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Wyszukujesz frazę "Opieliński, K." wg kryterium: Autor


Wyświetlanie 1-11 z 11
Tytuł:
Research and Modeling of Mechanical Crosstalk in Linear Arrays of Ultrasonic Transducers
Autorzy:
Celmer, M.
Opieliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/176916.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
mechanical crosstalk
ultrasonic transducer array
FEM modeling
COMSOL Multiphysics
Opis:
Linear arrays of ultrasonic transducers are commonly used as ultrasonic probes in medical diagnostics for imaging the interior of a human body in vivo. The crosstalk phenomenon occurs during the operation of transducers in which electrical voltages and mechanical vibrations are transmitted to adjacent components. As a result of such additional excitation of the transducers in the array, the directivity characteristics of the aperture used changes, and consequently there is interference with proper operation of a given array and the emergence of distortions in the obtained ultrasound image that reduce its quality. This paper studies the manner of propagation of mechanical crosstalk in the designed model of a linear array of ultrasonic transducers on the basis of unwanted signals, which appeared on elementary piezoelectric transducers when power is supplied to the selected transducer in the array. The universal model of linear array of ultrasonic transducers, which has been developed, allowed the simulation of mechanical crosstalk, taking into account the cross-coupling phenomenon in all of its structure with the use of finite elements method (FEM) implemented in COMSOL Multiphysics software. The analysis of crosstalk signals showed that they consist of aggregated pulses propagating with different speeds and frequencies. This signifies the formation of different vibration modes transmitted simultaneously via different paths. The paper is an original approach which enables to identify different vibration modes and estimate their participation in the crosstalk signal and their ways of propagation. Conclusions from the research allow predicting specific design changes which are significant due to the minimization of mechanical crosstalk in linear arrays of ultrasonic transducers.
Źródło:
Archives of Acoustics; 2016, 41, 3; 599-612
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
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:
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:
Model of multipath propagation of ultrasonic pulses generated in soft tissue by linear arrays
Autorzy:
Celmer, M.
Opieliński, K. J.
Powiązania:
https://bibliotekanauki.pl/articles/332417.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
model of multipath propagation of ultrasonic pulses
linear arrays of ultrasonic transducers
crosstalk
acoustical field
water
tissue
Opis:
Arrays of ultrasonic transducers used in medical diagnosis for safe and non-invasive visualization of the inside of a human body usually consist of many elementary piezoceramic transducers. In such an electromechanical construction of the array, while activating individual transducers, creation of crosstalk can be observed in the form of propagation of electric voltage and mechanical vibration on neighboring elements, which leads to distortion of the generated acoustical field, and in consequence reduces the quality of reconstructed medical images. Complexity of the problem rises rapidly in the case of arrays forming ultrasonic beams. In this paper, authors developed a numerical amplitude-phase model of multipath propagation of ultrasonic pulses generated in a soft tissue-like medium by such arrays. The model allowed simulation of acoustic field distributions, and to examine the influence of beam focusing in transmission mode on these distributions, taking into account electrical and mechanical crosstalk.
Źródło:
Hydroacoustics; 2016, 19; 37-48
1642-1817
Pojawia się w:
Hydroacoustics
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
Tytuł:
Ultrasonic Mammography with Circular Transducer Array
Autorzy:
Opieliński, K. J.
Pruchnicki, P.
Gudra, T.
Powiązania:
https://bibliotekanauki.pl/articles/177684.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasonic projection imaging
UPI
ultrasonic mammography
circular transducer array
woman’s breast tissue
Opis:
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.
Źródło:
Archives of Acoustics; 2014, 39, 4; 559-568
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Digitally Controlled Model of an Active Ultrasonic Transducer Matrix for Projection Imaging of Biological Media
Autorzy:
Opieliński, K. J.
Gudra, T.
Pruchnicki, P.
Powiązania:
https://bibliotekanauki.pl/articles/178008.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasonic projection
active ultrasonic transducer matrix
multielement ultrasonic probe
electrode attachment optimisation
Opis:
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.
Źródło:
Archives of Acoustics; 2010, 35, 1; 75-90
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasonic Method for Monitoring Environmental Risks Associated with Precipitation
Autorzy:
Gudra, T.
Banasiak, D.
Herman, K.
Opieliński, K.
Powiązania:
https://bibliotekanauki.pl/articles/176767.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasonic method
snow layer
monitoring of environmental risk
Opis:
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.
Źródło:
Archives of Acoustics; 2013, 38, 1; 125-135
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrasound Transmission Tomography Imaging of Structure of Breast Elastography Phantom Compared to US, CT and MRI
Autorzy:
Opieliński, K. J.
Pruchnicki, P.
Gudra, T.
Podgórski, P.
Kraśnicki, T.
Kurcz, J.
Sąsiadek, M.
Powiązania:
https://bibliotekanauki.pl/articles/176996.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasound transmission tomography
UTT
ultrasonography
US
computed tomography
magnetic resonance
MR
mammography
breast biopsy phantom
Opis:
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.
Źródło:
Archives of Acoustics; 2013, 38, 3; 321-334
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-11 z 11

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