1,721,075 research outputs found
Temperature changes during a microwave thermal ablation procedure
No full textAim of this work is to characterize temperature increases obtained during a microwave thermal ablation procedure, and to evaluate their influence on the obtained results. Measurements have been performed of the dielectric properties of ex-vivo bovine liver tissue and of the temperature increase close to the microwave antenna. Measured data have been compared with numerical results obtained solving the bio-heat equation (BHE). The limits of the BHE are put into evidence, as well as the influence of the liquid refrigerating the antenn
Experimental characterization and numerical modelling of the thermal lesion induced by microwave ablation
No full textSviluppo di simulatori dielettrici tessuto-equivalenti per studi dosimetrici su antenne interstiziali per termoablazione a microonde
No full textThermal ablation therapies, based on electromagnetic field sources at microwave (MW)
frequencies, are increasingly used in medicine due to their proven efficacy in the treatment of many diseases
(stenosis, tumours, etc.). Such techniques need standardized procedures for treatment optimisation. In this
study, tissue-equivalent dielectric simulators (phantoms) of liver and kidney tissue were designed and
realised to experimentally characterise interstitial MW antennas in reference condition
On the modelling of the temperature increase obtained in a microwave thermal ablation process
No full textNumerical models of microwave thermal ablation procedures
No full textMicrowave thermal ablations therapies are based
on the absorption of an electromagnetic field at microwave
frequencies to induce a very high and localized temperature
increase to remove unhealthy tissue. The development of clinical
protocols for treatment planning is strictly linked to the
availability of numerical models able to correctly predict the
procedure outcomes. In this paper, some numerical models
proposed in the literature were considered and their results were
compared
Evaluation of the thermal lesion in microwave ablation procedures
No full textIn this paper, the numerical and experimental evaluation of the dimension of the tissue's ablated area in microwave ablation procedures is discussed. The dependence of the temperature on time, both during and after the end of the ablation procedure, is studied both experimentally and numerically. Results show that the thermal lesion continues to grow after the end of the ablation procedure. © 2012 IEEE
Dielectric and Thermal Properties of Tissues Undergoing Microwave Thermal Ablation Procedures
No full textEXPERIMENTAL CAMPAIGN ON COMPOSITE MATERIALS TO SUPPORT NUMERICAL SIMULATIONS OF THE LOW VELOCITY IMPACT BEHAVIOUR
No full textNumerical-experimental validation of a GM-FDTD code for the study of cellular phones
No full textThis paper presents a numerical– experimental validation of a finite-difference time-domain code employing a graded-mesh (GMFDTD). To this aim, a prototype of a mobile phone (mock-up), equipped with a helical antenna, is manufactured and modelled using the GMFDTD code and a freeware code based on the method of moments (MoM). The return loss (RL), together with the near electric- and magnetic- field distributions, have been computed using the GM-FDTD code and compared with the MoM results and measurements. Moreover, the specific absorption rate (SAR) induced by the phone inside a cubic phantom has been measured and evaluated with the GM-FDTD code. The agreement between the numerical and experimental results is within acceptable measurement uncertainty
A new damage index for the indentation depth evaluation of composites under low velocity impact loads
No full textThe effectiveness of a new empirical model, aiming to predict the indentation depth resulting in a composite laminate from a hemispherical tup impacting it at low velocity, is here proposed. With this simple model including only the diameter of the impactor and the ratio between the impact energy and the perforation one, a material-independent parameter characterising the indentation depth is identified. Several samples with different thicknesses, impacted by various impactor tips, are tested for estimating this parameter. To reach the above mentioned scopes, low velocity impact tests were carried out on two different composite systems with different stacking sequences, thicknesses and fiber volume fractions: (a) glass/epoxy prepreg; (b) graphite/epoxy prepreg. The samples were simply supported on steel plates or clamped and they were struck at the center by hemispherical steel noses having 16 and 19.8 mm diameters. After impact, indentation was measured according to EN 6038 standard. The CFRP indentation data were drawn from a database: about 200 test records, generated by various researchers were individuated. The advantages of the new model are that the effect of the tup diameter is explicitly accounted for. Furthermore, a single material constant has to be experimentally determined and it can be assumed as an index for the indentation sensitivity, on the basis of which different materials can be ranked. The constant was found similar for GFRP and CFRP laminates denoting independence of constraint conditions, laminate type or laminae orientation and stacking sequence
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