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Tytuł:
Generation and measurement of acoustic streaming in limited space
Autorzy:
Secomski, W.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/332336.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
ultrasound
radiation force
blood
thrombolysis
Opis:
The aim of this work was to use the streaming phenomena to assist clot dissolution in blood vessel. Such treatment is called sonothrombolysis. Acoustic streaming is a steady flow in a fluid driven by the acoustic wave propagating in a lossy medium. It is a non-linear effect and it depends on ultrasound intensity, and sound absorption in the media. The source of ultrasound was a flat piezoceramic disc generating long pulses at 1 MHz frequency and 0.2 W/cm2 ITA acoustical intensity. The streaming was generated in a vessel simulating free space, and next repeated in a multi-well cell culture plate, and in the limited space inside the 8 mm diameter silicone tube positioned perpendicular to the ultrasonic beam. The tube was filled with a mixture of water, glycerol, and starch, so with acoustic properties similar to blood. The streaming velocity was recorded either by the Siemens Acuson Antares ultrasonic scanner operating in the color Doppler mode at 8.9 MHz, or by the custom built 20 MHz pulsed Doppler flowmeter. The results obtained using both systems were very similar. The recorded streaming velocities were 3.2 cm/s, 6.1 cm/s and 0.3 cm/s, respectively. They were an order of magnitude smaller than that calculated theoretically. However, the results obtained confirm existence of streaming, even very close to the source, in the limited space. This effect will be explored in in-vitro experiments of blood clot dissolution within the tube simulating a blood vessel.
Źródło:
Hydroacoustics; 2016, 19; 361-368
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Normalization of Multifocal Acoustic Radiation Force Impulse Images
Autorzy:
González-Salido, N.
Camacho, J.
Powiązania:
https://bibliotekanauki.pl/articles/176800.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
elastography
radiation force
ARFI
multifocal ARFI
Opis:
Imaging the tissue displacements caused by Acoustic Radiation Force Impulse (ARFI) provides qualitative tissue elasticity maps around the focus. To increase imaging range, multi-focus techniques combine several images obtained with different focal depths. Since the acoustic radiation force depends on focus depth, axial distance and steering angle, a normalization process is required before blending multi-focal ARFI images so that changes in the displayed displacements represent true tissue elasticity variations. This work analyzes the sources of displacement variability in multi-focal-zone ARFI and proposes a procedure to normalize and combine partial images. The proposal is based on the system focal configuration, transducer characteristics and global tissue parameters found by ultrasonic measurements. Performance of the proposed algorithm is experimentally evaluated with tissue mimicking phantoms.
Źródło:
Archives of Acoustics; 2017, 42, 2; 321-331
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of absorption and scattering on the velocity of acoustic streaming
Autorzy:
Secomski, W.
Wójcik, J.
Klimonda, Z.
Olszewski, R.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/332699.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Akustyczne
Tematy:
ultrasound
radiation force
starch
contrast agent
blood
thrombolysis
Opis:
Streaming velocity depends on intensity and absorption of ultrasound in the media. In some cases, such as ultrasound scattered on blood cells at high frequencies, or the presence of ultrasound contrast agents, scattering affects the streaming speed. The velocities of acoustic streaming in a blood-mimicking starch suspension in water and Bracco BR14 contrast agent were measured. The source of the streaming was a plane 20MHz ultrasonic transducer. Velocity was estimated from the averaged Doppler spectrum. The single particle driving force was calculated as the integral of the momentum density tensor components. For different starch concentrations, the streaming velocity increased from 8.9 to 12.5mm/s. This corresponds to a constant 14% velocity increase for a 1 g/l increase in starch concentration. For BR14, the streaming velocity remained constant at 7.2mm/s and was independent of the microbubbles concentration. The velocity was less than in reference, within 0.5mm/s measurement error. Theoretical calculations showed a 16% increase in streaming velocity for 1 g/l starch concentration rise, very similar to the experimental results. The theory has also shown the ability to reduce the streaming velocity by low-density scatterers, as was experimentally proved using the BR14 contrast agent.
Źródło:
Hydroacoustics; 2017, 20; 159-168
1642-1817
Pojawia się w:
Hydroacoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical trapping of the low index of refraction particles by focused vortex beams and two face-to-face focused beams
Autorzy:
Duan, Meiling
Zhang, Hanghang
Li, Jinhong
Powiązania:
https://bibliotekanauki.pl/articles/1835807.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
optical trapping
GSM vortex beams
two face-to-face focused beams
radiation force
Opis:
Using the extended Huygens–Fresnel principle and Rayleigh scattering theory, optical trapping of the low index of refraction particles using a focused Gaussian Schell-model (GSM) non-vortex beam, a focused GSM vortex beam, and two face-to-face focused GSM vortex beams have been studied. The results demonstrate that the focused GSM non-vortex beam cannot capture the low index of refraction particles, however, the focused GSM vortex beam can be a two-dimensional trap of particles in the z-axis, and the transverse gradient force Fgrad,x and the trapping equilibrium region increase as the topological charge m increases. As the focal length f or the refractive index of particles np decreases, the radiation forces increase and the trapping ability also enhances. To trap the low index particles in three-dimensional space, we adopt that the two face-to-face focused GSM vortex beams can be used to construct an optical potential well. The transverse gradient force of two face-to-face focused GSM vortex beams is twice that of a single GSM vortex beam. The limit of the radius for the low index of refraction particles that were stably captured has also been determined. The obtained results provide valuable information for trapping and manipulating the low index of refraction particles using GSM vortex beams, which may be applied in micromanipulation, biotechnology, nanotechnology and so on.
