Multiscale homogenization of aluminum honeycomb structures: Thermal analysis with orthotropic representative volume element and finite element method.

This study develops a thermal homogenization model for an aluminum honeycomb panel using the representative volume element (RVE) concept, considering the orthotropic nature of the structure. The RVE thermal homogenization method is a numerical approach for analyzing heterogeneous materials. It employs a constitutive model based on RVE performance to represent thermal behavior.

The Role of Nanofluids in Renewable Energy Engineering.

The phenomenon of nanofluid flows is intrinsically characterized by several scales and intricate physical processes [...

Effects of Pulsed Radiofrequency Source on Cardiac Ablation.

Heart arrhythmia is caused by abnormal electrical conduction through the myocardium, which in some cases, can be treated with heat. One of the challenges is to reduce temperature peaks-by still guaranteeing an efficient treatment where desired-to avoid any healthy tissue damage or any electrical issues within the device employed. A solution might be employing pulsed heat, in which thermal dose is given to the tissue with a variation in time.

Boundary layer considerations in a multi-layer model for LDL accumulation.

Boundary layer effects for Low-Density Lipoprotein (LDL) concentration problems in a multi-layer artery model are analyzed in this work. Both a straight artery and aorta-iliac bifurcation are analyzed. Mass, momentum and species governing equations are based on the porous media theory and solved with the commercial finite-element based code COMSOL Multiphysics.

Correlation between MMP and TIMP levels and elastic moduli of ascending thoracic aortic aneurysms.

Objective: The objective of this preliminary investigation is to determine if there is a relation between the biological levels of matrix metalloproteinases and tissue inhibitor of matrix metalloproteinase (TIMP) and the elastic moduli of the ascending aortic wall in patients with ascending thoracic aortic aneurysms (ATAA).

Methods: Circumferential specimens from twelve patients with ATAA were obtained from the greater curvature and their tensile properties (maximum elastic modulus) were tested uniaxially. The levels of MMP1, 2, 3, 8, and 9 as well as TIMP1 and 2 were determined in these aortic wall specimens using MMP/TIMP antibodies array.

Analysis of non-Newtonian effects within an aorta-iliac bifurcation region.

The geometry of the arteries at or near arterial bifurcation influences the blood flow field, which is an important factor affecting arteriogenesis. The blood can act sometimes as a non-Newtonian fluid. However, many studies have argued that for large and medium arteries, the blood flow can be considered to be Newtonian.

Particulate suspension effect on peristaltically induced unsteady pulsatile flow in a narrow artery: Blood flow model.

This work is concerned with theoretically investigating the pulsatile flow of a fluid with suspended particles in a flow driven by peristaltic waves that deform the wall of a small blood artery in the shape of traveling sinusoidal waves with constant velocity. The problem formulation in the wave frame of reference is presented and the governing equations are developed up to the second-order in terms of the asymptotic expansion of Womersley number which characterizes the unsteady effect in the wave frame. We suppose that the flow rate imposed, in this frame, is a function versus time.

Analysis of non-Newtonian effects on Low-Density Lipoprotein accumulation in an artery.

In this work, non-Newtonian effects on Low-Density Lipoprotein (LDL) transport across an artery are analyzed with a multi-layer model. Four rheological models (Carreau, Carreau-Yasuda, power-law and Newtonian) are used for the blood flow through the lumen. For the non-Newtonian cases, the arterial wall is modeled with a generalized momentum equation.

Low-density lipoprotein transport through an arterial wall under hyperthermia and hypertension conditions--An analytical solution.

An analytical solution for Low-Density Lipoprotein transport through an arterial wall under hyperthermia conditions is established in this work. A four-layer model is used to characterize the arterial wall. Transport governing equations are obtained as a combination between Staverman-Kedem-Katchalsky membrane equations and volume-averaged porous media equations.

Analysis and analytical characterization of bioheat transfer during radiofrequency ablation.

Understanding thermal transport and temperature distribution within biological organs is important for therapeutic aspects related to hyperthermia treatments such as radiofrequency ablation (RFA). Unlike surface heating, the RFA treatment volumetrically heats up the biological media using a heating probe which provides the input energy. In this situation, the shape of the affected region is annular, which is described by an axisymmetric geometry.

