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1

The Acoustic Field Distribution Inside the Ultrasonic Ring Array

Staszewski W., Gudra T., Opieliński K. J.

Archives of Acoustics

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2018

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Vol. 43, No. 3

455--463

EN

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.

2

Bioacoustic range equation

Opieliński K. J., Gudra T.

Hydroacoustics

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2016

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Vol. 19

307--318

EN

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.

3

Ultrasonic Mammography with Circular Transducer Array

Opieliński K. J., Pruchnicki P., Gudra T.

Archives of Acoustics

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2014

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Vol. 39, No. 4

559--568

EN

Ultrasonic projection imaging is similar to X-ray radiography. Nowadays, ultrasonic projection methods have been developed in the set-up of multi-element flat arrays with miniature transducers, where one of the array acts as a transmitter and the other one is a receiver. In the paper, a new method of the projection imaging using a 1024-element circular ultrasonic trans- ducer array is presented. It allows the choice of a projection scanning plane for any angle around a studied object submerged in water. Fast acquisition of measurement data is achieved as a result of parallel switch- ing of opposite transmitting and receiving transducers in the circular array and vertical movement of the array. The algorithm equalizing the length of measurement rays and the distances between them was elaborated for the reconstruction of projection images. Projection research results of breast phantom obtained by means of the elaborated measurement set- up and compared with mammography simulations (acquired through overlapping of X-ray tomographic images) show that ultrasonic projection method presented in this paper (so-called ultrasonic mammogra- phy) can be applied to the woman’s breast and be used as a diagnosis for an early detection of cancerous lesions. It can, most of all, be used as an alternative or complementary method to standard mammog- raphy, which is harmful because of ionizing radiation and invasive due to the mechanical compression of tissue.

4

Digital Signal Processing Approach in Air Coupled Ultrasound Time Domain Beamforming

Herman K., Gudra T., Furmankiewicz J.

Archives of Acoustics

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2014

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Vol. 39, No. 1

37--50

EN

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.

5

Ultrasound Transmission Tomography Imaging of Structure of Breast Elastography Phantom Compared to US, CT and MRI

Opieliński K. J., Pruchnicki P., Gudra T., Podgórski P., Kraśnicki T., Kurcz J., Sąsiadek M.

Archives of Acoustics

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2013

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Vol. 38, No. 3

321--334

EN

The paper presents an analysis of the results of ultrasound transmission tomography (UTT) imaging of the internal structure of a breast elastography phantom used for biopsy training, and compares them with the results of CT, MRI and, conventional US imaging; the results of the phantom examination were the basis for the analysis of UTT method resolution. The obtained UTT, CT and MRI images of the CIRS Model 059 breast phantom structure show comparable (in the context of size and location) heterogeneities inside it. The UTT image of distribution of the ultrasound velocity clearly demonstrates continuous changes of density. The UTT image of derivative of attenuation coefficient in relation to frequency is better for visualising sharp edges, and the UTT image of the distribution of attenuation coefficient visualises continuous and stepped changes in an indirect way. The inclusions visualized by CT have sharply delineated edges but are hardly distinguishable from the phantom gel background even with increased image contrast. MRI images of the studied phantom relatively clearly show inclusions in the structure. Ultrasonography images do not show any diversification of the structure of the phantom. The obtained examination results indicate that, if the scanning process is accelerated, ultrasound transmission tomography method can be successfully used to detect and diagnose early breast malignant lesions. Ultrasonic transmission tomography imaging can be applied in medicine for diagnostic examination of women’s breasts and similarly for X-ray computed tomography, while eliminating the need to expose patients to the harmful ionising radiation.

6

Ultrasonic Method for Monitoring Environmental Risks Associated with Precipitation

Gudra T., Banasiak D., Herman K., Opieliński K.

Archives of Acoustics

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2013

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Vol. 38, No. 1

125--135

EN

This paper presents a solution that utilises ultrasonic technology to allow monitoring snow layer thickness or water level based on measurement from air. It describes the principle of operation of a measurement device using three methods of compensating for changing external factors affecting appliance’s precision. Block diagram of the device is also provided. In order to verify the proposed solutions, the research team tested the device in laboratory and operating conditions. The results obtained this way make it possible to select a configuration of device operation depending on the required measurement precision and limitations associated with installing the system for actual operation.

7

Transmission of Ultrasonic Waves Via Optical Silica Glass Fiber Doped by 7.5% of TiO2 with the Use of Power Sandwich Transducer

Muc S., Gudra T.

Archives of Acoustics

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2011

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Vol. 36, No. 1

141-150

EN

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.

8

A Study of Interaction of Ultrasonic and Optical Wave in Optical Fiber Using the Air Gap

Gudra T., Muc S.

Archives of Acoustics

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2011

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Vol. 36, No. 3

613-628

EN

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.

9

Narrow Beam Ultrasonic Transducer Matrix Model for Projection Imaging of Biological Media

Opieliński K. J., Gudra T., Pruchnicki P.

