio, Franck; Madsen, Helge Aa.; Fischer, Andreas; Bak, Christian

    2018-06-01

    In the above-mentioned paper, two model formulae were tuned to fit experimental data of surface pressure spectra measured in various wind tunnels. They correspond to high and low Reynolds number flow scalings, respectively. It turns out that there exist typographical errors in both formulae numbered (9) and (10) in the original paper. There, these formulae read:

  16. Measurement of sound propagation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1995-01-01

    A new acoustic method for directly measuring the flow resistance, and the compressibility of fibrous materials such as glass wool, is given. Measured results for monochromatic sound in glass wool are presented and compared with theoretically calculated results. The agreement between experimental...

  17. Sounding experiments of high pressure gas discharge

    International Nuclear Information System (INIS)

    Biele, Joachim K.

    1998-01-01

    A high pressure discharge experiment (200 MPa, 5·10 21 molecules/cm 3 , 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm 3 ) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm 3 ) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at the combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved

  18. 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.

  19. Sound power measurement and certification

    International Nuclear Information System (INIS)

    MacKinnon, A.

    1993-01-01

    It is anticipated that there will be a substantial growth in the exploitation of renewable energy from the wind over the next few years. A major factor in this expected growth is the environmental acceptance or otherwise of wind turbines and in particular their noise characteristics. It is generally accepted within the turbine community that reliable methods of measuring and quantifying a turbine's acoustic signature are essential if this exploitation is to be realised. This paper will seek to review current practice both in the UK and further afield and will describe the development of a practical and reliable test method, which will aid the Wind Turbine Manufacturer, Developer and Planner. (author)

  20. Inner-ear sound pressures near the base of the cochlea in chinchilla: Further investigation

    Science.gov (United States)

    Ravicz, Michael E.; Rosowski, John J.

    2013-01-01

    The middle-ear pressure gain GMEP, the ratio of sound pressure in the cochlear vestibule PV to sound pressure at the tympanic membrane PTM, is a descriptor of middle-ear sound transfer and the cochlear input for a given stimulus in the ear canal. GMEP and the cochlear partition differential pressure near the cochlear base ΔPCP, which determines the stimulus for cochlear partition motion and has been linked to hearing ability, were computed from simultaneous measurements of PV, PTM, and the sound pressure in scala tympani near the round window PST in chinchilla. GMEP magnitude was approximately 30 dB between 0.1 and 10 kHz and decreased sharply above 20 kHz, which is not consistent with an ideal transformer or a lossless transmission line. The GMEP phase was consistent with a roughly 50-μs delay between PV and PTM. GMEP was little affected by the inner-ear modifications necessary to measure PST. GMEP is a good predictor of ΔPCP at low and moderate frequencies where PV ⪢ PST but overestimates ΔPCP above a few kilohertz where PV ≈ PST. The ratio of PST to PV provides insight into the distribution of sound pressure within the cochlear scalae. PMID:23556590

  1. Semiconductor-based electret sensors for sound and pressure

    NARCIS (Netherlands)

    Voorthuyzen, J.A.; Bergveld, Piet; Sprenkels, A.J.

    1989-01-01

    The theory and experimental results for integrated electret-based silicon sensors for the detection of sound and pressure are presented. A silicon electret microphone for use in hearing-aids is described. It has an experimentally determined sensitivity of 19 mV/Pa in the frequency range of 50 Hz to

  2. Measuring fluid pressure

    International Nuclear Information System (INIS)

    Lee, A.S.

    1978-01-01

    A method and apparatus are described for measuring the pressure of a fluid having characteristics that make it unsuitable for connection directly to a pressure gauge. The method is particularly suitable for the periodic measurement of the pressure of a supply of liquid Na to Na-lubricated bearings of pumps for pumping Na from a reservoir to the bearing via a filter, the reservoir being contained in a closed vessel containing an inert blanket gas, such as Ar, above the Na. (UK)

  3. MP3 player listening sound pressure levels among 10 to 17 year old students.

    Science.gov (United States)

    Keith, Stephen E; Michaud, David S; Feder, Katya; Haider, Ifaz; Marro, Leonora; Thompson, Emma; Marcoux, Andre M

    2011-11-01

    Using a manikin, equivalent free-field sound pressure level measurements were made from the portable digital audio players of 219 subjects, aged 10 to 17 years (93 males) at their typical and "worst-case" volume levels. Measurements were made in different classrooms with background sound pressure levels between 40 and 52 dBA. After correction for the transfer function of the ear, the median equivalent free field sound pressure levels and interquartile ranges (IQR) at typical and worst-case volume settings were 68 dBA (IQR = 15) and 76 dBA (IQR = 19), respectively. Self-reported mean daily use ranged from 0.014 to 12 h. When typical sound pressure levels were considered in combination with the average daily duration of use, the median noise exposure level, Lex, was 56 dBA (IQR = 18) and 3.2% of subjects were estimated to exceed the most protective occupational noise exposure level limit in Canada, i.e., 85 dBA Lex. Under worst-case listening conditions, 77.6% of the sample was estimated to listen to their device at combinations of sound pressure levels and average daily durations for which there is no known risk of permanent noise-induced hearing loss, i.e., ≤  75 dBA Lex. Sources and magnitudes of measurement uncertainties are also discussed.

  4. 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.

  5. Equivalent threshold sound pressure levels for acoustic test signals of short duration

    DEFF Research Database (Denmark)

    Poulsen, Torben; Daugaard, Carsten

    1998-01-01

    . The measurements were performed with two types of headphones, Telephonics TDH-39 and Sennheiser HDA-200. The sound pressure levels were measured in an IEC 318 ear simulator with Type 1 adapter (a flat plate) and a conical ring. The audiometric methods used in the experiments were the ascending method (ISO 8253...

  6. Pressure Measurement Systems

    Science.gov (United States)

    1990-01-01

    System 8400 is an advanced system for measurement of gas and liquid pressure, along with a variety of other parameters, including voltage, frequency and digital inputs. System 8400 offers exceptionally high speed data acquisition through parallel processing, and its modular design allows expansion from a relatively inexpensive entry level system by the addition of modular Input Units that can be installed or removed in minutes. Douglas Juanarena was on the team of engineers that developed a new technology known as ESP (electronically scanned pressure). The Langley ESP measurement system was based on miniature integrated circuit pressure-sensing transducers that communicated pressure information to a minicomputer. In 1977, Juanarena formed PSI to exploit the NASA technology. In 1978 he left Langley, obtained a NASA license for the technology, introduced the first commercial product, the 780B pressure measurement system. PSI developed a pressure scanner for automation of industrial processes. Now in its second design generation, the DPT-6400 is capable of making 2,000 measurements a second and has 64 channels by addition of slave units. New system 8400 represents PSI's bid to further exploit the 600 million U.S. industrial pressure measurement market. It is geared to provide a turnkey solution to physical measurement.

  7. The Effect of Superior Semicircular Canal Dehiscence on Intracochlear Sound Pressures

    Science.gov (United States)

    Nakajima, Hideko Heidi; Pisano, Dominic V.; Merchant, Saumil N.; Rosowski, John J.

    2011-11-01

    Semicircular canal dehiscence (SCD) is a pathological opening in the bony wall of the inner ear that can result in conductive hearing loss. The hearing loss is variable across patients, and the precise mechanism and source of variability is not fully understood. We use intracochlear sound pressure measurements in cadaveric preparations to study the effects of SCD size. Simultaneous measurement of basal intracochlear sound pressures in scala vestibuli (SV) and scala tympani (ST) quantifies the complex differential pressure across the cochlear partition, the stimulus that excites the partition. Sound-induced pressures in SV and ST, as well as stapes velocity and ear-canal pressure are measured simultaneously for various sizes of SCD followed by SCD patching. At low frequencies (<600 Hz) our results show that SCD decreases the pressure in both SV and ST, as well as differential pressure, and these effects become more pronounced as dehiscence size is increased. For frequencies above 1 kHz, the smallest pinpoint dehiscence can have the larger effect on the differential pressure in some ears. These effects due to SCD are reversible by patching the dehiscence.

  8. An analysis of collegiate band directors' exposure to sound pressure levels

    Science.gov (United States)

    Roebuck, Nikole Moore

    Noise-induced hearing loss (NIHL) is a significant but unfortunate common occupational hazard. The purpose of the current study was to measure the magnitude of sound pressure levels generated within a collegiate band room and determine if those sound pressure levels are of a magnitude that exceeds the policy standards and recommendations of the Occupational Safety and Health Administration (OSHA), and the National Institute of Occupational Safety and Health (NIOSH). In addition, reverberation times were measured and analyzed in order to determine the appropriateness of acoustical conditions for the band rehearsal environment. Sound pressure measurements were taken from the rehearsal of seven collegiate marching bands. Single sample t test were conducted to compare the sound pressure levels of all bands to the noise exposure standards of OSHA and NIOSH. Multiple regression analysis were conducted and analyzed in order to determine the effect of the band room's conditions on the sound pressure levels and reverberation times. Time weighted averages (TWA), noise percentage doses, and peak levels were also collected. The mean Leq for all band directors was 90.5 dBA. The total accumulated noise percentage dose for all band directors was 77.6% of the maximum allowable daily noise dose under the OSHA standard. The total calculated TWA for all band directors was 88.2% of the maximum allowable daily noise dose under the OSHA standard. The total accumulated noise percentage dose for all band directors was 152.1% of the maximum allowable daily noise dose under the NIOSH standards, and the total calculated TWA for all band directors was 93dBA of the maximum allowable daily noise dose under the NIOSH standard. Multiple regression analysis revealed that the room volume, the level of acoustical treatment and the mean room reverberation time predicted 80% of the variance in sound pressure levels in this study.

  9. Equivalent threshold sound pressure levels (ETSPL) for Interacoustics DD 45 supra-aural audiometric earphones

    DEFF Research Database (Denmark)

    Poulsen, Torben

    2010-01-01

    This paper describes the determination and results of pure tone Equivalent Threshold Sound Pressure Levels for the Interacoustics DD45 audiometric earphone equipped with standard Model 51 cushions. The size and shape of the DD45 transducer resembles the classical Telephonics TDH 39 earphone. Pure...... tone hearing threshold measurements were performed for both ears of 29 test subjects. All audiometric frequencies from 125 Hz to 8 kHz were used. The data are intended for inclusion in future standardized Reference Equivalent Threshold Sound Pressure Levels. The results show that the DD45 may be a good...

  10. Sound pressure level tools design used in occupational health by means of Labview software

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2015-01-01

    Conclusion: LabVIEW programming capabilities in the field of sound can be referred to the measurement of sound, frequency analysis, and sound control that actually the software acts like a sound level meter and sound analyzer. According to the mentioned features, we can use this software to analyze and process sound and vibration as a monitoring system.

  11. Estimation of sound pressure levels of voiced speech from skin vibration of the neck

    NARCIS (Netherlands)

    Svec, JG; Titze, IR; Popolo, PS

    How accurately can sound pressure levels (SPLs) of speech be estimated from skin vibration of the neck? Measurements using a small accelerometer were carried out in 27 subjects (10 males and 17 females) who read Rainbow and Marvin Williams passages in soft, comfortable, and loud voice, while skin

  12. Line pressure effects on differential pressure measurements

    International Nuclear Information System (INIS)

    Neff, G.G.; Evans, R.P.

    1982-01-01

    The performance of differential pressure transducers in experimental pressurized water reactor (PWR) systems was evaluated. Transient differential pressure measurements made using a simple calibration proportionality relating differential pressure to output voltage could have large measurement uncertainties. A more sophisticated calibration equation was derived to incorporate the effects of zero shifts and sensitivity shifts as pressure in the pressure sensing line changes with time. A comparison made between the original calibration proportionality equation and the derived compensation equation indicates that potential measurement uncertainties can be reduced

  13. Inferring the high-pressure strength of copper by measurement of longitudinal sound speed in a symmetric impact and release experiment

    Science.gov (United States)

    Rothman, Stephen; Edwards, Rhys; Vogler, Tracy J.; Furnish, M. D.

    2012-03-01

    Velocity-time histories of free- or windowed-surfaces have been used to calculate wave speeds and hence deduce the shear moduli for materials at high pressure. This is important to high velocity impact phenomena, e.g. shaped-charge jets, long rod penetrators, and other projectile/armour interactions. Historically the shock overtake method has required several experiments with different depths of material to account for the effect of the surface on the arrival time of the release. A characteristics method, previously used for analysis of isentropic compression experiments, has been modified to account for the effect of the surface interactions, thus only one depth of material is required. This analysis has been applied to symmetric copper impacts performed at Sandia National Laboratory's Star Facility. A shear modulus of 200GPa, at a pressure of ~180GPa, has been estimated. These results are in broad agreement with previous work by Hayes et al.

  14. Producing of Impedance Tube for Measurement of Acoustic Absorption Coefficient of Some Sound Absorber Materials

    Directory of Open Access Journals (Sweden)

    R. Golmohammadi

    2008-04-01

    Full Text Available Introduction & Objective: Noise is one of the most important harmful agents in work environment. In spit of industrial improvements, exposure with over permissible limit of noise is counted as one of the health complication of workers. In Iran, do not exact information of the absorption coefficient of acoustic materials. Iranian manufacturer have not laboratory for measured of sound absorbance of their products, therefore using of sound absorber is limited for noise control in industrial and non industrial constructions. The goal of this study was to design an impedance tube based on pressure method for measurement of the sound absorption coefficient of acoustic materials.Materials & Methods: In this study designing of measuring system and method of calculation of sound absorption based on a available equipment and relatively easy for measurement of the sound absorption coefficient related to ISO10534-1 was performed. Measuring system consist of heavy asbestos tube, a pure tone sound generator, calibrated sound level meter for measuring of some commonly of sound absorber materials was used. Results: In this study sound absorption coefficient of 23 types of available acoustic material in Iran was tested. Reliability of results by three repeat of measurement was tested. Results showed that the standard deviation of sound absorption coefficient of study materials was smaller than .Conclusion: The present study performed a necessary technology of designing and producing of impedance tube for determining of acoustical materials absorption coefficient in Iran.

  15. Directivity of Spherical Polyhedron Sound Source Used in Near-Field HRTF Measurements

    International Nuclear Information System (INIS)

    Yu Guang-Zheng; Xie Bo-Sun; Rao Dan

    2010-01-01

    The omnidirectional character is one of important requirements for the sound source used in near-field head-related transfer function (HRTF) measurements. Based on the analysis on the radiation sound pressure and directivity character of various spherical polyhedron sound sources, a spherical dodecahedral sound source with radius of 0.035m is proposed and manufactured. Theoretical and measured results indicate that the sound source is approximately omnidirectional below the frequency of 8 kHz. In addition, the sound source has reasonable magnitude response from 350Hz to 20kHz and linear phase characteristics. Therefore, it is suitable for the near-field HRTF measurements. (fundamental areas of phenomenology(including applications))

  16. Signal quality measures for unsupervised blood pressure measurement

    International Nuclear Information System (INIS)

    Abdul Sukor, J; Redmond, S J; Lovell, N H; Chan, G S H

    2012-01-01

    Accurate systolic and diastolic pressure estimation, using automated blood pressure measurement, is difficult to achieve when the transduced signals are contaminated with noise or interference, such as movement artifact. This study presents an algorithm for automated signal quality assessment in blood pressure measurement by determining the feasibility of accurately detecting systolic and diastolic pressures when corrupted with various levels of movement artifact. The performance of the proposed algorithm is compared to a manually annotated reference scoring (RS). Based on visual representations and audible playback of Korotkoff sounds, the creation of the RS involved two experts identifying sections of the recorded sounds and annotating sections of noise contamination. The experts determined the systolic and diastolic pressure in 100 recorded Korotkoff sound recordings, using a simultaneous electrocardiograph as a reference signal. The recorded Korotkoff sounds were acquired from 25 healthy subjects (16 men and 9 women) with a total of four measurements per subject. Two of these measurements contained purposely induced noise artifact caused by subject movement. Morphological changes in the cuff pressure signal and the width of the Korotkoff pulse were extracted features which were believed to be correlated with the noise presence in the recorded Korotkoff sounds. Verification of reliable Korotkoff pulses was also performed using extracted features from the oscillometric waveform as recorded from the inflatable cuff. The time between an identified noise section and a verified Korotkoff pulse was the key feature used to determine the validity of possible systolic and diastolic pressures in noise contaminated Korotkoff sounds. The performance of the algorithm was assessed based on the ability to: verify if a signal was contaminated with any noise; the accuracy, sensitivity and specificity of this noise classification, and the systolic and diastolic pressure

  17. Cuffless and Continuous Blood Pressure Estimation from the Heart Sound Signals

    Directory of Open Access Journals (Sweden)

    Rong-Chao Peng

    2015-09-01

    Full Text Available Cardiovascular disease, like hypertension, is one of the top killers of human life and early detection of cardiovascular disease is of great importance. However, traditional medical devices are often bulky and expensive, and unsuitable for home healthcare. In this paper, we proposed an easy and inexpensive technique to estimate continuous blood pressure from the heart sound signals acquired by the microphone of a smartphone. A cold-pressor experiment was performed in 32 healthy subjects, with a smartphone to acquire heart sound signals and with a commercial device to measure continuous blood pressure. The Fourier spectrum of the second heart sound and the blood pressure were regressed using a support vector machine, and the accuracy of the regression was evaluated using 10-fold cross-validation. Statistical analysis showed that the mean correlation coefficients between the predicted values from the regression model and the measured values from the commercial device were 0.707, 0.712, and 0.748 for systolic, diastolic, and mean blood pressure, respectively, and that the mean errors were less than 5 mmHg, with standard deviations less than 8 mmHg. These results suggest that this technique is of potential use for cuffless and continuous blood pressure monitoring and it has promising application in home healthcare services.

  18. Numerical Model on Sound-Solid Coupling in Human Ear and Study on Sound Pressure of Tympanic Membrane

    Directory of Open Access Journals (Sweden)

    Yao Wen-juan

    2011-01-01

    Full Text Available Establishment of three-dimensional finite-element model of the whole auditory system includes external ear, middle ear, and inner ear. The sound-solid-liquid coupling frequency response analysis of the model was carried out. The correctness of the FE model was verified by comparing the vibration modes of tympanic membrane and stapes footplate with the experimental data. According to calculation results of the model, we make use of the least squares method to fit out the distribution of sound pressure of external auditory canal and obtain the sound pressure function on the tympanic membrane which varies with frequency. Using the sound pressure function, the pressure distribution on the tympanic membrane can be directly derived from the sound pressure at the external auditory canal opening. The sound pressure function can make the boundary conditions of the middle ear structure more accurate in the mechanical research and improve the previous boundary treatment which only applied uniform pressure acting to the tympanic membrane.

  19. A sound and efficient measure of joint congruence.

    Science.gov (United States)

    Conconi, Michele; Castelli, Vincenzo Parenti

    2014-09-01

    In the medical world, the term "congruence" is used to describe by visual inspection how the articular surfaces mate each other, evaluating the joint capability to distribute an applied load from a purely geometrical perspective. Congruence is commonly employed for assessing articular physiology and for the comparison between normal and pathological states. A measure of it would thus represent a valuable clinical tool. Several approaches for the quantification of joint congruence have been proposed in the biomechanical literature, differing on how the articular contact is modeled. This makes it difficult to compare different measures. In particular, in previous articles a congruence measure has been presented which proved to be efficient and suitable for the clinical practice, but it was still empirically defined. This article aims at providing a sound theoretical support to this congruence measure by means of the Winkler elastic foundation contact model which, with respect to others, has the advantage to hold also for highly conforming surfaces as most of the human articulations are. First, the geometrical relation between the applied load and the resulting peak of pressure is analytically derived from the elastic foundation contact model, providing a theoretically sound approach to the definition of a congruence measure. Then, the capability of congruence measure to capture the same geometrical relation is shown. Finally, the reliability of congruence measure is discussed. © IMechE 2014.

  20. Development of sound absorption measuring system with acoustic chamber; Kogata kyuon koka sokutei sochi no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Takahira, M.; Noba, M. [Toyota Motor Corp., Aichi (Japan); Matsuoka, H. [Nippon Soken, Inc., Tokyo (Japan)

    1998-05-01

    In order to measure sound absorption performance necessary to develop sound absorption materials, development was made on a device consisting of a small sound box capable of measurement inexpensively and easily, as a measure against the reverberation chamber method. In order to obtain stabilized diffusion sound internally, the sound box has a shape of asymmetric seven-side body in which sides do not face squarely with each other. The box was so sized that a large number of resonant vibration postures can be constituted at the targeted frequency simultaneously in the box. The box has a commercially available cone speaker with good acoustic output characteristics in frequency range of higher than 500 Hz installed on an inner side of the box. The sound source uses a method to derive sound absorption rate from difference of sound pressure levels. In order to eliminate need of averaging treatment by using a multi-point measurement inside the box, a discussion was given to provide an opening on part of the box to place the sound receiving point outside the opening. A square test piece is placed on the floor 0.5 meter or more away from the speaker in the box. As a result of the experiment, it was verified that the sound absorption rate obtained by this device corresponds well with that by the reverberation chamber method. The size of the test piece was also found adequate. 2 refs., 11 figs., 1 tab.

  1. Sound level measurements using smartphone "apps": Useful or inaccurate?

    Directory of Open Access Journals (Sweden)

    Daniel R Nast

    2014-01-01

    Full Text Available Many recreational activities are accompanied by loud concurrent sounds and decisions regarding the hearing hazards associated with these activities depend on accurate sound measurements. Sound level meters (SLMs are designed for this purpose, but these are technical instruments that are not typically available in recreational settings and require training to use properly. Mobile technology has made such sound level measurements more feasible for even inexperienced users. Here, we assessed the accuracy of sound level measurements made using five mobile phone applications or "apps" on an Apple iPhone 4S, one of the most widely used mobile phones. Accuracy was assessed by comparing application-based measurements to measurements made using a calibrated SLM. Whereas most apps erred by reporting higher sound levels, one application measured levels within 5 dB of a calibrated SLM across all frequencies tested.

  2. Serial blood pressure measurements

    Directory of Open Access Journals (Sweden)

    N.R. Koehler

    2002-05-01

    Full Text Available The objective of the present investigation was to study the effects of a 60-s interval of venous congestion between two noninvasive measurements of arterial blood pressure (ABP on the fluctuation of ABP, assessed by the standard deviation of the differences between two readings. ABP was measured in 345 successive patients, at rest, four times each. For 269 participants, one pair of readings was obtained with a 60-s interval and the other pair without an interval. For 76 patients, the first pair was read at the same interval, and the second pair had venous congestion interposed and there was no waiting interval. There was no increased ABP oscillation, either when there was no interval between ABP readings, or when venous congestion was interposed compared to pairs of ABP measurements performed with a 60-s interval. There was no increase in ABP oscillations when successive ABP readings were taken without an interval or even with venous congestion interposed. Contrary to the present belief, there seems to be no loss of reliability when blood pressure recordings are taken immediately one after another, in the clinical setting.

  3. Pressure Measurement Sensor

    Science.gov (United States)

    1997-01-01

    FFPI Industries Inc. is the manufacturer of fiber-optic sensors that furnish accurate pressure measurements in internal combustion chambers. Such an assessment can help reduce pollution emitted by these engines. A chief component in the sensor owes its seven year- long development to Lewis Research Center funding to embed optical fibers and sensors in metal parts. NASA support to Texas A&M University played a critical role in developing this fiber optic technology and led to the formation of FFPI Industries and the production of fiber sensor products. The simple, rugged design of the sensor offers the potential for mass production at low cost. Widespread application of the new technology is forseen, from natural gas transmission, oil refining and electrical power generation to rail transport and the petrochemical paper product industry.

  4. Identification of impact force acting on composite laminated plates using the radiated sound measured with microphones

    Science.gov (United States)

    Atobe, Satoshi; Nonami, Shunsuke; Hu, Ning; Fukunaga, Hisao

    2017-09-01

    Foreign object impact events are serious threats to composite laminates because impact damage leads to significant degradation of the mechanical properties of the structure. Identification of the location and force history of the impact that was applied to the structure can provide useful information for assessing the structural integrity. This study proposes a method for identifying impact forces acting on CFRP (carbon fiber reinforced plastic) laminated plates on the basis of the sound radiated from the impacted structure. Identification of the impact location and force history is performed using the sound pressure measured with microphones. To devise a method for identifying the impact location from the difference in the arrival times of the sound wave detected with the microphones, the propagation path of the sound wave from the impacted point to the sensor is examined. For the identification of the force history, an experimentally constructed transfer matrix is employed to relate the force history to the corresponding sound pressure. To verify the validity of the proposed method, impact tests are conducted by using a CFRP cross-ply laminate as the specimen, and an impulse hammer as the impactor. The experimental results confirm the validity of the present method for identifying the impact location from the arrival time of the sound wave detected with the microphones. Moreover, the results of force history identification show the feasibility of identifying the force history accurately from the measured sound pressure using the experimental transfer matrix.

  5. Measuring the speed of sound in air using smartphone applications

    Science.gov (United States)

    Yavuz, A.

    2015-05-01

    This study presents a revised version of an old experiment available in many textbooks for measuring the speed of sound in air. A signal-generator application in a smartphone is used to produce the desired sound frequency. Nodes of sound waves in a glass pipe, of which one end is immersed in water, are more easily detected, so results can be obtained more quickly than from traditional acoustic experiments using tuning forks.

  6. [A focused sound field measurement system by LabVIEW].

    Science.gov (United States)

    Jiang, Zhan; Bai, Jingfeng; Yu, Ying

    2014-05-01

    In this paper, according to the requirement of the focused sound field measurement, a focused sound field measurement system was established based on the LabVIEW virtual instrument platform. The system can automatically search the focus position of the sound field, and adjust the scanning path according to the size of the focal region. Three-dimensional sound field scanning time reduced from 888 hours in uniform step to 9.25 hours in variable step. The efficiency of the focused sound field measurement was improved. There is a certain deviation between measurement results and theoretical calculation results. Focal plane--6 dB width difference rate was 3.691%, the beam axis--6 dB length differences rate was 12.937%.

  7. Spindle vibration and sound field measurement using optical vibrometry

    OpenAIRE

    Tatar, Kourosh

    2008-01-01

    Mechanical systems often produce a considerable amount of vibration and noise. To be able to obtain a complete picture of the dynamic behaviour of these systems, vibration and sound measurements are of significant importance. Optical metrology is well-suited for non-intrusive measurements on complex objects. The development and the use of remote non-contact vibration measurement methods for spindles are described and vibration measurements on thin- walled structures and sound field measuremen...

  8. 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

  9. Pavement sound absorption measurements in the U.S.

    Science.gov (United States)

    2012-08-19

    In the U.S., the topic of pavement sound absorption in regard to tire-pavement noise has shown increased interest and research over the last several years. Four types of pavement sound absorption measurements with various applications are discussed: ...

  10. Measurement of the sound power incident on the walls of a reverberation room with near field acoustic holography

    DEFF Research Database (Denmark)

    Jacobsen, Finn; Tiana Roig, Elisabet

    2010-01-01

    area; and it has always been regarded as impossible to measure the sound power that is incident on a wall directly. This paper examines a new method of determining this quantity from sound pressure measurements at positions on the wall using 'statistically optimised near field acoustic holography...

  11. Do high sound pressure levels of crowing in roosters necessitate passive mechanisms for protection against self-vocalization?

    Science.gov (United States)

    Claes, Raf; Muyshondt, Pieter G G; Dirckx, Joris J J; Aerts, Peter

    2018-02-01

    High sound pressure levels (>120dB) cause damage or death of the hair cells of the inner ear, hence causing hearing loss. Vocalization differences are present between hens and roosters. Crowing in roosters is reported to produce sound pressure levels of 100dB measured at a distance of 1m. In this study we measured the sound pressure levels that exist at the entrance of the outer ear canal. We hypothesize that roosters may benefit from a passive protective mechanism while hens do not require such a mechanism. Audio recordings at the level of the entrance of the outer ear canal of crowing roosters, made in this study, indeed show that a protective mechanism is needed as sound pressure levels can reach amplitudes of 142.3dB. Audio recordings made at varying distances from the crowing rooster show that at a distance of 0.5m sound pressure levels already drop to 102dB. Micro-CT scans of a rooster and chicken head show that in roosters the auditory canal closes when the beak is opened. In hens the diameter of the auditory canal only narrows but does not close completely. A morphological difference between the sexes in shape of a bursa-like slit which occurs in the outer ear canal causes the outer ear canal to close in roosters but not in hens. Copyright © 2017 Elsevier GmbH. All rights reserved.

  12. Velocity of sound measurements in gaseous per-fluorocarbons and their custom mixtures

    CERN Document Server

    Vacek, V; Lindsay, S

    2000-01-01

    An inexpensive sonar instrument was prepared for measurements of sound velocity in two fluorocarbon vapors; per-fluoro-n-propane (C3F8), per-fluoro-n-butane (C4F10), and their custom mixtures. The apparatus, measurement principle and instrument software are described. All sound velocity measurements in per-fluorocarbons were made in the low pressure range between 0.01 and 0.4 MPa, and at temperatures between 253 and 303 K. The purity of the C3F8 and C4F10 samples was checked using gas chromatography. Uncertainties in the speed of sound measurements were better than ± 0.1 %. Comparisons were made with theoretical predictions of sound velocity for the two individual components. The instrument was then used for concentration monitoring of custom C3F8/C4F10 mixtures.

  13. Automatic Blood Pressure Measurements During Exercise

    Science.gov (United States)

    Weaver, Charles S.

    1985-01-01

    Microprocessor circuits and a computer algorithm for automatically measuring blood pressure during ambulatory monitoring and exercise stress testing have been under development at SRI International. A system that records ECG, Korotkov sound, and arm cuff pressure for off-line calculation of blood pressure has been delivered to NASA, and an LSLE physiological monitoring system that performs the algorithm calculations in real-time is being constructed. The algorithm measures the time between the R-wave peaks and the corresponding Korotkov sound on-set (RK-interval). Since the curve of RK-interval versus cuff pressure during deflation is predictable and slowly varying, windows can be set around the curve to eliminate false Korotkov sound detections that result from noise. The slope of this curve, which will generally decrease during exercise, is the inverse of the systolic slope of the brachial artery pulse. In measurements taken during treadmill stress testing, the changes in slopes of subjects with coronary artery disease were markedly different from the changes in slopes of healthy subjects. Measurements of slope and O2 consumption were also made before and after ten days of bed rest during NASA/Ames Research Center bed rest studies. Typically, the maximum rate of O2 consumption during the post-bed rest test is less than the maximum rate during the pre-bed rest test. The post-bed rest slope changes differ from the pre-bed rest slope changes, and the differences are highly correlated with the drop in the maximum rate of O2 consumption. We speculate that the differences between pre- and post-bed rest slopes are due to a drop in heart contractility.

  14. Measurement of sound velocity profiles in fluids for process monitoring

    International Nuclear Information System (INIS)

    Wolf, M; Kühnicke, E; Lenz, M; Bock, M

    2012-01-01

    In ultrasonic measurements, the time of flight to the object interface is often the only information that is analysed. Conventionally it is only possible to determine distances or sound velocities if the other value is known. The current paper deals with a novel method to measure the sound propagation path length and the sound velocity in media with moving scattering particles simultaneously. Since the focal position also depends on sound velocity, it can be used as a second parameter. Via calibration curves it is possible to determine the focal position and sound velocity from the measured time of flight to the focus, which is correlated to the maximum of averaged echo signal amplitude. To move focal position along the acoustic axis, an annular array is used. This allows measuring sound velocity locally resolved without any previous knowledge of the acoustic media and without a reference reflector. In previous publications the functional efficiency of this method was shown for media with constant velocities. In this work the accuracy of these measurements is improved. Furthermore first measurements and simulations are introduced for non-homogeneous media. Therefore an experimental set-up was created to generate a linear temperature gradient, which also causes a gradient of sound velocity.

  15. Melting along the Hugoniot and solid phase transition for Sn via sound velocity measurements

    Science.gov (United States)

    Song, Ping; Cai, Ling-cang; Tao, Tian-jiong; Yuan, Shuai; Chen, Hong; Huang, Jin; Zhao, Xin-wen; Wang, Xue-jun

    2016-11-01

    It is very important to determine the phase boundaries for materials with complex crystalline phase structures to construct their corresponding multi-phase equation of state. By measuring the sound velocity of Sn with different porosities, different shock-induced melting pressures along the solid-liquid phase boundary could be obtained. The incipient shock-induced melting of porous Sn samples with two different porosities occurred at a pressure of about 49.1 GPa for a porosity of 1.01 and 45.6 GPa for a porosity of 1.02, based on measurements of the sound velocity. The incipient shock-induced melting pressure of solid Sn was revised to 58.1 GPa using supplemental measurements of the sound velocity. Trivially, pores in Sn decreased the shock-induced melting pressure. Based on the measured longitudinal sound velocity data, a refined solid phase transition and the Hugoniot temperature-pressure curve's trend are discussed. No bcc phase transition occurs along the Hugoniot for porous Sn; further investigation is required to understand the implications of this finding.

  16. Exterior sound level measurements of snowcoaches at Yellowstone National Park

    Science.gov (United States)

    2010-04-01

    Sounds associated with oversnow vehicles, such as snowmobiles and snowcoaches, are an important management concern at Yellowstone and Grand Teton National Parks. The John A. Volpe National Transportation Systems Centers Environmental Measurement a...

  17. Magnetic measurements under pressure

    Czech Academy of Sciences Publication Activity Database

    Zentková, M.; Arnold, Zdeněk; Mihalik, M.; Mihalik, M.; Zentko, A.; Kamarád, Jiří; Mitróová, Z.; Mat`aš, S.

    2006-01-01

    Roč. 57, 8/S (2006), s. 29-32 ISSN 1335-3632 Institutional research plan: CEZ:AV0Z10100521 Keywords : hydrostatic pressure * Prussian blue analogues * AC susceptibility * intermetallic compound * ferromagnetism * errimagnetism Subject RIV: BM - Solid Matter Physics ; Magnetism

  18. How male sound pressure level influences phonotaxis in virgin female Jamaican field crickets (Gryllus assimilis

    Directory of Open Access Journals (Sweden)

    Karen Pacheco

    2014-06-01

    Full Text Available Understanding female mate preference is important for determining the strength and direction of sexual trait evolution. The sound pressure level (SPL acoustic signalers use is often an important predictor of mating success because higher sound pressure levels are detectable at greater distances. If females are more attracted to signals produced at higher sound pressure levels, then the potential fitness impacts of signalling at higher sound pressure levels should be elevated beyond what would be expected from detection distance alone. Here we manipulated the sound pressure level of cricket mate attraction signals to determine how female phonotaxis was influenced. We examined female phonotaxis using two common experimental methods: spherical treadmills and open arenas. Both methods showed similar results, with females exhibiting greatest phonotaxis towards loud sound pressure levels relative to the standard signal (69 vs. 60 dB SPL but showing reduced phonotaxis towards very loud sound pressure level signals relative to the standard (77 vs. 60 dB SPL. Reduced female phonotaxis towards supernormal stimuli may signify an acoustic startle response, an absence of other required sensory cues, or perceived increases in predation risk.

  19. RASS sound speed profile (SSP) measurements for use in outdoor sound propagation models

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, S G [Physics Department, University of Auckland (New Zealand); Huenerbein, S v; Waddington, D [Research Institute for the Built and Human Environment, University of Salford (United Kingdom)], E-mail: s.vonhunerbein@salford.ac.uk

    2008-05-01

    The performance of outdoor sound propagation models depends to a great extent on meteorological input parameters. In an effort to improve speed and accuracy, model output synthetic sound speed profiles (SSP) are commonly used depending on meteorological classification schemes. In order to use SSP measured by RASS in outdoor sound propagation models, the complex profiles need to be simplified. In this paper we extend an investigation on the spatial and temporal characteristics of the meteorological data set required to yield adequate comparisons between models and field measurements, so that the models can be fairly judged. Vertical SSP from RASS, SODAR wind profiles as well as mast wind and temperature data from a flat terrain site and measured over a period of several months are used to evaluate applicability of the logarithmic approximation for a stability classification scheme proposed by the HARMONOISE working group.

  20. RASS sound speed profile (SSP) measurements for use in outdoor sound propagation models

    International Nuclear Information System (INIS)

    Bradley, S G; Huenerbein, S v; Waddington, D

    2008-01-01

    The performance of outdoor sound propagation models depends to a great extent on meteorological input parameters. In an effort to improve speed and accuracy, model output synthetic sound speed profiles (SSP) are commonly used depending on meteorological classification schemes. In order to use SSP measured by RASS in outdoor sound propagation models, the complex profiles need to be simplified. In this paper we extend an investigation on the spatial and temporal characteristics of the meteorological data set required to yield adequate comparisons between models and field measurements, so that the models can be fairly judged. Vertical SSP from RASS, SODAR wind profiles as well as mast wind and temperature data from a flat terrain site and measured over a period of several months are used to evaluate applicability of the logarithmic approximation for a stability classification scheme proposed by the HARMONOISE working group

  1. Speed of sound measurements of liquid C1–C4 alkanols

    International Nuclear Information System (INIS)

    Dávila, María J.; Gedanitz, Holger; Span, Roland

    2016-01-01

    Highlights: • Speeds of sound in alkanols were measured in a wide temperature and pressure range. • A pulse-echo method with a double path type sensor was employed. • A double polynomial equation was used to fit the experimental speed of sound data. • The accurate results were compared with available literature sources. - Abstract: Speed of sound measurements were made in methanol, ethanol, propan-1-ol, and butan-1-ol in the temperature range from (253.15 to 353.15) K at pressures up to 30 MPa by use of a pulse-echo method with a double path type sensor. The expanded overall uncertainty (k = 2) in speed of sound measurements are estimated to be 0.026% for methanol, 0.03% for ethanol, 0.013% for propan-1-ol and 0.01% for butan-1-ol. A double polynomial equation for the speed of sound with inputs of temperature and pressure has been fitted from the experimental results. These were compared with available literature sources and fundamental equations of state, showing good agreement among them to comparable alcohol purities and experimental uncertainties.

  2. A Loudness Function for Maintaining Spectral Balance at Changing Sound Pressure Levels

    DEFF Research Database (Denmark)

    Nielsen, Sofus Birkedal

    Our perception of loudness is a function of frequency as well as sound pressure level as described in ISO226:2003: Normal Equal Loudness Level Contours, which describes the needed sound pressure level for pure tones to be perceived equally loud. At a music performance, this is taking care...... of by the sound engineer by listening to the individual sound sources and adjust and equalize them to the wanted spectral balance including the whole chain of audio equipment and surroundings. At a live venue the sound pressure level will normally change during a concert, and typically increase over time......B is doubling of the effect to the loudspeakers). A level depending digital loudness function has been made based on ISO226:2003, and will be demonstrated. It can maintain the spectral balance at alternating levels and is based on fractional order digital filters. Tutorial. Abstract T3.3 (30th August 16:00 - 17...

  3. Pressure measurements in harsh environments

    International Nuclear Information System (INIS)

    Cook, C.W.; Ames, E.S.

    1979-01-01

    A fluid coupled plate (FCP) gage was designed which allows pressure measurements to be made in harsh environments (including debris) using conventional pressure transducers. The pressure transducer is isolated by means of a rigid force plate which is supported by a bellows having one corrugation. This portion of the gage is machined from a single piece of material. The interior of the gage is filled with a phenol fluid which has a low compressibility

  4. 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...

  5. LOFT fuel rod pressure measurement

    International Nuclear Information System (INIS)

    Billeter, T.R.

    1979-01-01

    Pressure sensors selected for measuring fuel rod pressure within the LOFT reactor exhibited stable, repeatable operating characteristics during calibrations at temperatures up to 800 0 F and pressures to 2500 psig. All sensors have a nominal sensitivity of .5 millivolts per psi, decreasing monotonically with temperature. Output signal increases linearly with increasing pressure up to 2000 psig. For imposed slow and rapid temperature variations and for pressure applied during these tests, the sensor indicates a pressure at variance with the actual value by up to 15% of reading. However, the imposed temperature rates of change often exceeded the value of -10 0 F/sec. specified for LOFT. The series of tests in an autoclave permit creation of an environment most closely resembling sensor operating conditions within LOFT. For multiple blowdowns and for longtime durations the sensor continued to provide pressure-related output signals. For temperature rates up to -87 0 F/sec, the indicated pressure measurement error remained less than 13% of reading. Adverse effects caused by heating the 1/16 inch O.D. signal cable to 800 0 F contributed only insignificantly to the noted pressure measurement error

  6. Reconstruction of Sound Source Pressures in an Enclosure Using the Phased Beam Tracing Method

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Ih, Jeong-Guon

    2009-01-01

    . First, surfaces of an extended source are divided into reasonably small segments. From each source segment, one beam is projected into the field and all emitted beams are traced. Radiated beams from the source reach array sensors after traveling various paths including the wall reflections. Collecting...... all the pressure histories at the field points, source-observer relations can be constructed in a matrix-vector form for each frequency. By multiplying the measured field data with the pseudo-inverse of the calculated transfer function, one obtains the distribution of source pressure. An omni......-directional sphere and a cubic source in a rectangular enclosure were taken as examples in the simulation tests. A reconstruction error was investigated by Monte Carlo simulation in terms of field point locations. When the source information was reconstructed by the present method, it was shown that the sound power...

  7. Sound pressure levels generated at risk volume steps of portable listening devices: types of smartphone and genres of music.

    Science.gov (United States)

    Kim, Gibbeum; Han, Woojae

    2018-05-01

    The present study estimated the sound pressure levels of various music genres at the volume steps that contemporary smartphones deliver, because these levels put the listener at potential risk for hearing loss. Using six different smartphones (Galaxy S6, Galaxy Note 3, iPhone 5S, iPhone 6, LG G2, and LG G3), the sound pressure levels for three genres of K-pop music (dance-pop, hip-hop, and pop-ballad) and a Billboard pop chart of assorted genres were measured through an earbud for the first risk volume that was at the risk sign proposed by the smartphones, as well as consecutive higher volumes using a sound level meter and artificial mastoid. The first risk volume step of the Galaxy S6 and the LG G2, among the six smartphones, had the significantly lowest (84.1 dBA) and highest output levels (92.4 dBA), respectively. As the volume step increased, so did the sound pressure levels. The iPhone 6 was loudest (113.1 dBA) at the maximum volume step. Of the music genres, dance-pop showed the highest output level (91.1 dBA) for all smartphones. Within the frequency range of 20~ 20,000 Hz, the sound pressure level peaked at 2000 Hz for all the smartphones. The results showed that the sound pressure levels of either the first volume step or the maximum volume step were not the same for the different smartphone models and genres of music, which means that the risk volume sign and its output levels should be unified across the devices for their users. In addition, the risk volume steps proposed by the latest smartphone models are high enough to cause noise-induced hearing loss if their users habitually listen to music at those levels.

  8. A comparison of two different sound intensity measurement principles

    DEFF Research Database (Denmark)

    Jacobsen, Finn; de Bree, Hans-Elias

    2005-01-01

    , and compares the two measurement principles with particular regard to the sources of error in sound power determination. It is shown that the phase calibration of intensity probes that combine different transducers is very critical below 500 Hz if the measurement surface is very close to the source under test...

  9. Sheep as a large animal ear model: Middle-ear ossicular velocities and intracochlear sound pressure.

    Science.gov (United States)

    Péus, Dominik; Dobrev, Ivo; Prochazka, Lukas; Thoele, Konrad; Dalbert, Adrian; Boss, Andreas; Newcomb, Nicolas; Probst, Rudolf; Röösli, Christof; Sim, Jae Hoon; Huber, Alexander; Pfiffner, Flurin

    2017-08-01

    Animals are frequently used for the development and testing of new hearing devices. Dimensions of the middle ear and cochlea differ significantly between humans and commonly used animals, such as rodents or cats. The sheep cochlea is anatomically more like the human cochlea in size and number of turns. This study investigated the middle-ear ossicular velocities and intracochlear sound pressure (ICSP) in sheep temporal bones, with the aim of characterizing the sheep as an experimental model for implantable hearing devices. Measurements were made on fresh sheep temporal bones. Velocity responses of the middle ear ossicles at the umbo, long process of the incus and stapes footplate were measured in the frequency range of 0.25-8 kHz using a laser Doppler vibrometer system. Results were normalized by the corresponding sound pressure level in the external ear canal (P EC ). Sequentially, ICSPs at the scala vestibuli and tympani were then recorded with custom MEMS-based hydrophones, while presenting identical acoustic stimuli. The sheep middle ear transmitted most effectively around 4.8 kHz, with a maximum stapes velocity of 0.2 mm/s/Pa. At the same frequency, the ICSP measurements in the scala vestibuli and tympani showed the maximum gain relative to the P EC (24 dB and 5 dB, respectively). The greatest pressure difference across the cochlear partition occurred between 4 and 6 kHz. A comparison between the results of this study and human reference data showed middle-ear resonance and best cochlear sensitivity at higher frequencies in sheep. In summary, sheep can be an appropriate large animal model for research and development of implantable hearing devices. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Measurement of fast transient pressures

    International Nuclear Information System (INIS)

    Procaccia, Henri

    1978-01-01

    The accuracy, reliability and sensitivity of a pressure transducers define its principal static characteristics. When the quantity measured varies with time, the measurement carries a dynamic error and a delay depending on the frequency of this variation. Hence, when fast pressure changes in a fluid have to be determined, different kinds of pressure transducers can be used depending on their inherent dynamic characteristics which must be compared with those of the transient phenomenon to be analysed. The text describes the pressure transducers generally employed in industry for analysing such phenomenon and gives two practical applications developed in the EDF: the first submits the measurements and results of pump cavitation tests carried out at the Vitry II EDF power station; the second deals with hammer blows particularly noticed in nuclear power stations and required the use of transducers of exceptionally high performance such as strain gauge transducers and piezoelectric transducers (response time within 1m sec.) [fr

  11. Investigation of the Sound Pressure Level (SPL) of earphones during music listening with the use of physical ear canal models

    Science.gov (United States)

    Aying, K. P.; Otadoy, R. E.; Violanda, R.

    2015-06-01

    This study investigates on the sound pressure level (SPL) of insert-type earphones that are commonly used for music listening of the general populace. Measurements of SPL from earphones of different respondents were measured by plugging the earphone to a physical ear canal model. Durations of the earphone used for music listening were also gathered through short interviews. Results show that 21% of the respondents exceed the standard loudness/duration relation recommended by the World Health Organization (WHO).

  12. Pressurized transient otoacoustic emissions measured using click and chirp stimuli.

    Science.gov (United States)

    Keefe, Douglas H; Patrick Feeney, M; Hunter, Lisa L; Fitzpatrick, Denis F; Sanford, Chris A

    2018-01-01

    Transient-evoked otoacoustic emission (TEOAE) responses were measured in normal-hearing adult ears over frequencies from 0.7 to 8 kHz, and analyzed with reflectance/admittance data to measure absorbed sound power and the tympanometric peak pressure (TPP). The mean TPP was close to ambient. TEOAEs were measured in the ear canal at ambient pressure, TPP, and fixed air pressures from 150 to -200 daPa. Both click and chirp stimuli were used to elicit TEOAEs, in which the incident sound pressure level was constant across frequency. TEOAE levels were similar at ambient and TPP, and for frequencies from 0.7 to 2.8 kHz decreased with increasing positive and negative pressures. At 4-8 kHz, TEOAE levels were larger at positive pressures. This asymmetry is possibly related to changes in mechanical transmission through the ossicular chain. The mean TEOAE group delay did not change with pressure, although small changes were observed in the mean instantaneous frequency and group spread. Chirp TEOAEs measured in an adult ear with Eustachian tube dysfunction and TPP of -165 daPa were more robust at TPP than at ambient. Overall, results demonstrate the feasibility and clinical potential of measuring TEOAEs at fixed pressures in the ear canal, which provide additional information relative to TEOAEs measured at ambient pressure.

  13. Method for measuring violin sound radiation based on bowed glissandi and its application to sound synthesis.

    Science.gov (United States)

    Perez Carrillo, Alfonso; Bonada, Jordi; Patynen, Jukka; Valimaki, Vesa

    2011-08-01

    This work presents a method for measuring and computing violin-body directional frequency responses, which are used for violin sound synthesis. The approach is based on a frame-weighted deconvolution of excitation and response signals. The excitation, consisting of bowed glissandi, is measured with piezoelectric transducers built into the bridge. Radiation responses are recorded in an anechoic chamber with multiple microphones placed at different angles around the violin. The proposed deconvolution algorithm computes impulse responses that, when convolved with any source signal (captured with the same transducer), produce a highly realistic violin sound very similar to that of a microphone recording. The use of motion sensors allows for tracking violin movements. Combining this information with the directional responses and using a dynamic convolution algorithm, helps to improve the listening experience by incorporating the violinist motion effect in stereo.

  14. 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...

  15. Laser vibrometry measurements of vibration and sound fields of a bowed violin

    Science.gov (United States)

    Gren, Per; Tatar, Kourosh; Granström, Jan; Molin, N.-E.; Jansson, Erik V.

    2006-04-01

    Laser vibrometry measurements on a bowed violin are performed. A rotating disc apparatus, acting as a violin bow, is developed. It produces a continuous, long, repeatable, multi-frequency sound from the instrument that imitates the real bow-string interaction for a 'very long bow'. What mainly differs is that the back and forward motion of the real bow is replaced by the rotating motion with constant velocity of the disc and constant bowing force (bowing pressure). This procedure is repeatable. It is long lasting and allows laser vibrometry techniques to be used, which measure forced vibrations by bowing at all excited frequencies simultaneously. A chain of interacting parts of the played violin is studied: the string, the bridge and the plates as well as the emitted sound field. A description of the mechanics and the sound production of the bowed violin is given, i.e. the production chain from the bowed string to the produced tone.

  16. Ice sheet anisotropy measured with polarimetric ice sounding radar

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2010-01-01

    For polar ice sheets, valuable stress and strain information can be deduced from crystal orientation fabrics (COF) and their prevailing c-axis alignment. Polarimetric radio echo sounding is a promising technique to measure the anisotropic electromagnetic propagation and reflection properties asso...

  17. Investigating the relationship between pressure force and acoustic waveform in footstep sounds

    DEFF Research Database (Denmark)

    Grani, Francesco; Serafin, Stefania; Götzen, Amalia De

    2013-01-01

    In this paper we present an inquiry into of the relationships between audio waveforms and ground reaction force in recorded footstep sounds. In an anechoic room, we recorded several footstep sounds produced while walking on creaking wood and gravel. The recordings were performed by using a pair o...... of sandals embedded with six pressure sensors each. Investigations of the relationships between recorded force and footstep sounds is presented, together with several possible applications of the system.......In this paper we present an inquiry into of the relationships between audio waveforms and ground reaction force in recorded footstep sounds. In an anechoic room, we recorded several footstep sounds produced while walking on creaking wood and gravel. The recordings were performed by using a pair...

  18. Separation and reconstruction of high pressure water-jet reflective sound signal based on ICA

    Science.gov (United States)

    Yang, Hongtao; Sun, Yuling; Li, Meng; Zhang, Dongsu; Wu, Tianfeng

    2011-12-01

    The impact of high pressure water-jet on the different materials target will produce different reflective mixed sound. In order to reconstruct the reflective sound signals distribution on the linear detecting line accurately and to separate the environment noise effectively, the mixed sound signals acquired by linear mike array were processed by ICA. The basic principle of ICA and algorithm of FASTICA were described in detail. The emulation experiment was designed. The environment noise signal was simulated by using band-limited white noise and the reflective sound signal was simulated by using pulse signal. The reflective sound signal attenuation produced by the different distance transmission was simulated by weighting the sound signal with different contingencies. The mixed sound signals acquired by linear mike array were synthesized by using the above simulated signals and were whitened and separated by ICA. The final results verified that the environment noise separation and the reconstruction of the detecting-line sound distribution can be realized effectively.

  19. Dynamic PIV measurement on the effect of sound wave in upper plenum of boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    In one of the power uprated plants in the United States, the steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound wave into the steam-dome. The resonance among the structure, flow and the pressure fluctuation resulted in the breakages. To understand the basic mechanism of the resonance, previous researches were done by a point measurement of the pressure and by a phase averaged measurement of the flow, while it was difficult to detect the interaction among them by the conventional method. In the preliminary study, Dynamic Particle Image Velocimetry (PIV) System was applied to investigate the effect of sound on the flow. (author)

  20. Effect of water vapor on sound absorption in nitrogen at low frequency/pressure ratios

    Science.gov (United States)

    Zuckerwar, A. J.; Griffin, W. A.