Źródło:
Optica Applicata; 2020, 50, 3; 447-461
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation for Acoustic Radiation Force from Rectangular Weakly Focusing Transducer Using the Ray Acoustic Model
Autorzy:
Yu, Lili
Qiao, Shuchang
Shou, Wende
Li, Junhua
Powiązania:
https://bibliotekanauki.pl/articles/2141691.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radiation force calculation
ray acoustic model
rectangular weakly focusing transducer
far-field integration
Opis:
Based on the ray acoustic model, a new relationship between the radiation force and the acoustic power is studied for a rectangular weakly focusing transducer. The effect of pressure reflection coefficient on this model is discussed. For a totally absorbing target, an approximate closed-form expression is also derived and the performance of this model is compared with that of the far-field integration model. The numerical results show that the agreement is excellent with these two models, which can be both used for correction of measured results, but the formula based on the ray acoustic model can be applied more widely in practice because of its simpler expression. The experimental results show further the effectiveness of the relationship between radiation force and acoustic power for rectangular weakly focusing transducer based on the ray acoustic model. The results presented in this paper are important for application of ultrasound transducers in therapy.
Źródło:
Archives of Acoustics; 2022, 47, 1; 81-88
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultradźwięki w zastosowaniach medycznych – nowe możliwości pomiarowe Zakładu Mechaniki i Akustyki
Medical ultrasounds – new metrological capabilities of Mechanics and Acoustics Department
Autorzy:
Dobrowolska, Danuta
Falińska, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/2200084.pdf
Data publikacji:
2022
Wydawca:
Główny Urząd Miar
Tematy:
moc ultradźwiękowa
waga siły promieniowania
onduktancja promieniowania
przetwornik ultradźwiękowy
hydrofon
ultrasound power
radiation force balance
radiation conductance
ultrasound transducer
hydrophone
Opis:
Artykuł przedstawia aparaturę pomiarową do wzorcowań i badań w dziedzinie ultradźwięków w zastosowaniach medycznych, zakupioną dla Głównego Urzędu Miar w 2021 roku i jej możliwości pod kątem zapewnienia w Polsce spójności pomiarowej w tej dziedzinie. Przedstawia też stan badań nad wdrożeniem w GUM metod realizowanych za pomocą zakupionych systemów pomiarowych oraz wskazuje perspektywy rozwoju.
The article presents measuring equipment for calibration and testing in the field of medical ultrasound, purchased for the Central Office of Measures in 2021, and its capabilities in terms of assuring measurement traceability in this area in Poland. It also presents the state of research on the implementation of the methods implemented in the GUM with the use of purchased measurement systems and indicates development prospects.
Źródło:
Metrologia i Probiernictwo : biuletyn Głównego Urzędu Miar; 2022, 1 (28); 37--42
2300-8806
Pojawia się w:
Metrologia i Probiernictwo : biuletyn Głównego Urzędu Miar
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aspects of Applicability King - St. Clair Approximation in a Non-Newtonian Fluid Mechanics
Autorzy:
Włoch, A.
Czyż, H.
Jasiński, T.
Powiązania:
https://bibliotekanauki.pl/articles/1032505.pdf
Data publikacji:
2017-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
acoustic radiation force
acoustic standing wave
medical applications of ultrasound
separation of red blood cells from human blood
Opis:
This studyis a contribution to research on the biomedical and clinical applications of ultrasound. Our research concerns the procedure for the separation of human blood fractions - erythrocytes. Ultrasonic waves can be used for the separation of cells in human blood. From a physical point of view, the human blood is a suspension of liquids and solids (cell elements), and behaves like a non-Newtonian fluid. Our work is devoted to the problem of the motion of red cells in human blood under the influence of ultrasonic wave. It defines a range of the applicability of approximation consisting in neglecting the nonlinear term in the friction force. It also analyzes the general properties of the equation of motion of the cell in the case of large attenuation constants, corresponding to the values of the drift forces for the cells with radii of a few μm. Finally, it defines the applicability criterion of the so-called King-St Clair approximation consisting in the assumption of equilibrium between the drift and the Stokes viscosity forces, neglecting the term representing inertia. This approximation permits analytical estimation of the time constants for the cell transport to points of stable equilibrium in an ultrasonic standing wave field.
