S U M M A R Y The propagation of elastic waves is modelled in media with a random distribution of fluidfilled circular cavities, which display high physical impedance in contrast to background media. Theoretical attenuation expressions for media with circular cavities, which may be filled with any material (e.g. vacuum, fluid, elastic materials), are formulated using an ensemble treatment for f...

The outstanding properties of selected soft magnetic materials make them successful candidates for building high performance sensors. In this paper we present our recent work regarding different sensing technologies based on the coupling of the magnetic properties of soft magnetic materials with their electric or elastic properties. In first place we report the influence on the magneto-impedanc...

In this paper, the elastic properties of passive materials (matching, backing and lens materials) for ultrasound transducers are explored at room temperature in the frequency range of 25-65MHz using the ultrasonic spectroscopy method. AlurninaJEPOTEK 301 and tungsten/EPO-TEK 301 composites were fabricated and measured. Experimental results display a monotonic rise in acoustic impedance of the c...

Aorta is formed in a dynamic environment which gives rise to imbalances between many forces that tend to extend the diameter and length. Furthermore, internal forces tend to resist this extension. Impedance tomography can show this imbalance to stimulate the stenosis of aortic valve, growth of the elastic, collagen and to effectively reduce the stresses in the underlying tissue. In blood flow, ...

Compliant Actuators are desirable for human friendly robotics, especially for assistive and rehabilitation robots that have direct physical interaction with human users. Various designs of Series Elastic Actuators (SEA) have been developed for these applications. This paper presents a novel SEA design with variable impedance for human-friendly robotics applications that overcomes the major limi...

The propagation of harmonic pressure waves through a Newtonian fluid contained within a thick-walled, viscoelastic tube is considered as a model of arterial blood flow. The fluid is assumed to be homogeneous and Newtonian, and its motion to be laminar and axisymmetric. The wall is assumed to be isotropic, incompressible, linear, and viscoelastic. It is also assumed that the motion is such that ...

For least squares regression, Efron et al. (2004) proposed an efficient solution path algorithm, the least angle regression (LAR). They showed that a slight modification of the LAR leads to the whole LASSO solution path. Both the LAR and LASSO solution paths are piecewise linear. Recently Wu (2011) extended the LAR to generalized linear models and the quasi-likelihood method. In this work we ex...

The goal of this study was to develop, on a rational basis, an index of the intrinsic diastolic elastic properties of the left ventricle. A relatively simple analytic model employing a thin-walled spherical geometry coupled with an approximate formulation of a two-dimensional constitutive relation, was used to examine the primary determinants of the pressure-volume relationship of the intact he...

Variability in airway caliber is a characteristic feature of asthma. Previous studies reported that the variability in respiratory system impedance (Zrs), measured by the forced oscillation technique during several minutes of tidal breathing, is increased in asthma and may be a marker of inherent instability of the airways. The aims of this study were to determine if short-term variability in i...

Traditional stiff actuators have a high reflected inertia, which do not meet the safety requirements, are bad to absorb shocks and cannot store and release energy which are for different applications required. Initiated by the introduction of the Series Elastic Actuator (SEA) by Gill A. Pratt in 1995, a wide range of Variable Impedance Actuators (VIA) are developed, for which inspiration was fo...