    1981-01-01

    Sound absorption measurements were made in N2-H2O binary mixtures at 297 K over the frequency/pressure range f/P of 0.1-2500 Hz/atm to investigate the vibrational relaxation peak of N2 and its location on f/P axis as a function of humidity. At low humidities the best fit to a linear relationship between the f/P(max) and humidity yields an intercept of 0.013 Hz/atm and a slope of 20,000 Hz/atm-mole fraction. The reaction rate constants derived from this model are lower than those obtained from the extrapolation of previous high-temperature data.

  1. Sound at the zoo: Using animal monitoring, sound measurement, and noise reduction in zoo animal management.

    Science.gov (United States)

    Orban, David A; Soltis, Joseph; Perkins, Lori; Mellen, Jill D

    2017-05-01

    A clear need for evidence-based animal management in zoos and aquariums has been expressed by industry leaders. Here, we show how individual animal welfare monitoring can be combined with measurement of environmental conditions to inform science-based animal management decisions. Over the last several years, Disney's Animal Kingdom® has been undergoing significant construction and exhibit renovation, warranting institution-wide animal welfare monitoring. Animal care and science staff developed a model that tracked animal keepers' daily assessments of an animal's physical health, behavior, and responses to husbandry activity; these data were matched to different external stimuli and environmental conditions, including sound levels. A case study of a female giant anteater and her environment is presented to illustrate how this process worked. Associated with this case, several sound-reducing barriers were tested for efficacy in mitigating sound. Integrating daily animal welfare assessment with environmental monitoring can lead to a better understanding of animals and their sensory environment and positively impact animal welfare. © 2017 Wiley Periodicals, Inc.

  2. Particularidades de la medición de presión sonora y vibraciones en grupos electrógenos MAN 18 V48/60 B // Distinctive features for sound pressure level and vibration measurements over engine generator sets type MAN 18 v48/60 b

    Directory of Open Access Journals (Sweden)

    Yanexi Cepero‐Aguilera

    2011-01-01

    measurement. It is analyzed everything stated in ISO 3744 standard but it was impossibleto apply such standard taking in mind the complexity of industrial environment. However, because theresearch is focused on generator it was registered the sound pressure level near generator bearings.Vibrations were also registered on bearings according to ISO 8528-9 standard. For comparativeanalysis it was necessary to convert FFT spectra into constant percent bandwidth spectra. As aresult, the spectral frequencies could not be correlated in both sound pressure level and vibrationspectra and a generator normal condition was found as a preliminary evaluation.Key words: sound pressure level, vibration measurements, constant percent bandwidth, enginegenerator sets.

  3. Repeatability and reproducibility of in situ measurements of sound reflection and airborne sound insulation index of noise barriers

    NARCIS (Netherlands)

    Garai, M.; Schoen, E.; Behler, G.; Bragado, B.; Chudalla, M.; Conter, M.; Defrance, J.; Demizieux, P.; Glorieux, C.; Guidorzi, P.

    2014-01-01

    In Europe, in situ measurements of sound reflection and airborne sound insulation of noise barriers are usually done according to CEN/TS 1793-5. This method has been improved substantially during the EU funded QUIESST collaborative project. Within the same framework, an inter-laboratory test has

  4. Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz

    DEFF Research Database (Denmark)

    Poulsen, Torben; Oakley, Sebastian

    2009-01-01

    Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen...... as a substitute for the classical Telephonics TDH 39. The results are given as the Equivalent Threshold Sound Pressure Level, ETSPL, measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic...

  5. A particle velocity sensor to measure the sound from a structure in the presence of background noise

    NARCIS (Netherlands)

    de Bree, H.E.; Druyvesteyn, W.F.

    2005-01-01

    The performance (or quality) of a product is often checked by measuring the radiated sound (noise) from the vibrating structure. Often this test has to be done in an environment with background noise, which makes the measurement difficult. When using a (pressure) microphone the background noise can

  6. Influence of impedance phase angle on sound pressures and reverberation times in a rectangular room

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Lee, Doheon; Santurette, Sébastien

    2014-01-01

    , but with an absorptive ceiling are investigated. The zero phase angle, which has commonly been assumed in practice, is regarded as reference and differences in the sound pressure level and early decay time from the reference are quantified. As expected, larger differences in the room acoustic parameters are found...

  7. A Measure Based on Beamforming Power for Evaluation of Sound Field Reproduction Performance

    Directory of Open Access Journals (Sweden)

    Ji-Ho Chang

    2017-03-01

    Full Text Available This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems in two conditions. First, in non-anechoic conditions, room reflections substantially deteriorate the spatial error, although these room reflections affect human localization to a lesser degree. Second, for 2.5-dimensional reproduction of spherical waves, the spatial error increases consistently due to the difference in the amplitude decay rate, whereas the degradation of human localization performance is limited. The measure proposed in this study is based on the beamforming powers of the desired and the reproduced fields. Simulation and experimental results show that the proposed measure is less sensitive to room reflections and the amplitude decay than the spatial error, which is likely to agree better with the human perception of source localization.

  8. A Measure Based on Beamforming Power for Evaluation of Sound Field Reproduction Performance

    DEFF Research Database (Denmark)

    Chang, Ji-ho; Jeong, Cheol-Ho

    2017-01-01

    This paper proposes a measure to evaluate sound field reproduction systems with an array of loudspeakers. The spatially-averaged squared error of the sound pressure between the desired and the reproduced field, namely the spatial error, has been widely used, which has considerable problems in two...... conditions. First, in non-anechoic conditions, room reflections substantially deteriorate the spatial error, although these room reflections affect human localization to a lesser degree. Second, for 2.5-dimensional reproduction of spherical waves, the spatial error increases consistently due...... to the difference in the amplitude decay rate, whereas the degradation of human localization performance is limited. The measure proposed in this study is based on the beamforming powers of the desired and the reproduced fields. Simulation and experimental results show that the proposed measure is less sensitive...

  9. Automated Office Blood Pressure Measurement.

    Science.gov (United States)

    Myers, Martin G

    2018-04-01

    Manual blood pressure (BP) recorded in routine clinical practice is relatively inaccurate and associated with higher readings compared to BP measured in research studies in accordance with standardized measurement guidelines. The increase in routine office BP is the result of several factors, especially the presence of office staff, which tends to make patients nervous and also allows for conversation to occur. With the disappearance of the mercury sphygmomanometer because of environmental concerns, there is greater use of oscillometric BP recorders, both in the office setting and elsewhere. Although oscillometric devices may reduce some aspects of observer BP measurement error in the clinical setting, they are still associated with higher BP readings, known as white coat hypertension (for diagnosis) or white coat effect (with treated hypertension). Now that fully automated sphygmomanometers are available which are capable of recording several readings with the patient resting quietly, there is no longer any need to have office staff present when BP is being recorded. Such readings are called automated office blood pressure (AOBP) and they are both more accurate than conventional manual office BP and not associated with the white coat phenomena. AOBP readings are also similar to the awake ambulatory BP and home BP, both of which are relatively good predictors of cardiovascular risk. The available evidence suggests that AOBP should now replace manual or electronic office BP readings when screening patients for hypertension and also after antihypertensive drug therapy is initiated. Copyright © 2018. The Korean Society of Cardiology.

  10. Second sound, osmotic pressure, and Fermi-liquid parameters in 3He-4He solutions

    International Nuclear Information System (INIS)

    Corruccini, L.R.

    1984-01-01

    Second-sound velocities and osmotic pressures are analyzed to obtain the first experimental values for the Landau compressibility parameter F 0 /sup s/ in 3 He- 4 He solutions. Data are presented as a function of pressure and 3 He concentration, and are compared to theoretical predictions. The square of the second-sound velocity at finite temperature is found to be accurately proportional to the internal energy of a perfect Fermi gas. Using inertial effective masses given by the Landau-Pomeranchuk theory, the square of the velocity is found to separate into two parts: a temperature-dependent part characterized completely by ideal Fermi-gas behavior and a temperature-independent part containing all the Fermi-liquid corrections. This is related to a similar separation found in the osmotic pressure

  11. Sound produced by an oscillating arc in a high-pressure gas

    Science.gov (United States)

    Popov, Fedor K.; Shneider, Mikhail N.

    2017-08-01

    We suggest a simple theory to describe the sound generated by small periodic perturbations of a cylindrical arc in a dense gas. Theoretical analysis was done within the framework of the non-self-consistent channel arc model and supplemented with time-dependent gas dynamic equations. It is shown that an arc with power amplitude oscillations on the order of several percent is a source of sound whose intensity is comparable with external ultrasound sources used in experiments to increase the yield of nanoparticles in the high pressure arc systems for nanoparticle synthesis.

  12. Time measurements with a mobile device using sound

    Science.gov (United States)

    Wisman, Raymond F.; Spahn, Gabriel; Forinash, Kyle

    2018-05-01

    Data collection is a fundamental skill in science education, one that students generally practice in a controlled setting using equipment only available in the classroom laboratory. However, using smartphones with their built-in sensors and often free apps, many fundamental experiments can be performed outside the laboratory. Taking advantage of these tools often require creative approaches to data collection and exploring alternative strategies for experimental procedures. As examples, we present several experiments using smartphones and apps that record and analyze sound to measure a variety of physical properties.

  13. Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS)

    Energy Technology Data Exchange (ETDEWEB)

    Bland, Geoffrey [NASA Goddard Space Flight Center (GSFC), Greenbelt, MD (United States)

    2016-06-30

    The use of small unmanned aircraft systems (sUAS) with miniature sensor systems for atmospheric research is an important capability to develop. The Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) project, lead by Dr. Gijs de Boer of the Cooperative Institute for Research in Environmental Sciences (CIRES- a partnership of NOAA and CU-Boulder), is a significant milestone in realizing this new potential. This project has clearly demonstrated that the concept of sUAS utilization is valid, and miniature instrumentation can be used to further our understanding of the atmospheric boundary layer in the arctic.

  14. What ears do for bats: a comparative study of pinna sound pressure transformation in chiroptera.

    Science.gov (United States)

    Obrist, M K; Fenton, M B; Eger, J L; Schlegel, P A

    1993-07-01

    Using a moveable loudspeaker and an implanted microphone, we studied the sound pressure transformation of the external ears of 47 species of bats from 13 families. We compared pinna gain, directionality of hearing and interaural intensity differences (IID) in echolocating and non-echolocating bats, in species using different echolocation strategies and in species that depend upon prey-generated sounds to locate their targets. In the Pteropodidae, two echolocating species had slightly higher directionality than a non-echolocating species. The ears of phyllostomid and vespertilionid species showed moderate directionality. In the Mormoopidae, the ear directionality of Pteronotus parnellii clearly matched the dominant spectral component of its echolocation calls, unlike the situation in three other species. Species in the Emballonuridae, Molossidae, Rhinopomatidae and two vespertilionids that use narrow-band search-phase echolocation calls showed increasingly sharp tuning of the pinna to the main frequency of their signals. Similar tuning was most evident in Hipposideridae and Rhinolophidae, species specialized for flutter detection via Doppler-shifted echoes of high-duty-cycle narrow-band signals. The large pinnae of bats that use prey-generated sounds to find their targets supply high sound pressure gain at lower frequencies. Increasing domination of a narrow spectral band in echolocation is reflected in the passive acoustic properties of the external ears (sharper directionality). The importance of IIDs for lateralization and horizontal localization is discussed by comparing the behavioural directional performance of bats with their bioacoustical features.

  15. Longitudinal sound velocities, elastic anisotropy, and phase transition of high-pressure cubic H2O ice to 82 GPa

    Science.gov (United States)

    Kuriakose, Maju; Raetz, Samuel; Hu, Qing Miao; Nikitin, Sergey M.; Chigarev, Nikolay; Tournat, Vincent; Bulou, Alain; Lomonosov, Alexey; Djemia, Philippe; Gusev, Vitalyi E.; Zerr, Andreas

    2017-10-01

    Water ice is a molecular solid whose behavior under compression reveals the interplay of covalent bonding in molecules and forces acting between them. This interplay determines high-pressure phase transitions, the elastic and plastic behavior of H2O ice, which are the properties needed for modeling the convection and internal structure of the giant planets and moons of the solar system as well as H2O -rich exoplanets. We investigated experimentally and theoretically elastic properties and phase transitions of cubic H2O ice at room temperature and high pressures between 10 and 82 GPa. The time-domain Brillouin scattering (TDBS) technique was used to measure longitudinal sound velocities (VL) in polycrystalline ice samples compressed in a diamond anvil cell. The high spatial resolution of the TDBS technique revealed variations of VL caused by elastic anisotropy, allowing us to reliably determine the fastest and the slowest sound velocity in a single crystal of cubic H2O ice and thus to evaluate existing equations of state. Pressure dependencies of the single-crystal elastic moduli Ci j(P ) of cubic H2O ice to 82 GPa have been obtained which indicate its hardness and brittleness. These results were compared with ab initio calculations. It is suggested that the transition from molecular ice VII to ionic ice X occurs at much higher pressures than proposed earlier, probably above 80 GPa.

  16. Solid phase stability of molybdenum under compression: Sound velocity measurements and first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiulu [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China); Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, 621010 Mianyang, Sichuan (China); Liu, Zhongli [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China); College of Physics and Electric Information, Luoyang Normal University, 471022 Luoyang, Henan (China); Jin, Ke; Xi, Feng; Yu, Yuying; Tan, Ye; Dai, Chengda; Cai, Lingcang [Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, P.O. Box 919-102, 621900 Mianyang, Sichuan (China)

    2015-02-07

    The high-pressure solid phase stability of molybdenum (Mo) has been the center of a long-standing controversy on its high-pressure melting. In this work, experimental and theoretical researches have been conducted to check its solid phase stability under compression. First, we performed sound velocity measurements from 38 to 160 GPa using the two-stage light gas gun and explosive loading in backward- and forward-impact geometries, along with the high-precision velocity interferometry. From the sound velocities, we found no solid-solid phase transition in Mo before shock melting, which does not support the previous solid-solid phase transition conclusion inferred from the sharp drops of the longitudinal sound velocity [Hixson et al., Phys. Rev. Lett. 62, 637 (1989)]. Then, we searched its structures globally using the multi-algorithm collaborative crystal structure prediction technique combined with the density functional theory. By comparing the enthalpies of body centered cubic structure with those of the metastable structures, we found that bcc is the most stable structure in the range of 0–300 GPa. The present theoretical results together with previous ones greatly support our experimental conclusions.

  17. ANALYSIS OF SOUND PRESSURE LEVEL (SPL AND LAY OUT OF ENGINES IN THE FACTORY

    Directory of Open Access Journals (Sweden)

    Wijianto Wijianto

    2017-01-01

    Full Text Available Modeling layout of engines in the factory is very useful to know how many dB sound pressure level that are occur in the building in order to avoid hearing damage of employees that are caused by noise. The objective of this research is to know how many dB sound pressure level that are occur in the factory with engine composition such as boiler, diesel, turbine, motor and gear box with dimension of building are 40 m length, 35 m width and 10 m height. With MATLAB analysis can be obtain that the highest SPL is 104.7 dB and the lowest is 93.5 dB, so, this range are dangerous for human hearing. To avoid hearing damage in this area, employees must use hearing protector.

  18. Exposure to classroom sound pressure level among dance teachers in Porto Alegre (RS

    Directory of Open Access Journals (Sweden)

    Nehring, Cristiane

    2013-01-01

    Full Text Available Introduction: Dance teachers are exposed to high sound intensities. Aim: To verify the sound intensity of music used by dance teachers during classes. Method: This was a transversal and prospective study. Dance teachers were evaluated with a sociodemographic questionnaire, and sound intensity level measurements were taken at the beginning, middle, and end of dance classes. Results: The sample comprised 35 teachers (average age, 31.8 years. The duration of their career as dance teachers was 1-37 years; they worked daily for approximately 1-10 h. Among the classes followed, there were 15 (42.85% classical ballet classes, 4 (11.42% tap dancing lessons, 5 (14.28% jazz dance classes, 2 (5.71 Arab dance lessons, 6 (17.14% street dance classes, and 3 (8.57% ballroom dancing lessons. The average values observed at the beginning, middle, and end of the classes were 80.91 dB (A, 83.22 dB (A, and 85.19 dB (A, respectively. The music played in the street dance classes exposed teachers to the highest sound intensity. Conclusion: The average level of sound intensity of the dance classes in this study was either below or equal to the limit considered harmful for hearing health. Analysis of different class types showed that the sound densities of street, ballroom, and tap dance classes were above the recommended limits.

  19. Photoacoustically Measured Speeds of Sound of Liquid HBO2: On Unlocking the Fuel Potential of Boron

    Energy Technology Data Exchange (ETDEWEB)

    Bastea, S; Crowhurst, J; Armstrong, M; ., N T

    2010-03-24

    Elucidation of geodynamic, geochemical, and shock induced processes is often limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. Here we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized Exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of > 2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

  20. Pressures Detector Calibration and Measurement

    CERN Document Server

    AUTHOR|(CDS)2156315

    2016-01-01

    This is report of my first and second projects (of 3) in NA61. I did data taking and analysis in order to do calibration of pressure detectors and verified it. I analyzed the data by ROOT software using the C ++ programming language. The first part of my project was determination of calibration factor of pressure sensors. Based on that result, I examined the relation between pressure drop, gas flow rate of in paper filter and its diameter.

  1. Dynamic PIV measurement of the effect of sound waves in the upper plenum of the boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    In recent years, power uprating of boiling power reactors has been conducted at several existing power plants in order to improve plant economy. In one power uprated plant (117.8% uprate) in the United States, steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound waves into the steam-dome. The resonance among the structure, the flow, and the pressure fluctuation resulted in the breakages. In order to clarify the basic mechanism of the resonance, previous studies were performed by conducting a point measurement of the pressure and a phase averaged measurement of the flow, although detecting the interaction among the structure, the flow, and the pressure fluctuation by the conventional method was difficult. In a preliminary study, a dynamic Particle Image Velocimetry (PIV) system was used to investigate the effect of sound on the flow. A dynamic PIV system is the newest entrant to the field of fluid flow measurement. Its paramount advantage is the instantaneous global evaluation of conditions over a plane extended across the entire velocity field. Using the dynamic PIV system, the influence of sound waves on the flow field was measured. As a result, when two speakers were placed diagonally and sound waves were presented in the same phase, vertical motion was strongly observed compared to horizontal motion. (author)

  2. Evaluating signal-to-noise ratios, loudness, and related measures as indicators of airborne sound insulation.

    Science.gov (United States)

    Park, H K; Bradley, J S

    2009-09-01

    Subjective ratings of the audibility, annoyance, and loudness of music and speech sounds transmitted through 20 different simulated walls were used to identify better single number ratings of airborne sound insulation. The first part of this research considered standard measures such as the sound transmission class the weighted sound reduction index (R(w)) and variations of these measures [H. K. Park and J. S. Bradley, J. Acoust. Soc. Am. 126, 208-219 (2009)]. This paper considers a number of other measures including signal-to-noise ratios related to the intelligibility of speech and measures related to the loudness of sounds. An exploration of the importance of the included frequencies showed that the optimum ranges of included frequencies were different for speech and music sounds. Measures related to speech intelligibility were useful indicators of responses to speech sounds but were not as successful for music sounds. A-weighted level differences, signal-to-noise ratios and an A-weighted sound transmission loss measure were good predictors of responses when the included frequencies were optimized for each type of sound. The addition of new spectrum adaptation terms to R(w) values were found to be the most practical approach for achieving more accurate predictions of subjective ratings of transmitted speech and music sounds.

  3. Blood pressure and anthropometric measurements in healthy ...

    African Journals Online (AJOL)

    Methods. We measured the blood pressures of 650 healthy, randomly ... In addition, blood pressure measurement should be a part of the routine clinical examination of children. ... familial risk factors.2 ... common cause of elevated blood pressure in children.4 They ... sphygmomanometer (Accoson, hospital model BS 274,.

  4. Vapor pressure measured with inflatable plastic bag

    Science.gov (United States)

    1965-01-01

    Deflated plastic bag in a vacuum chamber measures initial low vapor pressures of materials. The bag captures the test sample vapors and visual observation of the vapor-inflated bag under increasing external pressures yields pertinent data.

  5. Sound Power Estimation by Laser Doppler Vibration Measurement Techniques

    Directory of Open Access Journals (Sweden)

    G.M. Revel

    1998-01-01

    Full Text Available The aim of this paper is to propose simple and quick methods for the determination of the sound power emitted by a vibrating surface, by using non-contact vibration measurement techniques. In order to calculate the acoustic power by vibration data processing, two different approaches are presented. The first is based on the method proposed in the Standard ISO/TR 7849, while the second is based on the superposition theorem. A laser-Doppler scanning vibrometer has been employed for vibration measurements. Laser techniques open up new possibilities in this field because of their high spatial resolution and their non-intrusivity. The technique has been applied here to estimate the acoustic power emitted by a loudspeaker diaphragm. Results have been compared with those from a commercial Boundary Element Method (BEM software and experimentally validated by acoustic intensity measurements. Predicted and experimental results seem to be in agreement (differences lower than 1 dB thus showing that the proposed techniques can be employed as rapid solutions for many practical and industrial applications. Uncertainty sources are addressed and their effect is discussed.

  6. A study on impulsive sound attenuation for a high-pressure blast flow field

    International Nuclear Information System (INIS)

    Kang, Kuk Jeong; Ko, Sung Ho; Lee, Dong Soo

    2008-01-01

    The present work addresses a numerical study on impulsive sound attenuation for a complex high-pressure blast flow field; these characteristics are generated by a supersonic propellant gas flow through a shock tube into an ambient environment. A numerical solver for analyzing the high pressure blast flow field is developed in this study. From numerical simulations, wave dynamic processes (which include a first precursor shock wave, a second main propellant shock wave, and interactions in the muzzle blasts) are simulated and discussed. The pressure variation of the blast flow field is analyzed to evaluate the effect of a silencer. A live firing test is also performed to evaluate four different silencers. The results of this study will be helpful in understanding blast wave and in designing silencers

  7. A study on impulsive sound attenuation for a high-pressure blast flow field

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kuk Jeong [Agency for Defence Development, Daejeon (Korea, Republic of); Ko, Sung Ho; Lee, Dong Soo [Chungnam National University, Daejeon (Korea, Republic of)

    2008-01-15

    The present work addresses a numerical study on impulsive sound attenuation for a complex high-pressure blast flow field; these characteristics are generated by a supersonic propellant gas flow through a shock tube into an ambient environment. A numerical solver for analyzing the high pressure blast flow field is developed in this study. From numerical simulations, wave dynamic processes (which include a first precursor shock wave, a second main propellant shock wave, and interactions in the muzzle blasts) are simulated and discussed. The pressure variation of the blast flow field is analyzed to evaluate the effect of a silencer. A live firing test is also performed to evaluate four different silencers. The results of this study will be helpful in understanding blast wave and in designing silencers

  8. Peripheral vascular effects on auscultatory blood pressure measurement.

    Science.gov (United States)

    Rabbany, S Y; Drzewiecki, G M; Noordergraaf, A

    1993-01-01

    Experiments were conducted to examine the accuracy of the conventional auscultatory method of blood pressure measurement. The influence of the physiologic state of the vascular system in the forearm distal to the site of Korotkoff sound recording and its impact on the precision of the measured blood pressure is discussed. The peripheral resistance in the arm distal to the cuff was changed noninvasively by heating and cooling effects and by induction of reactive hyperemia. All interventions were preceded by an investigation of their effect on central blood pressure to distinguish local effects from changes in central blood pressure. These interventions were sufficiently moderate to make their effect on central blood pressure, recorded in the other arm, statistically insignificant (i.e., changes in systolic [p cooling experiments was statistically significant (p < 0.001). Moreover, both measured systolic (p < 0.004) and diastolic (p < 0.001) pressure decreases during the reactive hyperemia experiments were statistically significant. The findings demonstrate that alteration in vascular state generates perplexing changes in blood pressure, hence confirming experimental observations by earlier investigators as well as predictions by our model studies.

  9. Measurement on the effect of sound wave in upper plenum of boiling water reactor

    International Nuclear Information System (INIS)

    Kumagai, Kosuke; Someya, Satoshi; Okamoto, Koji

    2009-01-01

    In recent years, the power uprate of Boiling Water Reactors have been conducted at several existing power plants as a way to improve plant economy. In one of the power uprated plants (117.8% uprates) in the United States, the steam dryer breakages due to fatigue fracture occurred. It is conceivable that the increased steam flow passing through the branches caused a self-induced vibration with the propagation of sound wave into the steam-dome. The resonance among the structure, flow and the pressure fluctuation resulted in the breakages. To understand the basic mechanism of the resonance, previous researches were done by a point measurement of the pressure and by a phase averaged measurement of the flow, while it was difficult to detect the interaction among them by the conventional method. In this study, Dynamic Particle Image Velocimetry (PIV) System was applied to investigate the effect of sound on natural convection and forced convection. Especially, when the phases of acoustic sources were different, various acoustic wave effects were checked. (author)

  10. Student Nurses' Knowledge in Relation to Blood Pressure Measurement by Sphygmomanometry and Auscultation.

    Science.gov (United States)

    Torrance, Colin; Serginson, Eve

    1996-01-01

    British nursing students (78 of 93) completed a questionnaire about blood pressure; 90% were not familiar with Korotkoff sounds or auscultary gap; most thought blood pressure was the same in both arms; 63% knew resting was essential before measurement; 59% assessed the arm for cuff size; only 25% thought the cuff should be placed at heart level.…

  11. A microwave pressure sounder. [for remote measurement of atmospheric pressure

    Science.gov (United States)

    Peckham, G. E.; Flower, D. A.

    1981-01-01

    A technique for the remote measurement of atmospheric surface pressure will be described. Such measurements could be made from a satellite in polar orbit and would cover many areas for which conventional meteorological data are not available. An active microwave instrument is used to measure the strength of return echoes from the ocean surface at a number of frequencies near the 60 GHz oxygen absorption band. Factors which affect the accuracy with which surface pressure can be deduced from these measurements will be discussed and an instrument designed to test the method by making measurements from an aircraft will be described.

  12. Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz.

    Science.gov (United States)

    Poulsen, Torben; Oakley, Sebastian

    2009-05-01

    Hearing threshold sound pressure levels were measured for the Sennheiser HDA 280 audiometric earphone. Hearing thresholds were measured for 25 normal-hearing test subjects at the 11 audiometric test frequencies from 125 Hz to 8000 Hz. Sennheiser HDA 280 is a supra-aural earphone that may be seen as a substitute for the classical Telephonics TDH 39. The results are given as the equivalent threshold sound pressure level (ETSPL) measured in an acoustic coupler specified in IEC 60318-3. The results are in good agreement with an independent investigation from PTB, Braunschweig, Germany. From acoustic laboratory measurements ETSPL values are calculated for the ear simulator specified in IEC 60318-1. Fitting of earphone and coupler is discussed. The data may be used for a future update of the RETSPL standard for supra-aural audiometric earphones, ISO 389-1.

  13. Measurement of intraocular pressure with pressure phosphene tonometry in children.

    Science.gov (United States)

    Fan, Dorothy S P; Chiu, Thomas Y H; Congdon, Nathan; Chan, Jeffrey C W; Cheung, Eva Y Y; Lam, Dennis S C

    2011-01-01

    To study the accuracy and acceptability of intraocular pressure (IOP) measurement by the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer in children. Fifty children (5 to 14 years old) participated in this prospective comparative study. IOP was measured with the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer by three different examiners who were masked to the results. The children were also asked to grade the degree of discomfort from 0 to 5 (0 = no discomfort; 5 = most discomfort). The mean IOPs measured by the Goldmann tonometer, pressure phosphene tonometer, and non-contact tonometer were 15.9 mm Hg (standard deviation [SD]: = 5.5 mm Hg; range: 10 to 36 mm Hg), 16.0 mm Hg (SD: 2.9 mm Hg; range: 12 to 25 mm Hg), and 15.7 mm Hg (SD = 5.1 mm Hg; range: 8 to 32 mm Hg), respectively (P = .722). The mean difference between pressure phosphene tonometer and Goldmann tonometer readings was 2.9 mm Hg and that between non-contact tonometer and Goldmann tonometer readings was 2.1 mm Hg. The 95% confidence interval of the mean difference between pressure phosphene tonometer and Goldmann tonometer readings was -1.07 and 1.19, and that between non-contact tonometer and Goldmann tonometer readings was -1.07 and 0.53. The mean discomfort ratings for the pressure phosphene tonometer, non-contact tonometer, and Goldmann tonometer were 0.6, 2.0, and 2.3, respectively (P tonometer was less accurate than the non-contact tonometer compared with Goldmann tonometer, it gave a reasonably close estimate and had a high specificity of raised IOP. In addition, measurement by the pressure phosphene tonometer is most acceptable to children. The pressure phosphene tonometer can be considered as an alternative method of IOP measurement in children. Copyright 2011, SLACK Incorporated.

  14. Commentary on differential-pressure measurements at high reference pressures

    International Nuclear Information System (INIS)

    Hasbrouck, R.T.; Noyes, R.P.

    1981-01-01

    Some practical approaches to the difficult problems in calibrating and implementing differential-pressure measurements are discussed. The data presented were gathered several years ago in separate investigations. An attempt is made to compare the results of these investigations to the common mode concept as described by Peter K. Stein in his publication, The Measurement of Differential Quantities - Problems and Approaches. Although one of these investigations involed a 10,000- to 20,000-psi reference-pressure gas measured at an ambient temperature and the other a classic /sup Δ/P flow measurement of cryogenic temperature, the problems encountered were the same

  15. Evaluating standard airborne sound insulation measures in terms of annoyance, loudness, and audibility ratings.

    Science.gov (United States)

    Park, H K; Bradley, J S

    2009-07-01

    This paper reports the results of an evaluation of the merits of standard airborne sound insulation measures with respect to subjective ratings of the annoyance and loudness of transmitted sounds. Subjects listened to speech and music sounds modified to represent transmission through 20 different walls with sound transmission class (STC) ratings from 34 to 58. A number of variations in the standard measures were also considered. These included variations in the 8-dB rule for the maximum allowed deficiency in the STC measure as well as variations in the standard 32-dB total allowed deficiency. Several spectrum adaptation terms were considered in combination with weighted sound reduction index (R(w)) values as well as modifications to the range of included frequencies in the standard rating contour. A STC measure without an 8-dB rule and an R(w) rating with a new spectrum adaptation term were better predictors of annoyance and loudness ratings of speech sounds. R(w) ratings with one of two modified C(tr) spectrum adaptation terms were better predictors of annoyance and loudness ratings of transmitted music sounds. Although some measures were much better predictors of responses to one type of sound than were the standard STC and R(w) values, no measure was remarkably improved for predicting annoyance and loudness ratings of both music and speech sounds.

  16. Oscillometric blood pressure measurements: differences between measured and calculated mean arterial pressure.

    NARCIS (Netherlands)

    Kiers, H.D.; Hofstra, J.M.; Wetzels, J.F.M.

    2008-01-01

    Mean arterial pressure (MAP) is often used as an index of overall blood pressure. In recent years, the use of automated oscillometric blood pressure measurement devices is increasing. These devices directly measure and display MAP; however, MAP is often calculated from systolic blood pressure (SBP)

  17. Pirani pressure sensor with distributed temperature measurement

    NARCIS (Netherlands)

    de Jong, B.R.; Bula, W.P.; Zalewski, D.R.; van Baar, J.J.J.; Wiegerink, Remco J.

    2003-01-01

    Surface micro-machined distributed Pirani pressure gauges, with designed heater-to-heat sink distances (gap-heights) of 0.35 μm and 1.10 μm, are successfully fabricated, modeled and characterized. Measurements and model response correspond within 5% of the measured value in a pressure range of 10 to

  18. Palpatory method of measuring diastolic blood pressure

    Directory of Open Access Journals (Sweden)

    Dinesh Sahu

    2010-01-01

    Conclusion: The palpatory method would be very useful where frequent blood pressure measurement are being done manually like in wards, in busy OPD, patient on treadmill and also whenever stethoscope is not available. The blood pressure can be measured in noisy environment too.

  19. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    International Nuclear Information System (INIS)

    Liu Xiong; Yao Yan; Ma Jiahao; Zhang Zhaohua; Zhang Yanhang; Wang Qian; Ren Tianling

    2015-01-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm 2 . It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm 2 . In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm 2 . Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10 −2 mV/kPa. (paper)

  20. 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.

  1. Fast Neutral Pressure Measurements in NSTX

    International Nuclear Information System (INIS)

    R. Raman; H.W. Kugel; T. Provost; R. Gernhardt; T.R. Jarboe; M.G. Bell

    2002-01-01

    Several fast neutral pressure gauges have been installed on NSTX [National Spherical Torus Experiment] to measure the vessel and divertor pressure during inductive and coaxial helicity injected (CHI) plasma operations. Modified, PDX [Poloidal Divertor Experiment]-type Penning gauges have been installed on the upper and lower divertors. Neutral pressure measurements during plasma operations from these and from two shielded fast Micro ion gauges at different toroidal locations on the vessel mid-plane are described. A new unshielded ion gauge, referred to as the In-vessel Neutral Pressure (INP) gauge is under development

  2. Measuring Viscosities of Gases at Atmospheric Pressure

    Science.gov (United States)

    Singh, Jag J.; Mall, Gerald H.; Hoshang, Chegini

    1987-01-01

    Variant of general capillary method for measuring viscosities of unknown gases based on use of thermal mass-flowmeter section for direct measurement of pressure drops. In technique, flowmeter serves dual role, providing data for determining volume flow rates and serving as well-characterized capillary-tube section for measurement of differential pressures across it. New method simple, sensitive, and adaptable for absolute or relative viscosity measurements of low-pressure gases. Suited for very complex hydrocarbon mixtures where limitations of classical theory and compositional errors make theoretical calculations less reliable.

  3. Temporary threshold shifts from exposures to equal equivalent continuous A-weighted sound pressure level

    DEFF Research Database (Denmark)

    Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    2014-01-01

    the assumptions made using the A-weighting curve for the assessment of hearing damage. By modifying exposure ratings to compensate for the build-up of energy at mid and high-frequencies (above 1 kHz) due to the presence of the listener in the sound field and for the levels below an effect threshold that does...... not induce changes in hearing (equivalent quiet levels), ratings of the sound exposure that reflect the observed temporary changes in auditory function can be obtained.......According to existing methods for the assessment of hearing damage, signals with the same A-weighted equivalent level should pose the same hazard to the auditory system. As a measure of hazard, it is assumed that Temporary Thresholds Shifts (TTS) reflect the onset of alterations to the hearing...

  4. Binaural loudness for artificial-head measurements in directional sound fields

    DEFF Research Database (Denmark)

    Sivonen, Ville Pekka; Ellermeier, Wolfgang

    2008-01-01

    The effect of the sound incidence angle on loudness was investigated for fifteen listeners who matched the loudness of sounds coming from five different incidence angles in the horizontal plane to that of the same sound with frontal incidence. The stimuli were presented via binaural synthesis...... by using head-related transfer functions measured for an artificial head. The results, which exhibited marked individual differences, show that loudness depends on the direction from which a sound reaches the listener. The average results suggest a relatively simple rule for combining the two signals...... at the ears of an artificial head for binaural loudness predictions....

  5. So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae).

    Science.gov (United States)

    Sueur, Jérôme; Mackie, David; Windmill, James F C

    2011-01-01

    To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2) SPL rms re 2.10(-5) Pa with a peak at 99.2 (85.7-104.6) SPL re 2.10(-5) Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

  6. So small, so loud: extremely high sound pressure level from a pygmy aquatic insect (Corixidae, Micronectinae.

    Directory of Open Access Journals (Sweden)

    Jérôme Sueur

    Full Text Available To communicate at long range, animals have to produce intense but intelligible signals. This task might be difficult to achieve due to mechanical constraints, in particular relating to body size. Whilst the acoustic behaviour of large marine and terrestrial animals has been thoroughly studied, very little is known about the sound produced by small arthropods living in freshwater habitats. Here we analyse for the first time the calling song produced by the male of a small insect, the water boatman Micronecta scholtzi. The song is made of three distinct parts differing in their temporal and amplitude parameters, but not in their frequency content. Sound is produced at 78.9 (63.6-82.2 SPL rms re 2.10(-5 Pa with a peak at 99.2 (85.7-104.6 SPL re 2.10(-5 Pa estimated at a distance of one metre. This energy output is significant considering the small size of the insect. When scaled to body length and compared to 227 other acoustic species, the acoustic energy produced by M. scholtzi appears as an extreme value, outperforming marine and terrestrial mammal vocalisations. Such an extreme display may be interpreted as an exaggerated secondary sexual trait resulting from a runaway sexual selection without predation pressure.

  7. Experimental Pressure Measurements on Hydropower Turbine Runners

    Energy Technology Data Exchange (ETDEWEB)

    Harding, Samuel F.; Richmond, Marshall C.

    2017-04-28

    The range of hydrodynamic operating conditions to which the turbine is exposed results in significant pressure fluctuations on both the pressure and suction sides of the blades. Understanding these dynamic pressures has a range of applications. Structurally, the resulting dynamic loads are significant in understanding the design life and maintenance schedule of the bearing, shafts and runner components. The pulsing pressures have also been seen to have a detrimental effect on the surface condition of the blades. Biologically, the pressure gradients and pressure extremes are the primary driver of barotrauma for fish passing through hydroturbines. Improvements in computational fluid dynamics (CFD) can be used to simulate such unsteady pressures in the regions of concern. High frequency model scale and prototype measurements of pressures at the blade are important in the validation of these models. Experimental characterization of pressure fields over hydroturbine blades has been demonstrated by a number of studies which using multiple pressure transducers to map the pressure contours on the runner blades. These have been performed at both model and prototype scales, often to validate computational models of the pressure and flow fields over the blades. This report provides a review of existing studies in which the blade pressure was measured in situ. The report assesses the technology for both model and prototype scale testing. The details of the primary studies in this field are reported and used to inform the types of hardware required for similar experiments based on the Ice Harbor Dam owned by the US Corps of Engineers on the Snake River, WA, USA. Such a study would be used to validate the CFD performed for the BioPA.

  8. An Inexpensive and Versatile Version of Kundt's Tube for Measuring the Speed of Sound in Air

    Science.gov (United States)

    Papacosta, Pangratios; Linscheid, Nathan

    2016-01-01

    Experiments that measure the speed of sound in air are common in high schools and colleges. In the Kundt's tube experiment, a horizontal air column is adjusted until a resonance mode is achieved for a specific frequency of sound. When this happens, the cork dust in the tube is disturbed at the displacement antinode regions. The location of the…

  9. Intelligent pressure measurement in multiple sensor arrays

    International Nuclear Information System (INIS)

    Matthews, C.A.

    1995-01-01

    Pressure data acquisition has typically consisted of a group of sensors scanned by an electronic or mechanical multiplexer. The data accuracy was dependent upon the temperature stability of the sensors. This paper describes a new method of pressure measurement that combines individual temperature compensated pressure sensors, a microprocessor, and an A/D converter in one module. Each sensor has its own temperature characteristics stored in a look-up table to minimize sensor thermal errors. The result is an intelligent pressure module that can output temperature compensated engineering units over an Ethernet interface. Calibration intervals can be dramatically extended depending upon system accuracy requirements and calibration techniques used

  10. Locked-in syndrome caused by the pressure exerted by the sound gun

    Directory of Open Access Journals (Sweden)

    Ayse Belin Ozer

    2014-01-01

    Full Text Available A 19-year-old male patient who wounded himself with a gun in the cranial region had a Glasgow coma scale of 3E. At posttraumatic day 7, locked-in syndrome was considered upon detection of vertical eye movements, meaningful winks, and quadriplegia. Apart from the classical view, computed tomography (CT and postmortem examination of the brain showed an infarct area in the cerebellum. However, vertebrobasilar artery system was normal. In this case report, we would like to present that unlike cases with ischemia, specific CT findings may not be evident in posttraumatic cases and ischemia may occur in the cerebellum as a result of the pressure exerted by a sound gun.

  11. Thermogravimetric measurements of liquid vapor pressure

    International Nuclear Information System (INIS)

    Rong Yunhong; Gregson, Christopher M.; Parker, Alan

    2012-01-01

    Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

  12. Sound velocities of the 23 Å phase at high pressure and implications for seismic velocities in subducted slabs

    Science.gov (United States)

    Cai, N.; Chen, T.; Qi, X.; Inoue, T.; Li, B.

    2017-12-01

    Dense hydrous phases are believed to play an important role in transporting water back into the deep interior of the Earth. Recently, a new Al-bearing hydrous Mg-silicate, named the 23 Å phase (ideal composition Mg12Al2Si4O16(OH)14), was reported (Cai et al., 2015), which could be a very important hydrous phase in subducting slabs. Here for the first time we report the measurements of the compressional and shear wave velocities of the 23 Å phase under applied pressures up to 14 GPa and room temperature, using a bulk sample with a grain size of less than 20 μm and density of 2.947 g/cm3. The acoustic measurements were conducted in a 1000-ton uniaxial split-cylinder multi-anvil apparatus using ultrasonic interferometry techniques (Li et al., 1996). The pressures were determined in situ by using an alumina buffer rod as the pressure marker (Wang et al., 2015). A dual-mode piezoelectric transducer enabled us to measure P and S wave travel times simultaneously, which in turn allowed a precise determination of the sound velocities and elastic bulk and shear moduli at high pressures. A fit to the acoustic data using finite strain analysis combined with a Hashin-Shtrikman (HS) bounds calculation yields: Ks0 = 113.3 GPa, G0 = 42.8 GPa, and K' = 3.8, G' = 1.9 for the bulk and shear moduli and their pressure derivatives. The velocities (especially for S wave) of this 23 Å phase (ambient Vp = 7.53 km/s, Vs = 3.72 km/s) are lower than those of phase A, olivine, pyrope, etc., while the Vp/Vs ratio (from 2.02 to 1.94, decreasing with increasing pressure) is quite high. These results suggest that a hydrous assemblage containing 23 Å phase should be distinguishable from a dry one at high pressure and temperature conditions relevant to Al-bearing subducted slabs.

  13. Pancreas tumor interstitial pressure catheter measurement

    Science.gov (United States)

    Nieskoski, Michael D.; Gunn, Jason; Marra, Kayla; Trembly, B. Stuart; Pogue, Brian W.

    2016-03-01

    This paper highlights the methodology in measuring interstitial pressure in pancreatic adenocarcinoma tumors. A Millar Mikrotip pressure catheter (SPR-671) was used in this study and a system was built to amplify and filter the output signal for data collection. The Millar pressure catheter was calibrated prior to each experiment in a water column at 37°C, range of 0 to 60 inH2O (112 mmHg), resulting in a calibration factor of 33 mV / 1 inH2O. The interstitial pressures measured in two orthotopically grown pancreatic adenocarcinoma tumor were 57 mmHg and 48 mmHg, respectively. Verteporfin uptake into the pancreatic adenocarcinoma tumor was measured using a probe-based experimental dosimeter.

  14. Pressure measurements in magnetic-fusion devices

    International Nuclear Information System (INIS)

    Dylla, H.F.

    1981-11-01

    Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration

  15. On output measurements via radiation pressure

    DEFF Research Database (Denmark)

    Leeman, S.; Healey, A.J.; Forsberg, F.

    1990-01-01

    It is shown, by simple physical argument, that measurements of intensity with a radiation pressure balance should not agree with those based on calorimetric techniques. The conclusion is ultimately a consequence of the circumstance that radiation pressure measurements relate to wave momentum, while...... calorimetric methods relate to wave energy. Measurements with some typical ultrasound fields are performed with a novel type of hydrophone, and these allow an estimate to be made of the magnitude of the discrepancy to be expected between the two types of output measurement in a typical case....

  16. Pressure measurements in magnetic-fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Dylla, H.F.

    1981-11-01

    Accurate pressure measurements are important in magnetic fusion devices for: (1) plasma diagnostic measurements of particle balance and ion temperature; (2) discharge cleaning optimization; (3) vacuum system performance; and (4) tritium accountability. This paper reviews the application, required accuracy, and suitable instrumentation for these measurements. Demonstrated uses of ionization-type and capacitance-diaphragm gauges for various pressure and gas-flow measurements in tokamaks are presented, with specific reference to the effects of magnetic fields on gauge performance and the problems associated with gauge calibration.

  17. [Contemporary possibilities of intraocular pressure measurement].

    Science.gov (United States)

    Hornová, J; Baxant, A

    2013-10-01

    Authors introduced current possibilities of measuring intraocular pressure (IOP). A list of available methods of monitoring IOP is published; contact measurement method IOP directly on the cornea, but also over upper lid, methodology of minimal contact and non-contact measurement. Following contact methods are described; former measurements of IOP by impression Schiotz tonometer and the current methodology applanation. So far as the gold standard measurement Goldmann applanation tonometer (GAT) is considered, another methodology with applanation measurements are compared: Pascal dynamic contoured tonometer (DCT ), BioResonator - resonant applanation tonometer (ART ), digital applanation tonometer Tonopen and last hit: continuous measurement of IOP by Sensimed Triggerfish. Orientation and rapid assessment is palpation pressure control over the lid and measuring by tonometer Diaton. Rebound tonometer (RBT) iCare belongs to measurements with minimal contact, no need anesthetic drops and fluorescein, therefore a self - home version of IOP measurements (Icare ONE) is developed. Non-contact measurement of IOP by different pneumotonometers is popular for screening assessment of IOP. Reichert Ocular Response Analyzer (ORA) is a non-contact applanation IOP measurement and reveals additional properties of the cornea. In the discussion of a range methodology is evaluated, the experience of other authors and their own experience is compared. For monitoring of patients is necessary to select the most suitable methodology, measure repeatedly and accurately to allow long-term monitoring of intraocular pressure.

  18. Measurement of pressure pulsations in Francis turbines

    Energy Technology Data Exchange (ETDEWEB)

    Kobro, Einar

    2010-11-15

    The work presented in this thesis involves preparation and execution of measurements on Francis runners. The measurements were performed by means of onboard measuring equipment both in model runners and full-scale prototype runners. Also, analysis of the measured data, and the discussion of the results, is presented. The measurements resulted in large data sets. These data sets were used by the author to investigate the dynamic pressure and strain in the runners. The results of the analysis can be used as input in future turbine design. Andritz Hydro AG has used the data for verification of their numerical simulation tools. In connection with the refurbishment of Tokke power plant, two model runners were made available for onboard pressure measurements. To investigate the dynamic pressure in these runners, methods for integration of pressure transducers in the runner blades needed to be developed. After initial difficulties during the preparation, successful measurements were obtained from both model runners. At Tokke power plant, both the original and replacement runners were made accessible for onboard pressure and strain gauge measurements. On the original Kvaerner Brug AS runner, the test was prepared and performed by the author. This test failed, due to water intrusion in the logging chain. The second test was performed on the Andritz Hydro AG replacement runner. This test was prepared and performed by the author in close cooperation with Andritz Hydro AG, and the results were successful. The analysis results from both model and prototype runners show that the wake leaving the guide vanes is the most severe source of dynamic pressure in the runner. The draft tube vortex rope pulsation propagates upstream the runner, but does not appear as a significant frequency in the runner strain measurements. (Author)

  19. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhukhovitskii, D. I., E-mail: dmr@ihed.ras.ru; Fortov, V. E.; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N. [Joint Institute of High Temperatures, Russian Academy of Sciences, Izhorskaya 13, Bd. 2, 125412 Moscow (Russian Federation); Thomas, H. M. [Research Group Complex Plasma, DLR, Oberpfaffenhofen, 82234 Wessling (Germany); Ivlev, A. V.; Morfill, G. E. [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Schwabe, M. [Department of Chemical and Biomolecular Engineering, Graves Lab, D75 Tan Hall, University of California, Berkeley, CA 94720 (United States)

    2015-02-15

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas.

  20. Measurement of the speed of sound by observation of the Mach cones in a complex plasma under microgravity conditions

    International Nuclear Information System (INIS)

    Zhukhovitskii, D. I.; Fortov, V. E.; Molotkov, V. I.; Lipaev, A. M.; Naumkin, V. N.; Thomas, H. M.; Ivlev, A. V.; Morfill, G. E.; Schwabe, M.

    2015-01-01

    We report the first observation of the Mach cones excited by a larger microparticle (projectile) moving through a cloud of smaller microparticles (dust) in a complex plasma with neon as a buffer gas under microgravity conditions. A collective motion of the dust particles occurs as propagation of the contact discontinuity. The corresponding speed of sound was measured by a special method of the Mach cone visualization. The measurement results are incompatible with the theory of ion acoustic waves. The estimate for the pressure in a strongly coupled Coulomb system and a scaling law for the complex plasma make it possible to derive an evaluation for the speed of sound, which is in a reasonable agreement with the experiments in complex plasmas

  1. An objective measure for the sensitivity of room impulse response and its link to a diffuse sound field

    DEFF Research Database (Denmark)

    Prislan, Rok; Brunskog, Jonas; Jacobsen, Finn

    2014-01-01

    This study is relevant to acoustic measurements in reverberation rooms such as measurements of sound transmission, sound absorption, and sound power levels of noise sources. The study presents a quantitative measure for the diffuseness in a room, which is first introduced theoretically and sub...

  2. An analysis of the correlations between the turbulent flow and the sound pressure fields of subsonic jets

    OpenAIRE

    Bogey , Christophe; Bailly , Christophe

    2007-01-01

    International audience; Noise generation is investigated in subsonic isothermal round jets at Mach numbers M =0.6 and M =0.9, with Reynolds numbers ReD =1700 and ReD 105, using causality methods on data provided by large-eddy simulations. The correlations between broadband sound pressure signals and broadband turbulence signals along the jet axis and the shear layer are calculated. The normalized correlations are found to be significant between the pressure emitted in the downstream direction...

  3. Techniques and instrumentation for the measurement of transient sound energy flux

    Science.gov (United States)

    Watkinson, P. S.; Fahy, F. J.

    1983-12-01

    The evaluation of sound intensity distributions, and sound powers, of essentially continuous sources such as automotive engines, electric motors, production line machinery, furnaces, earth moving machinery and various types of process plants were studied. Although such systems are important sources of community disturbance and, to a lesser extent, of industrial health hazard, the most serious sources of hearing hazard in industry are machines operating on an impact principle, such as drop forges, hammers and punches. Controlled experiments to identify major noise source regions and mechanisms are difficult because it is normally impossible to install them in quiet, anechoic environments. The potential for sound intensity measurement to provide a means of overcoming these difficulties has given promising results, indicating the possibility of separation of directly radiated and reverberant sound fields. However, because of the complexity of transient sound fields, a fundamental investigation is necessary to establish the practicability of intensity field decomposition, which is basic to source characterization techniques.

  4. Strain measurements during pressurized thermal shock experiment

    International Nuclear Information System (INIS)

    Tarso Vida Gomes, P. de; Julio Ricardo Barreto Cruz; Tanius Rodrigues Mansur; Denis Henrique Bianchi Scaldaferri; Miguel Mattar Neto

    2005-01-01

    For the life extension of nuclear power plants, the residual life of most of their components must be evaluated along all their operating time. Concerning the reactor pressure vessel, the pressurized thermal shock (PTS) is a very important event to be considered. For better understanding the effects of this kind of event, tests are made. The approach described here consisted of building a simplified in-scale physical model of the reactor pressure vessel, submitting it to the actual operating temperature and pressure conditions and provoking a thermal shock by means of cold water flow in its external surface. To conduct such test, the Nuclear Technology Development Center (CDTN) has been conducting several studies related to PTS and has also built a laboratory that has made possible the simulation of the PTS loading conditions. Several cracks were produced in the external surface of the reactor pressure vessel model. Strain gages were fixed by means of electrical discharge welding over the cracks regions in both external and internal surfaces. The temperature was monitored in 10 points across the vessel wall. The internal pressure was manually controlled and monitored using a pressure transducer. Two PTS experiments were conducted and this paper presents the strain measurement procedures applied to the reactor pressure vessel model, during the PTS, using strain gages experimental methodology. (authors)

  5. A gas thermometer for vapor pressure measurements

    Science.gov (United States)

    Rusin, A. D.

    2008-08-01

    The pressure of an inert gas over the range 400 1000 K was measured on a tensimetric unit with a quartz membrane pressure gauge of enhanced sensitivity. It was shown that a reactor with a membrane null gauge could be used as a gas thermometer. The experimental confidence pressure and temperature intervals were 0.07 torr and 0.1 K at a significance level of 0.05. A Pt-Pt/10% Rh thermocouple was calibrated; the results were approximated by a polynomial of degree five. The error in temperature calculations was 0.25 K.