Archives of Acoustics

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2010

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Vol. 35, No. 1

91-109

EN

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.

10

Experimental Study of Simultaneous Transmission of Ultrasonic Waves and Optical Radiation via Optical Fiber Couplers

Muc S., Gudra T., Bereś-Pawlik E.

Archives of Acoustics

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2010

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Vol. 35, No. 1

111-122

EN

This article presents the results of experimental studies of simultaneous transmission of ultrasonic waves and laser signals in optical fibers by the use of both the optical single mode and multimode fiber couplers. This work was aimed, among other things, at the study of the way the acoustic energy affects a laser beam. The light wave was guided into one of the coupler’s arms. The optical power applied to one input of the coupler is separated into two coupler outputs according to the rate determined by the coupling coefficient. Only an ultrasonic wave generated by a sandwich type transducer is applied to the other arm of the coupler. In this experiment, as in case of the light wave, the acoustic power is separated into both the outputs. One can observe the interaction of both the waves on the two outputs – a modulation of the light wave by means of the ultrasonic wave is possible. The output signal was detected using a PIN diode and an optical power meter (OPM). Temporary courses were observed on an oscilloscope screen. The simultaneous transmission of ultrasounds and optical radiation in optical fibers can be used in the construction of medical equipmen.

11

A Digitally Controlled Model of an Active Ultrasonic Transducer Matrix for Projection Imaging of Biological Media

Opieliński K. J., Gudra T., Pruchnicki P.

Archives of Acoustics

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2010

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Vol. 35, No. 1

75-90

EN

The following work presents the idea of constructing a digitally controlled active piezoceramic transducer matrix for ultrasonic projection imaging of biological media in a similar way as in case of roentgenography (RTG). Multielement ultrasonic probes in the form of flat matrices of elementary piezoceramic transducers require attaching a large number of electrodes in order to activate the individual transducers. This paper presents the idea of minimising the number of transducer connections in an active row-column matrix system. This idea was verified by designing a model of a matrix consisting of 16 ultrasonic transducers with electrode attachments optimised by means of electronic switches in rows and columns and miniature transistor switches in the nodes of the matrix allowing to activate selected transducers. The results of measurements and simulations of parameters of the designed matrix show that it is suitable to be used in projection imaging of biological media as a sending probe. In to use the matrix as a universal sending or receiving probe, it was suggested to add further switches that would eliminate the undesired effect of crosstalks in case of switches used for toggling the transducers in the nodes of the matrix.

12

Experimental Study of Simultanoeus Transmission of a Light Wave and an Ultrasonic Wave in an Optical Fiber with the use of a Mach-Zehnder Interferometer

Muc S., Gudra T., Bereś-Pawlik E.

Archives of Acoustics

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2009

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Vol. 34, No. 4

697-714

EN

The possibility of acoustic wave propagation in optical waveguides creates new prospects for the simultaneous use of a light wave and an ultrasonic wave in, for instance, medicine for cutting biological tissues with a surgical ultrasonic laser knife. A Mach–Zehnder optical waveguide interferometer was used in the experimental studies of simultaneous transmission of those two wave types. If ultrasonic vibrations are delivered to one of the interferometer arms, a light modulation effect is produced. This paper presents measurement results for different methods of delivering ultrasonic waves to the optical fiber, i.e. using radial vibrations of a piezoelectric disk or longitudinal vibrations generated by a sandwich ultrasonic transducer with a velocity transformer.

13

Analiza sygnałów echolokacyjnych nietoperzy zarejestrowanych za pomocą różnych systemów pomiarowych

Herman K., Gudra T.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2009

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Vol. 15, nr 1

91-94

PL

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.

EN

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.

14

Non-contacting examination of materials using airborne ultrasonic transducer

Gudra T., Opieliński K. J., Kozłowski P. P.

Molecular and Quantum Acoustics

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2008

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Vol. 29

93-108

EN

In the paper a non-contacting ultrasonic examination of materials is presented. This method is based on the use of air or another gas as a transmission medium for ultrasonic waves between probes and the examined material. This paper concentrates on examination of three materials: polyurethane foam, balsa wood along and across fibres and porous ceramics. It was shown that quality assessment of different material is possible on the basis of spectral analysis of ultrasonic signal transmitted through a sample.

15

Wstępne wyniki badań fantomów i struktur biologicznych metodą ultradźwiękowej tomografii transmisyjnej

Gudra T., Opieliński K., Jeleń M.

Prace Naukowe Instytutu Telekomunikacji i Akustyki Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 83, nr 27

329-336

EN

The paper contains introductory results of investigation of different biological structures and their phantoms carded out by using the UTT method. The obtained images of internal structure cross-sections were compared with images obtained by means of classical ultrasonic reflection methods. The results of this analysis allow us to conclude that investigations using UTT enable obtaining more information about the internal structure of the investigated object than ultrasonic investigations consisting in visualising differences of acoustic impedances. In addition, UTT enables both qualitative and quantitative measurement. The results of microscopic histopathological examination of selected fragments of structures have corroborated the occurrence of pathological changes visible in tomographic images in the form of areas of different sound velocity values.

