Modelling and Analysis of Bidirectional DC-DC Converter

Bidirectional dc-dc converters are used lots of industrial areas such as electric vehicles, uninterruptable power supplies, fuel cells, solar panel cells as energy sources are searched in order to improve the quality of power at the transmission, distribution lines and other areas. The main contribution of this paper, applying the most common used control method on single phase isolated bidirectional full bridge dc-dc converter and comparing this control method (Extended Phase Shift – EPS) on efficiency way by with/without using snubber capacitors. In this paper, Isolated Bidirectional DC-DC Converter topology is modelled and controller algorithm is written by FORTRAN programming language. According to the results, it is observed that efficiency result of the converter, using snubber capacitors in the converter topology has higher performance than the snubberless system

Experimental study on the velocity limits of magnetized rotating plasmas

An experimental study on the physical limits of the rotation velocity of magnetized plasmas is presented. Experiments are performed in the Maryland Centrifugal Experiment (MCX) [R. F. Ellis , Phys. Plasmas 12, 055704 (2005)], a mirror magnetic field plasma rotating azimuthally. The externally applied parameters that control the plasma characteristics-applied voltage, external magnetic field, and fill pressure-are scanned across the entire available range of values. It is found that the plasma rotation velocity does not exceed the Alfven velocity, in agreement with the equilibrium requirements of magnetically confined plasmas. Measured rotation velocities are also lower than the critical ionization velocity in hydrogen, but a strict limit was not observable within MCX parametric capabilities. (c) 2008 American Institute of Physics

Hydrography and circulation in the Filchner Depression, Weddell Sea, Antarctica

Cold and dense ice shelf water (ISW) emerging from the Filchner-Ronne Ice Shelf cavity in the southwestern Weddell Sea flows northward through the Filchner Depression to eventually descend the con- tinental slope and contribute to the formation of bottom water. New ship-born observations of hydrogra- phy and currents from Filchner Depression in January 2013 suggest that the northward flow of ISW takes place in a middepth jet along the eastern flank of the depression, thus questioning the traditional view with outflow along the western flank. This interpretation of the data is supported by results from a regional numerical model, which shows that ISW flowing northward along the eastern coast of Berkner Island turns eastward and crosses the depression to its eastern side upon reaching the Filchner ice front. The ice front represents a sudden change in the thickness of the water column and thus a potential vorticity barrier. Transport estimates of northward ISW flux based on observations ranges from 0.2 to 1.0 Sv.publishedVersio

Tissue multifractality and Born approximation in analysis of light scattering: a novel approach for precancers detection

Multifractal, a special class of complex self-affine processes, are under recent intensive investigations because of their fundamental nature and potential applications in diverse physical systems. Here, we report on a novel light scattering-based inverse method for extraction/quantification of multifractality in the spatial distribution of refractive index of biological tissues. The method is based on Fourier domain pre-processing via the Born approximation, followed by the Multifractal Detrended Fluctuation Analysis. The approach is experimentally validated in synthetic multifractal scattering phantoms, and tested on biopsy tissue slices. The derived multifractal properties appear sensitive in detecting cervical precancerous alterations through an increase of multifractality with pathology progression, demonstrating the potential of the developed methodology for novel precancer biomarker identification and tissue diagnostic tool. The novel ability to delineate the multifractal optical properties from light scattering signals may also prove useful for characterizing a wide variety of complex scattering media of non-biological origin

Solving variational inequalities defined on a domain with infinitely many linear constraints

We study a variational inequality problem whose domain is defined by infinitely many linear inequalities. A discretization method and an analytic center based inexact cutting plane method are proposed. Under proper assumptions, the convergence results for both methods are given. We also provide numerical examples to illustrate the proposed method