  6. Uncertainties for pressure-time efficiency measurements

    OpenAIRE

    Ramdal, Jørgen; Jonsson, Pontus; Dahlhaug, Ole Gunnar; Nielsen, Torbjørn; Cervantes, Michel

    2010-01-01

     In connection with the pressure-time project at the Norwegian University of Science and Technology and Luleå University of Technology, a number of tests with the pressure-time method have been performed at the Waterpower Laboratory in Trondheim, Norway. The aim is to lower the uncertainty and improve usability of the method. Also a field test at the Anundsjoe power plant in Sweden has been performed. The pressure-time measurement is affected by random uncertainty. To minimize the effect of t...

  7. The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing

    Science.gov (United States)

    Collyer, Sally; Thorpe, C. William; Callaghan, Jean; Davis, Pamela J.

    2008-01-01

    Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing. Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and…

  8. Fully automatized apparatus for determining speed of sound for liquids in the temperature and pressure interval (283.15–343.15) K and (0.1–95) MPa

    International Nuclear Information System (INIS)

    Yebra, Francisco; Troncoso, Jacobo; Romaní, Luis

    2017-01-01

    Highlights: • An apparatus for measuring speed of sound of liquids is described. • Pressure and temperature control is fully automatized. • Uncertainty of the measurements is estimated in 0.1%. • Comparison with literature data confirms the reliability of the methodology. - Abstract: An instrument for determining the speed of sound as a function of temperature and pressure for liquids is described. It was totally automatized: pressure and temperature values are controlled and time of flight of the ultrasonic wave data were acquired using a digital system which automatically made all required actions. The instrument calibration was made only at atmospheric pressure using high quality data of water and methanol. For higher pressures, the calibration parameters were predicted using a model for the high pressure cell, through finite-element calculations (FEM), in order to realistically determine the changes in the cell induced by the compression. Uncertainties in pressure and temperature were 20 mK and 0.1 MPa, respectively and in speed of sound it was estimated to be about 0.1%. The speeds of sound for water, methanol, hexane, heptane, octane, toluene, ethanol and 1-propanol were determined in the temperature and pressure ranges (283.15–343.15) K and (0.1–95) MPa. Comparison with literature data reveals the high reliability of the experimental procedure.

  9. Measuring the osmotic pressure of active colloids

    Science.gov (United States)

    Wang, Michael; Soni, Vishal; Magkiriadou, Sofia; Ferrari, Melissa; Youssef, Mina; Driscoll, Michelle; Sacanna, Stefano; Chaikin, Paul; Irvine, William

    We study the behavior of a system of colloidal spinners, consisting of weakly magnetic colloids driven by a rotating magnetic field. First the particles are allowed to sediment to an equilibrium density profile in a gravitational field, from which we measure the equilibrium equation of state. By spinning the particles at various frequencies, we introduce activity into the system through the hydrodynamic interactions between particles. We observe that the activity expands the sedimentation profile to a new steady state, from which we measure the pressure as a function of the density and activity. We compare the effects of activity on the pressure and mean-squared displacement of spinners and tracer particles.

  10. Does the Position or Contact Pressure of the Stethoscope Make Any Difference to Clinical Blood Pressure Measurements

    Science.gov (United States)

    Pan, Fan; Zheng, Dingchang; He, Peiyu; Murray, Alan

    2014-01-01

    Abstract This study aimed to investigate the effect of stethoscope position and contact pressure on auscultatory blood pressure (BP) measurement. Thirty healthy subjects were studied. Two identical stethoscopes (one under the cuff, the other outside the cuff) were used to simultaneously and digitally record 2 channels of Korotkoff sounds during linear cuff pressure deflation. For each subject, 3 measurements with different contact pressures (0, 50, and 100 mm Hg) on the stethoscope outside the cuff were each recorded at 3 repeat sessions. The Korotkoff sounds were replayed twice on separate days to each of 2 experienced listeners to determine systolic and diastolic BPs (SBP and DBP). Variance analysis was performed to study the measurement repeatability and the effect of stethoscope position and contact pressure on BPs. There was no significant BP difference between the 3 repeat sessions, between the 2 determinations from each listener, between the 2 listeners and between the 3 stethoscope contact pressures (all P > 0.06). There was no significant SBP difference between the 2 stethoscope positions at the 2 lower stethoscope pressures (P = 0.23 and 0.45), but there was a small (0.4 mm Hg, clinically unimportant) significant difference (P = 0.005) at the highest stethoscope pressure. The key result was that, DBP from the stethoscope under the cuff was significantly lower than that from outside the cuff by 2.8 mm Hg (P stethoscope outside the cuff, tends to give a higher DBP than the true intra-arterial pressure, this study could suggest that the stethoscope position under the cuff, and closer to the arterial occlusion, might yield measurements closer to the actual invasive DBP. PMID:25546675

  11. Does the position or contact pressure of the stethoscope make any difference to clinical blood pressure measurements: an observational study.

    Science.gov (United States)

    Pan, Fan; Zheng, Dingchang; He, Peiyu; Murray, Alan

    2014-12-01

    This study aimed to investigate the effect of stethoscope position and contact pressure on auscultatory blood pressure (BP) measurement. Thirty healthy subjects were studied. Two identical stethoscopes (one under the cuff, the other outside the cuff) were used to simultaneously and digitally record 2 channels of Korotkoff sounds during linear cuff pressure deflation. For each subject, 3 measurements with different contact pressures (0, 50, and 100 mm Hg) on the stethoscope outside the cuff were each recorded at 3 repeat sessions. The Korotkoff sounds were replayed twice on separate days to each of 2 experienced listeners to determine systolic and diastolic BPs (SBP and DBP). Variance analysis was performed to study the measurement repeatability and the effect of stethoscope position and contact pressure on BPs. There was no significant BP difference between the 3 repeat sessions, between the 2 determinations from each listener, between the 2 listeners and between the 3 stethoscope contact pressures (all P > 0.06). There was no significant SBP difference between the 2 stethoscope positions at the 2 lower stethoscope pressures (P = 0.23 and 0.45), but there was a small (0.4 mm Hg, clinically unimportant) significant difference (P = 0.005) at the highest stethoscope pressure. The key result was that, DBP from the stethoscope under the cuff was significantly lower than that from outside the cuff by 2.8 mm Hg (P stethoscope outside the cuff, tends to give a higher DBP than the true intra-arterial pressure, this study could suggest that the stethoscope position under the cuff, and closer to the arterial occlusion, might yield measurements closer to the actual invasive DBP.

  12. Side abutment pressure distribution by field measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lian-guo Wang; Yang Song; Xing-hua He; Jian Zhang [State Key Laboratory for Geomechanics and Deep Underground Engineering, Xuzhou (China)

    2008-12-15

    Given the 7123 working face in the Qidong Coal Mine of the Wanbei Mining Group, nine dynamic roof monitors were installed in the crossheading to measure the amount and velocity of roof convergence in different positions and at different times and three steel bored stress sensors were installed in the return airway to measure rock stress at depth. On the basis of this arrangement, the rule of change of the distribution of the side abutment pressure with the advance of the working face and movement of overlying strata was studied. The rule of change and the stability of rock stress at depth were measured. Secondly, the affected area and stability time of the side abutment pressure were also studied. The results show that: 1) During working, the face advanced distance was from 157 m to 99 m, the process was not effected by mining induced pressure. When the distance was 82 m, the position of peak stress was 5 m away from the coal wall. When the distance was 37 m, the position of peak stress away from the coal wall was about 15 m to 20 m and finally reached a steady state; 2) the time and the range of the peak of side rock pressure obtained from stress sensors were consistent with the results from the dynamic roof monitors; 3) the position of the peak pressure was 25 m away from the coal wall. 14 refs., 6 figs.

  13. Eccentric pressurized tube for measuring creep rupture

    International Nuclear Information System (INIS)

    Schwab, P.R.

    1981-01-01

    Creep rupture is a long term failure mode in structural materials that occurs at high temperatures and moderate stress levels. The deterioration of the material preceding rupture, termed creep damage, manifests itself in the formation of small cavities on grain boundaries. To measure creep damage, sometimes uniaxial tests are performed, sometimes density measurements are made, and sometimes the grain boundary cavities are measured by microscopy techniques. The purpose of the present research is to explore a new method of measuring creep rupture, which involves measuring the curvature of eccentric pressurized tubes. Theoretical investigations as well as the design, construction, and operation of an experimental apparatus are included in this research

  14. Direct speed of sound measurement within the atmosphere during a national holiday in New Zealand

    Science.gov (United States)

    Vollmer, M.

    2018-05-01

    Measuring the speed of sound belongs to almost any physics curriculum. Two methods dominate, measuring resonance phenomena of standing waves or time-of-flight measurements. The second type is conceptually simpler, however, performing such experiments with dimensions of meters usually requires precise electronic time measurement equipment if accurate results are to be obtained. Here a time-of-flight measurement from a video recording is reported with a dimension of several km and an accuracy for the speed of sound of the order of 1%.

  15. Sound quality measures for speech in noise through a commercial hearing aid implementing digital noise reduction.

    Science.gov (United States)

    Ricketts, Todd A; Hornsby, Benjamin W Y

    2005-05-01

    This brief report discusses the affect of digital noise reduction (DNR) processing on aided speech recognition and sound quality measures in 14 adults fitted with a commercial hearing aid. Measures of speech recognition and sound quality were obtained in two different speech-in-noise conditions (71 dBA speech, +6 dB SNR and 75 dBA speech, +1 dB SNR). The results revealed that the presence or absence of DNR processing did not impact speech recognition in noise (either positively or negatively). Paired comparisons of sound quality for the same speech in noise signals, however, revealed a strong preference for DNR processing. These data suggest that at least one implementation of DNR processing is capable of providing improved sound quality, for speech in noise, in the absence of improved speech recognition.

  16. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  17. Equipment for liquid metal pressure measurement

    International Nuclear Information System (INIS)

    Jung, J.

    1977-01-01

    Equipment is proposed for measuring liquid metal pressure in piping or a tank. An auxiliary piping is connected to the piping or tank at the measuring point. The auxiliary piping transports liquid metal to a container by means of an electromagnetic pump. The piping also houses an electromagnetic flow ratemeter connected to an electric comparator. The comparator and the electromagnetic pump are connected to the pump output generator. (Z.M.)

  18. Evaluation of the effects of various sound pressure levels on the level of serum aldosterone concentration in rats

    Directory of Open Access Journals (Sweden)

    Parvin Nassiri

    2017-01-01

    Full Text Available Introduction: Noise exposure may have anatomical, nonauditory, and auditory influences. Considering nonauditory impacts, noise exposure can cause alterations in the automatic nervous system, including increased pulse rates, heightened blood pressure, and abnormal secretion of hormones. The present study aimed at examining the effect of various sound pressure levels (SPLs on the serum aldosterone level among rats. Materials and Methods: A total of 45 adult male rats with an age range of 3 to 4 months and a weight of 200 ± 50 g were randomly divided into 15 groups of three. Three groups were considered as the control groups and the rest (i.e., 12 groups as the case groups. Rats of the case groups were exposed to SPLs of 85, 95, and 105 dBA. White noise was used as the noise to which the rats were exposed. To measure the level of rats’ serum aldosterone, 3 mL of each rat’s sample blood was directly taken from the heart of anesthetized animals by using syringes. The taken blood samples were put in labeled test tubes that contained anticoagulant Ethylenediaminetetraacetic acid. In the laboratory, the level of aldosterone was assessed through Enzyme-linked immunosorbent assay protocol. The collected data were analyzed by the use of Statistical Package for Social Sciences (SPSS version 18. Results: The results revealed that there was no significant change in the level of rats’ serum aldosterone as a result of exposure to SPLs of 65, 85, and 95 dBA. However, the level of serum aldosterone experienced a remarkable increase after exposure to the SPL of 105 dBA (P < 0.001. Thus, the SPL had a significant impact on the serum aldosterone level (P < 0.001. In contrast, the exposure time and the level of potassium in the used water did not have any measurable influence on the level of serum aldosterone (P = 0.25 and 0.39. Conclusion: The findings of this study demonstrated that serum aldosterone can be used as a biomarker in the face of sound

  19. Whole Word Measures in Bilingual Children with Speech Sound Disorders

    Science.gov (United States)

    Burrows, Lauren; Goldstein, Brian A.

    2010-01-01

    Phonological acquisition traditionally has been measured using constructs that focus on segments rather than the whole words. Findings from recent research have suggested whole-word productions be evaluated using measures such as phonological mean length of utterance (pMLU) and the proportion of whole-word proximity (PWP). These measures have been…

  20. Sound speed and thermal property measurements of inert materials: laser spectroscopy and the diamond-anvil cell

    Energy Technology Data Exchange (ETDEWEB)

    Zaug, J.M.

    1997-07-01

    An indispensable companion to dynamical physics experimentation, static high-pressure diamond-anvil cell research continues to evolve, with laser diagnostic, as an accurate and versatile experimental deep planetary properties have bootstrapped each other in a process that has produced even higher pressures; consistently improved calibrations of temperature and pressure under static and dynamic conditions; and unprecedented data and understanding of materials, their elasticity, equations of state (EOS), and transport properties under extreme conditions. A collection of recent pressure and/or temperature dependent acoustic and thermal measurements and deduced mechanical properties and EOS data are summarized for a wide range of materials including H2, H2O, H2S, D2S, CO2, CH4, N2O, CH3OH,, SiO2, synthetic lubricants, PMMA, single crystal silicates, and ceramic superconductors. Room P&T sound speed measurements are presented for the first time on single crystals of beta-HMX. New high-pressure and temperature diamond cell designed and pressure calibrant materials are reviewed.

  1. Basic principles for measurement of intramuscular pressure

    Science.gov (United States)

    Hargens, A. R.; Ballard, R. E.

    1995-01-01

    We review historical and methodological approaches to measurements of intramuscular pressure (IMP) in humans. These techniques provide valuable measures of muscle tone and activity as well as diagnostic criteria for evaluation of exertional compartment syndrome. Although the wick and catheter techniques provide accurate measurements of IMP at rest, their value for exercise studies and diagnosis of exertional compartment syndrome is limited because of low frequency response and hydrostatic (static and inertial) pressure artifacts. Presently, most information on diagnosis of exertional compartment syndromes during dynamic exercise is available using the Myopress catheter. However, future research and clinical diagnosis using IMP can be optimized by the use of a miniature transducer-tipped catheter such as the Millar Mikro-tip.

  2. Photoacoustically Measured Speeds of Sound and the Equation of State of HBO2: On Understanding Detonation with Boron Fuel

    Energy Technology Data Exchange (ETDEWEB)

    Zaug, J M; Bastea, S; Crowhurst, J; Armstrong, M; Fried, L; Teslich, N

    2010-03-09

    Elucidation of geodynamic, geochemical, and shock induced processes is limited by challenges to accurately determine molecular fluid equations of state (EOS). High pressure liquid state reactions of carbon species underlie physiochemical mechanisms such as differentiation of planetary interiors, deep carbon sequestration, propellant deflagration, and shock chemistry. In this proceedings paper we introduce a versatile photoacoustic technique developed to measure accurate and precise speeds of sound (SoS) of high pressure molecular fluids and fluid mixtures. SoS of an intermediate boron oxide, HBO{sub 2} are measured up to 0.5 GPa along the 277 C isotherm. A polarized exponential-6 interatomic potential form, parameterized using our SoS data, enables EOS determinations and corresponding semi-empirical evaluations of >2000 C thermodynamic states including energy release from bororganic formulations. Our thermochemical model propitiously predicts boronated hydrocarbon shock Hugoniot results.

  3. Measurements of Pressure of Extracorporeal Shock Wave Lithotripter Using Pressure-Sensitive Papers

    Science.gov (United States)

    Inose, Naoto; Ide, Masao

    1993-05-01

    This paper describes measurements of pressures at the focal region of the extracorporeal shock wave lithotripter (ESWL) using pressure-sensitive papers. At the focal region of ESWL, ordinary hydrophones are quickly damaged, because of very high pressures. Recently, measurements of pressure at the focal region of ESWL using pressure-sensitive paper have been advised. Therefore, we have studied the effectiveness of pressure-sensitive papers in the measurement of high acoustic pressures at the focal region of ESWL.

  4. Measurement of the thermal diffusivity and speed of sound of hydrothermal solutions via the laser-induced grating technique

    International Nuclear Information System (INIS)

    Butenhoff, T.J.

    1994-01-01

    Hydrothermal processing is being developed as a method for organic destruction for the Hanford Site in Washington. Hydrothermal processing refers to the redox reactions of chemical compounds in supercritical or near-supercritical aqueous solutions. In order to design reactors for the hydrothermal treatment of complicated mixtures found in the Hanford wastes, engineers need to know the thermophysical properties of the solutions under hydrothermal conditions. The author used the laser-induced grating technique to measure the thermal diffusivity and speed of sound of hydrothermal solutions. In this non-invasive optical technique, a transient grating is produced in the hydrothermal solution by optical absorption from two crossed time-coincident nanosecond laser pulses. The grating is probed by measuring the diffraction efficiency of a third laser beam. The grating relaxes via thermal diffusion, and the thermal diffusivity can be determined by measuring the decay of the grating diffraction efficiency as a function of the pump-probe delay time. In addition, intense pump pulses produce counterpropagating acoustic waves that appear as large undulations in the transient grating decay spectrum. The speed of sound in the sample is simply the grating fringe spacing divided by the undulation period. The cell is made from a commercial high pressure fitting and is equipped with two diamond windows for optical access. Results are presented for dilute dye/water solutions with T = 400 C and pressures between 20 and 70 MPa

  5. 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.

  6. Time-of-Flight Measurement of Sound Speed in Air

    Science.gov (United States)

    Ganci, Salvatore

    2011-01-01

    This paper describes a set of simple experiments with a very low cost using a notebook as a measuring instrument without external hardware. The major purpose is to provide demonstration experiments for schools with very low budgets. (Contains 6 figures.)

  7. Detecting interferences with iOS applications to measure speed of sound

    Science.gov (United States)

    Yavuz, Ahmet; Kağan Temiz, Burak

    2016-01-01

    Traditional experiments measuring the speed of sound consist of studying harmonics by changing the length of a glass tube closed at one end. In these experiments, the sound source and observer are outside of the tube. In this paper, we propose the modification of this old experiment by studying destructive interference in a pipe using a headset, iPhone and iPad. The iPhone is used as an emitter with signal generator application and the iPad is used as the receiver with a spectrogram application. Two experiments are carried out for measures: the emitter inside of the tube with the receiver outside, and vice versa. We conclude that it is even possible to adequately and easily measure the speed of sound using a cup or a can of coke with the method described in this paper.

  8. Measurements of anisotropic sound propagation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    2000-01-01

    to the glass wool sheets was 75 dB/m, and for propagation parallel with the sheets 57 dB/m. For mass density 30 kg/m3, the corresponding numbers were 140 and 100 dB/m. The measured values were compared with calculated ones taking into account the movements of the fiber skeleton. The calculations need...

  9. Erratum: Correction to Table 3, in: Equivalent threshold sound pressure levels (ETSPL) for Sennheiser HDA 280 supra-aural audiometric earphones in the frequency range 125 Hz to 8000 Hz (International Journal of Audiology (2009) 48 (271-276))

    DEFF Research Database (Denmark)

    Poulsen, Torben

    2014-01-01

    The main results in Poulsen & Oakley (2009) are given as the equivalent threshold sound pressure level, ETSPL, measured in an acoustic coupler specifi ed in IEC 60318-3. These results are all correct. The ETSPL values for the ear simulator specifi ed in IEC 60318-1 were calculated from acoustic...

  10. Measured wavenumber: frequency spectrum associated with acoustic and aerodynamic wall pressure fluctuations.

    Science.gov (United States)

    Arguillat, Blandine; Ricot, Denis; Bailly, Christophe; Robert, Gilles

    2010-10-01

    Direct measurements of the wavenumber-frequency spectrum of wall pressure fluctuations beneath a turbulent plane channel flow have been performed in an anechoic wind tunnel. A rotative array has been designed that allows the measurement of a complete map, 63×63 measuring points, of cross-power spectral densities over a large area. An original post-processing has been developed to separate the acoustic and the aerodynamic exciting loadings by transforming space-frequency data into wavenumber-frequency spectra. The acoustic part has also been estimated from a simple Corcos-like model including the contribution of a diffuse sound field. The measured acoustic contribution to the surface pressure fluctuations is 5% of the measured aerodynamic surface pressure fluctuations for a velocity and boundary layer thickness relevant for automotive interior noise applications. This shows that for aerodynamically induced car interior noise, both contributions to the surface pressure fluctuations on car windows have to be taken into account.

  11. Convection measurement package for space processing sounding rocket flights. [low gravity manufacturing - fluid dynamics

    Science.gov (United States)

    Spradley, L. W.

    1975-01-01

    The effects on heated fluids of nonconstant accelerations, rocket vibrations, and spin rates, was studied. A system is discussed which can determine the influence of the convective effects on fluid experiments. The general suitability of sounding rockets for performing these experiments is treated. An analytical investigation of convection in an enclosure which is heated in low gravity is examined. The gravitational body force was taken as a time-varying function using anticipated sounding rocket accelerations, since accelerometer flight data were not available. A computer program was used to calculate the flow rates and heat transfer in fluids with geometries and boundary conditions typical of space processing configurations. Results of the analytical investigation identify the configurations, fluids and boundary values which are most suitable for measuring the convective environment of sounding rockets. A short description of fabricated fluid cells and the convection measurement package is given. Photographs are included.

  12. Measurement and classification of heart and lung sounds by using LabView for educational use.

    Science.gov (United States)

    Altrabsheh, B

    2010-01-01

    This study presents the design, development and implementation of a simple low-cost method of phonocardiography signal detection. Human heart and lung signals are detected by using a simple microphone through a personal computer; the signals are recorded and analysed using LabView software. Amplitude and frequency analyses are carried out for various phonocardiography pathological cases. Methods for automatic classification of normal and abnormal heart sounds, murmurs and lung sounds are presented. Various cases of heart and lung sound measurement are recorded and analysed. The measurements can be saved for further analysis. The method in this study can be used by doctors as a detection tool aid and may be useful for teaching purposes at medical and nursing schools.

  13. The sound power measurement and certification of wind turbines

    International Nuclear Information System (INIS)

    MacKinnon, A.; Henderson, R.

    1992-01-01

    It is anticipated that there will be a substantial growth in the exploitation of renewable energy from the wind over the next few years. A major factor in this expected growth is the environmental acceptance or otherwise of wind turbines and in particular their acoustic characteristics. It is generally accepted within the turbine community that reliable methods of measuring and quantifying a turbine's acoustic signature are essential if this exploitation is to be realised. This paper will seek to review current practice both in the UK and further afield and will describe the development of a practical and reliable test method, which will aid the wind turbine Manufacturer, Developer and Planner. (author)

  14. Differential effects of suppressors on hazardous sound pressure levels generated by AR-15 rifles: Considerations for recreational shooters, law enforcement, and the military.

    Science.gov (United States)

    Lobarinas, Edward; Scott, Ryan; Spankovich, Christopher; Le Prell, Colleen G

    2016-01-01

    Firearm discharges produce hazardous levels of impulse noise that can lead to permanent hearing loss. In the present study, we evaluated the effects of suppression, ammunition, and barrel length on AR-15 rifles. Sound levels were measured left/right of a user's head, and 1-m left of the muzzle, per MIL-STD-1474-D, under both unsuppressed and suppressed conditions. Nine commercially available AR-15 rifles and 14 suppressors were used. Suppressors significantly decreased peak dB SPL at the 1-m location and the left ear location. However, under most rifle/ammunition conditions, levels remained above 140 dB peak SPL near a user's right ear. In a subset of conditions, subsonic ammunition produced values near or below 140 dB peak SPL. Overall suppression ranged from 7-32 dB across conditions. These data indicate that (1) suppressors reduce discharge levels to 140 dB peak SPL or below in only a subset of AR-15 conditions, (2) shorter barrel length and use of muzzle brake devices can substantially increase exposure level for the user, and (3) there are significant left/right ear sound pressure differences under suppressed conditions as a function of the AR-15 direct impingement design that must be considered during sound measurements to fully evaluate overall efficacy.

  15. A Balloon Sounding Technique for Measuring SO2 Plumes

    Science.gov (United States)

    Morris, Gary A.; Komhyr, Walter D.; Hirokawa, Jun; Lefer, Barry; Krotkov, Nicholay; Ngan, Fong

    2010-01-01

    This paper reports on the development of a new technique for inexpensive measurements of SO2 profiles using a modified dual-ozonesonde instrument payload. The presence of SO2 interferes with the standard electrochemical cell (ECC) ozonesonde measurement, resulting in -1 molecule of O3 reported for each molecule of SO2 present (provided [O3] > [SO2]). In laboratory tests, an SO2 filter made with Cr03 placed on the inlet side of the sonde removes nearly 100% of the SO2 present for concentrations up to 60 ppbv and remained effective after exposure to 2.8 X 10(exp 16) molecules of SO2 [equivalent to a column approximately 150 DU (1 DU = 2.69 X 10(exp 20) molecules m(exp -2))]. Flying two ECC instruments on the same payload with one filtered and the other unfiltered yields SO2 profiles, inferred by subtraction. Laboratory tests and field experience suggest an SO2 detection limit of approximately 3 pbb with profiles valid from the surface to the ozonopause [i.e., approximately (8-10 km)]. Two example profiles demonstrate the success of this technique for both volcanic and industrial plumes.

  16. Acoustics. Measurement of sound insulation in buildings and of building elements. Laboratory measurements of the reduction of transmitted impact noise by floor coverings on a heavyweight standard floor

    CERN Document Server

    British Standards Institution. London

    1998-01-01

    Acoustics. Measurement of sound insulation in buildings and of building elements. Laboratory measurements of the reduction of transmitted impact noise by floor coverings on a heavyweight standard floor

  17. Hybrid Optical Unobtrusive Blood Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Guangfei Zhang

    2017-07-01

    Full Text Available Blood pressure (BP is critical in diagnosing certain cardiovascular diseases such as hypertension. Some previous studies have proved that BP can be estimated by pulse transit time (PTT calculated by a pair of photoplethysmography (PPG signals at two body sites. Currently, contact PPG (cPPG and imaging PPG (iPPG are two feasible ways to obtain PPG signals. In this study, we proposed a hybrid system (called the ICPPG system employing both methods that can be implemented on a wearable device, facilitating the measurement of BP in an inconspicuous way. The feasibility of the ICPPG system was validated on a dataset with 29 subjects. It has been proved that the ICPPG system is able to estimate PTT values. Moreover, the PTT measured by the new system shows a correlation on average with BP variations for most subjects, which could facilitate a new generation of BP measurement using wearable and mobile devices.

  18. Intraocular pressure measurements after conductive keratoplasty.

    Science.gov (United States)

    Kymionis, George D; Naoumidi, Tatiana L; Aslanides, Ioannis M; Kumar, Vinod; Astyrakakis, Nikolaos I; Tsilimbaris, Miltiadis; Pallikaris, Ioannis G

    2005-01-01

    To determine the possible impact of conductive keratoplasty (CK) on intraocular pressure (IOP) measurements. A prospective, single-center, noncomparative interventional case series was performed. Baseline and postoperative IOPs were measured by Goldmann applanation tonometry in 32 eyes of 18 patients who underwent CK for hyperopia correction. Mean follow-up was 11.9 months (range: 8 to 18 months). After CK, a statistically significant decrease in the measured IOP was observed (before CK: 14.22+/-1.64 vs after CK: 12.66+/-2.21, P<.001). The change in IOP readings postoperatively was not correlated with age, sex, keratometric readings, or attempted correction. Despite the limitations due to the small number of patients enrolled in this study, the applanation tonometer appears to underestimate the true IOP after CK.

  19. Pressure measurement using thermal properties of materials

    International Nuclear Information System (INIS)

    Cruz Pessoa, Jose Dalton; Calbo, Adonai Gimenes

    2004-01-01

    This work presents a design and two methods, one isothermal and one isovolumetric, for pressure measurements based on the compressibility coefficient (κ) and thermal expansibility (α) of the fluid under test. The setup and relevant construction details are described. To demonstrate the applicability of the isovolumetric measurement method, the setup was calibrated with respect to a Bourdon-type manometer; the other isothermic method was analyzed to determine construction details that could realize resolution requirements. The authors determined the effect of ambient temperature on device operation and the time response of the isovolumetric method. The device can be used to estimate the compressibility of a fluid and, in addition, could become an alternative for direct plant cell turgor measurement

  20. Experimental analysis of considering the sound pressure distribution pattern at the ear canal entrance as an unrevealed head-related localization clue

    Institute of Scientific and Technical Information of China (English)

    TONG Xin; QI Na; MENG Zihou

    2018-01-01

    By analyzing the differences between binaural recording and real listening,it was deduced that there were some unrevealed auditory localization clues,and the sound pressure distribution pattern at the entrance of ear canal was probably a clue.It was proved through the listening test that the unrevealed auditory localization clues really exist with the reduction to absurdity.And the effective frequency bands of the unrevealed localization clues were induced and summed.The result of finite element based simulations showed that the pressure distribution at the entrance of ear canal was non-uniform,and the pattern was related to the direction of sound source.And it was proved that the sound pressure distribution pattern at the entrance of the ear canal carried the sound source direction information and could be used as an unrevealed localization cluc.The frequency bands in which the sound pressure distribution patterns had significant differences between front and back sound source directions were roughly matched with the effective frequency bands of unrevealed localization clues obtained from the listening tests.To some extent,it supports the hypothesis that the sound pressure distribution pattern could be a kind of unrevealed auditory localization clues.

  1. Polynomial analysis of ambulatory blood pressure measurements

    NARCIS (Netherlands)

    Zwinderman, A. H.; Cleophas, T. A.; Cleophas, T. J.; van der Wall, E. E.

    2001-01-01

    In normotensive subjects blood pressures follow a circadian rhythm. A circadian rhythm in hypertensive patients is less well established, and may be clinically important, particularly with rigorous treatments of daytime blood pressures. Polynomial analysis of ambulatory blood pressure monitoring

  2. Time-of-Flight Measurement of the Speed of Sound in a Metal Bar

    Science.gov (United States)

    Ganci, Salvatore

    2016-01-01

    A simple setup was designed for a "time-of-flight" measurement of the sound speed in a metal bar. The experiment requires low cost components and is very simple to understand by students. A good use of it is as a demonstration experiment.

  3. Artifact rejection of distortion product otoacoustic emissions measured after sound exposure

    DEFF Research Database (Denmark)

    Reuter, Karen; Ordoñez, Rodrigo Pizarro; de Toro, Miguel Angel Aranda

    2007-01-01

    In a previous study [3] distortion product otoacoustic emissions (DPOAEs) were measured both before and after a moderate sound exposure, which caused a reduction of DPOAE levels. After the exposure DPOAEs had often levels below the noise floor. In the present paper it is discussed, whether...

  4. 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…

  5. Using a High-Speed Camera to Measure the Speed of Sound

    Science.gov (United States)

    Hack, William Nathan; Baird, William H.

    2012-01-01

    The speed of sound is a physical property that can be measured easily in the lab. However, finding an inexpensive and intuitive way for students to determine this speed has been more involved. The introduction of affordable consumer-grade high-speed cameras (such as the Exilim EX-FC100) makes conceptually simple experiments feasible. Since the…

  6. Implementation and effectiveness of sound mitigation measures on Texas highways (HB 790) : final report.

    Science.gov (United States)

    2016-10-01

    The 84th Texas Legislature passed House Bill (HB) 790 directing the Texas A&M Transportation Institute (TTI) to perform a study on the implementation and effectiveness of sound mitigation measures on the state highway system and certain toll roads an...

  7. Making Ultraviolet Spectro-Polarimetry Polarization Measurements with the MSFC Solar Ultraviolet Magnetograph Sounding Rocket

    Science.gov (United States)

    West, Edward; Cirtain, Jonathan; Kobayashi, Ken; Davis, John; Gary, Allen

    2011-01-01

    This paper will describe the Marshall Space Flight Center's Solar Ultraviolet Magnetograph Investigation (SUMI) sounding rocket program. This paper will concentrate on SUMI's VUV optics, and discuss their spectral, spatial and polarization characteristics. While SUMI's first flight (7/30/2010) met all of its mission success criteria, there are several areas that will be improved for its second and third flights. This paper will emphasize the MgII linear polarization measurements and describe the changes that will be made to the sounding rocket and how those changes will improve the scientific data acquired by SUMI.

  8. Device for precision measurement of speed of sound in a gas

    Science.gov (United States)

    Kelner, Eric; Minachi, Ali; Owen, Thomas E.; Burzynski, Jr., Marion; Petullo, Steven P.

    2004-11-30

    A sensor for measuring the speed of sound in a gas. The sensor has a helical coil, through which the gas flows before entering an inner chamber. Flow through the coil brings the gas into thermal equilibrium with the test chamber body. After the gas enters the chamber, a transducer produces an ultrasonic pulse, which is reflected from each of two faces of a target. The time difference between the two reflected signals is used to determine the speed of sound in the gas.

  9. A novel method for direct localized sound speed measurement using the virtual source paradigm

    DEFF Research Database (Denmark)

    Byram, Brett; Trahey, Gregg E.; Jensen, Jørgen Arendt

    2007-01-01

    ) mediums. The inhomogeneous mediums were arranged as an oil layer, one 6 mm thick and the other 11 mm thick, on top of a water layer. To complement the phantom studies, sources of error for spatial registration of virtual detectors were simulated. The sources of error presented here are multiple sound...... registered virtual detector. Between a pair of registered virtual detectors a spherical wave is propagated. By beamforming the received data the time of flight between the two virtual sources can be calculated. From this information the local sound speed can be estimated. Validation of the estimator used...... both phantom and simulation results. The phantom consisted of two wire targets located near the transducer's axis at depths of 17 and 28 mm. Using this phantom the sound speed between the wires was measured for a homogeneous (water) medium and for two inhomogeneous (DB-grade castor oil and water...

  10. Pressure evolution of the high-frequency sound velocity in liquid water

    International Nuclear Information System (INIS)

    Krisch, M.; Sette, F.; D'Astuto, M.; Lorenzen, M.; Mermet, A.; Monaco, G.; Verbeni, R.; Loubeyre, P.; Le Toullec, R.; Ruocco, G.; Cunsolo, A.

    2002-01-01

    The high-frequency sound velocity v ∞ of liquid water has been determined to densities of 1.37 g/cm 3 by inelastic x-ray scattering. In comparison to the hydrodynamic sound velocity v 0 , the increase of v ∞ with density is substantially less pronounced, indicating that, at high density, the hydrogen-bond network is decreasingly relevant to the physical properties of liquid water. Furthermore, we observe an anomaly in v ∞ at densities around 1.12 g/cm 3 , contrasting the smooth density evolution of v 0

  11. Pressure Measurement in Supersonic Air Flow by Differential Absorptive Laser-Induced Thermal Acoustics

    Science.gov (United States)

    Hart, Roger C.; Herring, Gregory C.; Balla, Robert J.

    2007-01-01

    Nonintrusive, off-body flow barometry in Mach-2 airflow has been demonstrated in a large-scale supersonic wind tunnel using seedless laser-induced thermal acoustics (LITA). The static pressure of the gas flow is determined with a novel differential absorption measurement of the ultrasonic sound produced by the LITA pump process. Simultaneously, stream-wise velocity and static gas temperature of the same spatially-resolved sample volume were measured with this nonresonant time-averaged LITA technique. Mach number, temperature and pressure have 0.2%, 0.4%, and 4% rms agreement, respectively, in comparison with known free-stream conditions.

  12. Partial pressure measurements with an active spectrometer

    International Nuclear Information System (INIS)

    Brooks, N.H.; Jensen, T.H.; Colchin, R.J.; Maingi, R.; Wade, M.R.; Finkenthal, D.F.; Naumenko, N.; Tugarinov, S.

    1998-07-01

    Partial pressure neutral ga measurements have been made using a commercial Penning gauge in conjunction with an active spectrometer. In prior work utilizing bandpass filters and conventional spectrometers, trace concentrations of the hydrogen isotopes H, D, T and of the noble gases He, Ne and Ar were determined from characteristic spectral lines in the light emitted by the neutral species of these elements. For all the elements mentioned, the sensitivity was limited by spectral contamination from a pervasive background of molecular hydrogen radiation. The active spectrometer overcomes this limitations by means of a digital lock-in method and correlation with reference spectra. Preliminary measurements of an admixture containing a trace amount of neon in deuterium show better than a factor of 20 improvement in sensitivity over conventional techniques. This can be further improved by correlating the relative intensities of multiple lines to sets of reference spectra

  13. Continuous Sound Velocity Measurements along the Shock Hugoniot Curve of Quartz

    Science.gov (United States)

    Li, Mu; Zhang, Shuai; Zhang, Hongping; Zhang, Gongmu; Wang, Feng; Zhao, Jianheng; Sun, Chengwei; Jeanloz, Raymond

    2018-05-01

    We report continuous measurements of the sound velocity along the principal Hugoniot curve of α quartz between 0.25 and 1.45 TPa, as determined from lateral release waves intersecting the shock front as a function of time in decaying-shock experiments. The measured sound velocities are lower than predicted by prior models, based on the properties of stishovite at densities below ˜7 g /cm3 , but agree with density functional theory molecular dynamics calculations and an empirical wide-regime equation of state presented here. The Grüneisen parameter calculated from the sound velocity decreases from γ ˜1 .3 at 0.25 TPa to 0.66 at 1.45 TPa. In combination with evidence for increased (configurational) specific heat and decreased bulk modulus, the values of γ suggest a high thermal expansion coefficient at ˜0. 25 - 0 .65 TPa , where SiO2 is thought to be a bonded liquid. From our measurements, dissociation of the molecular bonds persists to ˜0. 65 - 1 .0 TPa , consistent with estimates by other methods. At higher densities, the sound velocity is close to predictions from previous models, and the Grüneisen parameter approaches the ideal gas value.

  14. Precision measurement of the speed of sound and thermodynamic properties of gases

    International Nuclear Information System (INIS)

    Benedetto, G.; Gavioso, R.M.; Spagnolo, R.

    1999-01-01

    The speed of sound in pure fluids and mixtures is a characteristic and important physical propriety which depends of several intensive thermodynamic variables. This fact indicates that it can be calculated using the appropriate thermodynamic properties of the fluid. Alternatively, experimental evaluation of the speed of sound can be used to determine several fundamental thermophysical properties. Recently, very accurate measurements of the speed of sound in dilute gases have found relevant applications: 1) the last experimental determinations of the value of the universal gas constant R, by measurements in argon, at the triple point of water (1,2); 2) revision of the thermodynamic temperature scales in different temperature ranges (3-5); 3) derivation of the state of many pure gases, which includes methane, helium and ethylene (6-7); 4)determination of the heat capacities and densities of pure gases and mixture (8-16). The aim of this paper is to provide an extensive review of the measurement of the speed of sound in gases and of its theoretical basis, giving prominence to the relevant metrological aspects involved in the determination of this physical quantity

  15. On-line pressure measurement using scanning systems

    International Nuclear Information System (INIS)

    Morss, A.G.; Watson, A.P.

    1978-08-01

    Data collection methods can be improved significantly by using pressure scanning systems in conjunction with transducers for the measurement of pressure distribution in fluid flow rigs. However, the response of pressure transducers to the slight random pressure fluctuations that occur in practice can cause some measurement problems, especially for accurate work. The nature of these pressure fluctuations is examined and suitable analysis techniques are recommended. Results obtained using these techniques are presented. It is concluded that by using the correct techniques pressure transducer systems can be used to measure pressure distributions accurately and are sufficiently sensitive to measure very small systematic effects with great precision. (author)

  16. NIS method for uncertainty estimation of airborne sound insulation measurement in field

    Directory of Open Access Journals (Sweden)

    El-Basheer Tarek M.

    2017-01-01

    Full Text Available In structures, airborne sound insulation is utilized to characterize the acoustic nature of barriers between rooms. However, the assessment of sound insulation index is once in a while troublesome or indeed, even questionable, both in field and laboratory measurements, notwithstanding the way that there are some unified measurement methodology indicated in the ISO 140 series standards. There are issues with the reproducibility and repeatability of the measurement results. A few troubles might be brought on by non-diffuse acoustic fields, non-uniform reverberation time, or blunders of the reverberation time measurements. Some minor issues are additionally postured by flanking transmission. In this paper, investigation of the uncertainties of the above specified measurement parts and their impact on the consolidated uncertainty in 1/3-octave frequency band. The total measurement uncertainty model contributes several different partial uncertainties, which are evaluated by the method of type A or type B. Also, the determination of the sound reduction index decided by ISO 140-4 has been performed.

  17. High-pressure behavior of amorphous selenium from ultrasonic measurements and Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    He, Z.; Liu, X. R.; Hong, S. M., E-mail: hpswjtu@gmail.com, E-mail: smhong@home.swjtu.edu.cn [Laboratory of High Pressure Physics, Southwest Jiaotong University, Key Laboratory of Advanced Technologies of Materials, Ministry of Education of China, Chengdu 610031 (China); Wang, Z. G. [National Key Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Zhu, H. Y. [State Key Laboratory of Superhard Materials, Jilin University, Changchun 130012 (China); Peng, J. P. [School of Physical Science and Technology, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-07-07

    The high-pressure behavior of melt-quenched amorphous selenium (a-Se) has been investigated via ultrasonic measurements and Raman scattering at room temperature. The ultrasonic measurements were conducted on a-Se in a multi-anvil apparatus with two different sample assemblies at pressures of up to 4.5 and 4.8 GPa. We discovered that similar kinks occur in the slopes of the pressure dependence characteristics of the travel time and the sound velocity in both shear and longitudinal waves in the 2.0–2.5 GPa range. These kinks are independent of the sample assemblies, indicating an intrinsic transformation of the a-Se. Additionally, we deduced the pressure-volume relationship of a-Se from the sound velocity characteristics using the Birch–Murnaghan equation of state, and the results agreed well with those of previous reports. In situ high-pressure Raman scattering measurements of a-Se were conducted in a diamond anvil cell with an 830 nm excitation line up to a pressure of 4.3 GPa. We found that the characteristic band of a-Se at ∼250 cm{sup −1} experienced a smooth shift to a lower frequency with pressure, but a sharp slope change in the band intensity versus pressure occurred near 2.5 GPa. The results of X-ray diffraction and differential scanning calorimetry measurements indicate that the samples remain in their amorphous states after decompression. Thus, we proposed that the abnormal compression behavior of a-Se in the 2.0–2.5 GPa range can be attributed to pressure-induced local atomic reconfiguration, implying an amorphous-amorphous transition of the elementary selenium.

  18. Development and optimization of a device for diferencial pressure measurement

    International Nuclear Information System (INIS)

    Santarine, G.A.

    1980-01-01

    The measurements of reduced values of diferencial pressure, are studied. Several situations are described where the diferencial pressure accurate measurement is necessary in routine works in the Thermohydraulic Laboratory, as well as, the major pressure measurement devices and their respective range are studied. The development of a device for diferencial pressure measurement followed by the design development of the calibration bench covering the foreseen range, start up tests realization, optimization, calibration, performance analysis and conclusions, is showed. (Author) [pt

  19. Nonlinear parameter (B/A) measurements in methanol, 1-butanol and 1-octanol for different pressures and temperatures

    International Nuclear Information System (INIS)

    Plantier, F.; Daridon, J.L.; Lagourette, B.

    2002-01-01

    Experimental determinations versus pressure of the nonlinear acoustic parameter B/A have been conducted for methanol, 1-butanol and 1-octanol in the pressure range 0-50 MPa and temperature range 303.15-373.15 K. These measurements proceed from an experimental technique based on a phase comparison method allowing to measure the change in sound speed with the pressure for an isentropic process. The value of B/A is found to decrease with increasing pressure and seems to be an increasing function of temperature. A comparison with the data determined numerically by the classical thermodynamic method has also been performed. (author)

  20. Numerical simulation of aerodynamic sound radiated from a two-dimensional airfoil

    OpenAIRE

    飯田, 明由; 大田黒, 俊夫; 加藤, 千幸; Akiyoshi, Iida; Toshio, Otaguro; Chisachi, Kato; 日立機研; 日立機研; 東大生研; Mechanical Engineering Research Laboratory, Hitachi Ltd.; Mechanical Engineering Research Laboratory, Hitachi Ltd.; University of Tokyo

    2000-01-01

    An aerodynamic sound radiated from a two-dimensional airfoil has been computed with the Lighthill-Curle's theory. The predicted sound pressure level is agreement with the measured one. Distribution of vortex sound sources is also estimated based on the correlation between the unsteady vorticity fluctuations and the aerodynamic sound. The distribution of vortex sound source reveals that separated shear layers generate aerodynamic sound. This result is help to understand noise reduction method....

  1. 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...

  2. A Model for the prediction of Sound Levels within a Symphonic Orchestra based on measured Sound Strength

    NARCIS (Netherlands)

    Wenmaekers, R.H.C.; Hak, C.C.J.M.; Luxemburg, van L.C.J.

    2011-01-01

    Members and directors of symphonic orchestras are concerned about the noise levels musicians are exposed to and their ease of playing ensemble. The results of many research has shown that the noise levels within an orchestra can be high. Also, research has shown that the sound level will vary

  3. Organic Electroluminescent Sensor for Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Tomohide Niimi

    2012-10-01

    Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

  4. 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…

  5. A pressure plate study on fore and hindlimb loading and the association with hoof contact area in sound ponies at the walk and trot.

    Science.gov (United States)

    Oosterlinck, M; Pille, F; Back, W; Dewulf, J; Gasthuys, F

    2011-10-01

    The aim of this study was to evaluate the association between fore- and hind-hoof contact area and limb loading. Data from a previous study on forelimb loading and symmetry were compared with data on hindlimb kinetics, and the fore- and hind-hoof contact area at the walk and trot was evaluated. Five sound ponies, selected for symmetrical feet, were walked and trotted over a pressure plate embedded in a custom-made runway. The hindlimb peak vertical force (PVF) and vertical impulse (VI) were found to be significantly lower than in the forelimb, whereas their high symmetry ratios (>95%) did not show a significant difference from forelimb data. Hindlimb PVF in ponies was found to be slightly higher when compared to data reported for horses even though the ponies moved at a similar or lower relative velocity. The contact area had low intra-individual variability and was significantly smaller in the hind- than in the fore-hooves. A larger contact area was significantly associated with lower peak vertical pressure (PVP) but higher PVF and VI. No significant differences between left and right sides were found for contact area or loading variables. Pressure plate measurements demonstrated a significant association between hoof contact area and limb loading, in addition to intrinsic differences between fore and hindlimb locomotor function. The pressure plate provides the clinician with a tool to quantify simultaneously contralateral differences in hoof contact area and limb loading. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Blood Pressure Measurement: Clinic, Home, Ambulatory, and Beyond

    Science.gov (United States)

    Drawz, Paul E.; Abdalla, Mohamed; Rahman, Mahboob

    2014-01-01

    Blood pressure has traditionally been measured in the clinic setting using the auscultory method and a mercury sphygmomanometer. Technological advances have led to improvements in measuring clinic blood pressure and allowed for measuring blood pressures outside the clinic. This review outlines various methods for evaluating blood pressure and the clinical utility of each type of measurement. Home blood pressures and 24 hour ambulatory blood pressures have improved our ability to evaluate risk for target organ damage and hypertension related morbidity and mortality. Measuring home blood pressures may lead to more active participation in health care by patients and has the potential to improve blood pressure control. Ambulatory blood pressure monitoring enables the measuring nighttime blood pressures and diurnal changes, which may be the most accurate predictors of risk associated with elevated blood pressure. Additionally, reducing nighttime blood pressure is feasible and may be an important component of effective antihypertensive therapy. Finally, estimating central aortic pressures and pulse wave velocity are two of the newer methods for assessing blood pressure and hypertension related target organ damage. PMID:22521624

  7. Hyperacusis Questionnaire as a Tool for Measuring Hypersensitivity to Sound in a Tinnitus Research Population

    Directory of Open Access Journals (Sweden)

    Kathryn Fackrell

    2015-01-01

    Full Text Available Hypersensitivity to external sounds is often comorbid with tinnitus and may be significant for adherence to certain types of tinnitus management. Therefore, a clear measure of sensitivity to sound is important. The aim of this study was to evaluate the validity and reliability of the Hyperacusis Questionnaire (HQ for use as a measurement tool using data from a sample of 264 adults who took part in tinnitus research. We evaluated the HQ factor structure, internal consistency, convergent and discriminant validity, and floor and ceiling effects. Internal consistency was high (Cronbach’s alpha = 0.88 and moderate correlations were observed between the HQ, uncomfortable loudness levels, and other health questionnaires. Confirmatory factor analysis revealed that the original HQ three-factor solution and a one-factor solution were both a poor fit to the data. Four problematic items were removed and exploratory factor analysis identified a two-factor (attentional and social solution. The original three-factor structure of the HQ was not confirmed. All fourteen items do not accurately assess hypersensitivity to sound in a tinnitus population. We propose a 10-item (2-factor version of the HQ, which will need to be confirmed using a new tinnitus and perhaps nontinnitus population.

  8. Hyperacusis Questionnaire as a Tool for Measuring Hypersensitivity to Sound in a Tinnitus Research Population.

    Science.gov (United States)

    Fackrell, Kathryn; Fearnley, Constance; Hoare, Derek J; Sereda, Magdalena

    2015-01-01

    Hypersensitivity to external sounds is often comorbid with tinnitus and may be significant for adherence to certain types of tinnitus management. Therefore, a clear measure of sensitivity to sound is important. The aim of this study was to evaluate the validity and reliability of the Hyperacusis Questionnaire (HQ) for use as a measurement tool using data from a sample of 264 adults who took part in tinnitus research. We evaluated the HQ factor structure, internal consistency, convergent and discriminant validity, and floor and ceiling effects. Internal consistency was high (Cronbach's alpha = 0.88) and moderate correlations were observed between the HQ, uncomfortable loudness levels, and other health questionnaires. Confirmatory factor analysis revealed that the original HQ three-factor solution and a one-factor solution were both a poor fit to the data. Four problematic items were removed and exploratory factor analysis identified a two-factor (attentional and social) solution. The original three-factor structure of the HQ was not confirmed. All fourteen items do not accurately assess hypersensitivity to sound in a tinnitus population. We propose a 10-item (2-factor) version of the HQ, which will need to be confirmed using a new tinnitus and perhaps nontinnitus population.

  9. Measurement of sound velocity made easy using harmonic resonant frequencies with everyday mobile technology

    Science.gov (United States)

    Hirth, Michael; Kuhn, Jochen; Müller, Andreas

    2015-02-01

    Recent articles about smartphone experiments have described their applications as experimental tools in different physical contexts.1-4 They have established that smartphones facilitate experimental setups, thanks to the small size and diverse functions of mobile devices, in comparison to setups with computer-based measurements. In the experiment described in this article, the experimental setup is reduced to a minimum. The objective of the experiment is to determine the speed of sound with a high degree of accuracy using everyday tools. An article published recently proposes a time-of-flight method where sound or acoustic pulses are reflected at the ends of an open tube.5 In contrast, the following experiment idea is based on the harmonic resonant frequencies of such a tube, simultaneously triggered by a noise signal.

  10. 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....

  11. 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....

  12. Sensing line effects on PWR-based differential pressure measurements

    International Nuclear Information System (INIS)

    Evans, R.P.; Neff, G.G.

    1982-01-01

    An incorrrect configuration of the fluid-filled pressure sensing lines connecting differential pressure transducers to the pressure taps in a pressurized water reactor system can cause errors in the measurement and, during rapid pressure transients, could cause the transducer to fail. Testing was performed in both static and dynamic modes to experimentally determine the effects of sensing lines of various lengths, diameters, and materials. Testing was performed at ambient temperature with absolute line pressures at about 17 MPa using water as the pressure transmission fluid

  13. Auscultatory versus oscillometric measurement of blood pressure in octogenarians

    DEFF Research Database (Denmark)

    Rosholm, Jens-Ulrik; Pedersen, Sidsel Arnspang; Matzen, Lars

    2012-01-01

    Auscultatory measurement using a sphygmomanometer has been the predominant method for clinical estimation of blood pressure, but it is now rapidly being replaced by oscillometric measurement.......Auscultatory measurement using a sphygmomanometer has been the predominant method for clinical estimation of blood pressure, but it is now rapidly being replaced by oscillometric measurement....

