Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0) and a high (g0) fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0). Using a comparative anatomical approach for revealing macroscopic stru...

We derive the high frequency limit of the Helmholtz equation with source term when the source is the sum of two point sources. We study it in terms of Wigner measures (quadratic observables). We prove that the Wigner measure associated with the solution satisfies a Liouville equation with, as source term, the sum of the source terms that would be created by each of the two point sources taken s...

The high-power generation capability of pulsed mode Silicon Double Drift Region (DDR) IMPATT devices has been studied by using generalized simulation software developed by the authors. The software is based on drift-diffusion modeling scheme, incorporating thermal design. After optimization of the device design, it is observed that a maximum efficiency of 9% with an output power of 15W can be a...

The paper presents soft switching PWM DC-DC converters using power MOSFETs and IGBTs. The attention is focused mainly on the full-bridge converters suitable for high power applications. The properties of the PWM converters are described in comparison to other categories of soft switching converters. An overview of the switching techniques using in the DC-DC converters is included. Consideration...

Elastohydrodynamically lubricated (EHL) contacts are fundamental for several rotating machine elements. For example gears, rolling element bearings and lubricated chain drives work due to the principle of EHL. All of these machine elements require maintenance and, as condition based maintenance has increased in industry, the need for monitoring techniques has also increased. In order to avoid i...

introduction. the professional education can be a very stressful experience. the high level of stress often leads to disruptions in physiological and psychological health. although a moderate degree of stress can promote students’ creativity and achievement, the intense pressures and relentless demands of medical education may destroy personal relationship and ultimately, affect patient care. t...