Analysis of Low Density Lipoprotein (LDL) Transport Within a Curved Artery.

To elucidate the mechanism of the effect of LDL concentration on the thickening of intima in a curved artery, LDL transport in each layer of the curved arterial wall is studied analytically. A comprehensive concentration distribution expression of LDL in each layer of the curved artery wall is presented along with the characterization and estimation of the effect of curvature on the growth of atherosclerosis within the arterial wall. The effect of curvature on species concentration distribution is analyzed and the results are thoroughly benchmarked against prior pertinent works.

Effects of External and Internal Hyperthermia on LDL Transport and Accumulation Within an Arterial Wall in the Presence of a Stenosis.

Effects of hyperthermia on transport of low-density lipoprotein (LDL) through a stenosed arterial wall are analyzed comprehensively in the present work. The realistic and pertinent aspects of an arterial wall is represented by a multi-layer model, with a proper representation of the thickened intima region due to the atherosclerotic plaque formation. Effects of external and internal hyperthermia on LDL concentration levels are established along with the range of influence of these effects.

Modeling and analysis of transport in the mammary glands.

The transport of three toxins moving from the blood stream into the ducts of the mammary glands is analyzed in this work. The model predictions are compared with experimental data from the literature. The utility of the model lies in its potential to improve our understanding of toxin transport as a pre-disposing factor to breast cancer.

Mechanobiology of low-density lipoprotein transport within an arterial wall--impact of hyperthermia and coupling effects.

The effects of hyperthermia, coupling attributes and property variations on Low-density lipoprotein (LDL) transport within a multi-layered wall while accounting for the fluid structure interaction (FSI) is analyzed in this work. To understand the potential impact of the hyperthermia process, thermo-induced attributes are incorporated, accounting for the plasma flow, mass transfer, as well as the elastic wall structure. The coupling effect of osmotic pressure, Soret and Dufour diffusion is discussed and their influence on LDL transport is examined, demonstrating that only the Soret effect needs to be accounted for.

Analysis of detection enhancement using microcantilevers with long-slit-based sensors.

The present work analyzes theoretically and verifies the advantage of utilizing rectangular microcantilevers with long-slits in microsensing applications. The deflection profile of these microcantilevers is compared with that of typical rectangular microcantilevers under the action of dynamic disturbances. Various force-loading conditions are considered.

Low-density lipoprotein transport within a multi-layered arterial wall--effect of the atherosclerotic plaque/stenosis.

Low-density lipoprotein (LDL) transport while incorporating the thickening of the arterial wall and cholesterol lipid accumulation is analyzed. A multi-layered model is adopted to represent the heterogeneity using the Darcy-Brinkman and Staverman filtration equations to describe transport within the porous layers of the wall. The fiber matrix model is utilized to represent the cholesterol lipid accumulation and the resulting variable properties.

Effects of pressure on arterial failure.

A three-dimensional multilayer model of mechanical response for analyzing the effect of pressure on arterial failure is presented in this work. The multilayer arterial wall is considered to be composed of five different layers. The three-dimensional effects are incorporated within the five-concentric axisymmetric layers while incorporating the nonlinear elastic characteristics under combined extension and inflation.

Analysis of deflection enhancement using epsilon assembly microcantilevers based sensors.

The present work analyzes theoretically and verifies the advantage of utilizing ɛ-microcantilever assemblies in microsensing applications. The deflection profile of these innovative ɛ-assembly microcantilevers is compared with that of the rectangular microcantilever and modified triangular microcantlever. Various force-loading conditions are considered.

Effect of the fluid-structure interactions on low-density lipoprotein transport within a multi-layered arterial wall.

The effects of fluid-structure interactions (FSI) and pulsation on the transport of low-density lipoprotein (LDL) through an arterial wall are analyzed in this work. To this end, a comprehensive multi-layer model for both LDL transport as well as fluid-structure interaction (FSI) is introduced. The constructed model is analyzed and compared with the existing results in the limiting cases.