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Wyszukujesz frazę "Gudra, T." wg kryterium: Autor


Tytuł:
Computer model of acoustic link in a pipe with a flowing gas medium. Part II: Accuracy improvement ot medium flow velocity determination
Autorzy:
Gudra, T.
Opieliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/331539.pdf
Data publikacji:
1997
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
While constructing medium flow velocity meters with the use of the ultrasonic method, it is assumed, that the deviation of the ultrasonic beam caused by medium flow, is insignificant. The assumption seems to be correct, because the average flow velocity is usually much smaller than the ultrasonic wave velocity in a medium. Basing on the assumption, we can use a known expression, which makes it possible to calculate an average medium flow velocity through run-time measurement from the transmitter to the receiver and in an opposite direction. In the paper, it is shown, that the average flow velocity determined in this way, using the computer model of acoustic link in a pipe with a flowing gas medium, is measured with a significant error. This error depends on the flow pipe diameter, the transducer diameters and the means of placing the transducers in the pipe. Properly modifying the expression for ultrasonic run-time through flowing gas medium and taking into account the means of transducer placing in the pipe, we can eliminate the error related to the measurement geometry and we can find an optimum ultrasonic wave propagation angle.
Źródło:
Hydroacoustics; 1997, 1; 303-306
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonic Investigation of Snow and Ice Parameters
Autorzy:
Gudra, T.
Najwer, L.
Powiązania:
https://bibliotekanauki.pl/articles/1493199.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.68.Ge
42.79.Ls
43.35.Ae
92.60.Wc
Opis:
In the paper some ultrasonic methods of measurement of sound velocity and attenuation in snow and ice media are presented. The measurement setup consists of ultrasonic airborne transducers working at the frequency of f = 40 kHz. A non-contact method of reflection coefficient on air-snow border was applied during measurement of different types of snow in the density range of 120-700 kg/$m^3$. Examples of obtained signals are also presented. It was proved that there is a linear dependence between reflection coefficient and snow density. The state of snow or ice layer is not precisely correlated with their acoustical parameters: ultrasound wave velocity and attenuation of ultrasonic wave during the measurement of the layer depth using the non-contact method. Reflection coefficient of snow can be used for estimation of snow density.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 625-629
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza sygnałów echolokacyjnych nietoperzy zarejestrowanych za pomocą różnych systemów pomiarowych
Analysis of echolocation cues of bats registered by different measurement systems
Autorzy:
Herman, K.
Gudra, T.
Powiązania:
https://bibliotekanauki.pl/articles/261649.pdf
Data publikacji:
2009
Wydawca:
Politechnika Wrocławska. Wydział Podstawowych Problemów Techniki. Katedra Inżynierii Biomedycznej
Tematy:
nietoperze
echolokacja
ultradźwięki
bat
echolocation
ultrasound
Opis:
wybranych gatunków nietoperzy występujących na terenie Dolnego Śląska. Dokonano porównania takich sygnałów zarejestrowanych za pomocą systemów pomiarowych typu time expansion, frequency division oraz wysokorozdzielczych torów pomiarowych. Rozważono problemy związane z wpływem przetworników wejściowych oraz wpływem toru pomiarowego na parametry zarejestrowanych sygnałów bioecholokacyjnych.
selected bats' species from the Lower Silesia region are presented. Echolocation signals of bats recorded by various measurement systems based on time-expansion effect, frequency division effect and high resolution registration tracks were examined and compared. Some problems related to the registration methods, input transducers and their influence on parameters of analyzed bioecholocation signals, were considered, as well.
Źródło:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna; 2009, 15, 1; 91-94
1234-5563
Pojawia się w:
Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computer model of acoustic link in a pipe with a flowing gas medium. Part I: Perturbation of ultrasonic transducer directivity pattern
Autorzy:
Gudra, T.
Opieliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/332580.pdf
Data publikacji:
1997
Wydawca:
Polskie Towarzystwo Akustyczne
Opis:
The paper presents an aeroacoustic range equation which makes it possible to elaborate a computer model of ultrasonic link in air for static conditions. The model was made in form of a computer program called KML. Extending the static model, a simulation of uItrasonic wave propagation in a pipeline with flowing air for different profiles of laminar and turbulent flow and different link parameters was performed. The simulation made it possible to work out a computer model of an acoustic link in flowing gas. The model as a computer program can be used to calculate disturbance of ultrasonic beam rays shape and directivity pattem perturbation. Directivity pattem of ultrasonic transmitting transducer, deformed by flowing medium, becomes non-axial symmetric. As a result of the flow, ultrasonic beam rays are curvilinear and the source directivity pattern depends on rectilinearly measured distance.
Źródło:
Hydroacoustics; 1997, 1; 299-302
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Interaction of Ultrasonic and Optical Wave in Optical Fiber Using the Air Gap
Autorzy:
Gudra, T.
Muc, S.
Powiązania:
https://bibliotekanauki.pl/articles/177005.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
transmission of acoustic wave
transmission of optical wave
optical fiber
air gap
Opis:
There exist some possibilities for simultaneous delivery of laser radiation and ultrasounds of low frequency and high intensity: introducing ultrasound oscillations in the optical fiber by the rigid connection of the fiber to the vibrating element and non-contact influence of the ultrasonic wave on the laser beam. The article presents the results of Matlab simulations and experimental studies of influence of the ultrasonic wave on the laser beam. A role of the air gap, and its influence on laser- ultrasonic transmission in optical fiber was examined. Advantages and disadvantages of both solutions of interaction of ultrasonic and optical waves in, e.g., surgical applications are discussed.