  14. Blood pressure measurements in the ankle are not equivalent to blood pressure measurements in the arm.

    Science.gov (United States)

    Goldstein, Lara Nicole; Wells, Mike; Sliwa, Karen

    2014-07-25

    Blood pressure (BP) is often measured on the ankle in the emergency department (ED), but this has never been shown to be an acceptable alternative to measurements performed on the arm. To establish whether the differences between arm and ankle non-invasive BP measurements were clinically relevant (i.e. a difference of ≥10 mmHg). This was a prospective cross-sectional study in an urban ED making use of a convenience sample of 201 patients (18 - 50 years of age) who were not in need of emergency medical treatment. BP was measured in the supine position on both arms and ankles with the correct size cuff according to the manufacturer's guidelines. The arm and ankle BP measurements were compared. There was a clinically and statistically significant difference between arm and ankle systolic BP (SBP) and mean arterial pressure (MAP) (-13 mmHg, 95% confidence interval (CI) -28 - 1 mmHg and -5 mmHg, 95% CI -13 - 4 mmHg, respectively), with less difference in diastolic BP (DBP) (2 mmHg, 95% CI -7 - 10 mmHg). Only 37% of SBP measurements and 83% of MAP measurements were within an error range of 10 mmHg, while 95% of DBP measurements agreed within 10 mmHg. While the average differences (or the bias) were generally not large, large variations in individual patients (indicating poor precision) made the prediction of arm BP from ankle measurements unreliable. Ankle BP cannot be used as a substitute for arm BP in the ED.

  15. Pressure-driven sound turbulence in a high-β plasma

    International Nuclear Information System (INIS)

    Stenzel, R.L.

    1990-01-01

    In a large laboratory plasma [1 m diamx2 m, n e ≤10 12 cm -3 , β 0 ≅15 G, β e =nkT e /(β 0 2 /2μ 0 )≅0.5], strong density fluctuations (δn/n≅50%) near the lower hybrid frequency (ω ce ω ci ) 1/2 are identified as cross-field sound waves (k perpendicular much-gt k parallel , ω/k perpendicular ≅c s ) driven unstable by the electron diamagnetic drift v d =∇pxB/neβ 2 , v d >c s . Wave steepening and refraction saturate the instability. Wave-enhanced transport but insignificant particle acceleration are observed

  16. A sound pressure field during the quenching of a steel specimen in different water solutions

    Directory of Open Access Journals (Sweden)

    J. Prezelj

    2011-01-01

    Full Text Available The purpose of controlling the quenching process of an orange-hot steel workpiece is to ensure its required surface hardness. A sound in a cooling liquid generated by the quenching process was experimentally analyzed. It contains sufficient information about the ongoing process for its quantification, and it can be used in real time. Traditionally, the quenching and the resultant hardening can be controlled by selecting different process parameters, like, for example the characteristics of the cooling liquid, the velocity of the cooling liquid flow, its temperature, the temperature of the work-piece, and many others. The possibility of controlling the quenching process by using acoustic cavitation is considered in this article.

  17. Sound quality assessment of Diesel combustion noise using in-cylinder pressure components

    Science.gov (United States)

    Payri, F.; Broatch, A.; Margot, X.; Monelletta, L.

    2009-01-01

    The combustion process in direct injection (DI) Diesel engines is an important source of noise, and it is thus the main reason why end-users could be reluctant to drive vehicles powered with this type of engine. This means that the great potential of Diesel engines for environment preservation—due to their lower consumption and the subsequent reduction of CO2 emissions—may be lost. Moreover, the advanced combustion concepts—e.g. the HCCI (homogeneous charge compression ignition)—developed to comply with forthcoming emissions legislation, while maintaining the efficiency of current engines, are expected to be noisier because they are characterized by a higher amount of premixed combustion. For this reason many efforts have been dedicated by car manufacturers in recent years to reduce the overall level and improve the sound quality of engine noise. Evaluation procedures are required, both for noise levels and sound quality, that may be integrated in the global engine development process in a timely and cost-effective manner. In previous published work, the authors proposed a novel method for the assessment of engine noise level. A similar procedure is applied in this paper to demonstrate the suitability of combustion indicators for the evaluation of engine noise quality. These indicators, which are representative of the peak velocity of fuel burning and the resonance in the combustion chamber, are well correlated with the combustion noise mark obtained from jury testing. Quite good accuracy in the prediction of the engine noise quality has been obtained with the definition of a two-component regression, which also permits the identification of the combustion process features related to the resulting noise quality, so that corrective actions may be proposed.

  18. Measuring N2 Pressure Using Cyanobacteria

    Science.gov (United States)

    Silverman, S. N.; Kopf, S.; Gordon, R.; Bebout, B.; Som, S.

    2017-11-01

    We have shown that cyanobacteria can record information about N2 partial pressure both morphologically and isotopically, and thus may serve as useful geobarometers to help us better understand Earth's ancient atmosphere.

  19. Music and language expertise influence the categorization of speech and musical sounds: behavioral and electrophysiological measurements.

    Science.gov (United States)

    Elmer, Stefan; Klein, Carina; Kühnis, Jürg; Liem, Franziskus; Meyer, Martin; Jäncke, Lutz

    2014-10-01

    In this study, we used high-density EEG to evaluate whether speech and music expertise has an influence on the categorization of expertise-related and unrelated sounds. With this purpose in mind, we compared the categorization of speech, music, and neutral sounds between professional musicians, simultaneous interpreters (SIs), and controls in response to morphed speech-noise, music-noise, and speech-music continua. Our hypothesis was that music and language expertise will strengthen the memory representations of prototypical sounds, which act as a perceptual magnet for morphed variants. This means that the prototype would "attract" variants. This so-called magnet effect should be manifested by an increased assignment of morphed items to the trained category, by a reduced maximal slope of the psychometric function, as well as by differential event-related brain responses reflecting memory comparison processes (i.e., N400 and P600 responses). As a main result, we provide first evidence for a domain-specific behavioral bias of musicians and SIs toward the trained categories, namely music and speech. In addition, SIs showed a bias toward musical items, indicating that interpreting training has a generic influence on the cognitive representation of spectrotemporal signals with similar acoustic properties to speech sounds. Notably, EEG measurements revealed clear distinct N400 and P600 responses to both prototypical and ambiguous items between the three groups at anterior, central, and posterior scalp sites. These differential N400 and P600 responses represent synchronous activity occurring across widely distributed brain networks, and indicate a dynamical recruitment of memory processes that vary as a function of training and expertise.

  20. Detection of small-amplitude periodic surface pressure fluctuation by pressure-sensitive paint measurements using frequency-domain methods

    Science.gov (United States)

    Noda, Takahiro; Nakakita, Kazuyki; Wakahara, Masaki; Kameda, Masaharu

    2018-06-01

    Image measurement using pressure-sensitive paint (PSP) is an effective tool for analyzing the unsteady pressure field on the surface of a body in a low-speed air flow, which is associated with wind noise. In this study, the surface pressure fluctuation due to the tonal trailing edge (TE) noise for a two-dimensional NACA 0012 airfoil was quantitatively detected using a porous anodized aluminum PSP (AA-PSP). The emission from the PSP upon illumination by a blue laser diode was captured using a 12-bit high-speed complementary metal-oxide-semiconductor (CMOS) camera. The intensities of the captured images were converted to pressures using a standard intensity-based method. Three image-processing methods based on the fast Fourier transform (FFT) were tested to determine their efficiency in improving the signal-to-noise ratio (SNR) of the unsteady PSP data. In addition to two fundamental FFT techniques (the full data and ensemble averaging FFTs), a technique using the coherent output power (COP), which involves the cross correlation between the PSP data and the signal measured using a pointwise sound-level meter, was tested. Preliminary tests indicated that random photon shot noise dominates the intensity fluctuations in the captured PSP emissions above 200 Hz. Pressure fluctuations associated with the TE noise, whose dominant frequency is approximately 940 Hz, were successfully measured by analyzing 40,960 sequential PSP images recorded at 10 kfps. Quantitative validation using the power spectrum indicates that the COP technique is the most effective method of identification of the pressure fluctuation directly related to TE noise. It is possible to distinguish power differences with a resolution of 10 Pa^2 (4 Pa in amplitude) when the COP was employed without use of another wind-off data. This resolution cannot be achieved by the ensemble averaging FFT because of an insufficient elimination of the background noise.

  1. Ionic conductivity measurements of zirconia under pressure using impedance spectroscopy

    International Nuclear Information System (INIS)

    Takebe, H; Sakamoto, D; Ohtaka, O; Fukui, H; Yoshiasa, A; Yamanaka, T; Ota, K; Kikegawa, T

    2002-01-01

    We have set up an electrical conductivity measurement system under high-pressure and high-temperature conditions with a multi-anvil high-pressure apparatus using an AC complex impedance method. With this system, we have successfully measured the electrical conductivity of stabilized ZrO 2 (Y 2 O 3 -ZrO 2 solid solution) under pressures up to 5 GPa in the temperature range from 300 to 1200 K. The electrical conductivities obtained under pressure are compatible with those of previous results measured at ambient pressure

  2. Evaluation of Routine Atmospheric Sounding Measurements Using Unmanned Systems (ERASMUS) Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    de Boer, Gijs [Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences (CIRES); Lawrence, Dale [Univ. of Colorado, Boulder, CO (United States); Palo, Scott [Univ. of Colorado, Boulder, CO (United States); Argrow, Brian [Univ. of Colorado, Boulder, CO (United States); LoDolce, Gabriel [Univ. of Colorado, Boulder, CO (United States); Curry, Nathan [Univ. of Colorado, Boulder, CO (United States); Weibel, Douglas [Univ. of Colorado, Boulder, CO (United States); Finnamore, W [Univ. of Colorado, Boulder, CO (United States); D' Amore, P [Univ. of Colorado, Boulder, CO (United States); Borenstein, Steven [Univ. of Colorado, Boulder, CO (United States); Nichols, Tevis [Univ. of Colorado, Boulder, CO (United States); Elston, Jack [Blackswift Technologies, Boulder, CO (United States); Ivey, Mark [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bendure, Al [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schmid, Beat [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Long, Chuck [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Telg, Hagen [Univ. of Colorado, Boulder, CO (United States). Cooperative Inst. for Research in Environmental Sciences (CIRES); Gao, Rushan [National Oceanic and Atmospheric Administration (NOAA), Boulder, CO (United States). Earth System Research Lab.; Hock, T [National Center for Atmospheric Research, Boulder, CO (United States); Bland, Geoff [National Aeronautics and Space Administration (NASA), Washington, DC (United States)

    2017-03-01

    The Evaluation of Routine Atmospheric Sounding Measurements using Unmanned Systems (ERASMUS) campaign was proposed with two central goals; to obtain scientifically relevant measurements of quantities related to clouds, aerosols, and radiation, including profiles of temperature, humidity, and aerosol particles, the structure of the arctic atmosphere during transitions between clear and cloudy states, measurements that would allow us to evaluate the performance of retrievals from U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility remote sensors in the Arctic atmosphere, and information on the spatial variability of heat and moisture fluxes from the arctic surface; and to demonstrate unmanned aerial system (UAS) capabilities in obtaining measurements relevant to the ARM and ASR programs, particularly for improving our understanding of Arctic clouds and aerosols.

  3. Automated measurement of pressure injury through image processing.

    Science.gov (United States)

    Li, Dan; Mathews, Carol

    2017-11-01

    To develop an image processing algorithm to automatically measure pressure injuries using electronic pressure injury images stored in nursing documentation. Photographing pressure injuries and storing the images in the electronic health record is standard practice in many hospitals. However, the manual measurement of pressure injury is time-consuming, challenging and subject to intra/inter-reader variability with complexities of the pressure injury and the clinical environment. A cross-sectional algorithm development study. A set of 32 pressure injury images were obtained from a western Pennsylvania hospital. First, we transformed the images from an RGB (i.e. red, green and blue) colour space to a YC b C r colour space to eliminate inferences from varying light conditions and skin colours. Second, a probability map, generated by a skin colour Gaussian model, guided the pressure injury segmentation process using the Support Vector Machine classifier. Third, after segmentation, the reference ruler - included in each of the images - enabled perspective transformation and determination of pressure injury size. Finally, two nurses independently measured those 32 pressure injury images, and intraclass correlation coefficient was calculated. An image processing algorithm was developed to automatically measure the size of pressure injuries. Both inter- and intra-rater analysis achieved good level reliability. Validation of the size measurement of the pressure injury (1) demonstrates that our image processing algorithm is a reliable approach to monitoring pressure injury progress through clinical pressure injury images and (2) offers new insight to pressure injury evaluation and documentation. Once our algorithm is further developed, clinicians can be provided with an objective, reliable and efficient computational tool for segmentation and measurement of pressure injuries. With this, clinicians will be able to more effectively monitor the healing process of pressure

  4. Unsteady pressures on a blunt trailing edge measured with an embedded pressure scanner

    Science.gov (United States)

    Naughton, Jonathan; Nikoueeyan, Pourya; Hind, Michael; Strike, John; Dahland, Matz; Keeter, Steven

    2017-11-01

    Development of direct-mount pressure scanners can decrease the pneumatic tubing length required to connect the measurement ports to the scanner manifold resulting in improved dynamic range for unsteady pressure measurements. In this work, the performance of a direct-mount pressure scanner for time-resolved pressure measurement is demonstrated in a well-established flow; the pressure fluctuations near the base of flat plate is considered. The additive manufactured model is instrumented with a pressure scanner and flush-mounted high-speed pressure transducers. The configuration of the ports on the model allows for side-by-side comparison of the pressures measured via embedded pneumatic tubing routed to a pressure scanner with that measured by high-speed transducers. Prior to testing, the dynamic response of each embedded pressure port is dynamically calibrated via an in-situ calibration technique. Pressure data is then acquired for fixed angle-of-attack and different dynamic pitching conditions. The dynamic range of the measurements acquired via direct-mount scanner will be compared to those acquired by the high speed transducers for both static and dynamic pitching configurations. The uncertainties associated with Weiner deconvolution are also quantified for the measurements.

  5. On the theory of SODAR measurement techniques[SOund Detection And Ranging

    Energy Technology Data Exchange (ETDEWEB)

    Antoniou, I.; Joergensen, H.E. [Risoe National Lab. (Denmark); Ormel, F. [Energy Research Center of the Netherlands (Netherlands); Bradley, S.; Huenerbein, S. von [University of Salford (United Kingdom); Emeis, S. [Forschungszentrum Karlsruhe GmbH (Germany); Warmbier, G. [GWU-Umwelttechnik Gmbh (Germany)

    2003-04-01

    The need for alternative means to measure the wind speed for wind energy purposes has increased with the increase of the size of wind turbines. The cost and the technical difficulties for performing wind speed measurements has also increased with the size of the wind turbines, since it is demanded that the wind speed has to be measured at the rotor centre of the turbine and the size of both the rotor and the hub height have grown following the increase in the size of the wind turbines. The SODAR (SOund Detection And Ranging) is an alternative to the use of cup anemometers and offers the possibility of measuring both the wind speed distribution with height and the wind direction. At the same time the SODAR presents a number of serious drawbacks such as the low number of measurements per time period, the dependence of the ability to measure on the atmospheric conditions and the difficulty of measuring at higher wind speeds due to either background noise or the neutral condition of the atmosphere. Within the WISE project (EU project number NNE5-2001-297), a number of work packages have been defined in order to deal with the SODAR. The present report is the result of the work package 1. Within this package the objective has been to present and achieve the following: 1) An accurate theoretic model that describes all the relevant aspects of the interaction of the sound beam with the atmosphere in the level of detail needed for wind energy applications. 2) Understanding of dependence of SODAR performance on hard- and software configuration. 3) Quantification of principal difference between SODAR wind measurement and wind speed measurements with cup anemometers with regard to power performance measurements.

  6. Acoustical measurements of sound fields between the stage and the orchestra pit inside an historical opera house

    Science.gov (United States)

    Sato, Shin-Ichi; Prodi, Nicola; Sakai, Hiroyuki

    2004-05-01

    To clarify the relationship of the sound fields between the stage and the orchestra pit, we conducted acoustical measurements in a typical historical opera house, the Teatro Comunale of Ferrara, Italy. Orthogonal factors based on the theory of subjective preference and other related factors were analyzed. First, the sound fields for a singer on the stage in relation to the musicians in the pit were analyzed. And then, the sound fields for performers in the pit in relation to the singers on the stage were considered. Because physical factors vary depending on the location of the sound source, performers can move on the stage or in the pit to find the preferred sound field.

  7. Various high precision measurements of pressure in atomic energy industry

    International Nuclear Information System (INIS)

    Aritomi, Masanori; Inoue, Akira; Hosoma, Takashi; Tanaka, Izumi; Gabane, Tsunemichi.

    1987-01-01

    As for the pressure measurement in atomic energy industry, it is mostly the measurement using differential pressure transmitters and pressure transmitters for process measurement with the general accuracy of measurement of 0.2 - 0.5 % FS/year. However, recently for the development of nuclear fusion reactors and the establishment of nuclear fuel cycle accompanying new atomic energy technology, there are the needs of the pressure measurement having higher accuracy of 0.01 % FS/year and high resolution, and quartz vibration type pressure sensors appeared. New high accuracy pressure measurement techniques were developed by the advance of data processing and the rationalization of data transmission. As the results, the measurement of the differential pressure of helium-lithium two-phase flow in the cooling system of nuclear fusion reactors, the high accuracy measuring system for the level of plutonium nitrate and other fuel substance in tanks in fuel reprocessing and conversion, the high accuracy measurement of atmospheric pressure and wind velocity in ducts, chimneys and tunnels in nuclear facilities and so on became feasible. The principle and the measured data of quartz vibration type pressure sensors are shown. (Kako, I.)

  8. Acoustic sensor for remote measuring of pressure

    Directory of Open Access Journals (Sweden)

    Kataev V. F.

    2008-04-01

    Full Text Available The paper deals with sensors based on delay lines on surface acoustic waves (SAW, having a receiving-emitting and a reflective interdigital transducers (IDT. The dependence of the reflection coefficient of SAW on type and intensity of the load was studied. The authors propose a composite delay line in which the phase of the reflection coefficient depends on the pressure. Pressure leads to a shift of the reflective IDT relative to the transceiver, because they are located on different substrates. The paper also presents functional diagrams of the interrogator.

  9. Measuring infrared contributions to the QCD pressure

    CERN Document Server

    Kajantie, Keijo; Rummukainen, K; Schröder, Y

    2002-01-01

    For the pressure (or free energy) of QCD, four-dimensional (4d) lattice data is available at zero baryon density up to a few times the critical temperature $T_c$. Perturbation theory, on the other hand, has serious convergence problems even at very high temperatures. In a combined analytical and three-dimensional (3d) lattice method, we show that it is possible to compute the QCD pressure from about $2 T_c$ to infinity. The numerical accuracy is good enough to resolve in principle, e.g., logarithmic contributions related to 4-loop perturbation theory.

  10. Pressure field in measurement section of wind tunnel

    Directory of Open Access Journals (Sweden)

    Hnidka Jakub

    2017-01-01

    Full Text Available The University of Defence in Brno has a new low-speed wind tunnel. In order to confirm the quality of the wind inside of the measurement section, several measurements of the dynamic pressure have been performed with the Pitot-static tube. The pressure fields are then analysed and quality of the field is evaluated. Measurement of a pressure drop on the body of a standing helicopter was conducted.

  11. High levels of sound pressure: acoustic reflex thresholds and auditory complaints of workers with noise exposure

    Directory of Open Access Journals (Sweden)

    Alexandre Scalli Mathias Duarte

    2015-08-01

    Full Text Available INTRODUCTION: The clinical evaluation of subjects with occupational noise exposure has been difficult due to the discrepancy between auditory complaints and auditory test results. This study aimed to evaluate the contralateral acoustic reflex thresholds of workers exposed to high levels of noise, and to compare these results to the subjects' auditory complaints.METHODS: This clinical retrospective study evaluated 364 workers between 1998 and 2005; their contralateral acoustic reflexes were compared to auditory complaints, age, and noise exposure time by chi-squared, Fisher's, and Spearman's tests.RESULTS: The workers' age ranged from 18 to 50 years (mean = 39.6, and noise exposure time from one to 38 years (mean = 17.3. We found that 15.1% (55 of the workers had bilateral hearing loss, 38.5% (140 had bilateral tinnitus, 52.8% (192 had abnormal sensitivity to loud sounds, and 47.2% (172 had speech recognition impairment. The variables hearing loss, speech recognition impairment, tinnitus, age group, and noise exposure time did not show relationship with acoustic reflex thresholds; however, all complaints demonstrated a statistically significant relationship with Metz recruitment at 3000 and 4000 Hz bilaterally.CONCLUSION: There was no significance relationship between auditory complaints and acoustic reflexes.

  12. Ultrasound Characterization of Microbead and Cell Suspensions by Speed of Sound Measurements of Neutrally Buoyant Samples

    DEFF Research Database (Denmark)

    Cushing, Kevin W.; Garofalo, Fabio; Magnusson, Cecilia

    2017-01-01

    . The density of the microparticles is determined by using a neutrally buoyant selection process that involves centrifuging of microparticles suspended in different density solutions, CsCl for microbeads and Percoll for cells. The speed of sound at 3 MHz in the neutrally buoyant suspensions is measured...... and fixed cells, such as red blood cells, white blood cells, DU-145 prostate cancer cells, MCF-7 breast cancer cells, and LU-HNSCC-25 head and-neck squamous carcinoma cells in phosphate buffered saline. The results show agreement with published data obtained by other methods....

  13. Hybrid optical unobtrusive blood pressure measurements

    NARCIS (Netherlands)

    Zhang, G.; Shan, C.; Kirenko, I.; Long, X.; Aarts, R.M.

    2017-01-01

    Blood pressure (BP) is critical in diagnosing certain cardiovascular diseases such as hypertension. Some previous studies have proved that BP can be estimated by pulse transit time (PTT) calculated by a pair of photoplethysmography (PPG) signals at two body sites. Currently, contact PPG (cPPG) and

  14. Measurement of energetic radiation caused by thunderstorm activities by a sounding balloon and ground observation

    Science.gov (United States)

    Torii, T.

    2015-12-01

    Energetic radiation caused by thunderstorm activity is observed at various places, such as the ground, high mountain areas, and artificial satellites. In order to investigate the radiation source and its energy distribution, we measured energetic radiation by a sounding balloon, and the ground observation. On the measurement inside/above the thundercloud, we conducted a sounding observation using a radiosonde mounted two GM tubes (for gamma-rays, and for beta/gamma-rays), in addition to meteorological instruments. The balloon passed through a region of strong echoes in a thundercloud shown by radar image, at which time an increase in counting rate of the GM tube about 2 orders of magnitude occurred at the altitude from 5 km to 7.5 km. Furthermore, the counting rate of two GM tubes indicated the tendency different depending on movement of a balloon. This result suggests that the ratio for the gamma-rays (energetic photons) of the beta-rays (energetic electrons) varies according to the place in the thundercloud. Furthermore, we carried out a ground observation of the energetic gamma rays during winter thunderstorm at a coastal area facing the Sea of Japan. Two types of the energetic radiation have been observed at this time. We report the outline of these measurements and analysis in the session of the AGU meeting.

  15. Is the Speech Transmission Index (STI) a robust measure of sound system speech intelligibility performance?

    Science.gov (United States)

    Mapp, Peter

    2002-11-01

    Although RaSTI is a good indicator of the speech intelligibility capability of auditoria and similar spaces, during the past 2-3 years it has been shown that RaSTI is not a robust predictor of sound system intelligibility performance. Instead, it is now recommended, within both national and international codes and standards, that full STI measurement and analysis be employed. However, new research is reported, that indicates that STI is not as flawless, nor robust as many believe. The paper highlights a number of potential error mechanisms. It is shown that the measurement technique and signal excitation stimulus can have a significant effect on the overall result and accuracy, particularly where DSP-based equipment is employed. It is also shown that in its current state of development, STI is not capable of appropriately accounting for a number of fundamental speech and system attributes, including typical sound system frequency response variations and anomalies. This is particularly shown to be the case when a system is operating under reverberant conditions. Comparisons between actual system measurements and corresponding word score data are reported where errors of up to 50 implications for VA and PA system performance verification will be discussed.

  16. Heat transfer and pressure measurements for the SSME fuel turbine

    Science.gov (United States)

    Dunn, Michael G.; Kim, Jungho

    1991-01-01

    A measurement program is underway using the Rocketdyne two-stage Space Shuttle Main Engine (SSME) fuel turbine. The measurements use a very large shock tunnel to produce a short-duration source of heated and pressurized gas which is subsequently passed through the turbine. Within this environment, the turbine is operated at the design values of flow function, stage pressure ratio, stage temperature ratio, and corrected speed. The first stage vane row and the first stage blade row are instrumented in both the spanwise and chordwise directions with pressure transducers and heat flux gages. The specific measurements to be taken include time averaged surface pressure and heat flux distributions on the vane and blade, flow passage static pressure, flow passage total pressure and total temperature distributions, and phase resolved surface pressure and heat flux on the blade.

  17. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  18. Assessing pharmacy students' ability to accurately measure blood pressure using a blood pressure simulator arm.

    Science.gov (United States)

    Bottenberg, Michelle M; Bryant, Ginelle A; Haack, Sally L; North, Andrew M

    2013-06-12

    To compare student accuracy in measuring normal and high blood pressures using a simulator arm. In this prospective, single-blind, study involving third-year pharmacy students, simulator arms were programmed with prespecified normal and high blood pressures. Students measured preset normal and high diastolic and systolic blood pressure using a crossover design. One hundred sixteen students completed both blood pressure measurements. There was a significant difference between the accuracy of high systolic blood pressure (HSBP) measurement and normal systolic blood pressure (NSBP) measurement (mean HSBP difference 8.4 ± 10.9 mmHg vs NSBP 3.6 ± 6.4 mmHg; pdifference between the accuracy of high diastolic blood pressure (HDBP) measurement and normal diastolic blood pressure (NDBP) measurement (mean HDBP difference 6.8 ± 9.6 mmHg vs. mean NDBP difference 4.6 ± 4.5 mmHg; p=0.089). Pharmacy students may need additional instruction and experience with taking high blood pressure measurements to ensure they are able to accurately assess this important vital sign.

  19. Assessing Pharmacy Students’ Ability to Accurately Measure Blood Pressure Using a Blood Pressure Simulator Arm

    Science.gov (United States)

    Bryant, Ginelle A.; Haack, Sally L.; North, Andrew M.

    2013-01-01

    Objective. To compare student accuracy in measuring normal and high blood pressures using a simulator arm. Methods. In this prospective, single-blind, study involving third-year pharmacy students, simulator arms were programmed with prespecified normal and high blood pressures. Students measured preset normal and high diastolic and systolic blood pressure using a crossover design. Results. One hundred sixteen students completed both blood pressure measurements. There was a significant difference between the accuracy of high systolic blood pressure (HSBP) measurement and normal systolic blood pressure (NSBP) measurement (mean HSBP difference 8.4 ± 10.9 mmHg vs NSBP 3.6 ± 6.4 mmHg; pdifference between the accuracy of high diastolic blood pressure (HDBP) measurement and normal diastolic blood pressure (NDBP) measurement (mean HDBP difference 6.8 ± 9.6 mmHg vs. mean NDBP difference 4.6 ± 4.5 mmHg; p=0.089). Conclusions. Pharmacy students may need additional instruction and experience with taking high blood pressure measurements to ensure they are able to accurately assess this important vital sign. PMID:23788809

  20. Measuring sub-bandage pressure: comparing the use of pressure monitors and pulse oximeters.

    Science.gov (United States)

    Satpathy, A; Hayes, S; Dodds, S R

    2006-03-01

    To test the use of low-cost sub-bandage pressure monitors and pulse oximeters as part of a quality-control measure for graduated compression bandaging in leg ulcer clinics. Twenty-five healthy volunteers (mean age 40 years) providing 50 limbs were bandaged with a four-layer compression bandaging system. The ankle systolic pressure (ASP) was measured using a pulse oximeter (Nellcor NBP-40) before applying the graduated compression bandages. Interface pressure was measured by placing pressure sensors on the skin at three points (2cm above the medial malleolus; the widest part of the calf; and a point midway between them) in the supine and standing positions. The ASP was measured again with the pulse oximeter after the bandage had been applied, and the effect of the bandage on the ASP was recorded. The actual pressure created by the bandage was compared with the required pressure profile. Interface pressures varied with change of position and movement. With the operator blinded to the pressure monitors while applying the bandages, the target pressure of 35-40mmHg at the ankle was achieved in only 36% of limbs ([mean +/- 95% confidence interval]; 32.3 +/- 1.6mmHg [supine]; 38.4 +/- 2.4mmHg [standing position]). With the help of the pressure monitors, the target pressure was achieved in 78% of the limbs. There was no correlation between the pressure monitors and pulse oximeter pressures, demonstrating that the pulse oximeter is not a useful tool for measuring sub-bandage pressures. The results suggest a tool (interface pressure monitors) that is easy to operate should be available as part of quality assurance for treatment, training of care providers and education.

  1. Do Sound Public Finances Require Fiscal Rules or Is Market Pressure Enough?

    DEFF Research Database (Denmark)

    Bergman, Michael; Hutchison, Michael M.; Hougaard Jensen, Svend E.

    This paper discusses the balance between market pressure and fiscal rules in order to keep public finances on a sustainable path. We provide empirical evidence on market assessments of sovereign default risk to economic news, announcements of national austerity programs, EU programs designed...... to support government finances, and banking fragility emanating from several countries in the euro area affected by the European sovereign debt crisis. We find that, in general, the quality of market signals is an insufficient indicator alone to accurately guide the conduct of fiscal policy, particularly...

  2. Do Sound Public Finances Require Fiscal Rules Or Is Market Pressure Enough?

    DEFF Research Database (Denmark)

    Bergman, Ulf Michael; Hutchison, Michael; Jensen, Svend E. Hougaard

    This paper discusses the balance between market pressure and fiscal rules in order to keep public finances on a sustainable path. We provide empirical evidence on market assessments of sovereign default risk to economic news, announcements of national austerity programs, EU programs designed...... to support government finances, and banking fragility emanating from several countries in the euro area affected by the European sovereign debt crisis. We find that, in general, the quality of market signals is an insufficient indicator alone to accurately guide the conduct of fiscal policy, particularly...

  3. Integrating Sound Scattering Measurements in the Design of Complex Architectural Surfaces

    DEFF Research Database (Denmark)

    Peters, Brady

    2010-01-01

    Digital tools present the opportunity for incorporating performance analysis into the architectural design process. Acoustic performance is an important criterion for architectural design. There is much known about sound absorption but little about sound scattering, even though scattering is reco...

  4. Pressure History Measurement in a Microwave Beaming Thruster

    International Nuclear Information System (INIS)

    Oda, Yasuhisa; Ushio, Masato; Komurasaki, Kimiya; Takahashi, Koji; Kasugai, Atsushi; Sakamoto, Keishi

    2006-01-01

    In a microwave beaming thruster with a 1-dimensional nozzle, plasma and shock wave propagates in the nozzle absorbing microwave power. In this study, pressure histories in the thruster are measured using pressure gauges. Measured pressure history at the thruster wall shows constant pressure during plasma propagation in the nozzle. The result of measurement of the propagating velocities of shock wave and plasma shows that both propagate in the same velocity. These result shows that thrust producing model of analogy of pulse detonation engine is successful for the 1D thruster

  5. Use of O2 airglow for calibrating direct atomic oxygen measurements from sounding rockets

    Directory of Open Access Journals (Sweden)

    G. Witt

    2009-12-01

    Full Text Available Accurate knowledge about the distribution of atomic oxygen is crucial for many studies of the mesosphere and lower thermosphere. Direct measurements of atomic oxygen by the resonance fluorescence technique at 130 nm have been made from many sounding rocket payloads in the past. This measurement technique yields atomic oxygen profiles with good sensitivity and altitude resolution. However, accuracy is a problem as calibration and aerodynamics make the quantitative analysis challenging. Most often, accuracies better than a factor 2 are not to be expected from direct atomic oxygen measurements. As an example, we present results from the NLTE (Non Local Thermodynamic Equilibrium sounding rocket campaign at Esrange, Sweden, in 1998, with simultaneous O2 airglow and O resonance fluorescence measurements. O number densities are found to be consistent with the nightglow analysis, but only within the uncertainty limits of the resonance fluorescence technique. Based on these results, we here describe how better atomic oxygen number densities can be obtained by calibrating direct techniques with complementary airglow photometer measurements and detailed aerodynamic analysis. Night-time direct O measurements can be complemented by photometric detection of the O2 (b1∑g+−X3∑g- Atmospheric Band at 762 nm, while during daytime the O2 (a1Δg−X3∑g- Infrared Atmospheric Band at 1.27 μm can be used. The combination of a photometer and a rather simple resonance fluorescence probe can provide atomic oxygen profiles with both good accuracy and good height resolution.

  6. Interactions of polyethylene glycols with water studied by measurements of density and sound velocity

    International Nuclear Information System (INIS)

    Ayranci, Erol; Sahin, Melike

    2008-01-01

    Densities and sound velocities of ethylene glycol (EG) and polyethylene glycols (PEGs) of molecular weight 200, 300, 400, 550, 600, 1000, 1450, 3350, 8000, and 10,000 at (288.15, 298.15, and 308.15) K were measured with high precision vibrating tube densimeter and sound velocity measuring device. They were used to evaluate apparent molar volumes, V o , and apparent molar isentropic compressibilities, K ΦS . Infinite dilution values of these parameters, V o 0 , and K ΦS 0 , were obtained from their plot as a function of molality. The variations of V o 0 , and K ΦS 0 , with the number of repeating units in PEGs and with temperature were examined. Comparison of the experimentally obtained data was made with the available literature data and also with some values predicted according to group additivity approach. The results were interpreted in terms of hydration and conformational effects of PEGs in water. A correlation was also examined between V o 0 or K ΦS 0 values of PEGs in water and equilibrium moisture contents of PEGs as well as the water vapor permeabilities (WVP) of edible films containing PEGs

  7. Measurement of acoustic characteristics of Japanese Buddhist temples in relation to sound source location and direction.

    Science.gov (United States)

    Soeta, Yoshiharu; Shimokura, Ryota; Kim, Yong Hee; Ohsawa, Tomohiro; Ito, Ken

    2013-05-01

    Although temples are important buildings in the Buddhist community, the acoustic quality has not been examined in detail. Buddhist monks change the location and direction according to the ceremony, and associated acoustical changes have not yet been examined scientifically. To discuss the desired acoustics of temples, it is necessary to know the acoustic characteristics appropriate for each phase of a ceremony. In this study, acoustic measurements were taken at various source locations and directions in Japanese temples. A directional loudspeaker was used as the source to provide vocal acoustic fields, and impulse responses were measured and analyzed. The speech transmission index was higher and the interaural cross-correlation coefficient was lower for the sound source directed toward the side wall than that directed toward the altar. This suggests that the change in direction improves speech intelligibility, and the asymmetric property of direct sound and complex reflections from the altar and side wall increases the apparent source width. The large and coupled-like structure of the altar of a Buddhist temple may have reinforced the reverberation components and the table in the altar, which is called the "syumidan," may have decreased binaural coherence.

  8. Verification of the helioseismology travel-time measurement technique and the inversion procedure for sound speed using artificial data

    Energy Technology Data Exchange (ETDEWEB)

    Parchevsky, K. V.; Zhao, J.; Hartlep, T.; Kosovichev, A. G., E-mail: akosovichev@solar.stanford.edu [Stanford University, HEPL, Stanford, CA 94305 (United States)

    2014-04-10

    We performed three-dimensional numerical simulations of the solar surface acoustic wave field for the quiet Sun and for three models with different localized sound-speed perturbations in the interior with deep, shallow, and two-layer structures. We used the simulated data generated by two solar acoustics codes that employ the same standard solar model as a background model, but utilize different integration techniques and different models of stochastic wave excitation. Acoustic travel times were measured using a time-distance helioseismology technique, and compared with predictions from ray theory frequently used for helioseismic travel-time inversions. It is found that the measured travel-time shifts agree well with the helioseismic theory for sound-speed perturbations, and for the measurement procedure with and without phase-speed filtering of the oscillation signals. This testing verifies the whole measuring-filtering-inversion procedure for static sound-speed anomalies with small amplitude inside the Sun outside regions of strong magnetic field. It is shown that the phase-speed filtering, frequently used to extract specific wave packets and improve the signal-to-noise ratio, does not introduce significant systematic errors. Results of the sound-speed inversion procedure show good agreement with the perturbation models in all cases. Due to its smoothing nature, the inversion procedure may overestimate sound-speed variations in regions with sharp gradients of the sound-speed profile.

  9. Verification of the helioseismology travel-time measurement technique and the inversion procedure for sound speed using artificial data

    International Nuclear Information System (INIS)

    Parchevsky, K. V.; Zhao, J.; Hartlep, T.; Kosovichev, A. G.

    2014-01-01

    We performed three-dimensional numerical simulations of the solar surface acoustic wave field for the quiet Sun and for three models with different localized sound-speed perturbations in the interior with deep, shallow, and two-layer structures. We used the simulated data generated by two solar acoustics codes that employ the same standard solar model as a background model, but utilize different integration techniques and different models of stochastic wave excitation. Acoustic travel times were measured using a time-distance helioseismology technique, and compared with predictions from ray theory frequently used for helioseismic travel-time inversions. It is found that the measured travel-time shifts agree well with the helioseismic theory for sound-speed perturbations, and for the measurement procedure with and without phase-speed filtering of the oscillation signals. This testing verifies the whole measuring-filtering-inversion procedure for static sound-speed anomalies with small amplitude inside the Sun outside regions of strong magnetic field. It is shown that the phase-speed filtering, frequently used to extract specific wave packets and improve the signal-to-noise ratio, does not introduce significant systematic errors. Results of the sound-speed inversion procedure show good agreement with the perturbation models in all cases. Due to its smoothing nature, the inversion procedure may overestimate sound-speed variations in regions with sharp gradients of the sound-speed profile.

  10. Can Confirmation Measures Reflect Statistically Sound Dependencies in Data? The Concordance-based Assessment

    Directory of Open Access Journals (Sweden)

    Susmaga Robert

    2018-03-01

    Full Text Available The paper considers particular interestingness measures, called confirmation measures (also known as Bayesian confirmation measures, used for the evaluation of “if evidence, then hypothesis” rules. The agreement of such measures with a statistically sound (significant dependency between the evidence and the hypothesis in data is thoroughly investigated. The popular confirmation measures were not defined to possess such form of agreement. However, in error-prone environments, potential lack of agreement may lead to undesired effects, e.g. when a measure indicates either strong confirmation or strong disconfirmation, while in fact there is only weak dependency between the evidence and the hypothesis. In order to detect and prevent such situations, the paper employs a coefficient allowing to assess the level of dependency between the evidence and the hypothesis in data, and introduces a method of quantifying the level of agreement (referred to as a concordance between this coefficient and the measure being analysed. The concordance is characterized and visualised using specialized histograms, scatter-plots, etc. Moreover, risk-related interpretations of the concordance are introduced. Using a set of 12 confirmation measures, the paper presents experiments designed to establish the actual concordance as well as other useful characteristics of the measures.

  11. Measuring Young Children's Alphabet Knowledge: Development and Validation of Brief Letter-Sound Knowledge Assessments

    Science.gov (United States)

    Piasta, Shayne B.; Phillips, Beth M.; Williams, Jeffrey M.; Bowles, Ryan P.; Anthony, Jason L.

    2016-01-01

    Early childhood teachers are increasingly encouraged to support children's development of letter-sound abilities. Assessment of letter-sound knowledge is key in planning for effective instruction, yet the letter-sound knowledge assessments currently available and suitable for preschool-age children demonstrate significant limitations. The purpose…

  12. Innovations in plantar pressure and foot temperature measurements in diabetes

    NARCIS (Netherlands)

    Bus, S. A.

    2016-01-01

    Plantar pressure and temperature measurements in the diabetic foot primarily contribute to identifying abnormal values that increase risk for foot ulceration, and they are becoming increasingly more integrated in clinical practice and daily life of the patient. While plantar pressure measurements

  13. Equivalent threshold sound pressure levels for Sennheiser HDA 200 earphone and Etymotic Research ER-2 insert earphone in the frequency range 125 Hz to 16 kHz

    DEFF Research Database (Denmark)

    Han, Loc A; Poulsen, Torben

    1998-01-01

    Equivalent Threshold Sound Pressure Levels (ETSPLs) have been determined for the Sennheiser HDA 200 earphone and the Etymotic Research ER-2insert earphone. Thirty-one young normal-hearing test subjects participated and the thresholds were determined for all recommended frequencies in thefrequency...

  14. A novel application of Recursive Equation Method for determining thermodynamic properties of single phase fluids from density and speed-of-sound measurements

    International Nuclear Information System (INIS)

    Lago, S.; Giuliano Albo, P.A.

    2013-01-01

    Highlights: ► A novel method for calculating the isobaric specific heat capacity is presented. ► Heat capacity (C p ) was determined only by speed-of-sound and density measurements. ► (C p ) temperature dependence has been related to speed-of-sound by a new expression. ► Heat capacity for water, nonane, undecane, and rapeseed oil methyl ester are obtained. -- Abstract: The determination of thermal quantities from mechanical properties is still a challenge in the thermodynamic field. In this work, the authors suggest a preliminary numerical calculation which allows to determine the constant pressure specific heat capacity, starting from density and speed-of-sound experimental values, as input data. This method is a variant of the well characterized Recursive Equation Method (REM) [1] and permits to develop empirical equations of state for single phase fluids. In particular, the isobaric specific heat capacity has been obtained, in a wide range of temperatures and pressures, for pure water, n-nonane, n-undecane, and rapeseed oil methyl ester. The results have been compared with those available in the literature, when it was possible. Moreover, the typical uncertainty of heat capacity has been estimated to be in the order of 1.5%; however it has been shown that it can be improved when proper distributions of the experimental points are available

  15. Speed of sound in saturated aliphatic alcohols (propan-2-ol, butan-2-ol, and 2-methylpropan-1-ol) and alkanediols (ethane-1,2-diol, propane-1,2- and -1,3-diol) at temperature between 253.15 K and 353.15 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Dávila, María J.; Gedanitz, Holger; Span, Roland

    2016-01-01

    Highlights: • Speed of sound measurements were made in aliphatic alcohols and alkanediols. • Speeds of sound were measured in a wide temperature and pressure range. • A pulse-echo method with a double path type sensor operating at 8 MHz was employed. • A double polynomial equation was used to fit the experimental speed of sound data. • The accurate results were compared with available literature sources. - Abstract: Speeds of sound have been measured in three saturated aliphatic alcohols (propan-2-ol, butan-2-ol, and 2-methylpropan-1-ol) and three alkanediols (ethane-1,2-diol, propane-1,2- and -1,3-diol) in the temperature range from (253.15 to 353.15) K and pressures up to 30 MPa by use of a pulse-echo method with a double path type sensor operating at 8 MHz. The expanded overall uncertainties (k = 2) in the speed of sound measurements are estimated to be 0.013% for propan-2-ol, 0.019% for butan-2-ol, 0.01% for 2-methylpropan-1-ol, 0.009% for ethane-1,2-diol, 0.02% for propane-1,2-diol, and 0.07% for propane-1,3-diol. Experimental speeds of sound data were correlated with the temperature and pressure with an empirical double polynomial equation. Our results were also compared with the available literature data and a satisfactory agreement was found.

  16. Full scale measurement of wind induced pressures : 1 configuration of wind induced pressures

    NARCIS (Netherlands)

    Geurts, C.P.W.; Wijen, H.L.M.

    1994-01-01

    A research project 10 the spectral characteristics of wind induced pressures is in progress in Eindhoven. This project includes both wind tunnel and full scale measurements. Wind induced pressures are measured in full scale at the main building of Eindhoven University of Technology. This paper

  17. The optimal scheme of self blood pressure measurement as determined from ambulatory blood pressure recordings

    NARCIS (Netherlands)

    Verberk, Willem J.; Kroon, Abraham A.; Kessels, Alfons G. H.; Lenders, Jacques W. M.; Thien, Theo; van Montfrans, Gert A.; Smit, Andries J.; de Leeuw, Peter W.

    Objective To determine how many self-measurements of blood pressure (BP) should be taken at home in order to obtain a reliable estimate of a patient's BP. Design Participants performed self blood pressure measurement (SBPM) for 7 days (triplicate morning and evening readings). In all of them, office

  18. Velocity-pressure correlation measurements in complex free shear flows

    International Nuclear Information System (INIS)

    Naka, Yoshitsugu; Obi, Shinnosuke

    2009-01-01

    Simultaneous measurements of fluctuating velocity and pressure were performed in various turbulent free shear flows including a turbulent mixing layer and the wing-tip vortex trailing from a NACA0012 half-wing. Two different methods for fluctuating static pressure measurement were considered: a direct method using a miniature Pitot tube and an indirect method where static pressure was calculated from total pressure. The pressure obtained by either of these methods was correlated with the velocity measured by an X-type hot-wire probe. The results from these two techniques agreed with each other in the turbulent mixing layer. In the wing-tip vortex case, however, some discrepancies were found, although overall characteristics of the pressure-related statistics were adequately captured by both methods.

  19. Modern gas-based temperature and pressure measurements

    CERN Document Server

    Pavese, Franco

    2013-01-01

    This 2nd edition volume of Modern Gas-Based Temperature and Pressure Measurements follows the first publication in 1992. It collects a much larger set of information, reference data, and bibliography in temperature and pressure metrology of gaseous substances, including the physical-chemical issues related to gaseous substances. The book provides solutions to practical applications where gases are used in different thermodynamic conditions. Modern Gas-Based Temperature and Pressure Measurements, 2nd edition is the only comprehensive survey of methods for pressure measurement in gaseous media used in the medium-to-low pressure range closely connected with thermometry. It assembles current information on thermometry and manometry that involve the use of gaseous substances which are likely to be valid methods for the future. As such, it is an important resource for the researcher. This edition is updated through the very latest scientific and technical developments of gas-based temperature and pressure measurem...

  20. In vivo measurement of mechanical properties of human long bone by using sonic sound

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, M. Jayed, E-mail: zed.hossain06@gmail.com; Rahman, M. Moshiur, E-mail: razib-121@yahoo.com; Alam, Morshed [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka 1000 (Bangladesh)

    2016-07-12

    Vibration analysis has evaluated as non-invasive techniques for the in vivo assessment of bone mechanical properties. The relation between the resonant frequencies, long bone geometry and mechanical properties can be obtained by vibration analysis. In vivo measurements were performed on human ulna as a simple beam model with an experimental technique and associated apparatus. The resonant frequency of the ulna was obtained by Fast Fourier Transformation (FFT) analysis of the vibration response of piezoelectric accelerometer. Both elastic modulus and speed of the sound were inferred from the resonant frequency. Measurement error in the improved experimental setup was comparable with the previous work. The in vivo determination of bone elastic response has potential value in screening programs for metabolic bone disease, early detection of osteoporosis and evaluation of skeletal effects of various therapeutic modalities.

  1. Density and speed of sound of lithium bromide with organic solvents: Measurement and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Zafarani-Moattar, Mohammed Taghi [Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Research Institute of Fundamental Sciences, Tabriz 51664 (Iran, Islamic Republic of)], E-mail: zafarani47@yahoo.com; Shekaari, Hemayat [Department of Physical Chemistry, Faculty of Chemistry, University of Tabriz, Tabriz 51664 (Iran, Islamic Republic of); Research Institute of Fundamental Sciences, Tabriz 51664 (Iran, Islamic Republic of)

    2007-12-15

    Densities, {rho}, and speed of sound, u, of the solutions of LiBr with non-aqueous solvents (methanol, ethanol, 2-propanol, acetone, and acetonitrile) having a wide range of dielectric constants were measured at T = 298.15 K. Also, these measurements were made for the system (LiBr + N,N-dimethylacetamide) at T = 323.15 K. For the investigated systems, the limiting values for apparent molar volume, V{sub {phi}}{sup 0}, and the apparent molar isentropic compressibility, {kappa}{sub {phi}}{sup 0}, were obtained from the Redlich-Mayer and an abbreviated form of the Pitzer equations. The Pitzer and NRTL equations were satisfactorily used for the correlation of apparent molar volumes, V{sub {phi}}, and the apparent molar isentropic compressibility, {kappa}{sub {phi}}, values of the studied systems.

  2. Intraocular pressure measurement in patients with previous LASIK surgery using pressure phosphene tonometer.

    Science.gov (United States)

    Cheng, Arthur C K; Leung, Dexter Y L; Cheung, Eva Y Y; Fan, Dorothy S P; Law, Ricky W K; Lam, Dennis S C

    2005-04-01

    To compare intraocular pressure (IOP) assessment in post-LASIK patients using non-contact tonometry, pressure phosphene tonometry and applanation tonometry. Sixty-two consecutive LASIK patients were analysed preoperatively and postoperatively with non-contact, pressure phosphene and applanation tonometry. Comparisons among these values were assessed with paired sample Student t-test, Pearson's correlation test and Bland-Altman plotting. There was no significant difference for preoperative IOP measurement between non-contact, pressure phosphene and applanation tonometry. The mean +/-SD difference between the preoperative non-contact tonometry and postoperative pressure phosphene tonometry IOP measurements was 0.80 +/- 2.77 mmHg (P contact tonometry significantly underestimated IOP measurement by 9.96 +/- 2.25 mmHg (P < 0.001). Pressure phosphene tonometry may provide an alternative method for the assessment of IOP in post-LASIK patients.

  3. Measurements of the Exerted Pressure by Pelvic Circumferential Compression Devices

    Science.gov (United States)

    Knops, Simon P; van Riel, Marcel P.J.M; Goossens, Richard H.M; van Lieshout, Esther M.M; Patka, Peter; Schipper, Inger B

    2010-01-01

    Background: Data on the efficacy and safety of non-invasive Pelvic Circumferential Compression Devices (PCCDs) is limited. Tissue damage may occur if a continuous pressure on the skin exceeding 9.3 kPa is sustained for more than two or three hours. The aim of this study was to gain insight into the pressure build-up at the interface, by measuring the PCCD-induced pressure when applying pulling forces to three different PCCDs (Pelvic Binder® , SAM-Sling ® and T-POD® ) in a simplified model. Methods: The resulting exerted pressures were measured at four ‘anatomical’ locations (right, left, posterior and anterior) in a model using a pressure measurement system consisting of pressure cuffs. Results: The exerted pressure varied substantially between the locations as well as between the PCCDs. Maximum pressures ranged from 18.9-23.3 kPa and from 19.2-27.5 kPa at the right location and left location, respectively. Pressures at the posterior location stayed below 18 kPa. At the anterior location pressures varied markedly between the different PCCDs. Conclusion: The circumferential compression by the different PCCDs showed high pressures measured at the four locations using a simplified model. Difference in design and functional characteristics of the PCCDs resulted in different pressure build-up at the four locations. When following the manufacturer’s instructions, the exerted pressure of all three PCCDs tested exceeded the tissue damaging level (9.3 kPa). In case of prolonged use in a clinical situation this might put patients at risk for developing tissue damage. PMID:20361001

  4. Spherical resonator for vapor-phase speed of sound and measurements of 1,1,1,2,2,3,3-heptafluoro-3-methoxypropane (RE347mcc) and trans-1,3,3,3-tetrafluoropropene [R1234ze(E)

    International Nuclear Information System (INIS)

    Perkins, Richard A.; McLinden, Mark O.

    2015-01-01

    Highlights: • A spherical acoustic resonator for gas-phase speed of sound over the range T = (265 to 500) K, p < 10 MPa is described. • The sphere diameter was calibrated with argon and measurements on methane and ethane verified the performance of the system. • The sound speed of RE347mcc was measured over the range T = (325 to 500) K, p < 1.6 MPa. • The sound speed of R1234ze(E) was measured over the range T = (280 to 420) K, p < 2.8 MPa. • The average combined, expanded uncertainties for sound speed were 0.035 m · s"−"1 for RE347mcc and 0.064 m · s"−"1 for R1234ze(E). - Abstract: We describe an apparatus to measure the speed of sound of gas samples at temperatures from (265 to 500) K with pressures up to 10 MPa. The speed of sound was determined from the frequency of the three lowest-order radial resonance modes for the gas in a spherical cavity machined from type 321 stainless steel for corrosion resistance. The spherical resonator was contained in an isothermal copper block that was maintained at the temperature of interest by a multilayer thermostat with vacuum insulation. The dimensions of the spherical cavity were characterized as a function of temperature and pressure though calibration measurements with high-purity argon. The performance of the apparatus was demonstrated with measurements of high-purity methane and ethane. Measurements of the sound speed of 1,1,1,2,2,3,3-heptafluoro-3-methoxypropane (RE347mcc) are reported at temperatures from (325 to 500) K with pressures up to 1.6 MPa. Measurements on trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) are reported at temperatures from (280 to 420) K with pressures up to 2.8 MPa. The average relative combined expanded uncertainties of the measured sound speed for RE347mcc and R1234ze(E) are (0.029 and 0.041)%, respectively.

  5. [Comparison of invasive blood pressure measurement in the aorta with indirect oscillometric blood pressure measurement at the wrist and forearm].

