Impact of tsunamis on wave energy converters

With an increasing emphasis on renewable energy resources, wave power technology is fast becoming a realistic solution. However, the recent tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed creating large destructive waves. The question posed here is whether a nearshore wave energy converter (WEC) could withstand the force of an incoming tsunami. WECs of this type are usually located close to the boundary of dominance between linear and non linear e ects. An analytical 3D model is developed within the framework of a linear theory and applied to an array of xed plates [1]. The time derivative of the velocity potential allows the hydrodynamic force to be calculated, and the hydrostatic force can be calculated from the di erence in free surface heights on either side of the device. Results show that the loading for a typical tsunami is invariant with depth and maximum loading is felt at the center of the plate. By comparison with the loading from a typical swell, it is shown that the maximum force of a tsunami on a nearshore WEC will be approximately one hundreth of the magnitude of a regular sea state. We therefore conclude that an array of WECs will withstand a tsunami. A preliminary study on the non linear e ects on nearshore WECs, in particular the e ects of a sloping sea bed and multiple waves, is attempted through a comparison between the velocities of resonant and non resonant states. If after the rst wave recedes the device is left on dry land, a second wave may act as a shock on the plate and do more damage than it would to a partially submerged device. This e ect is demonstrated using a two dimensional non linear shallow water solver,VOLNA [2]. It is believed that dangerous con gurations could be found with more detailed investigations

Multisoliton complexes in a sea of radiation modes

We derive exact analytical solutions describing multi-soliton complexes and their interactions on top of a multi-component background in media with self-focusing or self-defocusing Kerr-like nonlinearities. These results are illustrated by numerical examples which demonstrate soliton collisions and field decomposition between localized and radiation modes.Comment: 7 pages, 7 figure

Spirochetal Lipoproteins and Immune Evasion.

Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment

A scale to measure consumer’s engagement with social media brand-related content

The purpose of this study is to fill the gap in the literature concerning to the measurement of consumer’s engagement with social media brand-related content (hereafter, CESBC). We introduce empirical evidence for the development and measurement of CESBC scale. The scale is based on the consumer's online brand-related framework and comprises three dimensions: consumption, contribution, and creation. We used qualitative techniques to prepare an initial list of items and tested and validated the CESBC scale with confirmatory factor analysis (CFA). Results (n = 2252) confirmed the three-factor structure of the CESBC and indicated its good psychometric properties

Relation between the autocorrelation and Wigner functions

We show a simple mechanism to measure the Wigner function of a harmonic oscillator. For this system we also show that autocorrelation and Wigner functions are equivalent.Comment: Modified title and slightly modified version from the one publishe

Exact bidirectional X-wave solutions in fiber Bragg gratings

We find exact solutions describing bidirectional pulses propagating in fiber Bragg gratings. They are derived by solving the coupled-mode theory equations and are expressed in terms of products of modified Bessel functions with algebraic functions. Depending on the values of the two free parameters the general bidirectional X-wave solution can also take the form of a unidirectional pulse. We analyze the symmetries and the asymptotic properties of the solutions and also discuss about additional waveforms that are obtained by interference of more than one solutions. Depending on their parameters such pulses can create a sharp focus with high contrast