Źródło:
Archives of Acoustics; 2011, 36, 3; 613-628
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transmission of Ultrasonic Waves Via Optical Silica Glass Fiber Doped by 7.5% of TiO2 with the Use of Power Sandwich Transducer
Autorzy:
Muc, S.
Gudra, T.
Powiązania:
https://bibliotekanauki.pl/articles/177364.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasounds
transmission of acoustic wave in an optical waveguide
Opis:
The possibility of acoustic wave propagation in optical waveguides creates new prospects for simultaneous transmission of laser beams and ultrasonic waves. Combined laser-ultrasonic technology could be useful in e.g. surgical treatment. The article presents the results of experimental studies of transmission of ultrasonic wave in optical fibres, the core of which is doped by 7.5% of TiO2, using a sandwichtype transducer. It also presents amplitude characteristics of an ultrasonic signal propagated in the optical fibre. Authors studied the effect which the length of the fibre has on the achieved output signal amplitudes. They presented the relation of the output signal amplitude from a capacitive sensor to the power applied to the sandwich-type transducer. The obtained results were compared with the results produced when using an optical fibre with a core doped by 3% of GeO2, in order to select optical fibre suitable for simultaneous transmission of ultrasonic waves and laser rays.
Źródło:
Archives of Acoustics; 2011, 36, 1; 141-150
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bioacoustic range equation
Autorzy:
Opieliński, K. J.
Gudra, T.
Powiązania:
https://bibliotekanauki.pl/articles/331511.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
bioacoustic link
hydroacoustic link
range equation
biological media
Opis:
In order to describe and analyze the bioacoustic link, the authors of this study used a modified range explicit equation formulated for a hydroacoustic link. The equation makes it possible to design a bioacoustic link by assuming a given study range in a biological medium, and estimating the required power ratio or power level drop, and then selecting a value for the ratio by means of ultrasonic transducer parameters. A biological medium submerged in water between a transmitting and receiving ultrasonic transducer was studied in a streamlined manner as quasi-homogeneous, or more specifically, in the form of a multilayered tissue structure with parallel border surfaces. In the paper, sample calculations of the relation between power level drop and the length of the bioacoustic link in biological media, for ultrasonic wave frequency in the range of 1 – 5 MHz were performed; using a modified range explicit equation formulated for a hydroacoustic link. The calculations were verified in an experiment.
Źródło:
Hydroacoustics; 2016, 19; 307-318
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Digital Signal Processing Approach in Air Coupled Ultrasound Time Domain Beamforming
Autorzy:
Herman, K.
Gudra, T.
Furmankiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/177033.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
beamforming
air-coupled ultrasounds
DSP
digital signal processing
bat signals
direction of arrival
Opis:
The work presents the results of experimental study on the possibilities of determining the source of an ultrasonic signal in two-dimensional space (distance, horizontal angle). During the research the team used a self-constructed linear array of MEMS microphones. Knowledge in the field of sonar systems was utilized to analyse and design a location system based on a microphone array. Using the above mentioned transducers and broadband ultrasound sources allows a quantitative comparison of estimation of the location of an ultrasonic wave source with the use of broadband modulated signals (modelled on bats’ echolocation signals) to be performed. During the laboratory research the team used various signal processing algorithms, which made it possible to select an optimal processing strategy, where the sending signal is known.
Źródło:
Archives of Acoustics; 2014, 39, 1; 37-50
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Acoustic Field Distribution Inside the Ultrasonic Ring Array
Autorzy:
Staszewski, W.
Gudra, T.
Opieliński, K. J.
Powiązania:
https://bibliotekanauki.pl/articles/177105.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound transmission tomography
acoustic field
ultrasonic multi-element array
Opis:
This paper presents and analyses the results of a simulation of the acoustic field distribution in sectors of a 1024-element ring array, intended for the diagnosis of female breast tissue with the use of ultrasonic tomography. The array was tested for the possibility to equip an ultrasonic tomograph with an additional modality - conventional ultrasonic imaging with the use of individual fragments (sections) of the ring array. To determine the acoustic field for sectors of the ring array with a varying number of activated ultrasonic transducers, a combined sum of all acoustic fields created by each elementary transducer was calculated. By the use of MATLAB software, a unique algorithm was developed, for a numerical determination of the distribution of pressure of an ultrasonic wave on any surface or area of the medium generated by the concave curvilinear structure of rectangular ultrasound transducers with a geometric focus of the beam. The analysis of the obtained results of the acoustic field distribution inside the ultrasonic ring array used in tomography allows to conclude that the optimal number of transducers in a sector enabling to obtain ultrasound images using linear echographic scanning is 32 ≤ n ≤ 128, taking into account that due to an increased temporal resolution of ultrasonic imaging, this number should be as low as possible.
Źródło:
Archives of Acoustics; 2018, 43, 3; 455-463
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Narrow Beam Ultrasonic Transducer Matrix Model for Projection Imaging of Biological Media
Autorzy:
Opieliński, K. J.
Gudra, T.
Pruchnicki, P.
Powiązania:
https://bibliotekanauki.pl/articles/178004.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasonic projection
directional ultrasonic transducer matrix
multielement ultrasonic probe
electrode attachment optimisation
Opis:
The following paper presents an idea of minimising the number of connections of individual piezoelectric transducers in a row-column multielement passive matrix system used for imaging of biological media structure by means of ultrasonic projection. It allows to achieve significant directivity with acceptable input impedance decrease. This concept was verified by designing a model of a passive ultrasonic matrix consisting of 16 elementary piezoceramic transducers, with electrode attachments optimised by means of electronic switches in rows and columns. Distributions of acoustic field generated by the constructed matrix model in water and results of the calculations conformed well.
Źródło:
Archives of Acoustics; 2010, 35, 1; 91-109
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł

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