Źródło:
Acta Physica Polonica A; 2017, 132, 1; 164-166
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Triple diffusive flow of Casson nanofluid with buoyancy forces and nonlinear thermal radiation over a horizontal plate
Autorzy:
Archana, Manjappa
Gireesha, Bijjanal Jayanna
Prasannakumara, Ballajja Chandrappa
Powiązania:
https://bibliotekanauki.pl/articles/240608.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
triple diffusion
casson nanofluid
nonlinear thermal radiation
buoyancy force
siła wyporu
promieniowanie cieplne
Opis:
The presence of more than one solute diffused in fluid mixtures is very often requested for discussing the natural phenomena such as transportation of contaminants, underground water, acid rain and so on. In the paper, the effect of nonlinear thermal radiation on triple diffusive convective boundary layer flow of Casson nanofluid along a horizontal plate is theoretically investigated. Similarity transformations are utilized to reduce the governing partial differential equations into a set of nonlinear ordinary differential equations. The reduced equations are numerically solved using Runge-Kutta-Fehlberg fourth-fifth order method along with shooting technique. The impact of several existing physical parameters on velocity, temperature, solutal and nanofluid concentration profiles are analyzed through graphs and tables in detail. It is found that, modified Dufour parameter and Dufour solutal Lewis number enhances the temperature and solutal concentration profiles respectively.
Źródło:
Archives of Thermodynamics; 2019, 40, 1; 49-69
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomic force microscopy investigation of electron beam (EB) irradiated composites based on biodegradable polymers and coconut fiber*
Autorzy:
Kodama, Y.
Oishi, A.
Nagasawa, N.
Nakayama, K.
Tamada, M.
Machado, L. D. B.
Powiązania:
https://bibliotekanauki.pl/articles/147470.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
atomic force microscopy (AFM)
coconut fiber
electron beam (EB) radiation
force modulation microscopy (FMM)
poly(ε-caprolactone) (PCL)
poly(L-lactic acid) (PLLA)
scanning electron microscopy (SEM)
Opis:
In this study, the addition of natural fibers to biodegradable PCL, PLLA blend and the effect of ionizing radiation on the surface of composites were investigated by force modulation microscopy (FMM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Hot pressed sheets were prepared using pellets of twin extruded PCL:PLLA 20:80 (w:w) blend containing 5% or 10% weight concentration of coconut fiber. In this study coconut fibers non treated chemically and acetylated ones were used. Irradiation was performed using an electron beam (EB) accelerator and an absorbed dose of 100 kGy. FMM images acquisition was obtained using a silicon cantilever, intermittent contact mode (tapping mode). Also, AFM images were obtained using tapping mode but J scanner. By FMM, it was possible to observe regions with different elasticity indicating fiber presence under the surface of the composite. Furthermore, it appears that the spherical structures size decreased on composites. This probably was induced by ionizing radiation.
Źródło:
Nukleonika; 2013, 58, 4; 459-468
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ocena wpływu promieniowania świetlnego na nanoskopowe właściwości powierzchni kompozytów termoutwardzalnych
The evaluation of the solar radiation impact on the nanoscoppic properties of the surface of the sheet moulder composite
Autorzy:
Sikora, A.
Fałat, T.
Adamowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/159373.pdf
Data publikacji:
2012
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
badania środowiskowe
promieniowanie słoneczne
tomografia komputerowa
mikroskopia sił atomowych
environmental tests
solar radiation
micro computer tomography
atomic force microscopy
Opis:
Ocena wpływu promieniowania słonecznego na właściwości mechaniczne materiałów jest jednym z podstawowych badań środowiskowych, które przywoływane są w normach przedmiotowych dotyczących różnego typu urządzeń i elementów stosowanych w elektrotechnice. Rozwój wysokorozdzielczych technik diagnostycznych pozwala na dokonywanie bardziej szczegółowych niż dotychczas analiz wpływu czynników środowiskowych na właściwości mechaniczne powierzchni, co może być szczególnie cenne w przypadku prac nad tzw. nanomateriałami. W pracy zostaną przedstawione wyniki analiz wykonanych dla próbki kompozytu termoutwardzalnego – SMC (sheet moulder composite), przeprowadzonych z wykorzystaniem mikroskopii sił atomowych oraz mikrotomografii komputerowej, odniesione do wykonanych zgodnie z wymaganiami normy testów odporności na udarność. Uzyskane wyniki pozwalają stwierdzić przydatność wysokorozdzielczych technik diagnostycznych w badaniach wpływu promieniowania świetnego na powierzchnię materiału.
The evaluation of the solar radiation influence on the mechanical properties of the material is one of the most popular investigation methods among various environmental tests, mentioned in standards related to various devices and components utilized in electrotechnics. The development of the high-resolution diagnostic methods allowed to perform much more detailed analysis of the influence of the environmental factors on the mechanical properties of the surface. Such tools can be particularly useful in case of the nanomaterials development. In this work we present the analysis of the solar radiation caused degradation of the SMC material - sheet moulder composite, investigated with atomic force microscopy and micro computer tomography. Obtained results were compared to the outcome of the measurements of the impact strength tests. The measurement data allow to confirm the usability of the high-resolution diagnostic methods in the determination of the influence of the solar radiation on the surface of the material.
Źródło:
Prace Instytutu Elektrotechniki; 2012, 259; 63-64
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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