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Wyszukujesz frazę "tissue heating" wg kryterium: Wszystkie pola


Wyświetlanie 1-6 z 6
Tytuł:
Numerical analysis of biological tissue heating using the dual-phase lag equation with temperature – dependent parameters
Autorzy:
Majchrzak, Ewa
Stryczyński, Mikołaj
Powiązania:
https://bibliotekanauki.pl/articles/2202034.pdf
Data publikacji:
2022
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
bioheat transfer
dual-phase lag model
temperature-dependent parameter
finite difference method
przepływ biociepła
model dwufazowego opóźnienia
metoda różnic skończonych
Opis:
The dual-phase lag equation is formulated for the case when the thermophysical parameters occurring in this equation are temperature-dependent. The axial-symmetrical domain of biological tissue heated by an external heat source is considered. The problem is solved using the implicit scheme of the finite difference method. At the stage of numerical computations, the analytical relationships taken from the literature describing changes in parameters are taken into account.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2022, 21, 3; 85--98
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Effects Induced in Liver Tissues by Pulsed Focused Ultrasonic Beams from Annular Array Transducer
Autorzy:
Kujawska, T.
Secomski, W.
Krawczyk, K.
Nowicki, A.
Powiązania:
https://bibliotekanauki.pl/articles/176937.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
annular array transducer
pulsed focused nonlinear ultrasound
electronically moved focus
tissue heating
biological effects
tissue necrosis
Opis:
Many therapeutic applications of pulsed focused ultrasound are based on heating of detected lesions which may be localized in tissues at different depths under the skin. In order to concentrate the acoustic energy inside tissues at desired depths a new approach using a planar multi-element annular array transducer with an electronically adjusted time-delay of excitation of its elements, was proposed. The 7-elements annular array transducer with 2.4 MHz center operating frequency and 20 mm outer diameter was produced. All its elements (central disc and 6 rings) had the same radiating area. The main purpose of this study was to investigate thermal fields induced in bovine liver in vitro by pulsed focused ultrasonic beams with various acoustic properties and electronically steered focal plane generated from the annular array transducer used. The measurements were performed for the radiating beams with the 20 mm focal depth. In order to maximize nonlinear effects introducing the important local temperature rise, the measurements have been performed in two-layer media comprising of a water layer, whose thickness was specific for the transducer used and equal to 13 mm, and the second layer of a bovine liver with a thickness of 20 mm. The thickness of the water layer was determined numerically as the axial distance where the amplitude of the second harmonics started to increase rapidly. The measurements of the temperature rise versus time were performed using a thermocouple placed inside the liver at the focus of the beam. The temperature rise induced in the bovine liver in vitro by beams with the average acoustic power of 1W, 2Wand 3Wand duty cycle of 1/5, 1/15 and 1/30, respectively, have been measured. For each beam used the exposure time needed for the local tissue heating to the temperature of 43.C (used in therapies based on ultrasonic enhancement of drug delivery or in therapies involving stimulation of immune system by enhancement of the heat shock proteins expression) and to the temperature of 56.C (used in HIFU therapies) was determined. Two sets of measurements were done for each beam considered. First, the thermocouple measurement of the temperature rise was done and next, the real-time monitoring of dynamics of growth of the necrosis area by using ultrasonic imaging technique, while the sample was exposed to the same acoustic beam. It was found that the necrosis area becomes visible in the ultrasonic image only for beams with the average acoustic power of 3 W, although after cutting the sample the thermo ablated area was visible with the naked eye even for the beams with lower acoustic power. The quantitative analysis of the obtained results allowed to determine the exposure time needed to get the necrosis area visible in the ultrasonic image.
Źródło:
Archives of Acoustics; 2011, 36, 4; 937-944
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical analysis of thermal processes in the system protective clothing – biological tissue subjected to an external heat flux
Autorzy:
Mochnacki, B.
Duda, M.