    Science.gov (United States)

    Saul, F; Aristidou, Y; Klaus, D; Wiemeyer, A; Lösse, B

    1995-09-01

    Indirectly measured blood pressure at the wrist or upper arm was compared with directly measured values in the aortic arch during routinely performed diagnostic cardiac catheterization in 100 patients (31-80 years, mean 59.3 years, 60% males). The noninvasive measurements were carried out by oscillometric devices, NAiS Blood Pressure Watch for measurements at the wrist, and Hestia OZ80 at the upper arm. Systolic blood pressure measured at the wrist was 4.3 +/- 14.1 mm Hg, and the diastolic value 6.0 +/- 8.9 mm Hg higher than when measured at the aortic arch; the difference was significant in both cases. Correlation coefficients were 0.85 for systolic and 0.71 for diastolic blood pressure. In 16% of the patients the systolic blood pressure at the wrist differed more than +/- 20 mm Hg. The diastolic blood pressure at the wrist measured more than +/- 20 mm Hg higher than in the aorta in 5% of the patients. At the upper arm mean systolic values were not different to the aorta. The diastolic pressure was 9.3 +/- 9.8 mm Hg higher in the aorta than at the upper arm. To verify the accuracy of values measured with the NAiS Blood Pressure Watch compared with the standard technique at the upper arm, sequential measurements were made at wrist and ipsilateral upper arm in the same group of 100 patients. The systolic blood pressure at the left wrist was 3.4 +/- 13.3 mm Hg higher and the diastolic pressure 3.8 +/- 9.5 mm Hg lower than at the upper arm. Only 53% of systolic values lay within a range of +/- 10 mm Hg. The correspondence between wrist and upper arm values was better for diastolic blood pressure, the values differing by less than +/- 10 mm Hg in two-thirds of patients. Self-measurement of arterial blood pressure with an oscillometric device at the wrist can be recommended only in individual cases with a difference of simultaneously measured values at the upper arm of less than +/- 10 mm Hg for systolic and diastolic blood pressures. The standard method for indirectly

  6. Comparison of ambulatory blood pressure monitoring and office blood pressure measurements in obese children and adolescents.

    Science.gov (United States)

    Renda, Rahime

    2018-04-01

    Obesity in adults has been related to hypertension and abnormal nocturnal dipping of blood pressure, which are associated with poor cardiovascular and renal outcomes. Here, we aimed to resolve the relationship between the degree of obesity, the severity of hypertension and dipping status on ambulatory blood pressure in obese children. A total 72 patients with primary obesity aged 7 to 18 years (mean: 13.48 ± 3.25) were selected. Patients were divided into three groups based on body mass index (BMİ) Z-score. Diagnosis and staging of ambulatory hypertension based on 24-h blood pressure measurements, obtained from ambulatory blood pressure monitoring. Based on our ambulatory blood pressure data, 35 patients (48.6%) had hypertension, 7 (20%) had ambulatory prehypertension, 21 (60%) had hypertension, and 7 patients (20%) had severe ambulatory hypertension. There was a significant relationship between severity of hypertension and the degree of obesity (p lood pressure results and loads were similar between groups. Diastolic and mean arterial blood pressure levels during the night, diastolic blood pressure loads, and heart rate during the day were significantly higher in Group 3 (p lood pressure at night, mean arterial pressure at night, diastolic blood pressure loads and heart rate at day. Increase in BMI Z-score does not a significant impact on daytime blood pressure and nocturnal dipping status.

  7. Alternating Current Delivered into the Scala Media Alters Sound Pressure at the Eardrum

    Science.gov (United States)

    Hubbard, Allyn E.; Mountain, David C.

    1983-11-01

    Alternating current delivered into the scala media of the gerbil cochlea modulates the amplitude of a test tone measured near the eardrum. Variations in the electromechanical effect with acoustic stimulus parameters and observed physiological vulnerability suggest that cochlear hair cells are the biophysical origin of the process. Cochlear hair cells have traditionally been thought of as passive receptor cells, but they may play an active role in cochlear micromechanics.

  8. The low-frequency sound power measuring technique for an underwater source in a non-anechoic tank

    Science.gov (United States)

    Zhang, Yi-Ming; Tang, Rui; Li, Qi; Shang, Da-Jing

    2018-03-01

    In order to determine the radiated sound power of an underwater source below the Schroeder cut-off frequency in a non-anechoic tank, a low-frequency extension measuring technique is proposed. This technique is based on a unique relationship between the transmission characteristics of the enclosed field and those of the free field, which can be obtained as a correction term based on previous measurements of a known simple source. The radiated sound power of an unknown underwater source in the free field can thereby be obtained accurately from measurements in a non-anechoic tank. To verify the validity of the proposed technique, a mathematical model of the enclosed field is established using normal-mode theory, and the relationship between the transmission characteristics of the enclosed and free fields is obtained. The radiated sound power of an underwater transducer source is tested in a glass tank using the proposed low-frequency extension measuring technique. Compared with the free field, the radiated sound power level of the narrowband spectrum deviation is found to be less than 3 dB, and the 1/3 octave spectrum deviation is found to be less than 1 dB. The proposed testing technique can be used not only to extend the low-frequency applications of non-anechoic tanks, but also for measurement of radiated sound power from complicated sources in non-anechoic tanks.

  9. Electrochemical noise measurements under pressurized water reactor conditions

    International Nuclear Information System (INIS)

    Van Nieuwenhove, R.

    2000-01-01

    Electrochemical potential noise measurements on sensitized stainless steel pressure tubes under pressurized water reactor (PWR) conditions were performed for the first time. Very short potential spikes, believed to be associated to crack initiation events, were detected when stressing the sample above the yield strength and increased in magnitude until the sample broke. Sudden increases of plastic deformation, as induced by an increased tube pressure, resulted in slower, high-amplitude potential transients, often accompanied by a reduction in noise level

  10. Using pressure square-like wave to measure the dynamic characteristics of piezoelectric pressure sensor

    International Nuclear Information System (INIS)

    Han, L-L; Tsung, T-T; Chen, L-C; Chang Ho; Jwo, C-S

    2005-01-01

    Piezoelectric pressure sensors are commonly used to measuring the dynamic characteristics in a hydraulic system. The dynamic measurements require a pressure sensor which has a high response rate. In this paper, we proposed use of a pressure square wave to excite the piezoelectric pressure sensor. Experimental frequencies are 0.5, 1.0, 1.5, and 2.0 kHz at 10, 15, 20 bar, respectively. Results show that the waveform of time-domain and frequencydomain response are quite different under above testing conditions. The higher the frequencies tested, the faster the pressure-rise speeds obtained. Similarly, the higher the testing pressure, the shorter the rise time attained

  11. [Invasive arterial blood pressure measurement using an aneroid pressure system in cattle].

    Science.gov (United States)

    Mosing, M; Franz, S; Iff, I; Schwendenwein, I

    2009-06-01

    The aim of this study was to compare the results of invasive arterial blood pressure measurement using an electronic pressure transducer (EPT) or an aneroid pressure system (APS) in cattle. A catheter was placed in the auricular artery of 11 adult cattle and connected to a pressure transducer via pressure line. The aneroid system was connected to the same catheter using a three-way stop-cock in the pressure line. On five occasions three consecutive measurements were performed with the APS. The mean blood pressure values of the EPT were recorded before each individual measurement. Values from each device were compared using Passing and Bablok regression of agreement and a Bland and Altman difference plot. One hundred and forty-seven paired measurements were analysed. The average bias between the two methods (EPT vs. APS) was -1.6 mmHg (95 % confidence interval [CI]: -3.0 to -0.2 mmHg). The coefficient of correlation was 1.0084. The aneroid system showed an almost perfect agreement with the EPT. This study shows that it can be used in a clinical setting as well as under field conditions to measure arterial blood pressure in cattle.

  12. Measurements of Turbulence at Two Tidal Energy Sites in Puget Sound, WA

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Jim; Polagye, Brian; Durgesh, Vibhav; Richmond, Marshall C.

    2012-06-05

    Field measurements of turbulence are pre- sented from two sites in Puget Sound, WA (USA) that are proposed for electrical power generation using tidal current turbines. Rapidly sampled data from multiple acoustic Doppler instruments are analyzed to obtain statistical mea- sures of fluctuations in both the magnitude and direction of the tidal currents. The resulting turbulence intensities (i.e., the turbulent velocity fluctuations normalized by the harmonic tidal currents) are typically 10% at the hub- heights (i.e., the relevant depth bin) of the proposed turbines. Length and time scales of the turbulence are also analyzed. Large-scale, anisotropic eddies dominate the energy spectra, which may be the result of proximity to headlands at each site. At small scales, an isotropic turbulent cascade is observed and used to estimate the dissipation rate of turbulent kinetic energy. Data quality and sampling parameters are discussed, with an emphasis on the removal of Doppler noise from turbulence statistics.

  13. TREATMENT OF HYPERTENSION USING TELEMEDICAL HOME BLOOD PRESSURE MEASUREMENTS

    DEFF Research Database (Denmark)

    Hoffmann-Petersen, N; Lauritzen, T; Bech, J N

    2015-01-01

    OBJECTIVE: Telemonitoring of home blood pressure measurements (TBPM) is a new and promising supplement to diagnosis, control and treatment of hypertension. We wanted to compare the outcome of antihypertensive treatment based on TBPM and conventional monitoring of blood pressure. DESIGN AND METHOD...... of the measurements and subsequent communication by telephone or E-mail. In the control group, patients received usual care. Primary outcome was reduction in daytime ambulatory blood pressure measurements (ABPM) from baseline to 3 months' follow-up. RESULTS: In both groups, daytime ABPM decreased significantly....../181), p = 0.34. Blood pressure reduction in the TBPM group varied with the different practices. CONCLUSIONS: No further reduction in ABPM or number of patients reaching blood pressure targets was observed when electronic transmission of TBPM was applied in the treatment of hypertension by GPs. Thus...

  14. Blood pressure measurement: one arm or both arm?

    Science.gov (United States)

    Kulkarni, Prasad K; Shekhar, Susheela; Reddy, B N; Nirmala, B C

    2011-09-01

    Guidelines for measuring blood pressure includes measurement of blood pressure on both arms but it is often ignored. Our case report aims at highlighting the need follow the guidelines. A 60 year old 59 kg weighing male asymptomatic patient without any comobidities was posted for bilateral inguinal hernia repair. The interarm blood pressure difference was discovered incidentally during his preanaesthetic evalution. On further evaluation patient was found to be having subclavian stenosis on left side which was asymptomatic. Intraoperative and post operative period was uneventful. Blood pressure measurement should be done in accordance with the stipulated guidelines. Inter arm blood pressure difference should be noted in all patients as not only for diagnosis and treatment of hypertension but also as a tool to diagnose asymptomatic peripheral vascular disesase.

  15. Pico gauges for minimally invasive intracellular hydrostatic pressure measurements

    DEFF Research Database (Denmark)

    Knoblauch, Jan; Mullendore, Daniel L.; Jensen, Kaare Hartvig

    2014-01-01

    Intracellular pressure has a multitude of functions in cells surrounded by a cell wall or similar matrix in all kingdoms of life. The functions include cell growth, nastic movements, and penetration of tissue by parasites. The precise measurement of intracellular pressure in the majority of cells......, however, remains difficult or impossible due to their small size and/or sensitivity to manipulation. Here, we report on a method that allows precise measurements in basically any cell type over all ranges of pressure. It is based on the compression of nanoliter and picoliter volumes of oil entrapped...... in the tip of microcapillaries, which we call pico gauges. The production of pico gauges can be accomplished with standard laboratory equipment, and measurements are comparably easy to conduct. Example pressure measurements are performed on cells that are difficult or impossible to measure with other methods....

  16. Maximum respiratory pressure measuring system : calibration and evaluation of uncertainty

    NARCIS (Netherlands)

    Ferreira, J.L.; Pereira, N.C.; Oliveira Júnior, M.; Vasconcelos, F.H.; Parreira, V.F.; Tierra-Criollo, C.J.

    2010-01-01

    The objective of this paper is to present a methodology for the evaluation of uncertainties in the measurements results obtained during the calibration of a digital manovacuometer prototype (DM) with a load cell sensor pressure device incorporated. Calibration curves were obtained for both pressure

  17. Definition-consistent measurement of exchange market pressure

    NARCIS (Netherlands)

    Klaassen, F.; Jager, H.

    2011-01-01

    Currencies can be under severe pressure, but in a managed exchange rate regime that is not fully visible via the change in the exchange rate. The literature has proposed a way to measure such exchange market pressure (EMP) indirectly, by adding interest rate changes and forex interventions to the

  18. Blood pressure self-measurement in the obstetric waiting room

    DEFF Research Database (Denmark)

    Wagner, Stefan; Kamper, Christina H.; Toftegaard, Thomas Skjødeberg

    2013-01-01

    a reliable blood pressure reading. Results: We found that the patients did not adhere to given instructions when performing blood pressure self-measurement in the waiting room. None of the 81 patients adhered to all six inves- tigated recommendations, while around a quarter adhered to five out of six...

  19. New Technique of Direct Intra-abdominal Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Elena Risin

    2006-10-01

    Conclusion: Direct measurement of intra-abdominal pressure using 14-Fr PVC round drain is a newly described technique that is simple, fast and credible. Future investigation will be needed to confirm the reliability of this method during postoperative follow-up of intra-abdominal pressures in selected patients.

  20. Noninvasive microbubble-based pressure measurements: a simulation study

    NARCIS (Netherlands)

    Postema, Michiel; Postema, M.A.B.; Bouakaz, Ayache; de Jong, N.

    2004-01-01

    This paper describes a noninvasive method to measure local hydrostatic pressures in fluid filled cavities. The method is based on the disappearance time of a gas bubble, as the disappearance time is related to the hydrostatic pressure. When a bubble shrinks, its response to ultrasound changes. From

  1. Gain measurements in CO2 CW low pressure lasers

    International Nuclear Information System (INIS)

    Rodrigues, N.A.S.; Chanes Junior, J.B.; Jayaram, K.

    1983-01-01

    A series of gain measurements in low pressure CO 2 CW laser were performed in order to study the behaviour of a CO 2 laser ampliflier as a function of pressure and discharge current. A theoretical model, based on rate equations is also presented to describe the laser behaviour and the experimental procedure adopted. (C.L.B.) [pt

  2. Automatic noninvasive measurement of systolic blood pressure using photoplethysmography

    Directory of Open Access Journals (Sweden)

    Glik Zehava

    2009-10-01

    Full Text Available Abstract Background Automatic measurement of arterial blood pressure is important, but the available commercial automatic blood pressure meters, mostly based on oscillometry, are of low accuracy. Methods In this study, we present a cuff-based technique for automatic measurement of systolic blood pressure, based on photoplethysmographic signals measured simultaneously in fingers of both hands. After inflating the pressure cuff to a level above systolic blood pressure in a relatively slow rate, it is slowly deflated. The cuff pressure for which the photoplethysmographic signal reappeared during the deflation of the pressure-cuff was taken as the systolic blood pressure. The algorithm for the detection of the photoplethysmographic signal involves: (1 determination of the time-segments in which the photoplethysmographic signal distal to the cuff is expected to appear, utilizing the photoplethysmographic signal in the free hand, and (2 discrimination between random fluctuations and photoplethysmographic pattern. The detected pulses in the time-segments were identified as photoplethysmographic pulses if they met two criteria, based on the pulse waveform and on the correlation between the signal in each segment and the signal in the two neighboring segments. Results Comparison of the photoplethysmographic-based automatic technique to sphygmomanometry, the reference standard, shows that the standard deviation of their differences was 3.7 mmHg. For subjects with systolic blood pressure above 130 mmHg the standard deviation was even lower, 2.9 mmHg. These values are much lower than the 8 mmHg value imposed by AAMI standard for automatic blood pressure meters. Conclusion The photoplethysmographic-based technique for automatic measurement of systolic blood pressure, and the algorithm which was presented in this study, seems to be accurate.

  3. Noise Exposure of Teachers in Nursery Schools-Evaluation of Measures for Noise Reduction When Dropping DUPLO Toy Bricks into Storage Cases by Sound Analyses.

    Science.gov (United States)

    Gebauer, Konstanze; Scharf, Thomas; Baumann, Uwe; Groneberg, David A; Bundschuh, Matthias

    2016-07-04

    Although noise is one of the leading work-related health risk factors for teachers, many nursery schools lack sufficient noise reduction measures. This intervention study evaluated the noise exposure of nursery school teachers when dropping DUPLO toy bricks into storage cases. Sound analyses of the impact included assessment of the maximum sound pressure level (LAFmax) as well as frequency analyses with 1/3 octave band filter. For the purpose of standardization, a customized gadget was developed. Recordings were performed in 11 cases of different materials and designs to assess the impact on sound level reduction. Thereby, the acoustic effects of three damping materials (foam rubber, carpet, and PU-foam) were investigated. The lowest LAFmax was measured in cases consisting of "metal grid" (90.71 dB) or of a woven willow "basket" (91.61 dB), whereas a case of "aluminium" (103.34 dB) generated the highest impact LAFmax. The frequency analyses determined especially low LAFmax in the frequency bands between 80 and 2500 Hz in cases designs "metal grid" and "basket". The insertion of PU-foam achieved the most significant attenuation of LAFmax (-13.88 dB) and, in the frequency analyses, the best sound damping. The dropping of DUPLO bricks in cases contributes to the high noise level in nursery schools, but measured LAFmax show no evidence for the danger of acute hearing loss. However, continuous exposure may lead to functional impairment of the hair cells and trigger stress reactions. We recommend noise reduction by utilizing cases of woven "basket" with an insert of PU-foam.

  4. Noise Exposure of Teachers in Nursery Schools—Evaluation of Measures for Noise Reduction When Dropping DUPLO Toy Bricks into Storage Cases by Sound Analyses

    Directory of Open Access Journals (Sweden)

    Konstanze Gebauer

    2016-07-01

    Full Text Available Background: Although noise is one of the leading work-related health risk factors for teachers, many nursery schools lack sufficient noise reduction measures. Methods: This intervention study evaluated the noise exposure of nursery school teachers when dropping DUPLO toy bricks into storage cases. Sound analyses of the impact included assessment of the maximum sound pressure level (LAFmax as well as frequency analyses with 1/3 octave band filter. For the purpose of standardization, a customized gadget was developed. Recordings were performed in 11 cases of different materials and designs to assess the impact on sound level reduction. Thereby, the acoustic effects of three damping materials (foam rubber, carpet, and PU-foam were investigated. Results: The lowest LAFmax was measured in cases consisting of “metal grid” (90.71 dB or of a woven willow “basket” (91.61 dB, whereas a case of “aluminium” (103.34 dB generated the highest impact LAFmax. The frequency analyses determined especially low LAFmax in the frequency bands between 80 and 2500 Hz in cases designs “metal grid” and “basket”. The insertion of PU-foam achieved the most significant attenuation of LAFmax (−13.88 dB and, in the frequency analyses, the best sound damping. Conclusion: The dropping of DUPLO bricks in cases contributes to the high noise level in nursery schools, but measured LAFmax show no evidence for the danger of acute hearing loss. However, continuous exposure may lead to functional impairment of the hair cells and trigger stress reactions. We recommend noise reduction by utilizing cases of woven “basket” with an insert of PU-foam.

  5. Development of a Blood Pressure Measurement Instrument with Active Cuff Pressure Control Schemes

    Directory of Open Access Journals (Sweden)

    Chung-Hsien Kuo

    2017-01-01

    Full Text Available This paper presents an oscillometric blood pressure (BP measurement approach based on the active control schemes of cuff pressure. Compared with conventional electronic BP instruments, the novelty of the proposed BP measurement approach is to utilize a variable volume chamber which actively and stably alters the cuff pressure during inflating or deflating cycles. The variable volume chamber is operated with a closed-loop pressure control scheme, and it is activated by controlling the piston position of a single-acting cylinder driven by a screw motor. Therefore, the variable volume chamber could significantly eliminate the air turbulence disturbance during the air injection stage when compared to an air pump mechanism. Furthermore, the proposed active BP measurement approach is capable of measuring BP characteristics, including systolic blood pressure (SBP and diastolic blood pressure (DBP, during the inflating cycle. Two modes of air injection measurement (AIM and accurate dual-way measurement (ADM were proposed. According to the healthy subject experiment results, AIM reduced 34.21% and ADM reduced 15.78% of the measurement time when compared to a commercial BP monitor. Furthermore, the ADM performed much consistently (i.e., less standard deviation in the measurements when compared to a commercial BP monitor.

  6. Home blood pressure measurement in elderly patients with cognitive impairment: comparison of agreement between relative-measured blood pressure and automated blood pressure measurement.

    Science.gov (United States)

    Plichart, Matthieu; Seux, Marie-Laure; Caillard, Laure; Chaussade, Edouard; Vidal, Jean-Sébastien; Boully, Clémence; Hanon, Olivier

    2013-08-01

    Home blood pressure measurement (HBPM) is recommended by guidelines for hypertension management. However, this method might be difficult to use in elderly individuals with cognitive disorders. Our aim was to assess the agreement and the feasibility of HBPM by a relative as compared with 24-h ambulatory blood pressure monitoring (ABPM) in elderly patients with dementia. Sixty outpatients with dementia aged 75 years and older with office hypertension (≥140/90 mmHg) were subjected successively to HBPM by a trained relative and 24-h ABPM. The order of the two methods was randomized. Current guidelines' thresholds for the diagnosis of hypertension were used. The mean (SD) age of the patients was 80.8 (6.1) years (55% women) and the mean (SD) mini-mental state examination score was 20.1 (6.9). The feasibility of relative-HBPM was very high, with a 97% success rate (defined by ≥12/18 measurements reported). The blood pressure measurements were highly correlated between the two methods (r=0.75 and 0.64 for systolic blood pressure and diastolic blood pressure, respectively; Pmethods for the diagnosis of sustained hypertension and white-coat hypertension was excellent (overall agreement, 92%; κ coefficient, 0.81; 95% CI, 0.61-0.93). Similar results were found for daytime-ABPM. In cognitively impaired elderly patients, HBPM by a relative using an automated device was a good alternative to 24-h ABPM.

  7. Experimental reslts from the HERO project: In situ measurements of ionospheric modifications using sounding rockets

    International Nuclear Information System (INIS)

    Rose, G.; Grandal, B.; Neske, E.; Ott, W.; Spenner, K.; Maseide, K.; Troim, J.

    1985-01-01

    The Heating Rocket project HERO comprised the first in situ experiments to measure artifical ionospheric modifications at F layer heights set up by radio waves transmitted from the Heating facility at Ramfjord near Tromso in Northern Norway. Four instrumented payloads were launched on sounding rockets from Andoya Rocket Range during the autumn of 1982 into a sunlit ionosphere with the sun close to the horizon. The payloads recorded modifications, in particular, the presence of electron plasma waves near the reflection level of the heating wave. The amplitude and phase of the three components of the electric and magnetic fields of the heating wave were measured simultaneously as a function of altitude. Coherent spectra of the three electric field components of the locally generated electron plasma waves were obtained in a 50-kHz-wide band. At the same time quasi-continuous measurements were made on several fixed frequencies from 4 kHz to 16 kHz below the heating frequency and in the VLF-range using linear dipole antennas. Moreover, measurements were made of electron temperature, suprathermal electrons and local electron density along the rocket trajectory. The experimental results will be presented and discussed

  8. Thermopower measurement under high pressure using 'seesaw heating method'

    International Nuclear Information System (INIS)

    Hedo, M; Nakamura, D; Takaesu, Y; Yagasaki, K; Nakama, T; Fujiwara, T; Uchima, K

    2010-01-01

    We have developed a set-up with modified 'seesaw heating method' for the thermopower measurement under pressures P up to 3 GPa at the temperature range between 2 K and 300 K. By using this set-up, the thermopower and electrical resistivity of the single crystalline YbMn 2 Ge 2 under high pressure were measured with enough accuracy. S(T) curve shows the characteristic feature at the magnetic transition in all pressure range, while no evidence of the magnetic phase transition is observed in ρ(T) at P > 1.25 GPa. The measurement results indicate that the simultaneous measurement of the thermopower and electrical resistivity is a useful tool to study the pressure-induced phase transitions.

  9. Radiation Pressure Measurements on Micron-Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P. D.; Spann, J. F.; Witherow, W. K.; West, E. A.; Gallagher, D. L.; Adrian, M. L.; Fishman, G. J.; Tankosic, D.; LeClair, A.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2- to 6.82-micron range and irradiating them from above with laser radiation focused to beam widths of approximately 175- 400 microns at ambient pressures particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of SiO2 and the corresponding extinction and scattering efficiencies.

  10. Measurement of the differential pressure of liquid metals

    Science.gov (United States)

    Metz, H.J.

    1975-09-01

    This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed. (auth)

  11. Measurement of the differential pressure of liquid metals

    International Nuclear Information System (INIS)

    Metz, H.J.

    1975-01-01

    This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed

  12. Pressure and Relative Humidity Measurement Devices for Mars 2020 Rover

    Science.gov (United States)

    Hieta, M.; Genzer, M.; Nikkanen, T.; Haukka, H.; Harri, A.-M.; Polkko, J.; Rodriguez-Manfredi, J. A.

    2017-09-01

    One of the scientific payloads onboard the NASA Mars 2020 rover mission is Mars Environmental Dynamic Analyzer (MEDA): a set of environmental sensors for Mars surface weather measurements. Finnish Meteorological Institute (FMI) provides a pressure measurement device (MEDA PS) and a relative humidity measurement device (MEDA HS) for MEDA.

  13. Blood pressure measurements in the ankle are not equivalent to ...

    African Journals Online (AJOL)

    Background. Blood pressure (BP) is often measured on the ankle in the emergency department (ED), but this has never been shown to be an acceptable alternative to measurements performed on the arm. Objective. To establish whether the differences between arm and ankle non-invasive BP measurements were clinically ...

  14. TMX-U neutral pressure measurement diagnostic systems

    International Nuclear Information System (INIS)

    Pickles, W.L.; Allen, S.L.; Hill, D.N.; Hunt, A.L.; Simonen, T.C.

    1984-01-01

    The Tandem Mirror Experiment-Upgrade (TMX-U) has a large and complex system of Baird Alpert, magnetron, and Penning gauges, in addition to mass spectrometers (RGA), all of which measure neutral pressures in the many internal regions of TMX-U. These pressure measurements are used as part of the confinement physics data base as well as for management of the TMX-U vacuum system. Dynamic pressures are modeled by a coupled-volumes simulation code, which includes wall reflus, getter pumping, and plasma pumping

  15. A human cadaver fascial compartment pressure measurement model.

    Science.gov (United States)

    Messina, Frank C; Cooper, Dylan; Huffman, Gretchen; Bartkus, Edward; Wilbur, Lee

    2013-10-01

    Fresh human cadavers provide an effective model for procedural training. Currently, there are no realistic models to teach fascial compartment pressure measurement. We created a human cadaver fascial compartment pressure measurement model and studied its feasibility with a pre-post design. Three faculty members, following instructions from a common procedure textbook, used a standard handheld intra-compartment pressure monitor (Stryker(®), Kalamazoo, MI) to measure baseline pressures ("unembalmed") in the anterior, lateral, deep posterior, and superficial posterior compartments of the lower legs of a fresh human cadaver. The right femoral artery was then identified by superficial dissection, cannulated distally towards the lower leg, and connected to a standard embalming machine. After a 5-min infusion, the same three faculty members re-measured pressures ("embalmed") of the same compartments on the cannulated right leg. Unembalmed and embalmed readings for each compartment, and baseline readings for each leg, were compared using a two-sided paired t-test. The mean baseline compartment pressures did not differ between the right and left legs. Using the embalming machine, compartment pressure readings increased significantly over baseline for three of four fascial compartments; all in mm Hg (±SD): anterior from 40 (±9) to 143 (±44) (p = 0.08); lateral from 22 (±2.5) to 160 (±4.3) (p cadaver using a standard embalming machine. Set-up is minimal and the model can be incorporated into teaching curricula. Copyright © 2013 Elsevier Inc. All rights reserved.

  16. MIPAS-ENVISAT limb-sounding measurements: trade-off study for improvement of horizontal resolution.

    Science.gov (United States)

    Ridolfi, Marco; Magnani, Luca; Carlotti, Massimo; Dinelli, Bianca Maria

    2004-11-01

    The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is a limb-scanning spectrometer that has operated onboard the Environmental Satellite since the end of March 2002. Common features of limb-scanning experiments are both high vertical resolution and poor horizontal resolution. We exploit the two-dimensional geo-fit retrieval approach [Appl. Opt. 40, 1872-1875 (2001)] to investigate the possibility of improving the horizontal resolution of MIPAS measurements. Two different strategies are considered for this purpose, one exploiting the possibility (offered by the geo-fit analysis method) for an arbitrary definition of the retrieval grid, the other based on the possibility of saving measurement time by degrading the spectral resolution of the interferometer. The performances of the two strategies are compared in terms of the trade-off between the attained horizontal resolution and the retrieval precision. We find that for ozone it is possible to improve by a factor of 2 the horizontal resolution, which in the nominal measurement plan is approximately 530 km. This improvement corresponds to a degradation of the retrieval precision, which on average varies from a factor of 1.4 to 2.5, depending on the adopted spectral resolution.

  17. Measurement of the velocity of sound in crystals by pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Willis, B.T.M.; Carlile, C.J.; Ward, R.C.; David, W.I.F.; Johnson, M.W.

    1986-03-01

    The diffraction method of observing elementary excitations in crystals has been applied to the study of one-phonon thermal diffuse scattering from pyrolytic graphite on a high resolution pulsed neutron diffractometer. The variation of the phase velocity of sound as a function of direction in the crystal and efficient method of determining sound velocities in crystals under extreme conditions. (author)

  18. 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…

  19. Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure Response of Protein-Stabilized Gold Nanoclusters

    Science.gov (United States)

    2016-01-01

    ARL-TR-7577 ● JAN 2016 US Army Research Laboratory Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure ...ARL-TR-7577 ● JAN 2016 US Army Research Laboratory Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure Response of...DATES COVERED (From - To) May 2014–September 2014 4. TITLE AND SUBTITLE Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure

  20. Analysis of In Situ Thermal Ion Measurements from the MICA Sounding Rocket

    Science.gov (United States)

    Fernandes, P. A.; Lynch, K. A.; Zettergren, M. D.; Hampton, D. L.; Fisher, L. E.; Powell, S. P.

    2014-12-01

    The MICA sounding rocket launched on 19 Feb. 2012 into several discrete, localized arcs in the wake of a westward traveling surge. In situ and ground-based observations provide a measured response of the ionosphere to preflight and localized auroral drivers. Initial analysis of the in situ thermal ion data indicate possible measurement of an ion conic at low altitude (< 325 km). In the low-energy regime, the response of the instrument varies from the ideal because the measured thermal ion population is sensitive to the presence of the instrument. The plasma is accelerated in the frame of the instrument due to flows, ram, and acceleration through the sheath which forms around the spacecraft. The energies associated with these processes are large compared to the thermal energy. Correct interpretation of thermal plasma measurements requires accounting for all of these plasma processes and the non-ideal response of the instrument in the low-energy regime. This is an experimental and modeling project which involves thorough analysis of ionospheric thermal ion data from the MICA campaign. Analysis includes modeling and measuring the instrument response in the low-energy regime as well as accounting for the complex sheath formed around the instrument. This results in a forward model in which plasma parameters of the thermal plasma are propagated through the sheath and instrument models, resulting in an output which matches the in situ measurement. In the case of MICA, we are working toward answering the question of the initiating source processes that result, at higher altitudes, in well-developed conics and outflow on auroral field lines.

  1. Measuring the vertical electrical field above an oceanic convection system using a meteorological sounding balloon

    Science.gov (United States)

    Chen, A. B.; Chiu, C.; Lai, S.; Chen, C.; Kuo, C.; Su, H.; Hsu, R.

    2012-12-01

    The vertical electric field above thundercloud plays an important role in the generation and modeling of transient luminous events. For example, Pasko [1995] proposed that the high quasi-static E-field following the positive cloud-to-ground lightning could accelerate and input energy to ambient electrons; as they collide and excite nitrogen and oxygen molecules in upper atmosphere, sprites may be induced. A series of balloon experiments led by Holzworth have investigated the temporal and spatial fluctuations of the electric field and conductivity in the upper atmosphere at different sites [Holzworth 2005, and references in]. But the strength and variation of the vertical electric field above thundercloud, especially oceanic ones, are not well documented so far. A lightweight, low-cost measurement system including an electric field meter and the associated aviation electronics are developed to carry out the in-situ measurement of the vertical electric field and the inter-cloud charge distribution. Our measuring system was first deployed using a meteorological sounding balloon from Taitung, Taiwan in May 2012. The measured electric field below 3km height shows an exponential decay and it is consistent with the expected potential gradient variation between ionosphere and the Earth surface. But the background strength of the measured E-field grows up exponentially and a violent fluctuations is also observed when the balloon flew over a developing oceanic convection cell. The preliminary results from this flight will be reported and discussed. This low-cost electric field meter is developed within one year. In the coming months, more flights will be performed with the aim to measure the rapid variation of the electric field above thundercloud as well as the E-field that may induce transient luminous events. Our ground campaigns show that the occurrence rates of blue and gigantic jet are relatively high in the vicinity of Taiwan. Our experiment can be used to diagnose

  2. Hepatic venous pressure gradients measured by duplex ultrasound

    International Nuclear Information System (INIS)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M.

    2002-01-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P -2 provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  3. Hepatic venous pressure gradients measured by duplex ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Tasu, J.-P.; Rocher, L.; Peletier, G.; Kuoch, V.; Kulh, E.; Miquel, A.; Buffet, C.; Biery, M

    2002-08-01

    AIMS: The hepatic venous pressure gradient is a major prognostic factor in portal hypertension but its measurement is complex and requires invasive angiography. This study investigated the relationship between the hepatic venous pressure gradient and a number of Doppler measurements, including the arterial acceleration index. METHOD: We measured the hepatic venous pressure gradient in 50 fasting patients at hepatic venography. Immediately afterwards, a duplex sonographic examination of the liver was performed at which multiple measurements and indices of the venous and arterial hepatic vasculature were made. RESULTS: Hepatic arterial acceleration was correlated directly with the hepatic venous pressure gradient (r = 0.83, P < 0.0001) and with the Child-Pugh score (r = 0.63, P < 0.0001). An acceleration index cut-off value of 1 m.s{sup -2} provided a positive predictive value of 95%, a sensitivity of 65% and a specificity of 95% for detecting patients with severe portal hypertension (hepatic venous pressure gradient > 12 mmHg). A correlation between the hepatic venous pressure gradient and the congestion index of the portal vein velocity (r = 0.45,P = 0.01) and portal vein velocity (r = 0.40,P = 0.044), was also noted. CONCLUSION: Measuring the hepatic arterial acceleration index may help in the non-invasive evaluation of portal hypertension. Tasu, J.-P. et al. (2002)

  4. MEASUREMENT OF FRICTIONAL PRESSURE DIFFERENTIALS DURING A VENTILATION SURVEY

    International Nuclear Information System (INIS)

    B.S. Prosser, PE; I.M. Loomis, PE, PhD

    2003-01-01

    During the course of a ventilation survey, both airflow quantity and frictional pressure losses are measured and quantified. The measurement of airflow has been extensively studied as the vast majority of ventilation standards/regulations are tied to airflow quantity or velocity. However, during the conduct of a ventilation survey, measurement of airflow only represents half of the necessary parameters required to directly calculate the airway resistance. The measurement of frictional pressure loss is an often misunderstood and misapplied part of the ventilation survey. This paper compares the two basic methods of frictional pressure drop measurements; the barometer and the gauge and tube. Personal experiences with each method will be detailed along with the authors' opinions regarding the applicability and conditions favoring each method

  5. Dew-point measurements at high water vapour pressure

    Science.gov (United States)

    Lomperski, S.; Dreier, J.

    1996-05-01

    A dew-point meter capable of measuring humidity at high vapour pressure and high temperature has been constructed and tested. Humidity measurements in pure steam were made over the temperature range 100 - 1500957-0233/7/5/003/img1C and a vapour pressure range of 1 - 4 bar. The dew-point meter performance was assessed by comparing measurements with a pressure transmitter and agreement between the two was within 0957-0233/7/5/003/img2% relative humidity. Humidity measurements in steam - air mixtures were also made and the dew-point meter readings were compared to those of a zirconia oxygen sensor. For these tests the dew-point meter readings were generally within 0957-0233/7/5/003/img2% relative humidity of the oxygen sensor measurements.

  6. Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

    Directory of Open Access Journals (Sweden)

    A. R. Rodi

    2012-11-01

    Full Text Available A method is described that estimates the error in the static pressure measurement on an aircraft from differential pressure measurements on the hemispherical surface of a Rosemount model 858AJ air velocity probe mounted on a boom ahead of the aircraft. The theoretical predictions for how the pressure should vary over the surface of the hemisphere, involving an unknown sensitivity parameter, leads to a set of equations that can be solved for the unknowns – angle of attack, angle of sideslip, dynamic pressure and the error in static pressure – if the sensitivity factor can be determined. The sensitivity factor was determined on the University of Wyoming King Air research aircraft by comparisons with the error measured with a carefully designed sonde towed on connecting tubing behind the aircraft – a trailing cone – and the result was shown to have a precision of about ±10 Pa over a wide range of conditions, including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, geometric altitude data from a combined Global Navigation Satellite System (GNSS and inertial measurement unit (IMU system are used to estimate acceleration effects on the error, and the algorithm is shown to predict corrections to a precision of better than ±20 Pa under those conditions. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are discussed.

  7. Vibro-acoustic model of a piezoelectric-based stethoscope for chest sound measurements

    International Nuclear Information System (INIS)

    Nelson, G; Rajamani, R; Erdman, A

    2015-01-01

    This article focuses on the influence of noise and vibration on chest sound measurements with a piezoelectric stethoscope. Two types of vibrations, namely inputs through the patient chest and disturbances from the physician, influence the acoustic measurement. The goal of this work is to develop a model to understand the propagation of these vibrational noises through the stethoscope and to the piezoelectric sensing element. Using the model, methods to reduce the influence of disturbances acting on the stethoscope from the physician handling the device are explored.A multi-DOF rigid body vibration model consisting of discrete connected components is developed for the piezoelectric stethoscope. Using a two-port lumped parameter model, the mechanical vibrations are related to the resulting electrical signal. The parameterized state space model is experimentally validated and its parameters are identified by using a thorax simulator and vibration shaker. Based on predictions from the model, the introduction of vibration isolation to reduce the influence of physician noise on the transducer is then pursued. It is shown that direct vibration isolation between the transducer and the rest of the stethoscope structure leads to a reduction in coupling with the patient’s chest. However, if isolation is instead introduced between the transducer housing and the rest of the stethoscope, then vibration isolation from the physician is achieved with far less reduction in patient coupling. Experimental results are presented to study the influence of the proposed design changes and confirm the predicted model behavior. (paper)

  8. Vibro-acoustic model of a piezoelectric-based stethoscope for chest sound measurements

    Science.gov (United States)

    Nelson, G.; Rajamani, R.; Erdman, A.

    2015-09-01

    This article focuses on the influence of noise and vibration on chest sound measurements with a piezoelectric stethoscope. Two types of vibrations, namely inputs through the patient chest and disturbances from the physician, influence the acoustic measurement. The goal of this work is to develop a model to understand the propagation of these vibrational noises through the stethoscope and to the piezoelectric sensing element. Using the model, methods to reduce the influence of disturbances acting on the stethoscope from the physician handling the device are explored. A multi-DOF rigid body vibration model consisting of discrete connected components is developed for the piezoelectric stethoscope. Using a two-port lumped parameter model, the mechanical vibrations are related to the resulting electrical signal. The parameterized state space model is experimentally validated and its parameters are identified by using a thorax simulator and vibration shaker. Based on predictions from the model, the introduction of vibration isolation to reduce the influence of physician noise on the transducer is then pursued. It is shown that direct vibration isolation between the transducer and the rest of the stethoscope structure leads to a reduction in coupling with the patient’s chest. However, if isolation is instead introduced between the transducer housing and the rest of the stethoscope, then vibration isolation from the physician is achieved with far less reduction in patient coupling. Experimental results are presented to study the influence of the proposed design changes and confirm the predicted model behavior.

  9. Suspended sediment assessment by combining sound attenuation and backscatter measurements - analytical method and experimental validation

    Science.gov (United States)

    Guerrero, Massimo; Di Federico, Vittorio

    2018-03-01

    The use of acoustic techniques has become common for estimating suspended sediment in water environments. An emitted beam propagates into water producing backscatter and attenuation, which depend on scattering particles concentration and size distribution. Unfortunately, the actual particles size distribution (PSD) may largely affect the accuracy of concentration quantification through the unknown coefficients of backscattering strength, ks2, and normalized attenuation, ζs. This issue was partially solved by applying the multi-frequency approach. Despite this possibility, a relevant scientific and practical question remains regarding the possibility of using acoustic methods to investigate poorly sorted sediment in the spectrum ranging from clay to fine sand. The aim of this study is to investigate the possibility of combining the measurement of sound attenuation and backscatter to determine ζs for the suspended particles and the corresponding concentration. The proposed method is moderately dependent from actual PSD, thus relaxing the need of frequent calibrations to account for changes in ks2 and ζs coefficients. Laboratory tests were conducted under controlled conditions to validate this measurement technique. With respect to existing approaches, the developed method more accurately estimates the concentration of suspended particles ranging from clay to fine sand and, at the same time, gives an indication on their actual PSD.

  10. Directional sound radiation from substation transformers

    International Nuclear Information System (INIS)

    Maybee, N.

    2009-01-01

    This paper presented the results of a study in which acoustical measurements at two substations were analyzed to investigate the directional behaviour of typical arrays having 2 or 3 transformers. Substation transformers produce a characteristic humming sound that is caused primarily by vibration of the core at twice the frequency of the power supply. The humming noise radiates predominantly from the tank enclosing the core. The main components of the sound are harmonics of 120 Hz. Sound pressure level data were obtained for various directions and distances from the arrays, ranging from 0.5 m to over 100 m. The measured sound pressure levels of the transformer tones displayed substantial positive and negative excursions from the calculated average values for many distances and directions. The results support the concept that the directional effects are associated with constructive and destructive interference of tonal sound waves emanating from different parts of the array. Significant variations in the directional sound pattern can occur in the near field of a single transformer or an array, and the extent of the near field is significantly larger than the scale of the array. Based on typical dimensions for substation sites, the distance to the far field may be much beyond the substation boundary and beyond typical setbacks to the closest dwellings. As such, the directional sound radiation produced by transformer arrays introduces additional uncertainty in the prediction of substation sound levels at dwellings within a few hundred meters of a substation site. 4 refs., 4 figs.

  11. 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...

  12. MRI measurements of intracranial pressure in the upright posture: The effect of the hydrostatic pressure gradient.

    Science.gov (United States)

    Alperin, Noam; Lee, Sang H; Bagci, Ahmet M

    2015-10-01

    To add the hydrostatic component of the cerebrospinal fluid (CSF) pressure to magnetic resonance imaging (MRI)-derived intracranial pressure (ICP) measurements in the upright posture for derivation of pressure value in a central cranial location often used in invasive ICP measurements. Additional analyses were performed using data previously collected from 10 healthy subjects scanned in supine and sitting positions with a 0.5T vertical gap MRI scanner (GE Medical). Pulsatile blood and CSF flows to and from the brain were quantified using cine phase-contrast. Intracranial compliance and pressure were calculated using a previously described method. The vertical distance between the location of the CSF flow measurement and a central cranial location was measured manually in the mid-sagittal T1 -weighted image obtained in the upright posture. The hydrostatic pressure gradient of a CSF column with similar height was then added to the MR-ICP value. After adjustment for the hydrostatic component, the mean ICP value was reduced by 7.6 mmHg. Mean ICP referenced to the central cranial level was -3.4 ± 1.7 mmHg compared to the unadjusted value of +4.3 ± 1.8 mmHg. In the upright posture, the hydrostatic pressure component needs to be added to the MRI-derived ICP values for compatibility with invasive ICP at a central cranial location. © 2015 Wiley Periodicals, Inc.

  13. Foldable micro coils for a transponder system measuring intraocular pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ullerich, S.; Schnakenberg, U. [Technische Hochschule Aachen (Germany). Inst. of Materials in Electrical Engineering 1; Mokwa, W. [Technische Hochschule Aachen (Germany). Inst. of Materials in Electrical Engineering 1]|[Fraunhofer Inst. of Microelectronic Circuits and Systems, Duisburg (Germany); Boegel, G. vom [Fraunhofer Inst. of Microelectronic Circuits and Systems, Duisburg (Germany)

    2001-07-01

    A foldable transponder system consisting of a chip and a micro coil for measuring intraocular pressure continuously is presented. The system will be integrated in the haptic of a soft artificial intraocular lens. Calculations of planar micro coils with 6 mm and 10.3 mm in diameter show the limits for planar coils with an outer diameter of 6 mm. For the realisation of the transponder system a 20 {mu}m thick coil with an outer diameter of 10.3 mm, an inner diameter of 7.7 mm, 16 turns and a gap of 20 {mu}m between the windings was selected. Measurements show a good agreement between calculated and measured values. Wireless pressure measurements were carried out showing a linear behaviour of the output signal with respect to the applied pressure. (orig.)

  14. Measurement of rock properties at elevated pressures and temperatures

    International Nuclear Information System (INIS)

    Pincus, H.J.; Hoskins, E.R.

    1985-01-01

    The papers in this volume were presented at an ASTM symposium held on 20 June 1983 in conjunction with the 24th Annual Rock Mechanics Symposium at Texas A and M University, College Station, TX. The purpose of these papers is to present recent developments in the measurement of rock properties at elevated pressures and temperatures, and to examine and interpret the data produced by such measurement. The need for measuring rock properties at elevated pressures and temperatures has become increasingly important in recent years. Location and design of nuclear waste repositories, development of geothermal energy sites, and design and construction of deep excavations for civil, military, and mining engineering require significantly improved capabilities for measuring rock properties under conditions substantially different from those prevailing in most laboratory and in situ work. The development of high-pressure, high-temperature capabilities is also significant for the analysis of tectonic processes

  15. A Model for the Sounding Rocket Measurement on an Ionospheric E-F Valley at the Hainan Low Latitude Station

    International Nuclear Information System (INIS)

    Wang Zheng; Shi Jiankui; Guan Yibing; Liu Chao; Zhu Guangwu; Torkar Klaus; Fredrich Martin

    2014-01-01

    To understand the physics of an ionospheric E-F valley, a new overlapping three-Chapman-layer model is developed to interpret the sounding rocket measurement in the morning (sunrise) on May 7, 2011 at the Hainan low latitude ionospheric observation station (19.5°N, 109.1°E). From our model, the valley width, depth and height are 43.0 km, 62.9% and 121.0 km, respectively. From the sounding rocket observation, the valley width, depth and height are 42.2 km, 47.0% and 123.5 km, respectively. The model results are well consistent with the sounding rocket observation. The observed E-F valley at Hainan station is very wide and deep, and rapid development of the photochemical process in the ionosphere should be the underlying reason. (astrophysics and space plasma)

  16. Standard values of maximum tongue pressure taken using newly developed disposable tongue pressure measurement device.

    Science.gov (United States)

    Utanohara, Yuri; Hayashi, Ryo; Yoshikawa, Mineka; Yoshida, Mitsuyoshi; Tsuga, Kazuhiro; Akagawa, Yasumasa

    2008-09-01

    It is clinically important to evaluate tongue function in terms of rehabilitation of swallowing and eating ability. We have developed a disposable tongue pressure measurement device designed for clinical use. In this study we used this device to determine standard values of maximum tongue pressure in adult Japanese. Eight hundred fifty-three subjects (408 male, 445 female; 20-79 years) were selected for this study. All participants had no history of dysphagia and maintained occlusal contact in the premolar and molar regions with their own teeth. A balloon-type disposable oral probe was used to measure tongue pressure by asking subjects to compress it onto the palate for 7 s with maximum voluntary effort. Values were recorded three times for each subject, and the mean values were defined as maximum tongue pressure. Although maximum tongue pressure was higher for males than for females in the 20-49-year age groups, there was no significant difference between males and females in the 50-79-year age groups. The maximum tongue pressure of the seventies age group was significantly lower than that of the twenties to fifties age groups. It may be concluded that maximum tongue pressures were reduced with primary aging. Males may become weaker with age at a faster rate than females; however, further decreases in strength were in parallel for male and female subjects.

  17. Wavenumber-frequency Spectra of Pressure Fluctuations Measured via Fast Response Pressure Sensitive Paint

    Science.gov (United States)

    Panda, J.; Roozeboom, N. H.; Ross, J. C.

    2016-01-01

    The recent advancement in fast-response Pressure-Sensitive Paint (PSP) allows time-resolved measurements of unsteady pressure fluctuations from a dense grid of spatial points on a wind tunnel model. This capability allows for direct calculations of the wavenumber-frequency (k-?) spectrum of pressure fluctuations. Such data, useful for the vibro-acoustics analysis of aerospace vehicles, are difficult to obtain otherwise. For the present work, time histories of pressure fluctuations on a flat plate subjected to vortex shedding from a rectangular bluff-body were measured using PSP. The light intensity levels in the photographic images were then converted to instantaneous pressure histories by applying calibration constants, which were calculated from a few dynamic pressure sensors placed at selective points on the plate. Fourier transform of the time-histories from a large number of spatial points provided k-? spectra for pressure fluctuations. The data provides first glimpse into the possibility of creating detailed forcing functions for vibro-acoustics analysis of aerospace vehicles, albeit for a limited frequency range.

  18. Temperature measurement in the liquid helium range at pressure

    International Nuclear Information System (INIS)

    Itskevich, E.S.; Krajdenov, V.F.

    1978-01-01

    The use of bronze and germanium resistance thermometers and the use of a (Au + 0.07 % Fe)-Cu thermocouple for temperature measurements from 1.5 to 4.2 K in the hydrostatic compression of up to 10 kbar are considered. To this aim, the thermometer resistance as a function of temperature and pressure is measured. It is revealed that pressure does not change the thermometric response of the bronze resistance thermometer but only shifts it to the region of lower temperatures. The identical investigations of the germanium resistance thermometer shows that strong temperature dependence and the shift of its thermometric response under the influence of pressure make the use of germanium resistance thermometers in high-pressure chambers very inconvenient. The results of the analysis of the (Au + 0.07 % Fe) - Cu thermocouple shows that with a 2 per cent accuracy the thermocouple Seebeck coefficient does not depend on pressure. It permits to use this thermocouple for temperature measurements at high pressures

  19. Moth hearing and sound communication

    DEFF Research Database (Denmark)

    Nakano, Ryo; Takanashi, Takuma; Surlykke, Annemarie

    2015-01-01

    Active echolocation enables bats to orient and hunt the night sky for insects. As a counter-measure against the severe predation pressure many nocturnal insects have evolved ears sensitive to ultrasonic bat calls. In moths bat-detection was the principal purpose of hearing, as evidenced by compar......Active echolocation enables bats to orient and hunt the night sky for insects. As a counter-measure against the severe predation pressure many nocturnal insects have evolved ears sensitive to ultrasonic bat calls. In moths bat-detection was the principal purpose of hearing, as evidenced...... by comparable hearing physiology with best sensitivity in the bat echolocation range, 20–60 kHz, across moths in spite of diverse ear morphology. Some eared moths subsequently developed sound-producing organs to warn/startle/jam attacking bats and/or to communicate intraspecifically with sound. Not only...... the sounds for interaction with bats, but also mating signals are within the frequency range where bats echolocate, indicating that sound communication developed after hearing by “sensory exploitation”. Recent findings on moth sound communication reveal that close-range (~ a few cm) communication with low...

  20. Exterior sound level measurements of over-snow vehicles at Yellowstone National Park.

    Science.gov (United States)

    2008-09-30

    Sounds associated with oversnow vehicles, such as snowmobiles and snowcoaches, are an : important management concern at Yellowstone and Grand Teton National Parks. The John A. : Volpe National Transportation Systems Centers Environmental Measureme...

