FORCED WAVES PROPAGATION IN GREAT LIVING ARTERIES TISSUES

2018 ◽  
Vol 18 (03) ◽  
pp. 1850032
Author(s):  
ISABELLA BARBIERI ◽  
EZIO CAROLI ◽  
GIOVANNI PALLOTTI
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Mathematical Model ◽  
Theoretical Model ◽  
Acoustic Waves ◽  
Wave Motion ◽  
Waves Propagation ◽  
Motion Parameters ◽  
Forced Waves ◽  
Axial Waves

Starting from experimental data, this work exploit the similarity of pressure and axial wave’s propagation of both pressure and axial waves in large vessel (e.g., aorta) with the solution of a mathematical model developed to describe the motion of acoustic waves in solid. In particular, we show how the motion parameters derived by fitting the experimental data measured in living dog arteries are related to mechanical properties of the vessel tissue using the same theoretical model. Furthermore, we briefly discuss the consequence on the predicted forced wave motion of inferring from experimental data a phase velocity depending from frequency.

Mathematical Model of the Sintering Process of Iron-Copper Bearings

2007 ◽  
Vol 23 ◽  
pp. 119-122
Author(s):  
Cristina Teișanu ◽  
Stefan Gheorghe ◽  
Ion Ciupitu
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Mathematical Model ◽  
Regression Analysis ◽  
Function Optimization ◽  
Chemical Compositions ◽  
Sintering Process ◽  
Molybdenum Disulphide ◽  
Iron Copper ◽  
Antifriction Properties

The most important features of the self-lubricating bearings are the antifriction properties such as friction coefficient and wear resistence and some mechanical properties such as hardness, tensile strength and radial crushing strength. In order to improve these properties new antifriction materials based on iron-copper powders with several additional components (tin, lead and molybdenum disulphide) have been developed by PM techniques. To find the optimal relationship between chemical compositions, antifriction and mechanical properties, in this paper a mathematical model of the sintering process is developed, which highlighted the accordance of the model with data by regression analysis. For the statistical processing of the experimental data the VH5 hardness values of the studied materials were considered. The development of mathematical model includes the enunciation of the model, the establishment of the performance function (optimization) and the establishment of the model equations and verifying. The accordance of the model with experimental data has been highlighted by regression analysis

Short Fiber Reinforcement of Elastomers

1974 ◽  
Vol 47 (5) ◽  
pp. 1074-1081 ◽  
Author(s):  
S. R. Moghe
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Mathematical Model ◽  
Fiber Orientation ◽  
Probability Distribution Function ◽  
Tensile Modulus ◽  
Short Fiber ◽  
Simple Mathematical Model ◽  
Short Fibers ◽  
Rubber Compounds

Abstract Based upon a simple mathematical model, the directional properties of elastomers mixed with uniaxially oriented short fibers are predicted. The model takes into account a probability distribution function for a number of fibers in any direction during fiber orientation. Theory is compared with experimental data on tensile modulus for a number of rubber compounds and fibers with good success. A possibility of characterizing calendering and extrusion processes in view of orientation and mechanical properties is discussed.

scholarly journals Inverse problems of experimental data interpretation in 3D ultrasound tomography

2019 ◽  
pp. 254-269
Author(s):  
А.В. Гончарский ◽  
В.А. Кубышкин ◽  
С.Ю. Романов ◽  
С.Ю. Серёжников
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Inverse Problem ◽  
Acoustic Waves ◽  
Soft Tissues ◽  
Nonlinear Coefficient ◽  
3D Ultrasound ◽  
Acoustic Properties ◽  
Ultrasound Wave ◽  
Ultrasound Tomography

Обратная задача 3D ультразвуковой томографии рассматривается в статье как нелинейная коэффициентная обратная задача для уравнения гиперболического типа. Используемая математическая модель хорошо описывает как дифракционные эффекты, так и поглощение ультразвука в неоднородной среде. В рассматриваемой постановке реконструируется скорость распространения акустической волны как функция трех координат. Количество неизвестных в нелинейной обратной задаче составляет порядка 50 миллионов. Разработанные итерационные алгоритмы решения обратной задачи ориентированы на использование GPUкластеров. Основным результатом работы является апробация алгоритмов на экспериментальных данных. В эксперименте использовался стенд для 3D ультразвуковых томографических исследований, разработанный в МГУ имени М.В. Ломоносова. Акустические параметры фантомов близки к акустическим параметрам мягких тканей человека. Объем экспериментальных данных составляет порядка 3 ГБ. Интерпретация данных эксперимента позволила не только продемонстрировать эффективность разработанных алгоритмов, но и подтвердила адекватность математической модели реальности. Для реализации разработанных численных алгоритмов использовался графический кластер суперкомпьютера Ломоносов-2. The inverse problem of 3D ultrasound tomography is considered in this paper as a nonlinear coefficient inverse problem for a hyperbolic equation. The employed mathematical model accurately describes the effects of ultrasound wave diffraction and absorption in inhomogeneous media. The velocity of acoustic waves inside the test sample is reconstructed as an unknown function of three spatial coordinates. The number of unknowns in the nonlinear inverse problem reaches 50 million. The developed iterative algorithms for solving the inverse problem are designed for GPU clusters. The main result of this study is testing the developed algorithms on experimental data. The experiments were carried out using a 3D ultrasound tomographic setup developed at Lomonosov Moscow State University. Acoustic properties of the test samples were close to those of human soft tissues. The volume of data collected in experiments is up to 3 GB. Experimental results show the efficiency of the proposed algorithms and confirm that the mathematical model is adequate to reality. The proposed algorithms were tested on the GPU partition of Lomonosov2 supercomputer.

