Dynamic mechanical activity in a tunnel can be measured as ground vibrations at offset distances. These signals can be processed in sensing algorithms for detection, location, and discrimination of the activity. The objective of this work is to demonstrate that seismic simulations can reveal the effect of the environment on seismic energy as it propagates from tunnels. Using massively parallel ...

The analysis of viscoelastic materials is one of the most important subjects in engineering structures. Several works have been so far made for the integral equation methods to viscoelastic problems. From the basic assumptions of viscoelastic constitutive equations and weighted residual techniques, a simple but effective Boundary Element (BE) formulation is developed for the Kelvin viscoelastic...

The rheological properties of four different Kuwaiti crude oils in the presence of polyacrylamide (PAA) were investigated. PAA was varied at three different concentrations of 25, 50, and 75 ppm to study the viscoelastic properties in the untreated samples. Four different temperatures (25, 30, 35, and 40 °C) were used to evaluate different viscoelastic parameters of the treated and untreated Kuw...

The use of PSpice models for piezoelectric devices and ultrasonic transmission media is of major importance when designing electronics for ultrasonic systems. Today, these models include viscoelastic loss but disregard loss due to diffraction, i.e. beam spreading. This paper presents a method for the inclusion of diffraction loss in PSpice simulations of ultrasonic systems. The conductive loss ...

This paper presents a biomechanical model for the small pits, called crypts, that line the colon. A continuum approach is adopted, with the crypt epithelium modelled as a growing beam attached to the underlying lamina by cell bonds, which generate tension within the layer. These cell attachments are assumed to be viscoelastic thus allowing for cell progression along the crypt. It is shown that ...

This paper deals with the propagation of magneto-thermo Rayleigh waves in a homogeneous viscoelastic half-space under initial stress. It has been observed that velocity of Rayleigh waves depends on viscosity, magnetic field, temperature and initial stress of the half-space. The frequency equation for Rayleigh waves under the effect of magnetic field, stress and temperature for both viscoelastic...

Recent years have seen increasing worldwide interest in the use of viscoelastic coagulation monitoring tests, performed using devices such as ROTEM and TEG. The use of such tests to guide haemostatic therapy may help reduce transfusion of allogeneic blood products in bleeding patients and is supported in European guidelines for managing trauma and severe perioperative bleeding. In addition, vis...

The adhesive performances of a PSA (Pressure Sensitive Adhesive) are attributed to their viscoelastic properties. In this paper we analyze the viscoelastic behavior of different PSAs having substantially similar adhesive performance. Linear and non linear analyses were performed using small amplitude oscillatory shear tests and tensile stress-strain tests, respectively. It is shown that linear ...

needle insertion is a minimally invasive technique in diagnosing and treating tumors. however, to perform a surgery accurately, the tissue should have minimum amount of displacement during needle insertion so that it reaches the target tissue. therefore, the tissue membrane has to move less to decrease rupturing under the membrane. in this study, the effect of different design parameters on dis...

In "imaging the biomechanical properties of tissues," a number of approaches analyze shear wave propagation initiated by a short radiation force push. Unfortunately, it has been experimentally observed that the displacement-versus-time curves for lossy tissues are rapidly damped and distorted in ways that can confound simple tracking approaches. This article addresses the propagation, decay and...