  1. Third sound measurements of superfluid 4He films on multiwall carbon nanotubes below 1 K

    International Nuclear Information System (INIS)

    Menachekanian, Emin; Abraham, John B S; Chen, Bob; Iaia, Vito; Li, Andrew; Williams, Gary A

    2014-01-01

    Third sound is studied for superfluid films of 4He adsorbed on multiwall carbon nanotubes packed into an annular resonator. The third sound is generated with mechanical oscillation of the cell, and detected with carbon bolometers. A filling curve at temperatures near 250 mK shows oscillations in the third sound velocity, with maxima at the completion of the 4th and 5th atomic layers. Sharp changes in the Q factor of the third sound are found at partial layer fillings. Temperature sweeps at a number of fill points show strong broadening effects on the Kosterlitz-Thouless (KT) transition, and rapidly increasing dissipation, in qualitative agreement with the predictions of Machta and Guyer. At the 4th layer completion there is a sudden reduction of the transition temperature T KT , and then a recovery back to linear variation with temperature, although the slope is considerably smaller than the KT prediction

  2. Beat-to-beat systolic time-interval measurement from heart sounds and ECG

    International Nuclear Information System (INIS)

    Paiva, R P; Carvalho, P; Couceiro, R; Henriques, J; Antunes, M; Quintal, I; Muehlsteff, J

    2012-01-01

    Systolic time intervals are highly correlated to fundamental cardiac functions. Several studies have shown that these measurements have significant diagnostic and prognostic value in heart failure condition and are adequate for long-term patient follow-up and disease management. In this paper, we investigate the feasibility of using heart sound (HS) to accurately measure the opening and closing moments of the aortic heart valve. These moments are crucial to define the main systolic timings of the heart cycle, i.e. pre-ejection period (PEP) and left ventricular ejection time (LVET). We introduce an algorithm for automatic extraction of PEP and LVET using HS and electrocardiogram. PEP is estimated with a Bayesian approach using the signal's instantaneous amplitude and patient-specific time intervals between atrio-ventricular valve closure and aortic valve opening. As for LVET, since the aortic valve closure corresponds to the start of the S2 HS component, we base LVET estimation on the detection of the S2 onset. A comparative assessment of the main systolic time intervals is performed using synchronous signal acquisitions of the current gold standard in cardiac time-interval measurement, i.e. echocardiography, and HS. The algorithms were evaluated on a healthy population, as well as on a group of subjects with different cardiovascular diseases (CVD). In the healthy group, from a set of 942 heartbeats, the proposed algorithm achieved 7.66 ± 5.92 ms absolute PEP estimation error. For LVET, the absolute estimation error was 11.39 ± 8.98 ms. For the CVD population, 404 beats were used, leading to 11.86 ± 8.30 and 17.51 ± 17.21 ms absolute PEP and LVET errors, respectively. The results achieved in this study suggest that HS can be used to accurately estimate LVET and PEP. (paper)

  3. Mars SubsurfAce Sounding by Time-Domain Electromagnetic MeasuRements

    Science.gov (United States)

    Tacconi, G.; Minna, L.; Pagnan, S.; Tacconi, M.

    1999-09-01

    MASTER (Mars subsurfAce Sounding by Time-domain Electromagnetic measuRements) is an experimental project proposed to fly aboard the Italian Drill (DEEDRI) payload for the Mars Surveyor Program 2003. MASTER will offer the scientific community the first opportunity to scan Mars subsurface structure by means of the technique employing time-domain electromagnetic measurements TDEM. Up today proposed experiments for scanning the Martian subsurface have focused on exploring the crust of the planet Mars up to few meters, while MASTER will explore electrical structures and related soil characteristics and processes at depths up to hundreds meters at least. TDEM represents an active remote sensing system and will be used likely a ULF/ELF/VLF ``radar." If a certain volumetric zone has different electrical conductivity, the current in the sample will vary generating a secondary scattered electromagnetic field containing the information about the explored volume. The volumetric mean value of the conductivity will be estimated according to the implicit near field e.m. propagation conditions, considering the skin depth (d) and the apparent resistivity (ra) as the most representative and critical parameters. As any active remotely sensed measurements the TDEM system behaves like a ``bistatic" communication channel and is mandatory to investigate the characteristics of the background noise at the receiver site. The MASTER system, can operate also as a passive listening device of the possible electromagnetic background noise on the Mars surface at ULF/ELF/VLF bands. Present paper will describe in details the application of the TDEM method as well as the approaches to the detection and estimation of the e.m. BGN on Mars surface, in terms of man made, natural BGN and intrinsic noise of the sensors and electronic systems. The electromagnetic background noise detection/estimation represents by itself a no cost experiment and the first experiment of this type on Mars.

  4. The Effects of Musician's Earplugs on Acoustic and Perceptual Measures of Choral and Solo Sound.

    Science.gov (United States)

    Cook-Cunningham, Sheri L

    2017-10-25

    The purpose of this investigation was to assess the effects of earplugs on acoustical and perceptual measures of choral and solo sound. The researcher tested the effects of musician's earplugs on choral and solo timbre and singer perceptions. Members of an intact women's university choir recorded Dona Nobis Pacem under two conditions, no earplugs and with earplugs over time. Approximately half of the choir members also participated as soloists, recording Over the Rainbow under the same two conditions. All recordings were analyzed using long-term average spectra (LTAS). After participating in each recording session, the participants responded to a questionnaire about ability to hear self (solo and choral context) and ability to hear others (choral context) under two conditions, no earplugs and with earplugs. LTAS results revealed that wearing earplugs in a choral setting caused decreased mean signal energy (>1 dB), resulting in less resonant singing. LTAS results also indicated that wearing earplugs in a solo setting had less effect on mean signal energy, resulting in a mean difference solo setting. Findings from this study could provide important information when structuring hearing conservation strategies. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  5. A Manganin Thin Film Ultra-High Pressure Sensor for Microscale Detonation Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Guodong Zhang

    2018-03-01

    Full Text Available With the development of energetic materials (EMs and microelectromechanical systems (MEMS initiating explosive devices, the measurement of detonation pressure generated by EMs in the microscale has become a pressing need. This paper develops a manganin thin film ultra-high pressure sensor based on MEMS technology for measuring the output pressure from micro-detonator. A reliable coefficient is proposed for designing the sensor’s sensitive element better. The sensor employs sandwich structure: the substrate uses a 0.5 mm thick alumina ceramic, the manganin sensitive element with a size of 0.2 mm × 0.1 mm × 2 μm and copper electrodes of 2 μm thick are sputtered sequentially on the substrate, and a 25 μm thick insulating layer of polyimide is wrapped on the sensitive element. The static test shows that the piezoresistive coefficient of manganin thin film is 0.0125 GPa−1. The dynamic experiment indicates that the detonation pressure of micro-detonator is 12.66 GPa, and the response time of the sensor is 37 ns. In a word, the sensor developed in this study is suitable for measuring ultra-high pressure in microscale and has a shorter response time than that of foil-like manganin gauges. Simultaneously, this study could be beneficial to research on ultra-high-pressure sensors with smaller size.

  6. An experimental device for accurate ultrasounds measurements in liquid foods at high pressure

    International Nuclear Information System (INIS)

    Hidalgo-Baltasar, E; Taravillo, M; Baonza, V G; Sanz, P D; Guignon, B

    2012-01-01

    The use of high hydrostatic pressure to ensure safe and high-quality product has markedly increased in the food industry during the last decade. Ultrasonic sensors can be employed to control such processes in an equivalent way as they are currently used in processes carried out at room pressure. However, their installation, calibration and use are particularly challenging in the context of a high pressure environment. Besides, data about acoustic properties of food under pressure and even for water are quite scarce in the pressure range of interest for food treatment (namely, above 200 MPa). The objective of this work was to establish a methodology to determine the speed of sound in foods under pressure. An ultrasonic sensor using the multiple reflections method was adapted to a lab-scale HHP equipment to determine the speed of sound in water between 253.15 and 348.15 K, and at pressures up to 700 MPa. The experimental speed-of-sound data were compared to the data calculated from the equation of state of water (IAPWS-95 formulation). From this analysis, the way to calibrate cell path was validated. After this calibration procedure, the speed of sound could be determined in liquid foods by using this sensor with a relative uncertainty between (0.22 and 0.32) % at a confidence level of 95 % over the whole pressure domain.

  7. Dynamic tire pressure sensor for measuring ground vibration.

    Science.gov (United States)

    Wang, Qi; McDaniel, James Gregory; Wang, Ming L

    2012-11-07

    This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure changes inside the tire, ground vibration can be amplified and isolated from environmental noise. In this work, verifications of the DTPS concept of sensing inside the tire have been carried out. In addition, comparisons between a DTPS, ground-mounted accelerometer, and directional microphone are made. A data analysis algorithm has been developed and optimized to reconstruct ground acceleration from DTPS data. Numerical and experimental studies of this DTPS reveal a strong potential for measuring ground vibration caused by a moving vehicle. A calibration of transfer function between dynamic tire pressure change and ground acceleration may be needed for different tire system or for more accurate application.

  8. A Computer Controlled Precision High Pressure Measuring System

    Science.gov (United States)

    Sadana, S.; Yadav, S.; Jha, N.; Gupta, V. K.; Agarwal, R.; Bandyopadhyay, A. K.; Saxena, T. K.

    2011-01-01

    A microcontroller (AT89C51) based electronics has been designed and developed for high precision calibrator based on Digiquartz pressure transducer (DQPT) for the measurement of high hydrostatic pressure up to 275 MPa. The input signal from DQPT is converted into a square wave form and multiplied through frequency multiplier circuit over 10 times to input frequency. This input frequency is multiplied by a factor of ten using phased lock loop. Octal buffer is used to store the calculated frequency, which in turn is fed to microcontroller AT89C51 interfaced with a liquid crystal display for the display of frequency as well as corresponding pressure in user friendly units. The electronics developed is interfaced with a computer using RS232 for automatic data acquisition, computation and storage. The data is acquired by programming in Visual Basic 6.0. This system is interfaced with the PC to make it a computer controlled system. The system is capable of measuring the frequency up to 4 MHz with a resolution of 0.01 Hz and the pressure up to 275 MPa with a resolution of 0.001 MPa within measurement uncertainty of 0.025%. The details on the hardware of the pressure measuring system, associated electronics, software and calibration are discussed in this paper.

  9. Extremely-high vacuum pressure measurement by laser ionization

    International Nuclear Information System (INIS)

    Kokubun, Kiyohide

    1991-01-01

    Laser ionization method has the very high sensitivity for detecting atoms and molecules. Hurst et al. successfully detected a single Cs atom by means of resonance ionization spectroscopy developed by them. Noting this high sensitivity, the authors have attempted to apply the laser ionization method to measure gas pressure, particularly in the range down to extremely high vacuum. At present, hot cathode ionization gauges are used for measuring gas pressure down to ultrahigh vacuum, however, those have a number of disadvantages. The pressure measurement using lasers does not have such disadvantages. The pressure measurement utilizing the laser ionization method is based on the principle that when laser beam is focused through a lens, the amount of atom or molecule ions generated in the focused space region is proportional to gas pressure. In this paper, the experimental results are presented on the nonresonant multiphoton ionization characteristics of various kinds of gases, the ion detection system with high sensitivity and an extremely high vacuum system prepared for the laser ionization experiment. (K.I.)

  10. Noninvasive blood pressure measurement scheme based on optical fiber sensor

    Science.gov (United States)

    Liu, Xianxuan; Yuan, Xueguang; Zhang, Yangan

    2016-10-01

    Optical fiber sensing has many advantages, such as volume small, light quality, low loss, strong in anti-jamming. Since the invention of the optical fiber sensing technology in 1977, optical fiber sensing technology has been applied in the military, national defense, aerospace, industrial, medical and other fields in recent years, and made a great contribution to parameter measurement in the environment under the limited condition .With the rapid development of computer, network system, the intelligent optical fiber sensing technology, the sensor technology, the combination of computer and communication technology , the detection, diagnosis and analysis can be automatically and efficiently completed. In this work, we proposed a noninvasive blood pressure detection and analysis scheme which uses optical fiber sensor. Optical fiber sensing system mainly includes the light source, optical fiber, optical detector, optical modulator, the signal processing module and so on. wavelength optical signals were led into the optical fiber sensor and the signals reflected by the human body surface were detected. By comparing actual testing data with the data got by traditional way to measure the blood pressure we can establish models for predicting the blood pressure and achieve noninvasive blood pressure measurement by using spectrum analysis technology. Blood pressure measurement method based on optical fiber sensing system is faster and more convenient than traditional way, and it can get accurate analysis results in a shorter period of time than before, so it can efficiently reduce the time cost and manpower cost.

  11. Fiber optic pressure sensors in skin-friction measurements

    Science.gov (United States)

    Kidwell, R.

    1985-01-01

    Fiber optic lever pressure sensors intended for use in a low speed wind tunnel environment were designed, constructed and tested for the measurement of normal and shear displacements associated with the pressures acting on a flat aluminum plate. On-site tests performed along with several static and dynamic measurements made have established that, with proper modifications and improvements, the design concepts are acceptable and can be utilized for their intended use. Several elastomers were investigated for use in sensors and for their incorporation into these sensors. Design and assembly techniques for probes and complete sensors were developed.

  12. Indications for portal pressure measurement in chronic liver disease

    DEFF Research Database (Denmark)

    Hobolth, Lise; Bendtsen, Flemming; Møller, Søren

    2012-01-01

    Portal hypertension leads to development of serious complications such as esophageal varices, ascites, renal and cardiovascular dysfunction. The importance of the degree of portal hypertension has been substantiated within recent years. Measurement of the portal pressure is simple and safe...... and the hepatic venous pressure gradient (HVPG) independently predicts survival and development of complications such as ascites, HCC and bleeding from esophageal varices. Moreover, measurements of HVPG can be used to guide pharmacotherapy for primary and secondary prophylaxis for variceal bleeding. Assessment...... of HVPG should therefore be considered as a part of the general characterization of patients with portal hypertension in departments assessing and treating this condition....

  13. Measurement of digital blood pressure after local cooling

    DEFF Research Database (Denmark)

    Nielsen, S L; Lassen, N A

    1977-01-01

    A double-inlet plastic cuff was designed for local cooling and systolic blood pressure measurement on the middle phalanx of the fingers. With a tourniquet on the proximal phalanx of one finger, cooling for 5 min made the digital artery temperature equal the skin temperature. The difference between...... the systolic pressure in a control finger and in the cooled finger give the reopening pressure in the digital arteries. At 30, 25, 20, 15, and 10 degrees C, respectively the percent decrease of the finger pressure was 0.2 (0.2), 1.5 (2.5), 8.5 (3.7), 11.4 (3.4), and 15.3 (3.1) in normal young women...

  14. Measuring element for determining the internal pressure in fuel rods

    International Nuclear Information System (INIS)

    Deckers, H.; Drexler, H.; Reiser, H.

    1983-01-01

    A pressure cell is situated inside the fuel rod, which contains a magnetic core or a core influenced by magnetism, whose position relative to an outer front surface of an end stopper of the fuel rod can vary. The fuel rod contains a pressure cell directly above the lower end stopper or connected to it. This can consist of closed bellows, where if the internal pressure in the fuel rod rises, a ferrite core moves axially. When the pressure drops, this returns to the initial position, which is precisely defined by a stop. To detect a rod defect, the position of the soft iron core relative to the lower edge of the end stopper is scanned by a special measuring device. (orig./HP) [de

  15. Microwave measurements of water vapor partial pressure at high temperatures

    International Nuclear Information System (INIS)

    Latorre, V.R.

    1991-01-01

    One of the desired parameters in the Yucca Mountain Project is the capillary pressure of the rock comprising the repository. This parameter is related to the partial pressure of water vapor in the air when in equilibrium with the rock mass. Although there are a number of devices that will measure the relative humidity (directly related to the water vapor partial pressure), they generally will fail at temperatures on the order of 150C. Since thee author has observed borehole temperatures considerably in excess of this value in G-Tunnel at the Nevada Test Site (NTS), a different scheme is required to obtain the desired partial pressure data at higher temperatures. This chapter presents a microwave technique that has been developed to measure water vapor partial pressure in boreholes at temperatures up to 250C. The heart of the system is a microwave coaxial resonator whose resonant frequency is inversely proportional to the square root of the real part of the complex dielectric constant of the medium (air) filling the resonator. The real part of the dielectric constant of air is approximately equal to the square of the refractive index which, in turn, is proportional to the partial pressure of the water vapor in the air. Thus, a microwave resonant cavity can be used to measure changes in the relative humidity or partial pressure of water vapor in the air. Since this type of device is constructed of metal, it is able to withstand very high temperatures. The actual limitation is the temperature limit of the dielectric material in the cable connecting the resonator to its driving and monitoring equipment-an automatic network analyzer in our case. In the following sections, the theory of operation, design, construction, calibration and installation of the microwave diagnostics system is presented. The results and conclusions are also presented, along with suggestions for future work

  16. A novel approach to office blood pressure measurement: 30-minute office blood pressure vs daytime ambulatory blood pressure

    NARCIS (Netherlands)

    Wel, M.C. van der; Buunk, I.E.; Weel, C. van; Thien, Th.; Bakx, J.C.

    2011-01-01

    PURPOSE: Current office blood pressure measurement (OBPM) is often not executed according to guidelines and cannot prevent the white-coat effect. Serial, automated, oscillometric OBPM has the potential to overcome both these problems. We therefore developed a 30-minute OBPM method that we compared

  17. Measurements of auroral particles by means of sounding rockets of mother-daughter type

    International Nuclear Information System (INIS)

    Falck, A.

    1985-11-01

    The scientific objective of the S17 payloads was to study the ionosphere during auroral situations and especially with regards to the local fine structure and a possible separation of spatial and temporal variations of auroral phenomena. The intensities of 8 keV and 2 keV electrons have been measured from one sounding rocket launched into a breakup aurora of moderate activity and from another rocket launched into a very active substorm situation. Both the rockets were of mother-daughter type i.e. had two separated payloads. The general features in the data of different particle energies were very similar over the whole flight time of the rockets. Special events and gradients and well identifiable shapes in the particle intensities were studied to see if the intensity fluctuations obtained from two detectors in one payload or from detectors into separate payloads were time delayed. Such time delays in the particle flux intensities were obvious in both of the rocket measurements and most of these time shifts could be understood as caused by spatial variations in the particle precipitation. In parts of the rocket flights the particle intensity variations were true temporal changes. The time lags between 8 keV and 2 keV electron intensities detected in the same payload, which could be observed and were obtained by crosscorrelation analyses, were in the range less than 0.3 s and most of them less than 0.1 s. If the time differences are assumed to be caused by the velocity dispersion of the particles, the particle data reported here placed the modulation source at a distance of less than 10 000 km from the rocket position. Measurements at the S17-1 mother payload of the electric field have been compared with data of precipitating electrons and low-light-level-TV-recording of the auroral situation. An inverted-V precipitation event was observed and was associated with auroral arcs and with reversals of the measured electric field components implicating the possibility of

  18. Experimental viscosity measurements of biodiesels at high pressure

    Directory of Open Access Journals (Sweden)

    Schaschke C.J.

    2016-01-01

    Full Text Available The viscosity of biodiesels of soybean and rapeseed biodiesels blended with mineral diesel fuel were measured at pressures of up to 200 MPa. Using a falling sinker-type viscometer reproducible viscosity data were obtained based on the time taken for a sinker to descend a fixed distance down an enclosed tube under the influence of gravity. Measurements were taken using pressures which correspond to those of interest in automotive common rail diesel engines, and at temperatures of between 25ºC and 80ºC. In all cases, the viscosity of the biodiesel blends were found to increase exponentially for which the blends were noted as being more viscous than pure mineral fuels. A pressure-freezing effect was not observed for the blends.

  19. Exhaust pressure pulsation observation from turbocharger instantaneous speed measurement

    Science.gov (United States)

    Macián, V.; Luján, J. M.; Bermúdez, V.; Guardiola, C.

    2004-06-01

    In internal combustion engines, instantaneous exhaust pressure measurements are difficult to perform in a production environment. The high temperature of the exhaust manifold and its pulsating character make its application to exhaust gas recirculation control algorithms impossible. In this paper an alternative method for estimating the exhaust pressure pulsation is presented. A numerical model is built which enables the exhaust pressure pulses to be predicted from instantaneous turbocharger speed measurements. Although the model is data based, a theoretical description of the process is also provided. This combined approach makes it possible to export the model for different engine operating points. Also, compressor contribution in the turbocharger speed pulsation is discussed extensively. The compressor contribution is initially neglected, and effects of this simplified approach are analysed.

  20. Evaluation of moving-coil loudspeaker and passive radiator parameters using normal-incidence sound transmission measurements: theoretical developments.

    Science.gov (United States)

    Leishman, Timothy W; Anderson, Brian E

    2013-07-01

    The parameters of moving-coil loudspeaker drivers are typically determined using direct electrical excitation and measurement. However, as electro-mechano-acoustical devices, their parameters should also follow from suitable mechanical or acoustical evaluations. This paper presents the theory of an acoustical method of excitation and measurement using normal-incidence sound transmission through a baffled driver as a plane-wave tube partition. Analogous circuits enable key parameters to be extracted from measurement results in terms of open and closed-circuit driver conditions. Associated tools are presented that facilitate adjacent field decompositions and derivations of sound transmission coefficients (in terms of driver parameters) directly from the circuits. The paper also clarifies the impact of nonanechoic receiving tube terminations and the specific benefits of downstream field decompositions.

  1. 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

  2. Low temperature measurement of the vapor pressures of planetary molecules

    Science.gov (United States)

    Kraus, George F.

    1989-01-01

    Interpretation of planetary observations and proper modeling of planetary atmospheres are critically upon accurate laboratory data for the chemical and physical properties of the constitutes of the atmospheres. It is important that these data are taken over the appropriate range of parameters such as temperature, pressure, and composition. Availability of accurate, laboratory data for vapor pressures and equilibrium constants of condensed species at low temperatures is essential for photochemical and cloud models of the atmospheres of the outer planets. In the absence of such data, modelers have no choice but to assume values based on an educated guess. In those cases where higher temperature data are available, a standard procedure is to extrapolate these points to the lower temperatures using the Clausius-Clapeyron equation. Last summer the vapor pressures of acetylene (C2H2) hydrogen cyanide (HCN), and cyanoacetylene (HC3N) was measured using two different methods. At the higher temperatures 1 torr and 10 torr capacitance manometers were used. To measure very low pressures, a technique was used which is based on the infrared absorption of thin film (TFIR). This summer the vapor pressure of acetylene was measured the TFIR method. The vapor pressure of hydrogen sulfide (H2S) was measured using capacitance manometers. Results for H2O agree with literature data over the common range of temperature. At the lower temperatures the data lie slightly below the values predicted by extrapolation of the Clausius-Clapeyron equation. Thin film infrared (TFIR) data for acetylene lie significantly below the values predicted by extrapolation. It is hoped to bridge the gap between the low end of the CM data and the upper end of the TFIR data in the future using a new spinning rotor gauge.

  3. Apparatus for measuring speed through the Doppler frequency shift of sound

    Science.gov (United States)

    Schier, Walter

    2011-04-01

    The Doppler frequency shift of sound apparatus is based on a one meter diameter rotary table with a "button" speaker at its outer edge. A semicircular waveguide encloses half the periphery and has a microphone pickup on its wall at the midpoint. The tangential speed of the button speaker can be determined two ways for comparison. One method calculates speed from the frequency shift of sound, the other uses the repeat sound pattern. Agreement to one percent is possible at speeds of about 25 mph. In the lab the microphone output is fed successively to pairs of students at ten computer stations. Students must also perform an exercise in their lab report that introduces them to the red shifted wavelengths of receding galaxies at determined distances from the earth thus introducing them to Hubble's law, the concept of the "Big Bang", and their estimate of the age of the universe.

  4. Improving the hospital 'soundscape': a framework to measure individual perceptual response to hospital sounds.

    Science.gov (United States)

    Mackrill, J B; Jennings, P A; Cain, R

    2013-01-01

    Work on the perception of urban soundscapes has generated a number of perceptual models which are proposed as tools to test and evaluate soundscape interventions. However, despite the excessive sound levels and noise within hospital environments, perceptual models have not been developed for these spaces. To address this, a two-stage approach was developed by the authors to create such a model. First, semantics were obtained from listening evaluations which captured the feelings of individuals from hearing hospital sounds. Then, 30 participants rated a range of sound clips representative of a ward soundscape based on these semantics. Principal component analysis extracted a two-dimensional space representing an emotional-cognitive response. The framework enables soundscape interventions to be tested which may improve the perception of these hospital environments.

  5. Radiation Pressure Measurements on Micron Size Individual Dust Grains

    Science.gov (United States)

    Abbas, M. M.; Craven, P.D.; Spann, J. F.; Tankosic, D.; Witherow, W. K.; LeClair, A.; West, E.; Sheldon, R.; Gallagher, D. L.; Adrian, M. L.

    2003-01-01

    Measurements of electromagnetic radiation pressure have been made on individual silica (SiO2) particles levitated in an electrodynamic balance. These measurements were made by inserting single charged particles of known diameter in the 0.2 micron to 6.82 micron range and irradiating them from above with laser radiation focused to beam-widths of approx. 175-400 micron, at ambient pressures approx. 10(exp -3) to 10(exp -4) torr. The downward displacement of the particle due to the radiation force is balanced by the electrostatic force indicated by the compensating dc potential applied to the balance electrodes, providing a direct measure of the radiation force on the levitated particle. Theoretical calculations of the radiation pressure with a least-squares fit to the measured data yield the radiation pressure efficiencies of the particles, and comparisons with Mie scattering theory calculations provide the imaginary part of the refractive index of silica and the corresponding extinction and scattering efficiencies.

  6. Combination of phlebography and sanguinous measurement of venous blood pressure

    International Nuclear Information System (INIS)

    Weber, J.

    1988-01-01

    Phlebographic visualisation offers the highest spatial resolution of all imaging methods both in respect of veins of the leg and pelvis and of the abdomen. Phlebography offers optimal conditions for assessing morphological changes at the veins and in their direct neighbourhood. No quantitative information is available via phlebography if haemodynamics are disturbed; qualitative information is yielded merely to a restricted extent (by assessing flow velocity and collaterals). Direct sanguinous measurement of venous blood pressure is particularly suitable for the quantitative and qualitative assessment of disturbed haemodynamic conditions; in this respect it stands out among the function tests based on the employment of apparatures. If it is combined with phlebography, it is possible not only to optimise the diagnostic yield in the hands of one investigator, but also to reduce the invasiveness of both methods to one single puncture, since the puncture needle is at the same time also an instrument to measure the pressure. The article points out the possibilities and limitations of combining a) ascending phlebography of the leg and pelvis with peripheral venous pressure measurement (phlebodynamometry) and b) visualisation of the veins of the pelvis and vena cava inferior with central sanguinous venous pressure measurement (CP). Indicatious and technical execution are described. (orig.) [de

  7. Measurements and modeling of VLLE at elevated pressures

    DEFF Research Database (Denmark)

    Laursen, Torben

    and pure component calibration. Samples from the different liquid phases in the high-pressure cell is taken using a moveable needle. The systems investigated have been a combination of the components: CO2, N2, di-methyl ether (DME), water, methanol, ethanol and 1-propanol. 41 isotherms have been measured...

  8. Deformation measurement of a pressure vessel flange by holographic interferometry

    International Nuclear Information System (INIS)

    Goncalves Junior, Armando A.; Schneider, C.A.

    1984-01-01

    An automatic metodology used for the measurement of displacement through the holographic interferometry is presented. In order to shown its performance and potentiality, the displacement field from a pipe's and flange, when submited to an internal pressure, is experimentally found. Holography's results are compared with other technique's results. (Author) [pt

  9. When and how should we measure intra- abdominal pressure?

    African Journals Online (AJOL)

    2008-11-11

    Nov 11, 2008 ... developing intra-abdominal hypertension (IAH) and. ACS. This may be ... the development of systemic inflammatory response syndrome (SIRS) ... of this technique are that it places the patient at increased risk for .... 9. Malbrain ML. Different techniques to measure intra-abdominal pressure (IAP): time for a.

  10. Measuring occupational stress: development of the pressure management indicator.

    Science.gov (United States)

    Williams, S; Cooper, C L

    1998-10-01

    The study of occupational stress is hindered by the lack of compact and comprehensive standardized measurement tools. The Pressure Management Indicator (PMI) is a 120-item self-report questionnaire developed from the Occupational Stress Indicator (OSI). The PMI is more reliable, more comprehensive, and shorter than the OSI. It provides an integrated measure of the major dimensions of occupational stress. The outcome scales measure job satisfaction, organizational satisfaction, organizational security, organizational commitment, anxiety--depression, resilience, worry, physical symptoms, and exhaustion. The stressor scales cover pressure from workload, relationships, career development, managerial responsibility, personal responsibility, home demands, and daily hassles. The moderator variables measure drive, impatience, control, decision latitude, and the coping strategies of problem focus, life work balance, and social support.

  11. Diffuse sound field: challenges and misconceptions

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2016-01-01

    Diffuse sound field is a popular, yet widely misused concept. Although its definition is relatively well established, acousticians use this term for different meanings. The diffuse sound field is defined by a uniform sound pressure distribution (spatial diffusion or homogeneity) and uniform...... tremendously in different chambers because the chambers are non-diffuse in variously different ways. Therefore, good objective measures that can quantify the degree of diffusion and potentially indicate how to fix such problems in reverberation chambers are needed. Acousticians often blend the concept...... of mixing and diffuse sound field. Acousticians often refer diffuse reflections from surfaces to diffuseness in rooms, and vice versa. Subjective aspects of diffuseness have not been much investigated. Finally, ways to realize a diffuse sound field in a finite space are discussed....

  12. A study of dynamic foot pressure measurement in diabetic patients

    Directory of Open Access Journals (Sweden)

    Milka D Madhale

    2017-01-01

    Full Text Available Introduction: Diabetic foot ulcer is a major source of morbidity and a leading cause of hospitalization. It is estimated that approximately 20% of hospital admissions among patients with diabetes mellitus are due to diabetic foot ulcer. It can lead to infection, gangrene, amputation, and even death if appropriate care is not provided. Overall, the lower limb amputation in diabetic patients is 15 times higher than in non-diabetics. In the majority of cases, the cause for the foot ulcer is the altered architecture of the foot due to neuropathy resulting in abnormal pressure points on the soles. Purpose: The aim of this study is to develop low cost, lightweight foot pressure scanner and check its reliability and validity which can help to prevent foot ulceration. Design/Methodology/Approach: In the present study, a low cost, lightweight foot pressure scanner is developed, and dynamic plantar pressures in a group of 110 Indian patients with diabetes with or without neuropathy and foot ulcers are measured. Practical Implications: If these pressure points can be detected, ulcers can be prevented by providing offloading footwear. Originality/Value: Differences are found in dynamic foot pressures in different study groups, namely, diabetic patients, patients with diabetic peripheral neuropathy, patients with foot ulcers, and nondiabetics. The differences are significant (P < 0.01, which showed the validity of the tool. Reliability and consistency of the tool was checked by test–retest method. Paper Type: Original Research work. Conclusion: Based on the results of the present study, it is concluded that the scanner is successfully developed and it can measure foot pressures. It is a novel device to proactively monitor foot health in diabetics in an effort to prevent and reduce diabetic foot complications.

  13. Fiber optic pressure sensors in skin-friction measurements

    Science.gov (United States)

    Cuomo, F. W.

    1986-01-01

    A fiber optic lever sensing technique that can be used to measure normal pressure as well as shear stresses is discussed. This method uses three unequal fibers combining small size and good sensitivity. Static measurements appear to confirm the theoretical models predicted by geometrical optics and dynamic tests performed at frequencies up to 10 kHz indicate a flat response within this frequency range. These sensors are intended for use in a low speed wind tunnel environment.

  14. Simultaneous compared with sequential blood pressure measurement results in smaller inter-arm blood pressure differences

    NARCIS (Netherlands)

    van der Hoeven, Niels V.; Lodestijn, Sophie; Nanninga, Stephanie; van Montfrans, Gert A.; van den Born, Bert-Jan H.

    2013-01-01

    There are currently few recommendations on how to assess inter-arm blood pressure (BP) differences. The authors compared simultaneous with sequential measurement on mean BP, inter-arm BP differences, and within-visit reproducibility in 240 patients stratified according to age ( <50 or ≥60 years) and

  15. Acoustic emission measurements at the pressure vessel ZB2

    International Nuclear Information System (INIS)

    Tirbonod, B.; Hanacek, L.

    1990-01-01

    The work presented here is the Swiss contribution to the project 'Zwischenbehaelter 2 (ZB2)' hosted by the 'Bundesministerium fuer Forschung und Technologie' of the Federal Republic of Germany. One of the crack-like defects introduced at the inside surface of the thick-walled pressure vessel ZB2 was locally monitored by acoustic emission. The measurement system was broadband (0.5 - 5 MHz) and allowed a threedimensional location of the source. The vessel was subjected to different tests. Signals were recorded during the second series of hydrotests, fast pressure cycles and fatigue test at 50 C. About 1 signal per hydrotest or cycle was recorded. For the hydrotests the signals were recorded generally at loading in the intermediate range of pressure; the sources were located in the artificial defect. Recurrent and non recurrent signals were recorded during the fatigue test. At loading, signals were captured up to the maximum pressure and for the recurrent signals at well defined pressure ranges. All the sources (except one, located in the base material ahead of the artificial defect) were situated in the artificial defect. The pressure and location depended on the loading phase and on the cycle range. The measurements were discussed by describing the signals by measurement, signal and source parameters. The goal was to identify the source mechanism and to assess the growth of the defect. For the hydrotests the identification of the mechanism at loading remains open. For the fatigue test the source situated in the base material was attributed to a primary mechanism; this source could assess the growth of the defect on the basis of linear elastic fracture mechanics. A secondary mechanism was suggested for recurrent sources active at loading. For all the tests, the sources active at unloading were attributed to a secondary mechanism. (author)

  16. Piston cylinder cell for high pressure ultrasonic pulse echo measurements

    Energy Technology Data Exchange (ETDEWEB)

    Kepa, M. W., E-mail: mkepa@staffmail.ed.ac.uk; Huxley, A. D. [SUPA, Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Ridley, C. J.; Kamenev, K. V. [Centre for Science at Extreme Conditions and School of Engineering, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)

    2016-08-15

    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe{sub 2}.

  17. Seat pressure measurement technologies: considerations for their evaluation.

    Science.gov (United States)

    Gyi, D E; Porter, J M; Robertson, N K

    1998-04-01

    Interface pressure measurement has generated interest in the automotive industry as a technique which could be used in the prediction of driver discomfort for various car seat designs, and provide designers and manufacturers with rapid information early on in the design process. It is therefore essential that the data obtained are of the highest quality, relevant and have some quantitative meaning. Exploratory experimental work carried out with the commercially available Talley Pressure Monitor is outlined. This led to a better understanding of the strengths and weaknesses of this system and the re-design of the sensor matrix. Such evaluation, in the context of the actual experimental environment, is considered essential.

  18. A Model to Determine the Level of Serum Aldosterone in the Workers Attributed to the Combined Effects of Sound Pressure Level, Exposure Time and Serum Potassium Level: A Field-Based Study

    Directory of Open Access Journals (Sweden)

    Parvin Nassiri

    2016-09-01

    Full Text Available Background Occupational exposure to excessive noise is one of the biggest work-related challenges in the world. This phenomenon causes the release of stress-related hormones, which in turn, negatively affects cardiovascular risk factors. Objectives The current study study aimed to determine the level of workers’ serum aldosterone in light of the combined effect of sound pressure level, exposure time and serum potassium level. Methods This cross-sectional, descriptive, analytical study was conducted on 45 workers of Gol-Gohar Mining and Industrial Company in the fall of 2014. The subjects were divided into three groups (one control and two case groups, each including 15 workers. Participants in the control group were selected from workers with administrative jobs (exposure to the background noise. On the other hand, participants in the case groups were selected from the concentrator and pelletizing factories exposed to excessive noise. Serum aldosterone and potassium levels of participants were assessed at three different time intervals: at the beginning of the shift and before exposure to noise (7:30 - 8:00 AM, during exposure to noise (10:00 - 10:30 AM, and during continuous exposure (1:30 - 2:00 PM. The obtained data were transferred into SPSS ver. 18. Repeated measures analysis of variance (ANOVA was used to develop the statistical model of workers’ aldosterone level in light of the combined effect of sound pressure level, exposure time, and serum potassium level. Results The results of the final statistical model to determine the level of serum aldosterone based on the combined effect of sound pressure level, exposure time and serum potassium level indicated that the sound pressure level had a significant influence on the human’s serum aldosterone level (P = 0.04. In addition, the effects of exposure time and serum potassium on aldosterone level were statistically significant with P-values of 0.008 and 0.001, respectively. Conclusions

  19. [Parkinson gait analysis using in-shoe plantar pressure measurements].

    Science.gov (United States)

    Pihet, D; Moretto, P; Defebvre, L; Thevenon, A

    2006-02-01

    The literature reports some studies describing the walking pattern of patients with Parkinson's disease, its deterioration with disease severity and the effects of various treatments. Other studies concerned the plantar pressure distribution when walking. The aim of this study was to validate the use of baropodometric measurements for gait analysis of parkinsonian patients at various stages of disease severity and in on and off phases. Fifteen normal control subjects and fifteen parkinsonian patients equipped with a plantar pressure measurement system performed walking tests. The parkinsonian patients performed the walking tests in off phase then in on phase. A clinical examination was performed to score the motor handicap on the UPDRS scale. Analysis of the plantar pressures of the parkinsonian subjects under various footprint areas detected significant baropodometric differences compared with controls, between groups with different UPDRS scores, and before and after L-Dopa treatment. Plantar pressures measurements allow a sufficiently fine discrimination for using it to detect parkinsonism and monitor patients with Parkinson's disease.

  20. Measurement of pressure on a surface using bubble acoustic resonances

    International Nuclear Information System (INIS)

    Aldham, Ben; Manasseh, Richard; Liffman, Kurt; Šutalo, Ilija D; Illesinghe, Suhith; Ooi, Andrew

    2010-01-01

    The frequency response of gas bubbles as a function of liquid ambient pressure was measured and compared with theory. A bubble size with equivalent spherical radius of 2.29 mm was used over a frequency range of 1000–1500 Hz. The ultimate aim is to develop an acoustic sensor that can measure static pressure and is sensitive to variations as small as a few kPa. The classical bubble resonance frequency is known to vary with ambient pressure. Experiments were conducted with a driven bubble in a pressurizable tank with a signal processing system designed to extract the resonant peak. Since the background response of the containing tank is significant, particularly near tank-modal resonances, it must be carefully removed from the bubble response signal. A dual-hydrophone method was developed to allow rapid and reliable real-time measurements. The expected pressure dependence was found. In order to obtain a reasonable match with theory, the classical theory was modified by the introduction of a 'mirror bubble' to account for the influence of a nearby surface. (technical design note)

  1. 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....

  2. A study of methods of prediction and measurement of the transmission sound through the walls of light aircraft

    Science.gov (United States)

    Forssen, B.; Wang, Y. S.; Crocker, M. J.

    1981-12-01

    Several aspects were studied. The SEA theory was used to develop a theoretical model to predict the transmission loss through an aircraft window. This work mainly consisted of the writing of two computer programs. One program predicts the sound transmission through a plexiglass window (the case of a single partition). The other program applies to the case of a plexiglass window window with a window shade added (the case of a double partition with an air gap). The sound transmission through a structure was measured in experimental studies using several different methods in order that the accuracy and complexity of all the methods could be compared. Also, the measurements were conducted on the simple model of a fuselage (a cylindrical shell), on a real aircraft fuselage, and on stiffened panels.

  3. Investigations on spatial sound design based on measured room impulse responses

    NARCIS (Netherlands)

    Melchior, F.

    2011-01-01

    Developments in the area of spatial sound reproduction have led to a large variety of established audio systems. Systems based on stereophonic principles are extended and growing from two channels via the ITU-R BS.775 surround setup to larger systems with more channels including elevated

  4. Smartphone-Aided Measurements of the Speed of Sound in Different Gaseous Mixtures

    Science.gov (United States)

    Parolin, Sara Orsola; Pezzi, Giovanni

    2013-01-01

    Here we describe classroom-based procedures aiming at the estimation of the speed of sound in different gas mixtures with the help of a plastic drain pipe and two iPhones or iPod touches. The procedures were conceived to be performed with simple and readily available tools.

  5. Ionospheric Electron Densities at Mars: Comparison of Mars Express Ionospheric Sounding and MAVEN Local Measurement

    Czech Academy of Sciences Publication Activity Database

    Němec, F.; Morgan, D. D.; Fowler, C.M.; Kopf, A.J.; Andersson, L.; Gurnett, D. A.; Andrews, D.J.; Truhlík, Vladimír

    2017-01-01

    Roč. 122, č. 12 (2017), s. 12393-12405 E-ISSN 2169-9402 Institutional support: RVO:68378289 Keywords : Mars * ionosphere * MARSIS * Mars Express * MAVEN * radar sounding Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) http://onlinelibrary.wiley.com/doi/10.1002/2017JA024629/full

  6. Pressure pulsation measurements in pipe and cluster flows

    International Nuclear Information System (INIS)

    Benemann, A.; Voj, P.

    1976-01-01

    Measuring and evaluation techniques of pressure pulsations in pipe and cluster flows are described. The measurements were made on a 1 m long SNR rod-cluster and its feed and drain pipes. At Reynolds numbers in the cluster of 8.9 x 10 4 flow velocities of 14 m/sec were achieved. With the aid of a block diagram recording of the measured values by piezoelectric crystal and piezo-resistive strain gange as well as data processing are explained. For the analytical treatment of the pressure pulsation signals characterizing the turbulence field computer codes of a digital computer and a fast-fourier analyzer (Hewlett-Packard 5450 A) were used. The results show good agreement with theoretical curves on the behaviour of turbulent boundary layers of cluster and pipe flows at high Reynolds numbers. (TK) [de

  7. Pressure drop ana velocity measurements in KMRR fuel rod bundles

    International Nuclear Information System (INIS)

    Yagn, Sun Kyu; Chung, Heung June; Chung, Chang Whan; Chun, Se Young; Song, Chul Wha; Won, Soon Yeun; Chung, Moon Ki

    1990-01-01

    The detailed hydraulic characteristic measurements in subchannels of longitudinally finned rod bundles using one-component LDV(Laser Doppler Velocimeter) were performed. Time mean axial velocity, turbulent intensity, and turbulent micro scales, such as time auto-correlation, Eulerian integral and micro scale, Kolmogorov length and time scale, and Taylor micro length scale were measured. The signals from LDV are inherently more or less discontinuous. The spectra of signals having such intermittent defects can be obtained by the fast Fourier transformation (FFT) of the auto-correlation function. The turbulent crossflow mixing rate between neighboring subchannels and dominant frequencies were evaluated from the measured data. Pressure drop data were obtained for the typical 36-element and 18-element fuel rod bundles fabricated by the design requirement of KMRR fuel and for other type of fuels assembled with 6-fin rods to investigate the fin effects on the pressure drop characteristics

  8. Blood pressure measurement in obese patients: comparison between upper arm and forearm measurements.

    Science.gov (United States)

    Pierin, Angela M G; Alavarce, Débora C; Gusmão, Josiane L; Halpern, Alfredo; Mion, Décio

    2004-06-01

    It is well known that blood pressure measurement with a standard 12-13 cm wide cuff is erroneous for large arms. To compare arm blood pressure measurements with an appropriate cuff and forearm blood pressure measurements (BPM) with a standard cuff, and both measurements by the Photopletismography (Finapres) method. One hundred and twenty-nine obese patients were studied (body mass index=40+/-7 kg/m2). The patients had three arm BPM taken by an automatic oscillometric device using an appropriate cuff and three forearm BPM with a standard cuff in the sitting position after a five-minute rest. Data were analysed by the analysis of variance. The correction values were obtained by the linear regression test. Systolic and diastolic arm BPM with an appropriate cuff were significantly lower (pforearm BPM with a standard cuff. The measurements obtained by Finapres were significantly lower (pforearm systolic and diastolic blood pressures and upper arm diastolic blood pressure. The equation to correct BPM in forearm in obese patients with arm circumference between 32-44 cm was: systolic BPM=33.2+/-0.68 x systolic forearm BPM, and diastolic BPM=25.2+0.59 x forearm diastolic BPM. This study showed that forearm blood pressure measurement overestimates the values of arm blood pressure measurement. In addition, it is possible to correct forearm BPM with an equation.

  9. Short period sound speed oscillation measured by intensive XBT survey and its role on GNSS/acoustic positioning

    Science.gov (United States)

    Kido, M.; Matsui, R.; Imano, M.; Honsho, C.

    2017-12-01

    In the GNSS/acoustic measurement, sound speed in ocean plays a key role of accuracy of final positioning. We have shown than longer period sound speed undulation can be properly estimated from GNSS-A analysis itself in our previous work. In this work, we have carried out intensive XBT measurement to get temporal variation of sound speed in short period to be compared with GNSS-A derived one. In the individual temperature profile obtained by intensive XBT measurements (10 minutes interval up to 12 times of cast), clear vertical oscillation up to 20 m of amplitude in the shallow part were observed. These can be interpreted as gravitational internal wave with short-period and hence short wavelength anomaly. Kido et al. (2007) proposed that horizontal variation of the ocean structure can be considered employing five or more transponders at once if the structure is expressed by two quantities, i.e., horizontal gradient in x/y directions. However, this hypothesis requires that the variation must has a large spatial scale (> 2-5km) so that the horizontal variation can be regarded as linear within the extent of acoustic path to seafloor transponders. Therefore the wavelength of the above observed internal wave is getting important. The observed period of internal wave was 30-60 minute. However its wavelength cannot be directly measured. It must be estimate based on density profile of water column. In the comparison between sound speed change and positioning, the delay of their phases were 90 degree, which indicates that most steep horizontal slope of internal wave correspond to largest apparent positioning shift.

  10. 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...

  11. The correlation between the first heart sound and cardiac output as measured by using digital esophageal stethoscope under anaesthesia.

    Science.gov (United States)

    Duck Shin, Young; Hoon Yim, Kyoung; Hi Park, Sang; Wook Jeon, Yong; Ho Bae, Jin; Soo Lee, Tae; Hwan Kim, Myoung; Jin Choi, Young

    2014-03-01

    The use of an esophageal stethoscope is a basic heart sounds monitoring procedure performed in patients under general anesthesia. As the size of the first heart sound can express the left ventricle function, its correlation with cardiac output should be investigated. The aim of this study was to investigate the effects of cardiac output (CO) on the first heart sound (S1) amplitude. Methods : Six male beagles were chosen. The S1 was obtained with the newly developed esophageal stethoscope system. CO was measured using NICOM, a non-invasive CO measuring device. Ephedrine and beta blockers were administered to the subjects to compare changes in figures, and the change from using an inhalation anesthetic was also compared. The S1 amplitude displayed positive correlation with the change rate of CO (r = 0.935, p < 0.001). The heart rate measured using the esophageal stethoscope and ECG showed considerably close figures through the Bland-Altman plot and showed a high positive correlation (r = 0.988, p < 0,001). In beagles, the amplitude of S1 had a significant correlation with changes in CO in a variety of situations.

  12. 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.

  13. Body mass index and blood pressure measurement during pregnancy.

    LENUS (Irish Health Repository)

    Hogan, Jennifer L

    2012-02-01

    OBJECTIVE: The accurate measurement of blood pressure requires the use of a large cuff in subjects with a high mid-arm circumference (MAC). This prospective study examined the need for a large cuff during pregnancy and its correlation with maternal obesity. METHODS: Maternal body mass index (BMI), fat mass, and MAC were measured. RESULTS: Of 179 women studied, 15.6% were obese. With a BMI of level 1 obesity, 44% needed a large cuff and with a BMI of level 2 obesity 100% needed a large cuff. CONCLUSION: All women booking for antenatal care should have their MAC measured to avoid the overdiagnosis of pregnancy hypertension.

  14. Measurements of acoustic pressure at high amplitudes and intensities

    International Nuclear Information System (INIS)

    Crum, L A; Bailey, M R; Kaczkowski, P; McAteer, J A; Pishchalnikov, Y A; Sapozhnikov, O A

    2004-01-01

    In our research group, we desire measurements of the large pressure amplitudes generated by the shock waves used in shock wave lithotripsy (SWL) and the large acoustic intensities used in High Intensity Focused Ultrasound (HIFU). Conventional piezoelectric or PVDF hydrophones can not be used for such measurements as they are damaged either by cavitation, in SWL applications, or heat, in HIFU applications. In order to circumvent these difficulties, we have utilized optical fiber hydrophones in SWL that do not cavitate, and small glass probes and a scattering technique for measurements of large HIFU intensities. Descriptions of these techniques will be given as well as some typical data

  15. Measurement of carotid bifurcation pressure gradients using the Bernoulli principle.

    Science.gov (United States)

    Illig, K A; Ouriel, K; DeWeese, J A; Holen, J; Green, R M

    1996-04-01

    Current randomized prospective studies suggest that the degree of carotid stenosis is a critical element in deciding whether surgical or medical treatment is appropriate. Of potential interest is the actual pressure drop caused by the blockage, but no direct non-invasive means of quantifying the hemodynamic consequences of carotid artery stenoses currently exists. The present prospective study examined whether preoperative pulsed-Doppler duplex ultrasonographic velocity (v) measurements could be used to predict pressure gradients (delta P) caused by carotid artery stenoses, and whether such measurements could be used to predict angiographic percent diameter reduction. Preoperative Doppler velocity and intraoperative direct pressure measurements were obtained, and per cent diameter angiographic stenosis measured in 76 consecutive patients who underwent 77 elective carotid endarterectomies. Using the Bernoulli principle (delta P = 4v(2), pressure gradients across the stenoses were calculated. The predicted delta P, as well as absolute velocities and internal carotid artery/common carotid velocity ratios were compared with the actual delta P measured intraoperatively and with preoperative angiography and oculopneumoplethysmography (OPG) results. An end-diastolic velocity of > or = 1 m/s and an end-diastolic internal carotid artery/common carotid artery velocity ratio of > or = 10 predicted a 50% diameter angiographic stenosis with 100% specificity. Although statistical significance was reached, preoperative pressure gradients derived from the Bernoulli equation could not predict actual individual intraoperative pressure gradients with enough accuracy to allow decision making on an individual basis. Velocity measurements were as specific and more sensitive than OPG results. Delta P as predicted by the Bernoulli equation is not sufficiently accurate at the carotid bifurcation to be useful for clinical decision making on an individual basis. However, end

  16. Propagation of Radiosonde Pressure Sensor Errors to Ozonesonde Measurements

    Science.gov (United States)

    Stauffer, R. M.; Morris, G.A.; Thompson, A. M.; Joseph, E.; Coetzee, G. J. R.; Nalli, N. R.

    2014-01-01

    Several previous studies highlight pressure (or equivalently, pressure altitude) discrepancies between the radiosonde pressure sensor and that derived from a GPS flown with the radiosonde. The offsets vary during the ascent both in absolute and percent pressure differences. To investigate this problem further, a total of 731 radiosonde-ozonesonde launches from the Southern Hemisphere subtropics to Northern mid-latitudes are considered, with launches between 2005 - 2013 from both longer-term and campaign-based intensive stations. Five series of radiosondes from two manufacturers (International Met Systems: iMet, iMet-P, iMet-S, and Vaisala: RS80-15N and RS92-SGP) are analyzed to determine the magnitude of the pressure offset. Additionally, electrochemical concentration cell (ECC) ozonesondes from three manufacturers (Science Pump Corporation; SPC and ENSCI-Droplet Measurement Technologies; DMT) are analyzed to quantify the effects these offsets have on the calculation of ECC ozone (O3) mixing ratio profiles (O3MR) from the ozonesonde-measured partial pressure. Approximately half of all offsets are 0.6 hPa in the free troposphere, with nearly a third 1.0 hPa at 26 km, where the 1.0 hPa error represents 5 persent of the total atmospheric pressure. Pressure offsets have negligible effects on O3MR below 20 km (96 percent of launches lie within 5 percent O3MR error at 20 km). Ozone mixing ratio errors above 10 hPa (30 km), can approach greater than 10 percent ( 25 percent of launches that reach 30 km exceed this threshold). These errors cause disagreement between the integrated ozonesonde-only column O3 from the GPS and radiosonde pressure profile by an average of +6.5 DU. Comparisons of total column O3 between the GPS and radiosonde pressure profiles yield average differences of +1.1 DU when the O3 is integrated to burst with addition of the McPeters and Labow (2012) above-burst O3 column climatology. Total column differences are reduced to an average of -0.5 DU when

  17. Detection and generation of first sound in4He by vibrating superleak transducers

    Science.gov (United States)

    Giordano, N.; Edison, N.

    1986-07-01

    Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid4He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation.

  18. Detection and generation of first sound in 4He by vibrating superleak transducers

    International Nuclear Information System (INIS)

    Giordano, N.; Edison, N.

    1986-01-01

    Measurement is made of the first-sound generation and detection efficiencies of vibrating superleak transducers (VSTs) operated in superfluid 4 He. This is accomplished by using an ordinary pressure transducer to generate first sound with a VST as the detector, and by using a pressure transducer to detect the sound generated by a VST. The results are in reasonably good agreement with the current theory of VST operation

  19. Speeds of sound in {(1 - x)CH4 + xN2} with x = (0.10001, 0.19999, and 0.5422) at temperatures between 170 K and 400 K and pressures up to 30 MPa

    International Nuclear Information System (INIS)

    Estela-Uribe, J.F.; Trusler, J.P.M.; Chamorro, C.R.; Segovia, J.J.; Martin, M.C.; Villamanan, M.A.