Powiązania:
https://bibliotekanauki.pl/articles/122560.pdf
Data publikacji:
2016
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
bio-heat transfer
protective clothing
tissue heating
simulations
przepływ biociepła
odzież ochronna
rozgrzana tkanka
układ równań Pennesa
Opis:
The non-homogeneous fragment of biological tissue is considered. Its shape roughly corresponds to the fragment of cross-section of the upper or lower limb. The tissue domain is protected by a layer of protective clothing. The purpose of numerical computations is to examine the effectiveness of the clothing insulation layer on the action of the external heat fluxes of differing intensity. Thermal processes in the tissue domain are described by the system of the Pennes equations. This system is supplemented by the appropriate boundary-initial conditions and the energy equations determining the transient temperature field in the fabric and air gap sub-domains (the air gap is treated as a solid body). At the stage of numerical computations, the program MSC. Marc has been used. In the final part of the paper, the examples of numerical simulations and also the conclusions are presented.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2016, 15, 2; 85-93
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase-lag effects in skin tissue during transient heating
Autorzy:
Kumar, R.
Vashishth, A. K.
Ghangas, S.
Powiązania:
https://bibliotekanauki.pl/articles/264536.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
tkanka skórna
transformata Laplace'a
opóźnienie trójfazowe
bioheat transfer
skin tissue
three-phase-lag
Laplace transform
transient heating
Opis:
A three-phase-lag (TPL) model is proposed to describe heat transfer in a finite domain skin tissue with temperature dependent metabolic heat generation. The Laplace transform method is applied to solve the problem. Three special types of heat flux are applied to the boundary of skin tissue for thermal therapeutic applications. The depth of tissue is influenced by the different oscillation heat flux. The comparison between the TPL and dual-phase-lag (DPL) models is analyzed and the effects of phase lag parameters […] and material constant […] on the tissue temperature distribution are presented graphically.
Źródło:
International Journal of Applied Mechanics and Engineering; 2019, 24, 3; 603-623
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of the heating process in the domain of tissue insulated by protective clothing
Autorzy:
Ciesielski, M.
Mochnacki, B.
Powiązania:
https://bibliotekanauki.pl/articles/122678.pdf
Data publikacji:
2014
Wydawca:
Politechnika Częstochowska. Wydawnictwo Politechniki Częstochowskiej
Tematy:
bioheat transfer
protective clothing
modeling of thermal processes
control volume method
Voronoi tessellation
przepływ ciepła
odzież ochronna
modelowanie procesów cieplnych
teselacja Voronoia
Opis:
In this paper the 2D heterogeneous tissue domain (forearm cross-section) insulated by a layer of protective clothing is considered. The aim of considerations is to develop an algorithm simulating the tissue heating process resulting from the sudden change of external boundary conditions. Here, the authors exploit a certain version of the control volume method (CVM) using the Voronoi tessellation. The mathematical model of heat exchange in the domain analyzed is formulated in the form of a boundary-initial problem based on the system of partial differential equations (energy equations) supplemented by the adequate boundary and initial conditions. In the final part of the paper, the examples of numerical simulations are shown.
Źródło:
Journal of Applied Mathematics and Computational Mechanics; 2014, 13, 2; 13-20
2299-9965
Pojawia się w:
Journal of Applied Mathematics and Computational Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wpływ temperatury ogrzewania na jakość lipidów podczas chłodniczego przechowywania ogrzanej tkanki mięsnej śledzia bałtyckiego (Clupea harengus membras)
Effects of heating temperature on the quality of lipids during refrigerated storage of heated muscle tissue of baltic herring (Clupea harengus membras)
Autorzy:
Domiszewski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/82616.pdf
Data publikacji:
2012
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Źródło:
Folia Pomeranae Universitatis Technologiae Stetinensis. Agricultura, Alimentaria, Piscaria et Zootechnica; 2012, 24
2081-1284
Pojawia się w:
Folia Pomeranae Universitatis Technologiae Stetinensis. Agricultura, Alimentaria, Piscaria et Zootechnica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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