Current Issue : April - June Volume : 2019 Issue Number : 2 Articles : 5 Articles
A new prototype of a tomographic system for microwave imaging is presented in this paper.\nThe target being tested is surrounded by an ad-hoc 3D-printed structure, which supports sixteen custom\nantenna elements. The transmission measurements between each pair of antennas are acquired through\na vector network analyzer connected to a modular switching matrix. The collected data are inverted\nby a hybrid nonlinear procedure combining qualitative and quantitative reconstruction algorithms.\nPreliminary experimental results, showing the capabilities of the developed system, are reported....
The ubiquitous diffusion of Power Electronic Converters (PECs) in many fields of\napplication including traction and energy conversion suggests the possibility of new and better\nintegration of advanced power conversion and Information and Communication Technology (ICT)\nservices. This work investigates the possible advancements in the use of optical communication\nlinks made of plastic optical fibers for control of PECs. The optical communication link connects the\nswitching control to the converter control, following the line of separation between the expertise\nof power electronic and control engineers. Control wise, a PEC is a black box compatible with\nany off-board controller, now immune from the Electromagnetic Interference (EMI) produced by\nthe power switches. The redundant optical link is ready for the high switching and sampling\nfrequencies, made possible by relying on SiC power semiconductor devices (100+ kHz). Distributed\ncontrol of multiple PEC units and advanced telemetry for diagnostics and prognostics are targeted.\nA proof-of-concept demonstrator is presented and tested. Moreover, the possible evolution towards\na power electronic cloud with remote management and orchestration is described....
The aim of this study is to investigate the helix angle effect on the helical gear\nload carrying capacity, including the bending and contact load carrying capacity.\nDuring the simulation, the transverse contact ratio is calculated with\nrespect to the constant pressure angle. By changing the helix angle, both the\noverlap contact ratio and total contact ratio are calculated and simulated. The\nbending stress and contact stress of a helical gear are calculated and simulated\nwith respect to the helix angle. Solid (CAD) modelling of a pinion gear was\nobtained using SOLIDWORKS software. The analytically obtained results and\nfinite elements method results are compared. It is observed that increasing\nthe helix angle causes an increase of the contact ratio of the helical gear. Furthermore,\nincreasing the contact ratio reduces the bending stress and contact\nstress of the helical gear. However, with a constant transverse contact ratio, it\nis possible to improve the total contact ratio depending on the helix angle. It\nis concluded that a higher helix angle increases the helical gear bending and\ncontact load carrying capacity....
Based on a cosmological model without singularity, a possible structure of the\nuniverse is presented. It is proved that there must simultaneously be two sorts\nof symmetry breaking in the universe. The universe is composed of infinite\ns-cosmic islands, infinite v-cosmic islands and infinite transition zone. The\nexisting and changing forms of the cosmic islands must be diverse. The cosmological\nprinciple holds only approximately within a cosmic island. No information\ncan be exchanged between an s-cosmic island and an adjacent\nv-cosmic island so that every observer thinks his cosmic island to be the\nwhole universe. It is possible that some cosmic islands are contracting, some\ncosmic islands are expanding, and other cosmic islands are stable for a time.\nBut the universe as a whole is always invariable and contains all possible existing\nforms of matter. To give a possible explanation for orphan quasars. To\npredict some characteristics of contracting large and huge black holes in a\ncosmic island. The characteristics of the light coming from the contracting\nhuge black holes are that the intensity of the light is huge relatively to their\ndistance, the red shifts are huge, the distribution of the huge red shifts and the\norphan quasars are anisotropic, and luminescence spectrum is very wide....
This study investigated the interactive effects of Hepatitis C virus on human cells using the\ncontact angle approach. The methodology involves the use of sessile drop approach to determine\nthe contact angle formed on the infected and uninfected blood cells in the presences\nof glycerin as the probe liquid. It was observed that the presence of the virus in the human\nblood cells depleted the immune system of infected cells giving rise to a decreased CD4\ncount on the average of.............
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