    2006-01-01

    The speed of sound in {(1 - x)CH 4 + xN 2 } has been measured with a spherical acoustic resonator. Two mixtures with x = (0.10001 and 0.19999) were studied along isotherms at temperatures between 220 K and 400 K with pressures up to 20 MPa; a few additional measurements at p = (25 and 30) MPa are also reported. A third mixture with x = 0.5422 was studied along pseudo-isochores at amount-of-substance densities between 0.2 mol . dm -3 and 5 mol . dm -3 . Corrections for molecular vibrational relaxation are discussed in detail and relaxation times are reported. The overall uncertainty of the measured speeds of sound is estimated to be not worse than ±0.02%, except for those measurements in the mixture with x = 0.5422 that lie along the pseduo-isochore at the highest amount-of-substance density. The results have been compared with the predictions of several equations of state used for natural gas systems

  20. Falls event detection using triaxial accelerometry and barometric pressure measurement.

    Science.gov (United States)

    Bianchi, Federico; Redmond, Stephen J; Narayanan, Michael R; Cerutti, Sergio; Celler, Branko G; Lovell, Nigel H

    2009-01-01

    A falls detection system, employing a Bluetooth-based wearable device, containing a triaxial accelerometer and a barometric pressure sensor, is described. The aim of this study is to evaluate the use of barometric pressure measurement, as a surrogate measure of altitude, to augment previously reported accelerometry-based falls detection algorithms. The accelerometry and barometric pressure signals obtained from the waist-mounted device are analyzed by a signal processing and classification algorithm to discriminate falls from activities of daily living. This falls detection algorithm has been compared to two existing algorithms which utilize accelerometry signals alone. A set of laboratory-based simulated falls, along with other tasks associated with activities of daily living (16 tests) were performed by 15 healthy volunteers (9 male and 6 female; age: 23.7 +/- 2.9 years; height: 1.74 +/- 0.11 m). The algorithm incorporating pressure information detected falls with the highest sensitivity (97.8%) and the highest specificity (96.7%).

  1. How important is the recommended slow cuff pressure deflation rate for blood pressure measurement?

    Science.gov (United States)

    Zheng, Dingchang; Amoore, John N; Mieke, Stephan; Murray, Alan

    2011-10-01

    Cuff pressure deflation rate influences blood pressure (BP) measurement. However, there is little quantitative clinical evidence on its effect. Oscillometric pulses recorded from 75 subjects at the recommended deflation rate of 2-3 mmHg per second were analyzed. Some pulses were removed to realize six faster rates (2-7 times faster than the original). Systolic, diastolic, and mean arterial blood pressures (SBP, DBP, MAP) were determined from the original and six reconstructed oscillometric waveforms. Manual measurement was based on the appearance of oscillometric pulse peaks, and automatic measurement on two model envelopes (linear and polynomial) fitted to the sequence of oscillometric pulse amplitudes. The effects of deflation rate on BP determination and within-subject BP variability were analyzed. For SBP and DBP determined from the manual measurement, different deflation rates resulted in significant changes (both p deflation rate effect (all p > 0.3). Faster deflation increased the within-subject BP variability (all p deflation rate, and for the automatic model-based techniques, the deflation rate had little effect.

  2. Space fireworks for upper atmospheric wind measurements by sounding rocket experiments

    Science.gov (United States)

    Yamamoto, M.

    2016-01-01

    Artificial meteor trains generated by chemical releases by using sounding rockets flown in upper atmosphere were successfully observed by multiple sites on ground and from an aircraft. We have started the rocket experiment campaign since 2007 and call it "Space fireworks" as it illuminates resonance scattering light from the released gas under sunlit/moonlit condition. By using this method, we have acquired a new technique to derive upper atmospheric wind profiles in twilight condition as well as in moonlit night and even in daytime. Magnificent artificial meteor train images with the surrounding physics and dynamics in the upper atmosphere where the meteors usually appear will be introduced by using fruitful results by the "Space firework" sounding rocket experiments in this decade.

  3. Second Sound Measurement using SMD resistors to simulate Quench locations on the 704 MHZ Single-Cell Cavity at CERN

    CERN Document Server

    Liao, K; Ciapala, E; Junginger, T; Weingarten, W

    2012-01-01

    Oscillating Superleak Transducers (OSTs) containing flexible porous membranes are widely used to detect the so-called second sound temperature wave when a quench event occurs in a superconducting RF cavity. In principle, from the measured speed of this wave and the travel time between the quench event and several OSTs, the location of the quench sites can be derived by triangulation. Second sound behaviour has been simulated through different surface mount (SMD) resistors setups on a Superconducting Proton Linac (SPL) test cavity, to help understanding the underlying physics and improve quench localisation. Experiments are described that have been conducted to search for explanation of heat transfer during cavity quench that causes contradictory triangulation results.

  4. Comparison of current tonometry techniques in measurement of intraocular pressure.

    Science.gov (United States)

    Kouchaki, Behrooz; Hashemi, Hassan; Yekta, Abbasali; Khabazkhoob, Mehdi

    2017-06-01

    To compare four tonometry techniques: Goldmann applanation tonometer (GAT), Dynamic contour tonometer (DCT), Non-contact tonometer (NCT), and Ocular Response Analyzer (ORA) in the measurement of intraocular pressure (IOP) and the impact of some corneal biomechanical factors on their performance. In this cross-sectional study, volunteers with normal ophthalmic examination and no history of eye surgery (except for uncomplicated cataract surgery) or trauma were selected. Twenty-five subjects were male, and 21 were female. The mean age was 48 ± 19.2 years. Anterior segment parameters were measured with Scheimpflug imaging. IOP was measured with GAT, DCT, NCT, and ORA in random order. A 95% limit of agreement of IOPs was analyzed. The impact of different parameters on the measured IOP with each device was evaluated by regression analysis. The average IOP measured with GAT, DCT, NCT, and ORA was 16.4 ± 3.5, 18.1 ± 3.4, 16.2 ± 3.9, and 17.3 ± 3.4 mmHg, respectively. The difference of IOP measured with NCT and GAT was not significant ( P  = 0.382). Intraocular pressure was significantly different between GAT with DCT and IOP CC ( P  tonometers.

  5. Measurement of viscosity of gaseous mixtures at atmospheric pressure

    Science.gov (United States)

    Singh, J. J.; Mall, G. H.; Chegini, H.

    1986-01-01

    Coefficients of viscosity of various types of gas mixtures, including simulated natural-gas samples, have been measured at atmospheric pressure and room temperature using a modified capillary tube method. Pressure drops across the straight capillary tube section of a thermal mass flowmeter were measured for small, well-defined, volume flow rates for the test gases and for standard air. In this configuration, the flowmeter provides the volumetric flow rates as well as a well-characterized capillary section for differential pressure measurements across it. The coefficients of viscosity of the test gases were calculated using the reported value of 185.6 micro P for the viscosity of air. The coefficients of viscosity for the test mixtures were also calculated using Wilke's approximation of the Chapman-Enskog (C-E) theory. The experimental and calculated values for binary mixtures are in agreement within the reported accuracy of Wilke's approximation of the C-E theory. However, the agreement for multicomponent mixtures is less satisfactory, possible because of the limitations of Wilkes's approximation of the classical dilute-gas state model.

  6. Characterization of condenser microphones under different environmental conditions for accurate speed of sound measurements with acoustic resonators

    Energy Technology Data Exchange (ETDEWEB)

    Guianvarc' h, Cecile; Pitre, Laurent [Laboratoire Commun de Metrologie LNE/Cnam, 61 rue du Landy, 93210 La Plaine Saint Denis (France); Gavioso, Roberto M.; Benedetto, Giuliana [Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Turin (Italy); Bruneau, Michel [Laboratoire d' Acoustique de l' Universite du Maine UMR CNRS 6613, av. Olivier Messiaen, 72085 Le Mans Cedex 9 (France)

    2009-07-15

    Condenser microphones are more commonly used and have been extensively modeled and characterized in air at ambient temperature and static pressure. However, several applications of interest for metrology and physical acoustics require to use these transducers in significantly different environmental conditions. Particularly, the extremely accurate determination of the speed of sound in monoatomic gases, which is pursued for a determination of the Boltzmann constant k by an acoustic method, entails the use of condenser microphones mounted within a spherical cavity, over a wide range of static pressures, at the temperature of the triple point of water (273.16 K). To further increase the accuracy achievable in this application, the microphone frequency response and its acoustic input impedance need to be precisely determined over the same static pressure and temperature range. Few previous works examined the influence of static pressure, temperature, and gas composition on the microphone's sensitivity. In this work, the results of relative calibrations of 1/4 in. condenser microphones obtained using an electrostatic actuator technique are presented. The calibrations are performed in pure helium and argon gas at temperatures near 273 K and in the pressure range between 10 and 600 kPa. These experimental results are compared with the predictions of a realistic model available in the literature, finding a remarkable good agreement. The model provides an estimate of the acoustic impedance of 1/4 in. condenser microphones as a function of frequency and static pressure and is used to calculate the corresponding frequency perturbations induced on the normal modes of a spherical cavity when this is filled with helium or argon gas.

  7. Photoluminescence excitation measurements using pressure-tuned laser diodes

    Science.gov (United States)

    Bercha, Artem; Ivonyak, Yurii; Medryk, Radosław; Trzeciakowski, Witold A.; Dybała, Filip; Piechal, Bernard

    2015-06-01

    Pressure-tuned laser diodes in external cavity were used as tunable sources for photoluminescence excitation (PLE) spectroscopy. The method was demonstrated in the 720 nm-1070 nm spectral range using a few commercial laser diodes. The samples for PLE measurements were quantum-well structures grown on GaAs and on InP. The method is superior to standard PLE measurements using titanium sapphire laser because it can be extended to any spectral range where anti-reflection coated laser diodes are available.

  8. Photoluminescence excitation measurements using pressure-tuned laser diodes

    International Nuclear Information System (INIS)

    Bercha, Artem; Ivonyak, Yurii; Mędryk, Radosław; Trzeciakowski, Witold A.; Dybała, Filip; Piechal, Bernard

    2015-01-01

    Pressure-tuned laser diodes in external cavity were used as tunable sources for photoluminescence excitation (PLE) spectroscopy. The method was demonstrated in the 720 nm-1070 nm spectral range using a few commercial laser diodes. The samples for PLE measurements were quantum-well structures grown on GaAs and on InP. The method is superior to standard PLE measurements using titanium sapphire laser because it can be extended to any spectral range where anti-reflection coated laser diodes are available

  9. Comparative sound velocity measurements between porous rock and fully-dense material under crustal condition: The cases of Darley Dale sandstone and copper block

    Science.gov (United States)

    Kung, J.; Chien, Y. V.; Wu, W.; Dong, J.; Chang, Y.; Tsai, C.; Yang, M.; Wang, K.

    2012-12-01

    Previous studies showed that the voids and their geometry in the sedimentary rocks have great influence on the compressibility of rock, which reflects on its elastic velocities. Some models were developed to discuss the relations among velocity, porosity and void geometry. Therefore, the information of porosity, and void geometry and its distribution in rock is essential for understanding how the elastic properties of porous rocks affected by their poregeometry. In this study, we revisited a well-studied porous rock, Darley Dale sandstone, which has been studied by different groups with different purposes. Most of them are the deformation experiments. Different from previous studies, we measured the sound velocity of Darley dale sandstone under hydrostatic conditions. Also, we employed different techniques to investigate the pore geometry and porosity of Darley Dale sandstone to gain the insight of velocity changing behavior under the crustal conditions. Here, we measured a fully-dense copper block for a comparison. We performed X-ray CT scanning (XCT) to image the pore space of sandstone to construct the 3-D image of pore geometry, distribution and the pore size. The CT image data are allowed us to estimate the porosity of sandstone, too. One the other hand, the porosity of sample was measured using imbibitions method at ambient conditions and helium porosimeter at high pressure (up to 150 MPa). A set of specimens were cored from Darley Dale sandstone block. P and S wave velocities of specimens were measured at ambient conditions. We also performed high pressure velocity measurements on a selected rock specimen and a copper block up to 150 MPa under dry condition. Porosity of a set of rock specimens measured by imbibitions method was spanned from 6% to 15%, largely distributed within a range of 8%-11%. Compared the porosity obtained from three different techniques, imbibitions method, helium porosimeter and XCT, values from those measurements are in good agreement

  10. Prospective blood pressure measurement in renal transplant recipients.

    Science.gov (United States)

    David, V G; Yadav, B; Jeyaseelan, L; Deborah, M N; Jacob, S; Alexander, S; Varughese, S; John, G T

    2014-05-01

    Blood pressure (BP) control at home is difficult when managed only with office blood pressure monitoring (OBPM). In this prospective study, the reliability of BP measurements in renal transplant patients with OBPM and home blood pressure monitoring (HBPM) was compared with ambulatory blood pressure monitoring (ABPM) as the gold standard. Adult patients who had living-related renal transplantation from March 2007 to February 2008 had BP measured by two methods; OBPM and ABPM at pretransplantation, 2(nd), 4(th), 6(th), and 9(th) months and all the three methods: OBPM, ABPM, and HBPM at 6 months after transplantation. A total of 49 patients, age 35 ± 11 years, on prednisolone, tacrolimus, and mycophenolate were evaluated. A total of 39 were males (79.6%). Systolic BP (SBP) and diastolic BP (DBP) measured by OBPM were higher than HBPM when compared with ABPM. When assessed using OBPM and awake ABPM, both SBP and DBP were significantly overestimated by OBPM with mean difference of 3-12 mm Hg by office SBP and 6-8 mm Hg for office DBP. When HBPM was compared with mean ABPM at 6 months both the SBP and DBP were overestimated by and 7 mm Hg respectively. At 6 months post transplantation, when compared with ABPM, OBPM was more specific than HBPM in diagnosing hypertension (98% specificity, Kappa: 0.88 vs. 89% specificity, Kappa: 0.71). HBPM was superior to OBPM in identifying patients achieving goal BP (89% specificity, Kappa: 0.71 vs. 50% specificity Kappa: 0.54). In the absence of a gold standard for comparison the latent class model analysis still showed that ABPM was the best tool for diagnosing hypertension and monitoring patients reaching targeted control. OBPM remains an important tool for the diagnosis and management of hypertension in renal transplant recipients. HBPM and ABPM could be used to achieve BP control.

  11. Prospective blood pressure measurement in renal transplant recipients

    Directory of Open Access Journals (Sweden)

    V G David

    2014-01-01

    Full Text Available Blood pressure (BP control at home is difficult when managed only with office blood pressure monitoring (OBPM. In this prospective study, the reliability of BP measurements in renal transplant patients with OBPM and home blood pressure monitoring (HBPM was compared with ambulatory blood pressure monitoring (ABPM as the gold standard. Adult patients who had living-related renal transplantation from March 2007 to February 2008 had BP measured by two methods; OBPM and ABPM at pretransplantation, 2 nd , 4 th , 6 th , and 9 th months and all the three methods : OBPM, ABPM, and HBPM at 6 months after transplantation. A total of 49 patients, age 35 ± 11 years, on prednisolone, tacrolimus, and mycophenolate were evaluated. A total of 39 were males (79.6%. Systolic BP (SBP and diastolic BP (DBP measured by OBPM were higher than HBPM when compared with ABPM. When assessed using OBPM and awake ABPM, both SBP and DBP were significantly overestimated by OBPM with mean difference of 3-12 mm Hg by office SBP and 6-8 mm Hg for office DBP. When HBPM was compared with mean ABPM at 6 months both the SBP and DBP were overestimated by and 7 mm Hg respectively. At 6 months post transplantation, when compared with ABPM, OBPM was more specific than HBPM in diagnosing hypertension (98% specificity, Kappa : 0.88 vs. 89% specificity, Kappa : 0.71. HBPM was superior to OBPM in identifying patients achieving goal BP (89% specificity, Kappa : 0.71 vs. 50% specificity Kappa : 0.54. In the absence of a gold standard for comparison the latent class model analysis still showed that ABPM was the best tool for diagnosing hypertension and monitoring patients reaching targeted control. OBPM remains an important tool for the diagnosis and management of hypertension in renal transplant recipients. HBPM and ABPM could be used to achieve BP control.

  12. New calibration method for I-scan sensors to enable the precise measurement of pressures delivered by 'pressure garments'.

    Science.gov (United States)

    Macintyre, Lisa

    2011-11-01

    Accurate measurement of the pressure delivered by medical compression products is highly desirable both in monitoring treatment and in developing new pressure inducing garments or products. There are several complications in measuring pressure at the garment/body interface and at present no ideal pressure measurement tool exists for this purpose. This paper summarises a thorough evaluation of the accuracy and reproducibility of measurements taken following both of Tekscan Inc.'s recommended calibration procedures for I-scan sensors; and presents an improved method for calibrating and using I-scan pressure sensors. The proposed calibration method enables accurate (±2.1 mmHg) measurement of pressures delivered by pressure garments to body parts with a circumference ≥30 cm. This method is too cumbersome for routine clinical use but is very useful, accurate and reproducible for product development or clinical evaluation purposes. Copyright © 2011 Elsevier Ltd and ISBI. All rights reserved.

  13. A noncontact intraocular pressure measurement device using a micro reflected air pressure sensor for the prediagnosis of glaucoma

    International Nuclear Information System (INIS)

    Kim, Kyoung Hwan; Kim, Byeong Hee; Seo, Young Ho

    2012-01-01

    This study investigates a novel, portable tonometer using a micro reflected air pressure sensor for the prediagnosis of glaucoma. Because glaucoma progresses slowly and is not painful, glaucoma patients require a portable prediagnosis system to periodically measure intraocular pressure at home. Conventionally, intraocular pressure is measured by an air-puff tonometer whereby the cornea is deformed by a short pulse of air pressure and the magnitude of the corneal deformation is measured by optic systems such as a combination of laser- and photodiodes. In this study, a micro reflected air pressure sensor was designed, fabricated, and tested in order to measure the magnitude of corneal deformation without optic systems. In an experimental study, artificial eyes with different internal pressures were fabricated and these pressures were measured by the aforementioned system. (paper)

  14. Comparison of stethoscope bell and diaphragm, and of stethoscope tube length, for clinical blood pressure measurement.

    Science.gov (United States)

    Liu, Chengyu; Griffiths, Clive; Murray, Alan; Zheng, Dingchang

    2016-06-01

    This study investigated the effect of stethoscope side and tube length on auscultatory blood pressure (BP) measurement. Thirty-two healthy participants were studied. For each participant, four measurements with different combinations of stethoscope characteristics (bell or diaphragm side, standard or short tube length) were each recorded at two repeat sessions, and eight Korotkoff sound recordings were played twice on separate days to one experienced listener to determine the systolic and diastolic BPs (SBP and DBP). Analysis of variance was carried out to study the measurement repeatability between the two repeat sessions and between the two BP determinations on separate days, as well as the effects of stethoscope side and tube length. There was no significant paired difference between the repeat sessions and between the repeat determinations for both SBP and DBP (all P-values>0.10, except the repeat session for SBP using short tube and diaphragm). The key result was that there was a small but significantly higher DBP on using the bell in comparison with the diaphragm (0.66 mmHg, P=0.007), and a significantly higher SBP on using the short tube in comparison with the standard length (0.77 mmHg, P=0.008). This study shows that stethoscope characteristics have only a small, although statistically significant, influence on clinical BP measurement. Although this helps understand the measurement technique and resolves questions in the published literature, the influence is not clinically significant.

  15. Profile temperature, salinity, and hydrostatic pressure from CTD casts in McMurdo Sound from 2011-11-26 to 2011-12-03 (NCEI Accession 0131073)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Full-depth CTD profiles taken on along-sound and cross-sound transects of McMurdo Sound. Eleven stations with six independent sites were visited.

  16. Measurement of the speed of sound in trabecular bone by using a time reversal acoustics focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kang Il [Kangwon National University, Chuncheon (Korea, Republic of); Choi, Bok-Kyoung [Maritime Security Research Center, KIOST, Ansan (Korea, Republic of)

    2014-10-15

    A new method for measuring the speed of sound (SOS) in trabecular bone by using a time reversal acoustics (TRA) focusing system was proposed and validated with measurements obtained by using the conventional pulse-transmission technique. The SOS measured in 14 bovine femoral trabecular bone samples by using the two methods was highly correlated each other, although the SOS measured by using the TRA focusing system was slightly lower by an average of 2.2 m/s. The SOS measured by using the two methods showed high correlation coefficients of r = 0.92 with the apparent bone density, consistent with the behavior in human trabecular bone in vitro. These results prove the efficacy of the new method based on the principle of TRA to measure the SOS in trabecular bone.

  17. Interpreting Aerodynamics of a Transonic Impeller from Static Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Fangyuan Lou

    2018-01-01

    Full Text Available This paper investigates the aerodynamics of a transonic impeller using static pressure measurements. The impeller is a high-speed, high-pressure-ratio wheel used in small gas turbine engines. The experiment was conducted on the single stage centrifugal compressor facility in the compressor research laboratory at Purdue University. Data were acquired from choke to near-surge at four different corrected speeds (Nc from 80% to 100% design speed, which covers both subsonic and supersonic inlet conditions. Details of the impeller flow field are discussed using data acquired from both steady and time-resolved static pressure measurements along the impeller shroud. The flow field is compared at different loading conditions, from subsonic to supersonic inlet conditions. The impeller performance was strongly dependent on the inducer, where the majority of relative diffusion occurs. The inducer diffuses flow more efficiently for inlet tip relative Mach numbers close to unity, and the performance diminishes at other Mach numbers. Shock waves emerging upstream of the impeller leading edge were observed from 90% to 100% corrected speed, and they move towards the impeller trailing edge as the inlet tip relative Mach number increases. There is no shock wave present in the inducer at 80% corrected speed. However, a high-loss region near the inducer throat was observed at 80% corrected speed resulting in a lower impeller efficiency at subsonic inlet conditions.

  18. Measurement of the pressure pulse from a detonating explosive

    International Nuclear Information System (INIS)

    Bourne, N K; Milne, A M; Biers, R A

    2005-01-01

    A series of experiments has been carried out to determine the pressure pulse exiting from a polymethylmethacrylate (PMMA) plate, of varying thickness, subject to the shock pulse exerted by a detonating charge of fixed mass. This calibration will define a new donor explosive and inert gap material for use in one of the qualification tests for energetic materials, the large scale gap test. The peak pressure was recorded on the central axis of the attenuator using calibrated piezoresistive manganin gauges as a function of the quantity of PMMA applied to the output of the donor charge. The stress history within the PMMA was measured as a function of run distance and the peak pressure plotted against thickness as a calibration. The shock front was known to have curvature and a measurement of this was attempted. The behaviour of the transmitted shock at small gap thicknesses was shown to be anomalous since the front was partially in a reactive and partially within an inert medium

  19. A user's guide to intra-abdominal pressure measurement.

    LENUS (Irish Health Repository)

    Sugrue, Michael

    2015-01-01

    The intra-abdominal pressure (IAP) measurement is a key to diagnosing and managing critically ill medical and surgical patients. There are an increasing number of techniques that allow us to measure the IAP at the bedside. This paper reviews these techniques. IAP should be measured at end-expiration, with the patient in the supine position and ensuring that there is no abdominal muscle activity. The intravesicular IAP measurement is convenient and considered the gold standard. The level where the mid-axillary line crosses the iliac crest is the recommended zero reference for the transvesicular IAP measurement; moreover, marking this level on the patient increases reproducibility. Protocols for IAP measurement should be developed for each ICU based on the locally available tools and equipment. IAP measurement techniques are safe, reproducible and accurate and do not increase the risk of urinary tract infection. Continuous IAP measurement may offer benefits in specific situations in the future. In conclusion, the IAP measurement is a reliable and essential adjunct to the management of patients at risk of intra-abdominal hypertension.

  20. Measurement of local void fraction at elevated temperature and pressure

    International Nuclear Information System (INIS)

    Duncan, D.; Trabold, T.A.

    1993-03-01

    Significant advances have recently been made in analytical and computational methods for the prediction of local thermal-hydraulic conditions in gas/liquid two-phase flows. There is, however, a need for extensive experimental data, for the dual purposes of constitutive relation development and code qualification. There is especially true of systems involving complicated geometries and/or extreme flow conditions for which little, if any, applicable information exists in the open literature. For the tests described in the present paper, a novel electrical probe has been applied to measure the void fraction in atmospheric pressure air/water flows, and steam/water mixtures at high temperature and pressure. The data acquired in the latter experiments are compared with the results of a one-dimensional two-fluid computational analysis

  1. Interpretation of strain measurements on nuclear pressure vessels

    International Nuclear Information System (INIS)

    Andersen, S.I.; Engbaek, P.

    1979-11-01

    Selected results from strain measurements on 4 nuclear pressure vessels are presented and discussed. The measurements were made in several different regions of the vessels: transition zones in vessel heads, flanges and bottom parts, nozzels, internal vessel structure and flange bolts. The results presented are based on data obtained by approximately 700 strain-gauges, and a comprehensive knowledge of the quality obtained by such measurements is established. It is shown that a thorough control procedure before and after the test as well as detailed knowledge of the behaviour of the signal from the individual gauges during the test is necessary. If this is omitted, it can be extremely difficult to distinguish between the real structural behaviour and a malfunctioning of a specific gauge installation. In general, most of the measuring results exhibit a very linear behaviour with a negligible zeroshift. However, deviations from linear behaviour are observed in several cases. This nonlinearity can be explained by friction (flange connections) or by gaps (concentrical nozzles) in certain regions, whereas local plastic deformations during the first pressure loadings of the vessel seem to be the reason in other regions. (author)

  2. Dynamic pressure measures for long pipeline leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Likun Wang; Hongchao Wang; Min Xiong; Bin Xu; Dongjie Tan; Hengzhang Zhou [PetroChina Pipeline Company, Langfang (China). R and D Center

    2009-07-01

    Pipeline leak detection method based on dynamic pressure is studied. The feature of dynamic pressure which is generated by the leakage of pipeline is analyzed. The dynamic pressure method is compared with the static pressure method for the advantages and disadvantages in pipeline leak detection. The dynamic pressure signal is suitable for pipeline leak detection for quick-change of pipeline internal pressure. Field tests show that the dynamic pressure method detects pipeline leak rapidly and precisely. (author)

  3. Comparison of three protocols for measuring the maximal respiratory pressures

    Directory of Open Access Journals (Sweden)

    Isabela Maria B. Sclauser Pessoa

    Full Text Available Introduction To avoid the selection of submaximal efforts during the assessment of maximal inspiratory and expiratory pressures (MIP and MEP, some reproducibility criteria have been suggested. Criteria that stand out are those proposed by the American Thoracic Society (ATS and European Respiratory Society (ERS and by the Brazilian Thoracic Association (BTA. However, no studies were found that compared these criteria or assessed the combination of both protocols. Objectives To assess the pressure values selected and the number of maneuvers required to achieve maximum performance using the reproducibility criteria proposed by the ATS/ERS, the BTA and the present study. Materials and method 113 healthy subjects (43.04 ± 16.94 years from both genders were assessed according to the criteria proposed by the ATS/ERS, BTA and the present study. Descriptive statistics were used for analysis, followed by ANOVA for repeated measures and post hoc LSD or by Friedman test and post hoc Wilcoxon, according to the data distribution. Results The criterion proposed by the present study resulted in a significantly higher number of maneuvers (MIP and MEP – median and 25%-75% interquartile range: 5[5-6], 4[3-5] and 3[3-4] for the present study criterion, BTA and ATS/ERS, respectively; p < 0.01 and higher pressure values (MIP – mean and 95% confidence interval: 103[91.43-103.72], 100[97.19-108.83] and 97.6[94.06-105.95]; MEP: median and 25%-75% interquartile range: 124.2[101.4-165.9], 123.3[95.4-153.8] and 118.4[95.5-152.7]; p < 0.05. Conclusion The proposed criterion resulted in the selection of pressure values closer to the individual’s maximal capacity. This new criterion should be considered in future studies concerning MIP and MEP measurements.

  4. 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.

  5. Urethral pressure reflectometry. A method for simultaneous measurements of pressure and cross-sectional area in the female urethra

    DEFF Research Database (Denmark)

    Klarskov, Niels

    2012-01-01

    A novel technique for simultaneous measurements of pressure and cross-sectional area (CA) in the female urethra, denoted Urethral Pressure Reflectometry (UPR), was devised. A very thin and highly flexible polyurethane-bag was placed in the urethra. A pump applied increasing and decreasing pressur...

  6. Non-invasive continuous finger blood pressure measurement during orthostatic stress compared to intra-arterial pressure

    NARCIS (Netherlands)

    Imholz, B. P.; Settels, J. J.; van der Meiracker, A. H.; Wesseling, K. H.; Wieling, W.

    1990-01-01

    The aim of the study was to evaluate whether invasive blood pressure responses to orthostatic stress can be replaced by non-invasive continuous finger blood pressure responses. DESIGN - Intrabrachial and Finapres blood pressures were simultaneously measured during passive head up tilt and during

  7. Simultaneous compared with sequential blood pressure measurement results in smaller inter-arm blood pressure differences.

    Science.gov (United States)

    van der Hoeven, Niels V; Lodestijn, Sophie; Nanninga, Stephanie; van Montfrans, Gert A; van den Born, Bert-Jan H

    2013-11-01

    There are currently few recommendations on how to assess inter-arm blood pressure (BP) differences. The authors compared simultaneous with sequential measurement on mean BP, inter-arm BP differences, and within-visit reproducibility in 240 patients stratified according to age (simultaneous and three sequential BP measurements were taken in each patient. Starting measurement type and starting arm for sequential measurements were randomized. Mean BP and inter-arm BP differences of the first pair and reproducibility of inter-arm BP differences of the first and second pair were compared between both methods. Mean systolic BP was 1.3±7.5 mm Hg lower during sequential compared with simultaneous measurement (Psequential measurement was on average higher than the second, suggesting an order effect. Absolute systolic inter-arm BP differences were smaller on simultaneous (6.2±6.7/3.3±3.5 mm Hg) compared with sequential BP measurement (7.8±7.3/4.6±5.6 mm Hg, PSimultaneous measurement of BP at both arms reduces order effects and results in smaller inter-arm BP differences, thereby potentially reducing unnecessary referral and diagnostic procedures. ©2013 Wiley Periodicals, Inc.

  8. Temperature measurement in low pressure plasmas. Temperaturmessungen im Niederdruckplasma

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbauer, K.A.; Wilting, H.; Schramm, G. (Duesseldorf Univ. (Germany, F.R.). Abt. fuer Histologie und Embryologie)

    1989-11-01

    The present work discusses the influence of various parameters on the substrate temperature in a low pressure plasma. The measurement method chosen utilized Signotherm (Merck) temperature sensors embedded in silicon between two glass substrates. All measurements were made in a 200 G Plasma Processor from Technics Plasma GmbH. The substrate temperature is dependent on the process time, the RF power, the process gas and the position in the chamber. The substrate temperature increases with increasing process time and increasing power. Due to the location of the microwave port from the magnetron to the chamber, the substrate temperature is highest in the center of the chamber. Measurements performed in an air plasma yielded higher results than in an oxygen plasma. (orig.).

  9. Simultaneous sound velocity and thickness measurement by the ultrasonic pitch-catch method for corrosion-layer-forming polymeric materials.

    Science.gov (United States)

    Kusano, Masahiro; Takizawa, Shota; Sakai, Tetsuya; Arao, Yoshihiko; Kubouchi, Masatoshi

    2018-01-01

    Since thermosetting resins have excellent resistance to chemicals, fiber reinforced plastics composed of such resins and reinforcement fibers are widely used as construction materials for equipment in chemical plants. Such equipment is usually used for several decades under severe corrosive conditions so that failure due to degradation may result. One of the degradation behaviors in thermosetting resins under chemical solutions is "corrosion-layer-forming" degradation. In this type of degradation, surface resins in contact with a solution corrode, and some of them remain asa corrosion layer on the pristine part. It is difficult to precisely measure the thickness of the pristine part of such degradation type materials by conventional pulse-echo ultrasonic testing, because the sound velocity depends on the degree of corrosion of the polymeric material. In addition, the ultrasonic reflection interface between the pristine part and the corrosion layer is obscure. Thus, we propose a pitch-catch method using a pair of normal and angle probes to measure four parameters: the thicknesses of the pristine part and the corrosion layer, and their respective sound velocities. The validity of the proposed method was confirmed by measuring a two-layer sample and a sample including corroded parts. The results demonstrate that the pitch-catch method can successfully measure the four parameters and evaluate the residual thickness of the pristine part in the corrosion-layer-forming sample. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Step Prediction During Perturbed Standing Using Center Of Pressure Measurements

    Directory of Open Access Journals (Sweden)

    Milos R. Popovic

    2007-04-01

    Full Text Available The development of a sensor that can measure balance during quiet standing and predict stepping response in the event of perturbation has many clinically relevant applica- tions, including closed-loop control of a neuroprothesis for standing. This study investigated the feasibility of an algorithm that can predict in real-time when an able-bodied individual who is quietly standing will have to make a step to compensate for an external perturbation. Anterior and posterior perturbations were performed on 16 able-bodied subjects using a pul- ley system with a dropped weight. A linear relationship was found between the peak center of pressure (COP velocity and the peak COP displacement caused by the perturbation. This result suggests that one can predict when a person will have to make a step based on COP velocity measurements alone. Another important feature of this finding is that the peak COP velocity occurs considerably before the peak COP displacement. As a result, one can predict if a subject will have to make a step in response to a perturbation sufficiently ahead of the time when the subject is actually forced to make the step. The proposed instability detection algorithm will be implemented in a sensor system using insole sheets in shoes with minitur- ized pressure sensors by which the COPv can be continuously measured. The sensor system will be integrated in a closed-loop feedback system with a neuroprosthesis for standing in the near future.

  11. Out-of-office blood pressure: from measurement to control

    Directory of Open Access Journals (Sweden)

    Baguet JP

    2012-05-01

    Full Text Available Jean-Philippe Baguet1,21Department of Cardiology, University Hospital, 2Bioclinic Radiopharmaceutics Laboratory, INSERM U1039, Joseph Fourier University, Grenoble, FranceAbstract: Hypertension is an important risk factor for the development of cardiovascular disease, and is a major cause of morbidity and mortality worldwide. Traditionally, hypertension diagnosis and treatment and clinical evaluations of antihypertensive efficacy have been based on office blood pressure (BP measurements; however, there is increasing evidence that office measures may provide inadequate or misleading estimates of a patient’s true BP status and level of cardiovascular risk. The introduction, and endorsement by treatment guidelines, of 24-hour ambulatory BP monitoring and self (or home BP monitoring has facilitated more reliable and reproducible estimations of true BP, including the identification of white-coat and masked hypertension, and evaluation of BP variability. In addition, ambulatory BP monitoring enables accurate assessment of treatment effectiveness over 24 hours and both ambulatory and self BP monitoring may lead to better tailoring of therapy according to BP profile and concomitant disease. This review describes the clinical benefits and limitations of out-of-office assessments and their applications for effective management of hypertension and attainment of BP control.Keywords: ambulatory, ABPM, SBPM, blood pressure measurement, hypertension

  12. Measuring and understanding total dissolved gas pressure in groundwater

    Science.gov (United States)

    Ryan, C.; Roy, J. W.; Randell, J.; Castellon, L.

    2009-05-01

    Since dissolved gases are important to a number of aspects of groundwater (e.g. age dating, active or passive bioremediation, greenhouse gas fluxes, understanding biogeochemical processes involving gases, assessing potential impacts of coal bed methane activities), accurate concentration measurements, and understanding of their subsurface behaviour are important. Researchers have recently begun using total dissolved gas pressure (TGP) sensor measurements, more commonly applied for surface water monitoring, in concert with gas composition analyses to estimate more accurate groundwater gas concentrations in wells. We have used hydraulic packers to isolate the well screens where TDP is being measured, and pump tests to indicate that in-well degassing may reduce TDG below background groundwater levels. Thus, in gas-charged groundwater zones, TGPs can be considerably underestimated in the absence of pumping or screen isolation. We have also observed transient decreased TGPs during pumping that are thought to result from ebullition induced when the water table or water level in the well is lowered below a critical hydrostatic pressure.

  13. Prospective Comparative Analysis of 4 Different Intraocular Pressure Measurement Techniques and Their Effects on Pressure Readings.

    Science.gov (United States)

    Berk, Thomas A; Yang, Patrick T; Chan, Clara C

    2016-10-01

    To compare intraocular pressure (IOP) measurement using the Goldmann applanation tonometry (GAT) without fluorescein, with fluorescein strips, with fluorescein droplets, and IOP measurement with Tono-Pen Avia (TPA). This was a prospective comparative clinical analysis. It was performed in clinical practice. The study population consisted of 40 volunteer patients, 1 eye per patient. All patients who were 18 years and older having routine ophthalmological examination were eligible to participate. Active corneal abrasions and/or ulcers, previous glaucoma surgery, or prostheses interfering with GAT measurement were excluded. GAT IOP was measured first without fluorescein, then with fluorescein strip, then with fluorescein droplet, and finally with the TPA device. The main outcome measure was central corneal IOP. Mean±SD IOP measurements for GAT without fluorescein, with fluorescein strip, with fluorescein droplet, and for TPA groups were 12.65±3.01, 14.70±2.82, 15.78±2.64, and 16.33±3.08 mm Hg, respectively. Repeated-measures analysis of variance corrected with the Greenhouse-Geisser estimate ([Latin Small Letter Open E]=0.732) showed that measuring technique had a significant effect on IOP measurements (F2.20,85.59=34.66, P<0.001). The pairwise post hoc testing showed statistically significant mean differences (P≤0.001) between all techniques except when GAT with fluorescein droplet was compared with TPA (P=0.222). The Bland-Altman analyses showed 95% limits of agreement maximum potential discrepancies in measurement ranging from 5.89 mm Hg in the GAT with fluorescein strip versus droplet compared with 11.83 mm Hg in the GAT with fluorescein strip versus TPA comparison. IOP measurement technique significantly impacted the values obtained. The ophthalmologist should ensure consistent measurement technique to minimize variability when following patients.

  14. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Abhay B. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Kalange, Ashok E. [Department of Electronic Science, University of Pune, Pune 411 007 (India); Tuljaram Chaturchand College, Baramati 413 102 (India); Bodas, Dhananjay, E-mail: dhananjay.bodas@gmail.co [Center for Nanobio Sciences, Agharkar Research Institute, Pune 411 004 (India); Gangal, S.A. [Department of Electronic Science, University of Pune, Pune 411 007 (India)

    2010-04-15

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  15. Simulations of piezoelectric pressure sensor for radial artery pulse measurement

    International Nuclear Information System (INIS)

    Joshi, Abhay B.; Kalange, Ashok E.; Bodas, Dhananjay; Gangal, S.A.

    2010-01-01

    A radial artery pulse is used to diagnose human body constitution (Prakruti) in Ayurveda. A system consisting of piezoelectric sensor (22 mm x 12 mm), data acquisition card and LabView software was used to record the pulse data. The pulse obtained from the sensor was noisy, even though signal processing was done. Moreover due to large sized senor accurate measurements were not possible. Hence, a need was felt to develop a sensor of the size of the order of finger tip with a resonant frequency of the order of 1 Hz. A micromachined pressure sensor based on piezoelectric sensing mechanism was designed and simulated using CoventorWare. Simulations were carried out by varying dimensions of the sensor to optimize the resonant frequency, stresses and voltage generated as a function of applied pressure. All simulations were done with pressure ranging of 1-30 kPa, which is the range used by Ayurvedic practitioners for diagnosis. Preliminary work on fabrication of such a sensor was carried out successfully.

  16. Fast pressure measurements for the TMX-U fusion experiment

    International Nuclear Information System (INIS)

    Hunt, A.L.; Coffield, F.E.; Pickles, W.L.

    1982-01-01

    The pressure on the boundary of the Lawrence Livermore National Laboratory's (LLNL) tandem mirror (TMX-U) plasma experiment is difficult to trace for several reasons: (1) the TMX-U boundary is in the high vacuum range (10 -5 to 10 -6 Pa) and requires an ionization gauge; (2) the boundary includes high-energy neutral particles and radiation, so the gauge must be optically baffled from the plasma; (3) the gauge must be shielded from the magnetic flux density of 0.03 T; (4) maximum conductance to the gauge must be preserved so that the time response remains about 1 ms; (5) a fast electrical circuit is required to measure the small ion-current changes at a rate consistent with the geometrical and experimental time constant of 1 ms. We have developed solutions to these limitations, including fast ionization gauge (FIG) circuitry for the remote gauge operation and the CAMAC system for recording the pressure-time history in the TMX-U computer data base. We also give some examples of actual fast pressure histories during plasma operation

  17. Non-destructive residual pressure self-measurement method for the sensing chip of optical Fabry-Perot pressure sensor.

    Science.gov (United States)

    Wang, Xue; Wang, Shuang; Jiang, Junfeng; Liu, Kun; Zhang, Xuezhi; Xiao, Mengnan; Xiao, Hai; Liu, Tiegen

    2017-12-11

    We introduce a simple residual pressure self-measurement method for the Fabry-Perot (F-P) cavity of optical MEMS pressure sensor. No extra installation is required and the structure of the sensor is unchanged. In the method, the relationship between residual pressure and external pressure under the same diaphragm deflection condition at different temperatures is analyzed by using the deflection formula of the circular plate with clamped edges and the ideal gas law. Based on this, the residual pressure under the flat condition can be obtained by pressure scanning process and calculation process. We carried out the experiment to compare the residual pressures of two batches MEMS sensors fabricated by two kinds of bonding process. The measurement result indicates that our approach is reliable enough for the measurement.

  18. Light aircraft sound transmission studies - Noise reduction model

    Science.gov (United States)

    Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

    1987-01-01

    Experimental tests conducted on the fuselage of a single-engine Piper Cherokee light aircraft suggest that the cabin interior noise can be reduced by increasing the transmission loss of the dominant sound transmission paths and/or by increasing the cabin interior sound absorption. The validity of using a simple room equation model to predict the cabin interior sound-pressure level for different fuselage and exterior sound field conditions is also presented. The room equation model is based on the sound power flow balance for the cabin space and utilizes the measured transmitted sound intensity data. The room equation model predictions were considered good enough to be used for preliminary acoustical design studies.

  19. 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...

  20. Brief report: sound output of infant humidifiers.

    Science.gov (United States)

    Royer, Allison K; Wilson, Paul F; Royer, Mark C; Miyamoto, Richard T

    2015-06-01

    The sound pressure levels (SPLs) of common infant humidifiers were determined to identify the likely sound exposure to infants and young children. This primary investigative research study was completed at a tertiary-level academic medical center otolaryngology and audiology laboratory. Five commercially available humidifiers were obtained from brick-and-mortar infant supply stores. Sound levels were measured at 20-, 100-, and 150-cm distances at all available humidifier settings. Two of 5 (40%) humidifiers tested had SPL readings greater than the recommended hospital infant nursery levels (50 dB) at distances up to 100 cm. In this preliminary study, it was demonstrated that humidifiers marketed for infant nurseries may produce appreciably high decibel levels. Further characterization of the effect of humidifier design on SPLs and further elucidation of ambient sound levels associated with hearing risk are necessary before definitive conclusions and recommendations can be made. © American Academy of Otolaryngology—Head and Neck Surgery Foundation 2015.

  1. DC Electric Field measurement in the Mid-latitude Ionosphere during MSTID by S-520-27 Sounding Rocket Experiments

    Science.gov (United States)

    Ishisaka, K.; Yamamoto, M.; Yokoyama, T.; Tanaka, M.; Abe, T.; Kumamoto, A.

    2015-12-01

    In the middle latitude ionospheric F region, mainly in summer, wave structures of electron density that have wave length of 100-200 km and period of one hour are observed. This phenomena is called Medium Scale Traveling Ionosphiric Disturbance; MSTID. MSTID has been observed by GPS receiving network, and its characteristic were studied. In the past, MSTID was thought to be generated by the Perkins instability, but its growth ratio was too small to be effective so far smaller than the real. Recently coupling process between ionospheric E and F regions are studied by using two radars and by computer simulations. Through these studies, we now have hypothesis that MSTID is generated by the combination of E-F region coupling and Perkins instability. The S-520-27 sounding rocket experiment on E-layer and F-layer was planned in order to verify this hypothesis. S-520-27 sounding rocket was launched at 23:57 JST on 20th July, 2013 from JAXA Uchinoura Space Center. S-520-27 sounding rocket reached 316km height. The S-520-27 payload was equipped with Electric Field Detector (EFD) with a two set of orthogonal double probes to measure DC electric field in the spin plane of the payload. The electrodes of two double probe antennas were used to gather the potentials which were detected with high impedance pre-amplifier using the floating (unbiased) double probe technique. As a results of measurements of DC electric fields by the EFD, the natural electric field was about +/-5mV/m, and varied the direction from southeast to east. Then the electric field was mapped to the horizontal plane at 280km height along the geomagnetic field line. In this presentation, we show the detail result of DC electric field measurement by S-520-27 sounding rocket and then we discuss about the correlation between the natural electric field and TEC variation by using the GPS-TEC.

  2. Extraction of airfoil data using PIV and pressure measurements

    DEFF Research Database (Denmark)

    Yang, Hua; Shen, Wen Zhong; Sørensen, Jens Nørkær

    2011-01-01

    of the rotor. The extraction technique is verified by employing the derived airfoil characteristics as input to computations using the BEM technique and comparing the calculated axial and tangential forces to the measured data. The comparison also demonstrates that the used technique of determining the AOA...... airfoil data are compared to 2D data from wind tunnel experiments and XFOIL computations. The comparison suggests that the rotor is subject to severe 3D effects originating from the geometry of the rotor, and explains why the Blade Element Momentum technique with 2D airfoil data over‐predicts the loading......A newly developed technique for determining the angle of attack (AOA) on a rotating blade is used to extract AOAs and airfoil data from measurements obtained during the MEXICO (Model rotor EXperiments in COntrolled conditions) rotor experiment. Detailed surface pressure and Particle Image...

  3. Quantitative Thermochemical Measurements in High-Pressure Gaseous Combustion

    Science.gov (United States)

    Kojima, Jun J.; Fischer, David G.

    2012-01-01

    We present our strategic experiment and thermochemical analyses on combustion flow using a subframe burst gating (SBG) Raman spectroscopy. This unconventional laser diagnostic technique has promising ability to enhance accuracy of the quantitative scalar measurements in a point-wise single-shot fashion. In the presentation, we briefly describe an experimental methodology that generates transferable calibration standard for the routine implementation of the diagnostics in hydrocarbon flames. The diagnostic technology was applied to simultaneous measurements of temperature and chemical species in a swirl-stabilized turbulent flame with gaseous methane fuel at elevated pressure (17 atm). Statistical analyses of the space-/time-resolved thermochemical data provide insights into the nature of the mixing process and it impact on the subsequent combustion process in the model combustor.

  4. Heart sounds analysis via esophageal stethoscope system in beagles.

    Science.gov (United States)

    Park, Sang Hi; Shin, Young Duck; Bae, Jin Ho; Kwon, Eun Jung; Lee, Tae-Soo; Shin, Ji-Yun; Kim, Yeong-Cheol; Min, Gyeong-Deuk; Kim, Myoung hwan

    2013-10-01

    Esophageal stethoscope is less invasive and easy to handling. And it gives a lot of information. The purpose of this study is to investigate the correlation of blood pressure and heart sound as measured by esophageal stethoscope. Four male beagles weighing 10 to 12 kg were selected as experimental subjects. After general anesthesia, the esophageal stethoscope was inserted. After connecting the microphone, the heart sounds were visualized and recorded through a self-developed equipment and program. The amplitudes of S1 and S2 were monitored real-time to examine changes as the blood pressure increased and decreased. The relationship between the ratios of S1 to S2 (S1/S2) and changes in blood pressure due to ephedrine was evaluated. The same experiment was performed with different concentration of isoflurane. From S1 and S2 in the inotropics experiment, a high correlation appeared with change in blood pressure in S1. The relationship between S1/S2 and change in blood pressure showed a positive correlation in each experimental subject. In the volatile anesthetics experiment, the heart sounds decreased as MAC increased. Heart sounds were analyzed successfully with the esophageal stethoscope through the self-developed program and equipment. A proportional change in heart sounds was confirmed when blood pressure was changed using inotropics or volatile anesthetics. The esophageal stethoscope can achieve the closest proximity to the heart to hear sounds in a non-invasive manner.

  5. Pressure plate analysis of toe-heel and medio-lateral hoof balance at the walk and trot in sound sport horses.

    Science.gov (United States)

    Oosterlinck, M; Hardeman, L C; van der Meij, B R; Veraa, S; van der Kolk, J H; Wijnberg, I D; Pille, F; Back, W

    2013-12-01

    Empirically, equine distal limb lameness is often linked to hoof imbalance. To objectively quantify dynamic toe-heel and medio-lateral hoof balance of the vertical ground reaction force in sound sport horses, seven Royal Dutch Sport Horses were led at the walk and trot over a dynamically calibrated pressure plate. Forelimb hoof prints were divided into a toe and heel region and a medial and lateral zone. Toe-heel and medio-lateral hoof balance of the vertical ground reaction force were calculated throughout the stance. Toe-heel balance was highly symmetrical between contralateral limbs at both gaits. At the walk, medio-lateral balance of both forelimbs presented higher loading in the lateral part of the hoof throughout the stance. However, at the trot, left medio-lateral balance presented higher loading of the medial part of the hoof at impact, whereas the right limb showed higher loading of the lateral part of the hoof in all horses, and both limbs presented increased lateral loading at the end of the stance. This study provides objective data for toe-heel and medio-lateral hoof balance in sound sport horses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Electrical probe measurements in low and high pressure discharges

    International Nuclear Information System (INIS)

    Andersson, D.

    1976-11-01

    The construction of an apparatus for automatic determination of electron distributions is described, whereafter measurements of electron energy distributions before and after a stationary plasma sheath in a low pressure mercury discharge are presented. The sheath appears at a constriction of the discharge tube. The measurements have been made with a spheric probe, using the second-derivative method, and the results show that the energy distribution on the anode side of the sheath is a sum of a thermal population and an accelerated distribution. Near the sheath the accelerated electrons suffice to carry the discharge current, but far from it the current must be carried by an anisotropy in the thermal part of the distribution function. A comparison is made with calculated distributions. The cross-sections for electron-neutral and Coulomb collisions are not sufficient to account for the damping of the accelerated population, suggesting the presence of a plasma instability. In order to study the distribution function of the axial velocity component, preliminary measurements of the first derivative of the current to a plane probe have been made. Such measurements yield information about the anisotropy and the current transport, and may perhaps shed some light on the phenomenon of current limitation. Some measurements on a TIG welding arc are also described. (Auth.)

  7. Measurement of micro Bubbles generated by a pressurized dissolution method

    Energy Technology Data Exchange (ETDEWEB)

    Hosokawa, S; Tanaka, K; Tomiyama, A [Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501 (Japan); Maeda, Y; Yamaguchi, S; Ito, Y, E-mail: hosokawa@mech.kobe-u.ac.j [Panasonic Electric Works Co., Ltd., 1048 Kadoma, Osaka 571-8686 (Japan)

    2009-02-01

    Diameters of micro-bubbles are apt to range from about one mm to several-hundred mm, and therefore, it is difficult to measure a correct diameter distribution using a single measurement method. In this study, diameters of bubbles generated by a pressurized dissolution method are measured by using phase Doppler anemometry (PDA) and an image processing method, which is based on the Sobel filter and Hough transform. The diameter distribution and the Sauter mean diameter of micro bubbles are evaluated based on the diameters measured by both methods. Experiments are conducted for several mass flow rates of dissolved gas and of air bubbles entrained in the upstream of the decompression nozzle to examine effects of the entrained bubbles on bubble diameter. As a result, the following conclusions are obtained: (1) Diameter distribution of micro bubbles can be accurately measured for a wide range of diameter by using PDA and the image processing method. (2) The mean diameter of micro-bubbles generated by gasification of dissolved gas is smaller than that generated by breakup of air bubbles entrained in the upstream of the decompression nozzle. (3) The mean bubble diameter increases with the entrainment of air bubbles in the upstream of the decompression nozzle at a constant mass flow rate of dissolved gas.