MATHEMATICAL MODEL FOR HEAT DEPOSITION IN TISSUE DURING PHOTODYNAMICAL THERAPY

1996 ◽  
Vol 04 (02) ◽  
pp. 261-276
Author(s):  
ALFRED ŠVARC ◽  
MISLAV JURIN ◽  
SUZANA BOROVIĆ ◽  
HRVOJE ZORC ◽  
MARKO DOKO
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Theoretical Model ◽  
Light Source ◽  
Normal Tissue ◽  
Treatment Time ◽  
Red Light ◽  
Heat Deposition ◽  
Model Predictions

A mathematical model for the heat deposition in tissue during the exposition to the red light, essential for the phototherapy, is presented. The comparison of model predictions with in vivo experimental data for the normal CBA/HZgr mice hind leg tissue is done in order to illustrate the domain of confidence of the theoretical model. The highest usable power of the light source, and consequently the lowest phototherapy treatment time with no influence upon normal tissue is determined.

Use of Nonferrous Metallurgy Waste: Clayey Portion of the Zircon-Ilmenite Ore Gravity Tailings and Pyrite Cinders in Tile-Making

2020 ◽  
Vol 989 ◽  
pp. 47-53
Author(s):  
A.K. Kairakbaev ◽  
Ye. S. Abdrakhimova ◽  
V.Z. Abdrakhimov
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Mathematical Model ◽  
Linear Regression ◽  
Product Quality ◽  
Nonferrous Metallurgy ◽  
Combined Effects ◽  
Ceramic Mixture ◽  
The Common ◽  
Pyrite Cinders

Studies have shown that using nonferrous metallurgy waste in the ceramic mixture for the making of roof tiles improves the final product quality; one can use the clayey portion of the zircon-ilmenite ore gravity tailings as the clay, pyrite cinders as leaners and sintering intensifier, and wollastonite as an agent to reduce shrinkage and prevent deformation-related buckling. The common method of linear regression was used to study the dependency of the basic physico-mechanical properties of tiles on how much clay from the zircon-ilmenite ore gravity tailings, pyrite cinders, and wollastonite is used in manufacture. The resultant mathematical model takes into account the combined effects these components have on the physico-mechanical properties of tiles; it matches well the experimental data.

The effect of pressure on the compressibility of aluminum alloys

2020 ◽  
pp. 102-107
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Liquid Metal ◽  
Control Systems ◽  
Physical And Mechanical Properties ◽  
Reliable Data ◽  
Output Process ◽  
Automated Control ◽  
Input And Output ◽  
Crystallization Under Pressure

To obtain reliable data on the properties of liquid metal and create automated control systems, the technological process of molding with crystallization under pressure is studied. A mathematical model of the input and output process parameters is developed. It is established that the compressibility of the melt can represent the main controlled parameter influencing on the physical-mechanical properties of the final products. The obtained castings using this technology are not inferior in their physical and mechanical properties to those produced by forging or stamping.

The substantiation of the formalized estimation of effectiveness of technological and production systems

2018 ◽  
Vol 15 (1) ◽  
pp. 169-181
Author(s):  
M. I. Sidorov ◽  
М. Е. Stavrovsky ◽  
V. V. Irogov ◽  
E. S. Yurtsev
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Production Systems ◽  
Van Der Pol

Using the example of van der Pol developed a mathematical model of frictional self-oscillations in topochemically kinetics. Marked qualitative correspondence of the results of calculation performed using the experimental data of researchers.

scholarly journals Experimental demonstration of negative refraction with 3D locally resonant acoustic metafluids

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Benoit Tallon ◽  
Artem Kovalenko ◽  
Olivier Poncelet ◽  
Christophe Aristégui ◽  
Olivier Mondain-Monval ◽  
...  
Keyword(s):  
Experimental Data ◽  
Yield Stress ◽  
Multiple Scattering ◽  
Silicone Rubber ◽  
Acoustic Waves ◽  
Scattering Theory ◽  
Negative Refraction ◽  
Volume Fraction ◽  
Experimental Demonstration ◽  
Acoustic Beam

AbstractNegative refraction of acoustic waves is demonstrated through underwater experiments conducted at ultrasonic frequencies on a 3D locally resonant acoustic metafluid made of soft porous silicone-rubber micro-beads suspended in a yield-stress fluid. By measuring the refracted angle of the acoustic beam transmitted through this metafluid shaped as a prism, we determine the acoustic index to water according to Snell’s law. These experimental data are then compared with an excellent agreement to calculations performed in the framework of Multiple Scattering Theory showing that the emergence of negative refraction depends on the volume fraction $$\Phi$$ Φ of the resonant micro-beads. For diluted metafluid ($$\Phi =3\%$$ Φ = 3 % ), only positive refraction occurs whereas negative refraction is demonstrated over a broad frequency band with concentrated metafluid ($$\Phi =17\%$$ Φ = 17 % ).

Sign in / Sign up

Export Citation Format

Share Document