16

Komputerowa analiza wielowarstwowych układów dopasowujących do przetworników piezoceramicznych pracujących w powietrzu

Gudra T., Kosmalski R.

Prace Naukowe Instytutu Telekomunikacji i Akustyki Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 83, nr 27

399-406

PL

Opracowany program komputerowy pozwala na badanie wpływu liczby warstw na kształt i wartość funkcji przenoszenia, a także na ocenę wpływu impedancji i grubości warstw oraz obciążenia części tylnej przetwornika na tę funkcję. Kształt funkcji przenoszenia może być w ten sposób odpowiednio modyfikowany w zależności od potrzeb; można np. zwiększyć wartość przesyłanej przez przetwornik energii lub poszerzyć pasmo przenoszenia przetwornika. Dobór impedancji o obliczonej wartości jest jedynie ograniczony posiadaniem materiałów o ściśle określonych wartościach, nie zawsze jednak możliwych do zrealizowania w praktyce. Przedstawiona metoda wyznaczania impedancji poszczególnych warstw dopasowujących oparta o zasadę dopasowania energetycznego oraz zależności wyprowadzonych przez Czebyszewa, De Siletsa i Souqueta pozwala na wyznaczenie wartości impedancji i charakterystyki funkcji przenoszenia dla układów o dowolnej liczbie warstw.

EN

The paper presents the problem of calculating multiplayer matching systems to apply in piezoceramic transducers radiating energy into gas medium. The relations enabling the calculation of acoustic impedance for various numbers of layers on the basis of the Tschebyschev, De Silets and Souquet formulas are presented. A software was elaborated, which allows to calculate the impedance of particular layers, the investigation of influence of quantity of layers on the shape and value of the transmittance function, and also allows to estimate the influence of impedance and layer thickness on the transmittance function.

17

Badania aglomeracji dźwiękowej pęcherzyków gazu w cieczy

Czyż H., Gudra T., Opieliński K.

Prace Naukowe Instytutu Telekomunikacji i Akustyki Politechniki Wrocławskiej. Konferencje

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2001

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Vol. 83, nr 27

251-256

EN

This paper presents the results of an experiment, which is a continuation of our research series about the sound agglomeration of gas bubbles in the liquid. An idea of the experimental system has been presented so far. The process of gathering the gas bubbles around the equilibrium positions in the ultrasonic standing wave (the loops of the ultrasonic standing wave) was observed. The concentration of the gas bubbles increases around such points and decreases in the regions between the loops and the nodes of the ultrasonic standing wave. The time required to obtain an equilibrium distribution of the gas bubbles near the stable equilibrium points has been measured. The result of the measurement indicates that it's the value of the same order of magnitude as the sound agglomeration times calculated theoretically. The experimental results show that the speed of process of gathering the gas bubbles depends on; the parameters of acoustic field and gas bubbles size. The theoretical results are in good agreement with the experimental data. The measuring method and the method of its analysis were described in the paper.

18

Investigation of Biological Structures and Their Phantoms Using Ultrasound Transmission Tomography

Gudra T., Opieliński K.

Molecular and Quantum Acoustics

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2001

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Vol. 22

85-94

EN

The paper contains introductory of investigation of different biological structures and their phantoms carried aut by using the UTT method. The otained images of internal structure cross-sections were compared with images obtained by means of classical ultrasonic reflection methods. The results of tis analysis allow us to conclude that investigations using UTTenable obtaning more information aboute the internal structure of the investigated object than ultrasonic investigations consisting in visualising differences of acoustic impedances. In addition, UTT enables both qualitative and quantitive measurement.

19

Analysis f Possibilities of Biological Structure Phantom Building for Purposes of Ultrasound Transmission Tomography

Gudra T., Opieliński K., Zarzycki-Reich A.

Molecular and Quantum Acoustics

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2000

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Vol. 21

69-78

20

Analysis of a resonator with a directional ultrasonic vibration converter of R-L type using the finite elements method

Gudra T.

Archives of Acoustics

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2000

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Vol. 25, no. 2

157-174

EN

Some results of the analysis of the R-L type resonator with directional converter using the finite elements method (FEM) are presented in the paper. Three types of resonator tuning result from the analysis and they can be used for converters of other type. The modal patterns in anti-phase and in-phase vibration modes for all types of tuning are presented. The choice of particular tuning depends on the way of using the converter. The modulus of the relation between the surface displacement amplitude for a longitudinal vibrating resonator and the side displacement amplitude for a radial vibrating resonator can be interpreted as the gain coefficient of converter's vibration amplitude. Moreover the influence of rode and disk resonator dimensions on proper frequencies of the converter vibration is described.