  8. Measurement of micro Bubbles generated by a pressurized dissolution method

    International Nuclear Information System (INIS)

    Hosokawa, S; Tanaka, K; Tomiyama, A; Maeda, Y; Yamaguchi, S; Ito, Y

    2009-01-01

    Diameters of micro-bubbles are apt to range from about one mm to several-hundred mm, and therefore, it is difficult to measure a correct diameter distribution using a single measurement method. In this study, diameters of bubbles generated by a pressurized dissolution method are measured by using phase Doppler anemometry (PDA) and an image processing method, which is based on the Sobel filter and Hough transform. The diameter distribution and the Sauter mean diameter of micro bubbles are evaluated based on the diameters measured by both methods. Experiments are conducted for several mass flow rates of dissolved gas and of air bubbles entrained in the upstream of the decompression nozzle to examine effects of the entrained bubbles on bubble diameter. As a result, the following conclusions are obtained: (1) Diameter distribution of micro bubbles can be accurately measured for a wide range of diameter by using PDA and the image processing method. (2) The mean diameter of micro-bubbles generated by gasification of dissolved gas is smaller than that generated by breakup of air bubbles entrained in the upstream of the decompression nozzle. (3) The mean bubble diameter increases with the entrainment of air bubbles in the upstream of the decompression nozzle at a constant mass flow rate of dissolved gas.

  9. Effect of Hemifacial Spasm on Intraocular Pressure Measurement.

    Science.gov (United States)

    Cicik, Erdogan; Yildirim, Rengin; Arici, Ceyhun; Dikkaya, Funda; Arslan, Osman Sevki

    2018-01-01

    To evaluate the effect of hemifacial spasm (HFS) on intraocular pressure (IOP) measurement. Twenty-four consecutive patients with HFS and 25 age- and gender-matched randomly selected eyes of healthy volunteers underwent corneal pachymetry and IOP measurements using Goldmann applanation tonometer (GAT) and noncontact tonometer (NCT). IOP measurements were performed before (during HFS) and 2 weeks after Botox injections in HFS patients and in healthy volunteers without Botox injections. There was no statistical difference between involved eye side and uninvolved eye side of HFS patients in measured central corneal thickness. Similarly, no difference was found between involved eye side of HFS patients and controls. There were no statistically significant differences comparing IOP values before treatment and levels measured at 2 weeks of Botox injections, either with GAT ( p = 0.33, 0.11) or NCT ( p = 0.80, 0.43) devices in the involved eyes and uninvolved eyes of patients with HFS, respectively. There were also no significant differences in these parameters (GAT ( p = 0.63) and NCT ( p = 0.54)) in controls. Contractions in facial muscles may not lead to significant increase in IOP in HFS patients. This result may help clinical decision making in the treatment of glaucoma patients with HFS. This trial is registered with NCT03390803.

  10. Sound Propagation An impedance Based Approach

    CERN Document Server

    Kim, Yang-Hann

    2010-01-01

    In Sound Propagation: An Impedance Based Approach , Professor Yang-Hann Kim introduces acoustics and sound fields by using the concept of impedance. Kim starts with vibrations and waves, demonstrating how vibration can be envisaged as a kind of wave, mathematically and physically. One-dimensional waves are used to convey the fundamental concepts. Readers can then understand wave propagation in terms of characteristic and driving point impedance. The essential measures for acoustic waves, such as dB scale, octave scale, acoustic pressure, energy, and intensity, are explained. These measures are

  11. A study of methods of prediction and measurement of the transmission of sound through the walls of light aircraft

    Science.gov (United States)

    Forssen, B.; Wang, Y. S.; Raju, P. K.; Crocker, M. J.

    1981-08-01

    The acoustic intensity technique was applied to the sound transmission loss of panel structures (single, composite, and stiffened). A theoretical model of sound transmission through a cylindrical shell is presented.

  12. Neutron flux measurements in C-9 capsule pressure tube

    International Nuclear Information System (INIS)

    Barbos, D.; Roth, C. S.; Gugiu, D.; Preda, M.

    2001-01-01

    C-9 capsule is a fuel testing facility in which the testing consists of a daily cycle ranging between the limits 100% power to 50% power. C-9 in-pile section with sample holder an instrumentation are introduced in G-9 and G-10 experimental channels. The experimental fuel channel has a maximum value when the in-pile section (pressure tube) is in G-9 channel and minimum value in G-10 channel. In this paper the main goals are determination or measurements of: - axial thermal neutron flux distribution in C-9 pressure tube both in G-9 and G-10 channel; - ratio of maximum neutron flux value in G-9 and the same value in G-9 channel and the same value in G-10 channel; - neutron flux-spectrum. On the basis of axial neutron flux distribution measurements, the experimental fuel element in sample holder position in set. Both axial neutron flux distribution of thermal neutrons and neutron flux-spectrum were performed using multi- foil activation technique. Activation rates were obtained by absolute measurements of the induced activity using gamma spectroscopy methods. To determine the axial thermal neutron flux distribution in G-9 and G-10, Cu 100% wire was irradiated at the reactor power of 2 MW. Ratio between the two maximum values, in G-9 and G-10 channels, is 2.55. Multi-foil activation method was used for neutron flux spectrum measurements. The neutron spectra and flux were obtained from reaction rate measurements by means of SAND 2 code. To obtain gamma-ray spectra, a HPGe detector connected to a multichannel analyzer was used. The spectrometer is absolute efficiency calibrated. The foils were irradiated at 2 MW reactor power in previously determined maximum flux position resulted from wire measurements. This reaction rates were normalized for 10 MW reactor power. Neutron self shielding corrections for the activation foils were applied. The self-shielding corrections are computed using Monte Carlo simulation methods. The measured integral flux is 1.1·10 14 n/cm 2 s

  13. The value of pressure ulcer risk assessment and interface pressure measurements in patients: A nursing perspective

    NARCIS (Netherlands)

    J.T.M. Weststrate

    2005-01-01

    textabstractPressure sores in an intensive care unit 35 and related variables: a descriptive study Prevalence of pressure ulcers, risk factors 47 and the use of pressure-relieving mattresses in ICU patients The clinical relevance of the Waterlow 61 Pressure Sore Risk Scale in the ICU The

  14. New intraocular pressure measurement method using reflected pneumatic pressure from cornea deformed by air puff of ring-type nozzle.

    Science.gov (United States)

    Kim, Hyung Jin; Seo, Yeong Ho; Kim, Byeong Hee

    2017-01-01

    In this study, a non-contact type intraocular pressure (IOP) measuring system using reflected pneumatic pressure is proposed to overcome the disadvantages of existing measurement systems. A ring-type nozzle, a key component in the proposed system, is designed via computational fluid analysis. It predicts the reflected pneumatic pressure based on the nozzle exit angle and inner and outer diameters of the nozzle, which are 30°, 7 mm, and 9 mm, respectively. Performance evaluation is conducted using artificial eyes fabricated using polydimethylsiloxane with the specifications of human eyes. The IOP of the fabricated artificial eyes is adjusted to 10, 30, and 50 mm Hg, and the reflected pneumatic pressure is measured as a function of the distance between the ring-type nozzle and artificial eye. The measured reflected pneumatic pressure is high when the measurement distance is short and eye pressure is low. The cornea of an artificial eye is significantly deformed at a low IOP, and the applied pneumatic pressure is more concentrated in front of the ring-type nozzle because of the deformed cornea. Thus, the reflected pneumatic pressure at a low IOP has more inflows into the pressure sensor inserted inside the nozzle. The sensitivity of the output based on the IOP at measurement distances between 3-5 mm is -0.0027, -0.0022, -0.0018, -0.0015, and -0.0012. Sensitivity decreases as the measurement distance increases. In addition, the reflected pneumatic pressure owing to the misalignment at the measurement distances of 3-5 mm is not affected within a range of 0.5 mm. Therefore, the measurement range is acceptable up to a 1 mm diameter from the center of an artificial eye. However, the accuracy gradually decreases as the reflected pneumatic pressure from a misalignment of 1 mm or more decreases by 26% or more.

  15. Context-aware patient guidance during blood pressure self-measurement

    DEFF Research Database (Denmark)

    Sandager, Puk; Lindahl, Camilla; Schlütter, Jacob Mørup

    2013-01-01

    The importance of accurate measurement of blood pressure in the screening and management of hypertension during pregnancy is well established. Blood pressure levels can be measured manually by healthcare staff or by using a blood pressure self-measurement device, either at home or in the clinic...... the blood pressure self-measurement process. Preliminary results indicate that such active and context-aware guidance leads to more reliable measurements by inhibiting non-adherent patient behavior...

  16. Gaseous Multiplication factor measurements on low pressure ethylene

    International Nuclear Information System (INIS)

    Hevia Vives, Alberto

    2008-01-01

    The present investigation consists of a study of a Proportional Counter considered as a fundamental part of an Absolute Neutron Dosimeter developed for the Chilean Nuclear Energy Commission. The proportional counter consists of a Polyethylene Cathode of approximately 5 cm in diameter and an Anode consisting of a central wire of 5 μm in diameter. The proportional counter is biased at 650 V. The gas pressure ranges from 12 to 36 Torr of pure Ethylene. The work comes up as a need to obtain gas gain curves (Gas Multiplication Factors) for the proportional counter operated in the conditions as mentioned. This is a consequence of the scarcity of the existing information referred to Ethylene for the range of bias and gas pressure required in this case. Likewise, the research involved in this study contributed with useful information for the institution involved in the design and construction of the neutron dosimeter, as well as for the scientific community through the publication of this work. The results were obtained by using the above-mentioned Neutron Dosimeter but instead of using recoil protons by fast neutrons, the measurements were completed by directly using a 241 Am alpha particle source installed inside the dosimeter. The analysis of results as well as a detailed study of the pulse shapes provided by the proportional counter was performed by using the well-known MathCAD software. This software contains a text interface that includes symbolic and numeric calculations. Results of the research show that for the high Reduced Electric Fields ( Sa > 1500 Volts/cmTorr) used throughout the present work, Townsend law is still valid. This law states that the Multiplication Factors may be considered as dependent on the Reduced Electric Field instead of depending on the bias and gas pressure separately

  17. Student measurement of blood pressure using a simulator arm compared with a live subject's arm.

    Science.gov (United States)

    Lee, Jennifer J; Sobieraj, Diana M; Kuti, Effie L

    2010-06-15

    To compare accuracy of blood pressure measurements using a live subject and a simulator arm, and to determine students' preferences regarding measurement. This was a crossover study comparing blood pressure measurements from a live subject and a simulator arm. Students completed an anonymous survey instrument defining opinions on ease of measurement. Fifty-seven students completed blood pressure measurements on live subjects while 72 students completed blood pressure measurements using the simulator arm. There were no significant systematic differences between the 2 measurement techniques. Systolic blood pressure measurements from a live subject arm were less likely to be within 4 mm Hg compared with measurements of a simulator arm. Diastolic blood pressure measurements were not significantly different between the 2 techniques. Accuracy of student measurement of blood pressure using a simulator arm was similar to the accuracy with a live subject. There was no difference in students' preferences regarding measurement techniques.

  18. Non-Invasive Measurement of Intracranial Pressure Pulsation using Ultrasound

    Science.gov (United States)

    Ueno, Toshiaki; Ballard, R. E.; Yost, W. T.; Hargens, A. R.

    1997-01-01

    Exposure to microgravity causes a cephalad fluid shift which may elevate intracranial pressure (ICP). Elevation in ICP may affect cerebral hemodynamics in astronauts during space flight. ICP is, however, a difficult parameter to measure due to the invasiveness of currently available techniques. We already reported our development of a non-invasive ultrasound device for measurement of ICP. We recently modified the device so that we might reproducibly estimate ICP changes in association with cardiac cycles. In the first experiment, we measured changes in cranial distance with the ultrasound device in cadavera while changing ICP by infusing saline into the lateral ventricle. In the second experiment, we measured changes in cranial distance in five healthy volunteers while placing them in 60 deg, 30 deg head-up tilt, supine, and 10 deg head-down tilt position. In the cadaver study, fast Fourier transformation revealed that cranial pulsation is clearly associated with ICP pulsation. The ratio of cranial distance and ICP pulsation is 1.3microns/mmHg. In the tilting study, the magnitudes of cranial pulsation are linearly correlated to tilt angles (r=0.87). The ultrasound device has sufficient sensitivity to detect cranial pulsation in association with cardiac cycles. By analyzing the magnitude of cranial pulsation, estimates of ICP during space flight are possible.

  19. 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.

  20. Reliable intraocular pressure measurement using automated radio-wave telemetry

    Directory of Open Access Journals (Sweden)

    Paschalis EI

    2014-01-01

    Full Text Available Eleftherios I Paschalis,* Fabiano Cade,* Samir Melki, Louis R Pasquale, Claes H Dohlman, Joseph B CiolinoMassachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA*These authors contributed equally to this workPurpose: To present an autonomous intraocular pressure (IOP measurement technique using a wireless implantable transducer (WIT and a motion sensor.Methods: The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline IOP.Results: On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg and mean vehicle IOP (13.27±2.1 mmHg (P=0.45, suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001, and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001. Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001. Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute, during which the IOP is not expected to change.Conclusion: IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.Keywords: IOP, pressure transducer, wireless, MEMS, implant, intraocular

  1. 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.)

  2. Pressure drop measurements in LMFBR wire wrapped blanket assemblies

    International Nuclear Information System (INIS)

    Chiu, C.; Hawley, J.; Rohsenow, W.M.; Todreas, N.E.

    1977-07-01

    In this experiment, measurements of subchannel static pressure for an interior and edge subchannel were taken at two elevations in two wire-wrapped 61-pin bundles. One of the bundles has geometric characteristics of P/D = 1.067 and H/D = 8.0 (4 inch lead length and 0.501 inch rod diameter) and the other bundle has geometric characteristics of P/D = 1.067 and H/D = 4.0 (2 inch lead length and 0.501 inch rod diameter). The bundle average friction factors as well as the local subchannel friction factors for both interior and edge subchannels were determined from the experimental static pressure data. The average subchannel flow rates for both edge and interior subchannels were determined in a separate experiment. Results show that two correlations suggested by Rehme and Novendstern for the bundle average friction factor cannot predict the data within the range of experimental error. The bundle average friction factors for both bundles under test were underestimated by Rehme's correlation and overestimated by Novendstern's correlation. The results of the local subchannel friction factors indicate the effect of the wire lead length is more pronounced in the interior subchannel friction factor than in the edge subchannel friction factor. As the wire wrap lead length decreases, both interior and edge subchannel friction factors increase

  3. Pressure drop measurements in LMFBR wire wrapped blanket assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Chiu, C.; Hawley, J.; Rohsenow, W.M.; Todreas, N.E.

    1977-07-01

    In this experiment, measurements of subchannel static pressure for an interior and edge subchannel were taken at two elevations in two wire-wrapped 61-pin bundles. One of the bundles has geometric characteristics of P/D = 1.067 and H/D = 8.0 (4 inch lead length and 0.501 inch rod diameter) and the other bundle has geometric characteristics of P/D = 1.067 and H/D = 4.0 (2 inch lead length and 0.501 inch rod diameter). The bundle average friction factors as well as the local subchannel friction factors for both interior and edge subchannels were determined from the experimental static pressure data. The average subchannel flow rates for both edge and interior subchannels were determined in a separate experiment. Results show that two correlations suggested by Rehme and Novendstern for the bundle average friction factor cannot predict the data within the range of experimental error. The bundle average friction factors for both bundles under test were underestimated by Rehme's correlation and overestimated by Novendstern's correlation. The results of the local subchannel friction factors indicate the effect of the wire lead length is more pronounced in the interior subchannel friction factor than in the edge subchannel friction factor. As the wire wrap lead length decreases, both interior and edge subchannel friction factors increase.

  4. Stress Rupture Life Reliability Measures for Composite Overwrapped Pressure Vessels

    Science.gov (United States)

    Murthy, Pappu L. N.; Thesken, John C.; Phoenix, S. Leigh; Grimes-Ledesma, Lorie

    2007-01-01

    Composite Overwrapped Pressure Vessels (COPVs) are often used for storing pressurant gases onboard spacecraft. Kevlar (DuPont), glass, carbon and other more recent fibers have all been used as overwraps. Due to the fact that overwraps are subjected to sustained loads for an extended period during a mission, stress rupture failure is a major concern. It is therefore important to ascertain the reliability of these vessels by analysis, since the testing of each flight design cannot be completed on a practical time scale. The present paper examines specifically a Weibull statistics based stress rupture model and considers the various uncertainties associated with the model parameters. The paper also examines several reliability estimate measures that would be of use for the purpose of recertification and for qualifying flight worthiness of these vessels. Specifically, deterministic values for a point estimate, mean estimate and 90/95 percent confidence estimates of the reliability are all examined for a typical flight quality vessel under constant stress. The mean and the 90/95 percent confidence estimates are computed using Monte-Carlo simulation techniques by assuming distribution statistics of model parameters based also on simulation and on the available data, especially the sample sizes represented in the data. The data for the stress rupture model are obtained from the Lawrence Livermore National Laboratories (LLNL) stress rupture testing program, carried out for the past 35 years. Deterministic as well as probabilistic sensitivities are examined.

  5. Characterization of the Ignition Over-Pressure/Sound Suppression Water in the Space Launch System Mobile Launcher Using Volume of Fluid Modeling

    Science.gov (United States)

    West, Jeff

    2015-01-01

    The Space Launch System (SLS) Vehicle consists of a Core Stage with four RS-25 engines and two Solid Rocket Boosters (SRBs). This vehicle is launched from the Launchpad using a Mobile Launcher (ML) which supports the SLS vehicle until its liftoff from the ML under its own power. The combination of the four RS-25 engines and two SRBs generate a significant Ignition Over-Pressure (IOP) and Acoustic Sound environment. One of the mitigations of these environments is the Ignition Over-Pressure/Sound Suppression (IOP/SS) subsystem installed on the ML. This system consists of six water nozzles located parallel to and 24 inches downstream of each SRB nozzle exit plane as well as 16 water nozzles located parallel to and 53 inches downstream of the RS-25 nozzle exit plane. During launch of the SLS vehicle, water is ejected through each water nozzle to reduce the intensity of the transient pressure environment imposed upon the SLS vehicle. While required for the mitigation of the transient pressure environment on the SLS vehicle, the IOP/SS subsystem interacts (possibly adversely) with other systems located on the Launch Pad. One of the other systems that the IOP/SS water is anticipated to interact with is the Hydrogen Burn-Off Igniter System (HBOI). The HBOI system's purpose is to ignite the unburned hydrogen/air mixture that develops in and around the nozzle of the RS-25 engines during engine start. Due to the close proximity of the water system to the HBOI system, the presence of the IOP/SS may degrade the effectiveness of the HBOI system. Another system that the IOP/SS water may interact with adversely is the RS-25 engine nozzles and the SRB nozzles. The adverse interaction anticipated is the wetting, to a significant degree, of the RS-25 nozzles resulting in substantial weight of ice forming and water present to a significant degree upstream of the SRB nozzle exit plane inside the nozzle itself, posing significant additional blockage of the effluent that exits the nozzle

  6. Reliable intraocular pressure measurement using automated radio-wave telemetry

    Science.gov (United States)

    Paschalis, Eleftherios I; Cade, Fabiano; Melki, Samir; Pasquale, Louis R; Dohlman, Claes H; Ciolino, Joseph B

    2014-01-01

    Purpose To present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor. Methods The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP. Results On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change. Conclusion IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results. PMID:24531415

  7. Reliable intraocular pressure measurement using automated radio-wave telemetry.

    Science.gov (United States)

    Paschalis, Eleftherios I; Cade, Fabiano; Melki, Samir; Pasquale, Louis R; Dohlman, Claes H; Ciolino, Joseph B

    2014-01-01

    To present an autonomous intraocular pressure (IOP) measurement technique using a wireless implantable transducer (WIT) and a motion sensor. The WIT optical aid was implanted within the ciliary sulcus of a normotensive rabbit eye after extracapsular clear lens extraction. An autonomous wireless data system (AWDS) comprising of a WIT and an external antenna aided by a motion sensor provided continuous IOP readings. The sensitivity of the technique was determined by the ability to detect IOP changes resulting from the administration of latanoprost 0.005% or dorzolamide 2%, while the reliability was determined by the agreement between baseline and vehicle (saline) IOP. On average, 12 diurnal and 205 nocturnal IOP measurements were performed with latanoprost, and 26 diurnal and 205 nocturnal measurements with dorzolamide. No difference was found between mean baseline IOP (13.08±2.2 mmHg) and mean vehicle IOP (13.27±2.1 mmHg) (P=0.45), suggesting good measurement reliability. Both antiglaucoma medications caused significant IOP reduction compared to baseline; latanoprost reduced mean IOP by 10% (1.3±3.54 mmHg; P<0.001), and dorzolamide by 5% (0.62±2.22 mmHg; P<0.001). Use of latanoprost resulted in an overall twofold higher IOP reduction compared to dorzolamide (P<0.001). Repeatability was ±1.8 mmHg, assessed by the variability of consecutive IOP measurements performed in a short period of time (≤1 minute), during which the IOP is not expected to change. IOP measurements in conscious rabbits obtained without the need for human interactions using the AWDS are feasible and provide reproducible results.

  8. Feasibility of heart sounds measurements from an accelerometer within an ICD pulse generator.

    Science.gov (United States)

    Siejko, Krzysztof Z; Thakur, Pramodsingh H; Maile, Keith; Patangay, Abhilash; Olivari, Maria-Teresa

    2013-03-01

    The feasibility of detecting heart sounds (HS) from an accelerometer sensor enclosed within an implantable cardioverter defibrillator (ICD) pulse generator (PG) was explored in a noninvasive pilot study on heart failure (HF) patients with audible third HS (S3). Accelerometer circuitry enhanced for HS was incorporated into non-functional ICDs. A study was conducted on 30 HF patients and 10 normal subjects without history of cardiac disease. The devices were taped to the skin surface over both left and right pectoral regions to simulate subcutaneous implants. A lightweight reference accelerometer was taped over the cardiac apex. Waveforms were recorded simultaneously with a surface electrocardiogram for 2 minutes. Algorithms were developed to perform off-line automatic detection of HS and HS time intervals (HSTIs). S1, S2, and S3 vibrations were detected in all accelerometer locations for all 40 subjects, including 16 subjects without an audible S3. A substantial proportion of S3 energy was infrasonic (remote ambulatory monitoring of HF progression and the detection of the onset of HF decompensation. ©2012, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

  9. Physico-mechanical properties determination using microscale homotopic measurements: Application to sound and caries-affected primary tooth dentin

    Science.gov (United States)

    Marangos, Orestes; Misra, Anil; Spencer, Paulette; Bohaty, Brenda; Katz, J. Lawrence

    2009-01-01

    Microscale elastic moduli, composition and density have rarely been determined at the same location for biological materials. In this paper, we have performed homotopic measurements to determine the physico-mechanical properties of a second primary molar specimen exhibiting sound and caries-affected regions. A microscale acoustic impedance map of a section through this sample was acquired using scanning acoustic microscopy (SAM). Scanning electron microscopy was then used to obtain mineral mass fraction of the same section using backscattered images. Careful calibration of each method was performed to reduce system effects and obtain accurate data. Resorption, demineralization and hypermineralization mechanisms were considered in order to derive relationships between measured mineral mass fraction and material mass density. As a result, microscale mass density was determined at the same lateral resolution and location as the SAM data. The mass density and the acoustic impedance were combined to find the microscale elastic modulus and study the relationship between microscale composition and mechanical properties. PMID:19059013

  10. Non-Invasive Measurement of Pulsatile Intracranial Pressures Using Ultrasound

    Science.gov (United States)

    Ueno, Toshiaki; Ballard, Richard E.; Shuer, Lawrence M.; Cantrell, John H.; Cantrell, John H.; Hargens, Alan R.

    1997-01-01

    Early detection of elevated intracranial pressure (ICP) will aid clinical decision-making for head trauma, brain tumor and other cerebrovascular diseases. Conventional methods, however, require surgical procedures which take time and are accompanied by increased risk of infection. Accordingly we have developed and refined a new ultrasound device to measure skull movements which are known to occur in conjunction with altered ICP. The principle of this device is based upon pulse phase locked loop (PPLL), which enables us to detect changes in distance on the order of microns between an ultrasound transducer on one side of the skull and the opposite inner surface of the cranium. The present study was designed to verify this measurement technique in cadavera. Transcranial distance was increased in steps of 10 mmHg from zero to 50 mmHg by saline infusion into the lateral ventricle of two cadavera. In separate experiments, pulsations of ICP with the amplitudes of zero to 2 mmHg were generated by rhythmic injections of saline using a syringe. When the ICP was stepwise increased from zero to 50 mmHg, transcranial distance increased in proportion with the ICP increase (y=12 x - 76, r=0.938), where y is changes in transcranial distance in microns and x is ICP in mmHg. In the data recorded while ICP pulsations were generated, fast Fourier transform analysis demonstrated that cranial pulsations were clearly associated with ICP pulsations. The results indicate that changes in transcranial distance is linearly correlated with those in ICP, and also that the PPLL device has sufficient sensitivity to detect transcranial pulsations which occur in association with the cardiac cycle. By analyzing the magnitude of cranial pulsations, we may be able to estimate the pressure-volume index in the cranium. As a result, estimates of intracranial compliance may be possible by using the PPLL device. Further studies are necessary in normal subjects and patients.

  11. Evaluation of the Automatic Density Compensation for Pressurizer Level Measurement

    International Nuclear Information System (INIS)

    Jeong, Insoo; Min, Seohong; Ahn, Myunghoon

    2014-01-01

    When using two transmitters, it is difficult for the operators to identify the correct level of the pressurizer (PZR) upon failure of one of the two transmitters. For this reason, Korean Utility Requirements Document (KURD) requires that the operators to use three independent level indicators. Two hot calibrated transmitters and one cold calibrated transmitter compose PZR level transmitters in APR1400. In this paper, the deviation between cold calibration and hot calibration is evaluated, and the application of compensated PZR level measurement and uncompen-sated PZR level measurement during the normal operation of APR1400 are introduced. The PZR level signals for APR1400 come in three channels. To satisfy the KURD requirements for PZR level measurement, and at the same time to accomplish correction design and implementation, applicability and differences between hot calibration and cold calibration, compensated level and uncompensated level were evaluated as follows: For proper indication of PZR levels under normal operating condition, two of the three transmitters went through hot calibration and the remaining one transmitter went through cold calibration. This was to allow indicating entire regions of PZR regardless of the plant operation modes. For automatic density compensation per KURD requirements, the algorithm of the density compensated PZR level implemented in the DCS controller and PRV logic is adopted as a signal validation method

  12. 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....

  13. New method to improve the accuracy of quench position measurement on a superconducting cavity by a second sound method

    Directory of Open Access Journals (Sweden)

    ZhenChao Liu

    2012-09-01

    Full Text Available Quench is a common phenomenon in a superconducting cavity and often limits the accelerating gradient of the cavity. Accurate location of the quench site, typically located at a material or geometrical defect, is the key to improve the cavity accelerating gradient. Here, the second sound propagation in liquid helium II is used to detect the quench location on the cavity. The technique is relatively convenient and complements the traditional temperature mapping which measures the “prequench” temperature rise on the cavity using an array of sensors. The speed of the second sound in liquid helium II is roughly 1.7  cm/ms at 2 K which is sufficiently fast to provide a millimeter-size position resolution. However, the dynamics of the quench at the cavity surface are also found to significantly affect the achievable resolution with real cavities. Here we use a dynamic quench model, based on ANSYS, to calculate the quench area and the temperature distribution on the cavity. The detection error caused by the thermal conduction in the niobium was calculated.

  14. Quantitative Assessment of Blood Pressure Measurement Accuracy and Variability from Visual Auscultation Method by Observers without Receiving Medical Training

    Science.gov (United States)

    Feng, Yong; Chen, Aiqing

    2017-01-01

    This study aimed to quantify blood pressure (BP) measurement accuracy and variability with different techniques. Thirty video clips of BP recordings from the BHS training database were converted to Korotkoff sound waveforms. Ten observers without receiving medical training were asked to determine BPs using (a) traditional manual auscultatory method and (b) visual auscultation method by visualizing the Korotkoff sound waveform, which was repeated three times on different days. The measurement error was calculated against the reference answers, and the measurement variability was calculated from the SD of the three repeats. Statistical analysis showed that, in comparison with the auscultatory method, visual method significantly reduced overall variability from 2.2 to 1.1 mmHg for SBP and from 1.9 to 0.9 mmHg for DBP (both p auscultation methods). In conclusion, the visual auscultation method had the ability to achieve an acceptable degree of BP measurement accuracy, with smaller variability in comparison with the traditional auscultatory method. PMID:29423405

  15. Experimental measurements of static pressure and pressure drop in a duct enclosing a seven wire-wrapped rod bundle

    International Nuclear Information System (INIS)

    Graca, M.C.; Ballve, H.; Fernandez y Fernandez, E.; Carajilescov, P.

    1981-01-01

    The friction factor and the static pressure distributions, in the axial and transversal directions, in the wall of the hexagonal duct, enclosing a seven wire-wrapped rod bundle, were experimentally measured, using an air opened loop. The Reynolds numbers are the range 10 3 - 5x10 4 . The friction factors are compared to existing correlations. The static pressure distributions show that the static pressure is not hydrostatic in the cross section of the flow. (Author) [pt

  16. Liquid crystalline fiber optic colorimeter for hydrostatic pressure measurement

    Science.gov (United States)

    Wolinski, Tomasz R.; Bajdecki, Waldemar K.; Domanski, Andrzej W.; Karpierz, Miroslaw A.; Konopka, Witold; Nasilowski, T.; Sierakowski, Marek W.; Swillo, Marcin; Dabrowski, Roman S.; Nowinowski-Kruszelnicki, Edward; Wasowski, Janusz

    2001-08-01

    This paper presents results of tests performed on a fiber optic system of liquid crystalline transducer for hydrostatic pressure monitoring based on properties of colorimetry. The system employs pressure-induced deformations occurring in liquid crystalline (LC) cells configured in a homogeneous Frederiks geometry. The sensor is compared of a round LC cell placed inside a specially designed pressure chamber. As a light source we used a typical diode operating at red wavelength and modulated using standard techniques. The pressure transducer was connected to a computer with a specially designed interface built on the bas of advanced ADAM modules. Results indicate that the system offers high response to pressure with reduced temperature sensitivity and, depending on the LC cell used, can be adjusted for monitoring of low hydrostatic pressures up to 6 MPa. These studies have demonstrated the feasibility of fiber optic liquid crystal colorimeter for hydrostatic pressure sensing specially dedicated to pipe- lines, mining instrumentation, and process-control technologies.

  17. Blood pressure measurement in epidemiological investigations in teenagers

    International Nuclear Information System (INIS)

    Coppieters, Yves; Parent, Florence; Berghmans, Luc; Godin, Isabelle; Leveque, Alain

    2001-01-01

    Background: The use of sphygmomanometers may lead to problems in investigations on health of young people. The purpose of this paper is to present the validation of the blood pressure (BP) collected during the survey 'Youth Heart Health' in Hainaut by using second sample of young people in Hainaut for which BP was measured by a manual taking of tension and by an electronic device. Methods: Validation was done with a control sample of 343 young with five successive BP measures: twice with the mercury sphygmomanometer and three with DXL. We compared the manual and the electronic measures in order to study the correlation between the two methods. The control sample was used in order to compare the BP measurements with the results of the survey on the health of young people in Hainaut. Results: The differences between manual systolic BP and Dinamap measures are significant (differences in averages 3.6 mmHg; d.s. 7.8; 95% CI: 2.8-4.4 mmHg; p < 0.001) and the regression coefficient is -0.015. Diastolic BP is significantly higher with the manual method than with Dinamap (differences in means: 8.2 mmHg; d.s. 7.0; 95% CI: 7.4-8.9 mmHg; p < 0.001) and the coefficient of regression is 0.096. We observe a difference in BP between the general survey and the control group (10.3 mmHg for systolic manual control and of 10.9 mmHg for systolic electronic control; 3.3 mmHg for diastolic manual control and of 11.5 mmHg for diastolic electronic control). Conclusions: The values of BP of the 'Youth Heart Health' are significantly higher. These observations indicate the difficulties in the choice of the tool for measurements of BP in epidemiological investigations in the teenagers. In order to decrease skews of observations in the measurement of BP, it is recommended to use a valid electronic instrument. Dinamap XL is an instrument of choice in such studies of young people. Environmental and organisational factors may also explain the observed difference, which means that survey

  18. Endoscopic PIV measurements in a low pressure turbine rig

    Energy Technology Data Exchange (ETDEWEB)

    Kegalj, Martin; Schiffer, Heinz-Peter [Technische Universitaet Darmstadt (Germany). Department of Gas Turbines and Aerospace Propulsion

    2009-10-15

    Particle-Image-Velocimetry (PIV) is a useful way to acquire information about the flow in turbomachinery. Several premises have to be fulfilled to achieve high-quality data, for example, optical access, low vibrations and low reflections. However, not all test facilities comply with these requirements. If there is no optical access to the test area, measurements cannot be performed. The use of borescopic optics is a possible solution to this issue, as the access required is very small. Several different techniques can be used to measure the three components of the velocity vector, one of which is Stereo-PIV. These techniques require either large optical access from several viewing angles or highly complex setups. Orthogonal light sheet orientations in combination with borescopic optics using Planar-PIV can deliver sufficient information about the flow. This study will show the feasibility of such an approach in an enclosed test area, such as the interblade space in a Low-Pressure-Turbine-Rig. The results from PIV will be compared with data collected with conventional techniques, such as the Five-Hole-Probe and the 2-component Hot-Wire-Anemometry. An analysis of time- and phase-averaged data will be performed. (orig.)

  19. Time-averaged second-order pressure and velocity measurements in a pressurized oscillating flow prime mover

    Energy Technology Data Exchange (ETDEWEB)

    Paridaens, Richard [DynFluid, Arts et Metiers, 151 boulevard de l' Hopital, Paris (France); Kouidri, Smaine [LIMSI-CNRS, Orsay Cedex (France)

    2016-11-15

    Nonlinear phenomena in oscillating flow devices cause the appearance of a relatively minor secondary flow known as acoustic streaming, which is superimposed on the primary oscillating flow. Knowledge of control parameters, such as the time-averaged second-order velocity and pressure, would elucidate the non-linear phenomena responsible for this part of the decrease in the system's energetic efficiency. This paper focuses on the characterization of a travelling wave oscillating flow engine by measuring the time-averaged second order pressure and velocity. Laser Doppler velocimetry technique was used to measure the time-averaged second-order velocity. As streaming is a second-order phenomenon, its measurement requires specific settings especially in a pressurized device. Difficulties in obtaining the proper settings are highlighted in this study. The experiments were performed for mean pressures varying from 10 bars to 22 bars. Non-linear effect does not constantly increase with pressure.

  20. Exploring Noise: Sound Pollution.

    Science.gov (United States)

    Rillo, Thomas J.

    1979-01-01

    Part one of a three-part series about noise pollution and its effects on humans. This section presents the background information for teachers who are preparing a unit on sound. The next issues will offer learning activities for measuring the effects of sound and some references. (SA)

  1. Time response measurements of pressure sensors using pink noise technique

    International Nuclear Information System (INIS)

    Pereira, Iraci Martinez; Santos, Roberto Carlos dos

    2009-01-01

    This work presents an experimental setup for Pink Noise method application on pressure transmitters' response times. The Pink Noise method consists on injecting artificial pressure noise into the pressure transmitter. The artificial pressure noise is generated using a current-to-pressure (I-to-P) converter, which is driven by a random noise signal generator. The output pressure transmitter noise is then analyzed using conventional Noise Analysis Technique. Noise signals may be interpreted using spectral techniques or empirical time series models. The frequency domain method consists of evaluating the Power Spectral Density (PSD) function. The information needed for time constant estimation can be obtained by fitting an all-pole transfer function to this power spectral density. (author)

  2. Optical measurement of acoustic radiation pressure of the near-field acoustic levitation through transparent object

    OpenAIRE

    Nakamura, Satoshi; Furusawa, Toshiaki; Sasao, Yasuhiro; Katsura, Kogure; Naoki, Kondo

    2013-01-01

    It is known that macroscopic objects can be levitated for few to several hundred micrometers by near-field acoustic field and this phenomenon is called near-field acoustic levitation (NFAL). Although there are various experiments conducted to measure integrated acoustic pressure on the object surface, up to now there was no direct method to measure pressure distribution. In this study we measured the acoustic radiation pressure of the near-field acoustic levitation via pressure-sensitive paint.

  3. Design and Development of a Pressure Transmitter Using Modified Inductance Measuring Network and Bellow Sensor

    OpenAIRE

    Venkata Lakshmi Narayana K.; Bhujanga Rao A.

    2013-01-01

    In this paper, a pressure transmitter using a modified op-amp based network for inductance measurement using a bellow as sensor has been proposed to measure the pressure and to convert pressure changes in to an electrical current which can be transmitted to a remote indicator. The change in inductance due to change in pressure is measured by an improved modified operational amplifier based network. The proposed network permits offset inductance compensation of sensing coil and also minimizes ...

  4. Conception and preliminary evaluation of an optical fibre sensor for simultaneous measurement of pressure and temperature

    International Nuclear Information System (INIS)

    Bremer, K; Moss, B; Leen, G; Mueller, I; Lewis, E; Lochmann, S

    2009-01-01

    This paper presents a novel concept of simultaneously measuring pressure and temperature using a silica optical fibre extrinsic Fabry-Perot interferometric (EFPI) pressure sensor incorporating a fibre Bragg grating (FBG), which is constructed entirely from fused-silica. The novel device is used to simultaneously provide accurate pressure and temperature readings at the point of measurement. Furthermore, the FBG temperature measurement is used to eliminate the temperature cross-sensitivity of the EFPI pressure sensor.

  5. Measurement of sound velocity on metal surfaces by impulsive stimulated Brillouin scattering

    International Nuclear Information System (INIS)

    Shimada, Yukihiro; Murakami, Hiroshi; Nishimura, Akihiko

    2005-01-01

    Impulsive stimulated Brillouin Scattering (ISBS) experiment was performed in order to measure acoustic waves on metal surfaces. The ISBS technique offers robust method of obtaining acoustic velocities without physical contact. The generation and detection mechanism were discussed. (author)

  6. Measurement of sea ice thickness using electromagnetic sounding; Denji tansaho wo mochiita kaihyoatsu no keisoku

    Energy Technology Data Exchange (ETDEWEB)

    Kawauchi, K; Suzuki, I; Goto, N [Muroran Institute of Technology, Hokkaido (Japan); Hoshiyama, K

    1997-10-22

    Thickness of sea ice is measured by an electromagnetic method making use of the peculiarities of sea ice. Sea ice floats on the seawater (saline water), and the result is two horizontal layers greatly different from each other in conductivity, with seawater being highly conductive and ice being non-conductive. A study is conducted on Lake Kumatori, a saline lake in Abashiri City, in which effort a board of naturally frozen sea ice and a board of sea ice allowed to form on the sea surface at a spot from which ice has been removed are examined. A portable electromagnetic probe EM38 of GEONICS Company is employed to perform measurement in a horizontal dipole mode. To determine the relationship between the obtained conductivity measurements and sea ice thickness, holes are bored in the sea ice boards for the measurement of their thickness for the formulation of an experimental regression equation. Measurements along the traverse line 1 and traverse line 3 are converted into sea ice thickness by use of the experimental regression equation, and the result is that ice thickness is the greatest near the quay growing thinner away from the shore. The study shows that sea ice thickness may be measured accurately by electromagnetic probing. 3 refs., 10 figs.

  7. Deuterium isotope differences in 2-propanone (CH3)2CO/(CD3)2CO: a high-pressure sound-speed, density, and heat capacities study

    International Nuclear Information System (INIS)

    Szydlowski, J.; Gomes de Azevedo, R.; Rebelo, L.P.N.; Esperanca, J.M.S.S.; Guedes, H.J.R.

    2005-01-01

    A new high-pressure, non-intrusive ultrasonic microcell [J. Chem. Thermodyn. 36 (2004) 211-222] was used to carry out sound-speed measurements in deuteriated 2-propanone (acetone-d 6 ) in broad ranges of temperature (288 6 . (p, ρ, T) data for acetone-d 6 were also determined but in a narrower T, p range (298 to 333 K; 0.1 to 60 MPa). In this interval, several thermodynamic properties were thus determined, such as: isentropic (κ s ) and isothermal (κ T ) compressibility, isobaric thermal expansivity (α p ), isobaric (c p ) and isochoric (c v ) specific heat capacity, and the thermal pressure coefficient (γ v ). Comparisons with our data for acetone-h 6 enabled us to establish the magnitude and sign of deuterium isotope effects for identical properties. These effects are a consequence of distinct vibrational mode frequencies in an isotope-invariant force constants' field. Molar heat capacities and their isotope effects were theoretically determined by employing an Einstein-like model for the vibrational frequencies of acetone-h 6 and acetone-d 6

  8. Reliability of blood pressure measurement and cardiovascular risk prediction

    NARCIS (Netherlands)

    van der Hoeven, N.V.

    2016-01-01

    High blood pressure is one of the leading risk factors for cardiovascular disease, but difficult to reliably assess because there are many factors which can influence blood pressure including stress, exercise or illness. The first part of this thesis focuses on possible ways to improve the

  9. An instrument to measure differential pore pressures in deep ocean sediments: Pop-Up-Pore-Pressure-Instrument (PUPPI)

    International Nuclear Information System (INIS)

    Schultheiss, P.J.; McPhail, S.D.; Packwood, A.R.; Hart, B.

    1985-01-01

    A Pop-Up-Pore-Pressure-Instrument (PUPPI) has been developed to measure differential pore pressures in sediments. The differential pressure is the pressure above or below normal hydrostatic pressure at the depth of the measurement. It is designed to operate in water depths up to 6000 metres for periods of weeks or months, if required, and measures differential pore pressures at depths of up to 3 metres into the sediments with a resolution of 0.05 kPa. It is a free-fall device with a lance which penetrates the sediments. This lance and the ballast weight is disposed when the PUPPI is acoustically released from the sea floor. When combined with permeability and porosity values of deep-sea sediments the pore pressure measurements made using the PUPPI suggest advection velocities as low as 8.8 mm/yr. The mechanical, electrical and acoustic systems are described together with data obtained from both shallow and deep water trials. (author)

  10. Central venous pulse pressure analysis using an R-synchronized pressure measurement system.

    Science.gov (United States)

    Fujita, Yoshihisa; Hayashi, Daisuke; Wada, Shinya; Yoshioka, Naoki; Yasukawa, Takeshi; Pestel, Gunther

    2006-12-01

    The information derived from central venous catheters is underused. We developed an EKG-R synchronization and averaging system to obtained distinct CVP waveforms and analyzed components of these. Twenty-five paralyzed surgical patients undergoing CVP monitoring under mechanical ventilation were studied. CVP and EKG signals were analyzed employing our system, the mean CVP and CVP at end-diastole during expiration were compared, and CVP waveform components were measured using this system. CVP waveforms were clearly visualized in all patients. They showed the a peak to be 1.8+/- 0.7 mmHg, which was the highest of three peaks, and the x trough to be lower than the y trough (-1.6+/- 0.7 mmHg and -0.9+/- 0.5 mmHg, respectively), with a mean pulse pressure of 3.4 mmHg. The difference between the mean CVP and CVP at end-diastole during expiration was 0.58+/- 0.81 mmHg. The mean CVP can be used as an index of right ventricular preload in patients under mechanical ventilation with regular sinus rhythm. Our newly developed system is useful for clinical monitoring and for education in circulatory physiology.

  11. A comparison of blood pressure measurements in newborns.

    LENUS (Irish Health Repository)

    O'Shea, Joyce

    2012-02-01

    Blood pressure monitoring is an essential component of neonatal intensive care. We compared invasive and noninvasive (Dinamap, Marquette, and Dash) recordings in newborns and also noninvasive values obtained from upper and lower limbs. Infants\\' blood pressure was recorded every 6 hours for 72 hours using three noninvasive devices and compared with invasive readings taken simultaneously. Twenty-five babies were enrolled in the study, with birth weights of 560 to 4500 g and gestation 24 + 1 to 40 + 5 weeks. Three hundred thirty-two recordings were obtained. Comparison between invasive and noninvasive readings revealed that all three noninvasive monitors overread mean blood pressure. There was no significant difference between the cuff recordings obtained from the upper or lower limbs. All three noninvasive devices overestimated mean blood pressure values compared with invasive monitoring. Clinicians may be falsely reassured by noninvasive monitoring. Mean blood pressure values obtained from the upper and lower limb are similar.

  12. Magnetostrictive device for high-temperature sound and vibration measurement in nuclear power stations

    International Nuclear Information System (INIS)

    Hans, R.; Podgorski, J.

    1977-01-01

    The demands on the monitoring systems in nuclear power stations are increasing continuously, not only because of more stringent safety requirements but also for reasons of plant availability and thus economic efficiency. The noise and vibration measurements which therefore have to be taken make it necessary to provide measuring devices with a high degree of efficiency, adequate sensitivity and resistance to high temperatures, radiation and corrosion. Probes using the magnetostrictive effect, whereby a ferromagnetic core changes its length in a magnetic field - a phenomenon which has been known for approximately fifty years - fulfill all the conditions for application in nuclear power stations. (orig.) [de

  13. Development of a commercial Transducer for Measuring Pressure and Friction on the Model Die Surface

    DEFF Research Database (Denmark)

    Andersen, Claus Bo; Ravn, Bjarne Gottlieb; Wanheim, Tarras

    2001-01-01

    deflection in the tool causes incorrect shape of the final component. The dinemsions of the die-cavity have to be corrected taking into account die deflection due to the high internal pressure. The modelling material technique is suitable for measuring internal pressure, but so far only a transducer...... to measure normal pressure has been available....

  14. The Development of a Psychometrically-Sound Instrument to Measure Teachers' Multidimensional Attitudes toward Inclusive Education

    Science.gov (United States)

    Mahat, Marian

    2008-01-01

    The "Multidimensional Attitudes toward Inclusive Education Scale" (MATIES) was developed to effectively measure affective, cognitive and behavioural aspects of attitudes, within the realm of inclusive education that includes physical, social and curricular inclusion. Models within Item Response Theory and Classical Test Theory were used…

  15. Modeling and measuring sound propagation of hooded crow calls in open field habitats

    DEFF Research Database (Denmark)

    Jensen, Kenneth Kragh; Larsen, Ole Næsbye; Attenborough, Keith

    representative of crow territorial communication and taking into account ground effect and air turbulence, we predict an optimal transmission frequency range between 0,5-1.6 kHz. In a natural open field crow habitat we measure, with sender and receiver heights of 2.8 m and transmission distances up to 320 m...

  16. Sound Radiation of Aerodynamically Excited Flat Plates into Cavities

    Directory of Open Access Journals (Sweden)

    Johannes Osterziel

    2017-10-01

    Full Text Available Flow-induced vibrations and the sound radiation of flexible plate structures of different thickness mounted in a rigid plate are experimentally investigated. Therefore, flow properties and turbulent boundary layer parameters are determined through measurements with a hot-wire anemometer in an aeroacoustic wind tunnel. Furthermore, the excitation of the vibrating plate is examined by laser scanning vibrometry. To describe the sound radiation and the sound transmission of the flexible aluminium plates into cavities, a cuboid-shaped room with adjustable volume and 34 flush-mounted microphones is installed at the non flow-excited side of the aluminium plates. Results showed that the sound field inside the cavity is on the one hand dependent on the flow parameters and the plate thickness and on the other hand on the cavity volume which indirectly influences the level and the distribution of the sound pressure behind the flexible plate through different excited modes.

  17. 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....

  18. Bladder pressure measurements and urinary tract infection in trauma patients.

    Science.gov (United States)

    Duane, Therèse M; Young, Andrew; Weber, William; Wolfe, Luke G; Malhotra, Ajai K; Aboutanos, Michel B; Whelan, James F; Mayglothling, Julie; Ivatury, Rao R

    2012-04-01

    The purpose of this trial was to determine if using a closed technique for bladder pressure measurements (BPMs) would eliminate them as a risk factor for urinary tract infection (UTI) in trauma patients, as was shown previously using an open technique. Data were collected prospectively from January 2006 until December 2009 by a dedicated epidemiology nurse and combined with trauma registry data at our Level 1 trauma center. All trauma patients admitted to the surgical trauma intensive care unit (STICU) with and without UTIs were compared for demographic and epidemiologic data. A closed system was used in which the urinary drainage catheter (UDC) remained connected to the bag and 45 mL of saline was injected through a two-way valved sideport, with subsequent measurements through the sideport. There were 1,641 patients in the trial. The UTI group was sicker (Injury Severity Score [ISS] 18.7±11.9 no UTI vs. 28±10.7 UTI; p<0.0001), with longer stays (11.4±12.4 days no UTI vs. 37.9±20.3 days UTI; p<0.0001) and more UDC days (4.3±6.6 no UTI vs. 23.9±16.6 UTI; p<0.0001). The BPM group had more UDC days (15.6 days±16.0 BPM vs. 5.4 days±7.3 no BPM; p<0.0001), yet no difference in UTI rate/1,000 UDC days (5.7 no BPM vs. 8.0 BPM; p=0.5291). Logistic regression demonstrated only UDC days to be a predictor of UTI (1.125; 95% confidence interval [CI] 1.097-1.154; p<0.0001), whereas ISS (1.083, 95% CI 1.063-1.104; p<0.0001) and age (1.051, 95% CI 1.037-1.065; p<0.0001) were the only predictors of death. Although patients undergoing BPM have more UTIs than patients without BPM, the measurements are not an independent predictor of UTI when done by the closed technique. These findings emphasize the judicious use of BPM with a closed system and, more importantly, the need for early removal of catheters.

  19. Peripheral arterial volume distensibility: significant differences with age and blood pressure measured using an applied external pressure

    International Nuclear Information System (INIS)

    Zheng, Dingchang; Murray, Alan

    2011-01-01

    A new arterial distensibility measurement technique was assessed in 100 healthy normotensive subjects. Arterial transmural pressures on the whole right arm were reduced with a 50 cm long cuff inflated to 10, 20, 30 and 40 mmHg. The electrocardiogram, and finger and ear photoplethysmograms were recorded simultaneously. Arm pulse propagation time, pulse wave velocity (PWV) and arterial volume distensibility were determined. With a 40 mmHg reduction in transmural pressure, arm pulse propagation time increased from 61 to 83 ms, PWV decreased from 12 to 8 m s −1 and arterial distensibility increased from 0.102% to 0.232% per mmHg (all P < 0.0001). At all cuff pressures, arterial distensibility was significantly related to resting mean arterial pressure (MAP), diastolic blood pressure (DBP) and age, and for systolic blood pressure at 30 and 40 mmHg (all P < 0.05). At 40 mmHg cuff pressure, arterial distensibility fell by 54% for a MAP increase from 75 to 105 mmHg, 57% for a DBP increase from 60 to 90 mmHg and 47% for an age increase from 20 to 70 years. These changes were more than double than those without cuff pressure. Our technique showed that systemic volume distensibility of the peripheral arm artery reduced with age, with a greater effect at higher external and lower transmural pressures

  20. A novel high pressure, high temperature vessel used to conduct long-term stability measurements of silicon MEMS pressure transducers

    Science.gov (United States)

    Wisniewiski, David

    2014-03-01

    The need to quantify and to improve long-term stability of pressure transducers is a persistent requirement from the aerospace sector. Specifically, the incorporation of real-time pressure monitoring in aircraft landing gear, as exemplified in Tire Pressure Monitoring Systems (TPMS), has placed greater demand on the pressure transducer for improved performance and increased reliability which is manifested in low lifecycle cost and minimal maintenance downtime through fuel savings and increased life of the tire. Piezoresistive (PR) silicon MEMS pressure transducers are the primary choice as a transduction method for this measurement owing to their ability to be designed for the harsh environment seen in aircraft landing gear. However, these pressure transducers are only as valuable as the long-term stability they possess to ensure reliable, real-time monitoring over tens of years. The "heart" of the pressure transducer is the silicon MEMS element, and it is at this basic level where the long-term stability is established and needs to be quantified. A novel High Pressure, High Temperature (HPHT) vessel has been designed and constructed to facilitate this critical measurement of the silicon MEMS element directly through a process of mechanically "floating" the silicon MEMS element while being subjected to the extreme environments of pressure and temperature, simultaneously. Furthermore, the HPHT vessel is scalable to permit up to fifty specimens to be tested at one time to provide a statistically significant data population on which to draw reasonable conclusions on long-term stability. With the knowledge gained on the silicon MEMS element, higher level assembly to the pressure transducer envelope package can also be quantified as to the build-effects contribution to long-term stability in the same HPHT vessel due to its accommodating size. Accordingly, a HPHT vessel offering multiple levels of configurability and robustness in data measurement is presented, along