During the past few decades, a significant amount of research has been conducted in the area of non-destructive damage evaluation (NDE) based on changes in dynamic properties of a structure. System Identification and damage detection plays a crucial role in structural dynamics and vibro-acoustic system optimization. The later approach is based on the ‘Modal Analysis” The dynamic behaviors of th...

Traditional treatment beams for non-small-cell lung cancer are limited to the axial plane. For many tumor geometries, non-axial orientations appear to reduce the dose to normal tissues (e.g. heart, liver). We hypothesize that non-axial beams provide a significant reduction in incidental irradiation of the heart and liver, while maintaining adequate target coverage. CT scans of twenty-four patie...

Modern dual photon energy linear accelerators often come with a few megavoltage electron beams. The megavoltage electron beam has limited range and relative sharp distal falloff in its depth dose curve compared to that of megavoltage photon beam. Its radiation dose is often delivered appositionally to cover the target volume to its distal 90% depth dose (d90), while avoiding the normal--sometim...

We consider a mathematical model of a linear vibrational system described by the second-order system of differential equations Mẍ +Dẋ+Kx = 0, where M, K and D are positive definite matrices, called mass, stiffness and damping, respectively. We are interested in finding an optimal damping matrix which will damp a certain part of the undamped eigenfrequencies. For this we use a minimization crite...

We describe a new class of propagation-invariant light beams with Fourier transform given by an eigenfunction of the quantum mechanical pendulum. These beams, whose spectra (restricted to a circle) are doubly periodic Mathieu functions in azimuth, depend on a field strength parameter. When the parameter is zero, pendulum beams are Bessel beams, and as the parameter approaches infinity, they res...

there are several techniques in use for non-linear refractive index measurement, namely, interferometric techniques, in which conventional inter-ferometers are used, degenerate for wave mixing (dfwm), and z-scan, each of these techniques suffers from some shortcmings. for example conventional interferometers like fabry-perot and twyman-green need high quality optical components, unwanted reflec...

Piecewise-linear oscillators are often considered as finite degrees-of-freedom models of cracked elastic structures [1-3] but may also represent specifics of original systems. In many cases, the corresponding periodic solutions combine different pieces of linear solutions valid for two different subspaces of the configuration space [4,5]. It is always preferable though to deal with closed form ...

A new result enables direct calculation of thermoelastic damping in vibrating elastic solids. The mechanism for energy loss is thermal diffusion caused by inhomogeneous deformation, flexure in thin plates. The general result is combined with the Kirchhoff assumption to obtain a new equation for the flexural vibration of thin plates incorporating thermoelastic loss as a damping term. The thermal...