Recent progress in mid-range wireless power transfer

This is a review paper describing recent progress of mid-range applications of wireless power transfer. Starting from Tesla's principles of wireless power transfer a century ago, it outlines magneto-inductive research activities in the last decade on wireless power transfer with the transmission distance in the order of or greater than the coil dimension. It covers the basic characteristics of 2-coil systems, 4-coil systems, systems with relay resonators and the wireless domino-resonator systems. © 2012 IEEE.published_or_final_versio

Load monitoring and output power control of a wireless power transfer system without any wireless communication feedback

For mid-range wireless power applications, the load is normally far away from the power source. In this project, a new method is proposed to determine the load impedance and load power without using any direct output feedback. Based only on the information of the input voltage and current, the load impedance and load power can be monitored and controlled without using any wired or wireless feedback from the load. This new method can therefore eliminate the need for any directly measured output feedback, which was previously thought to be essential. It also makes the power control of a wireless power transfer very simple. The concept is verified by the comparison between the computed results and practical results of an 8-ring domino wireless power transfer system. A good degree of accuracy has been achieved in the verification. 2013 IEEE.published_or_final_versio

Low-power wind energy conversion system with variable structure control for DC grids

This paper presents a discussion on the use of variable structure control, i.e., sliding mode control, for improving the dynamic control performance of a low-power wind energy conversion system (WECS) that is connected to a DC microgrid. The sliding mode control is applied to the wind turbine system to extract the maximum possible power from the wind, thus achieving the state of maximum power point tracking to reach the maximum power generation (MPG), and also applied to the power converter to reach the maximum power injection (MPI) to the load. The amount of energy extractable from a dynamically changing wind using the WECS with sliding mode control is compared with that of the classic PI controller. Simulation results show that for a dynamically changing wind, more energy can be harvested with the sliding mode control as compared to the PI control. © 2014 IEEE.published_or_final_versio

Observation of enhanced visible and infrared emissions in photonic crystal thin-film light-emitting diodes

Photonic crystals, in the form of closed-packed nano-pillar arrays patterned by nanosphere lithography, have been formed on the n-faces of InGaN thin-film vertical light-emitting diodes (LEDs). Through laser lift-off of the sapphire substrate, the thin-film LEDs conduct vertically with reduced dynamic resistances, as well as reduced thermal resistances. The photonic crystal plays a role in enhancing light extraction, not only at visible wavelengths but also at infrared wavelengths boosting heat radiation at high currents, so that heat-induced effects on internal quantum efficiencies are minimized. The observations are consistent with predictions from finite-difference time-domain simulations. © 2014 AIP Publishing LLC.published_or_final_versio

Monitoring of multiple loads in wireless power transfer systems without direct output feedback

In this paper, a computational method that uses only the input voltage and current to identify the impedances of multiple loads in wireless power transfer systems without any direct load measurements is proposed. The method has been practically realized in a wireless power domino-resonator system comprising 8 resonators. A good degree of accuracy has been achieved in the practical verification. Although the method is demonstrated in a relatively complex system, the principle applies to any wireless power transfer system with 3 or more coil-resonators. Without the requirements for direct load measurements, control circuitry of a wireless power transfer system with multiple loads can avoid the needs for using wireless communication system for feedback purposes. © 2014 IEEE.published_or_final_versio

A new algorithm for instantaneous speed and position estimation of surface-mounted permanent magnet synchronous motors

Session 5-5: Motor Drives II: paper 5-5-1This paper describes a patent-pending method that can be used to estimate the speed and position of surface-mounted permanent magnet synchronous motors (SMPMSM) with cylindrical rotor structure and sinusoidal back emf. The concept involves the use of the power inverter's switching actions and switching current to provide instantaneous real-time information for extracting the speed information. The theory and algorithm are included to explain the proposed concept, which has been verified by simulations on a SMPMSM drive under the control of a sensorless speed control scheme. © 2013 IEEE.published_or_final_versio

Avaliação de Metais Traço no Sedimento do Sistema Estuarino dos Rios Piraquê-açu e Piraquê-mirim (Aracruz-ES)

Aguardand

ESTUDO SOBRE CARACTERÍSTICAS GENÉTICAS DE Mycobacterium tuberculosis ISOLADO DE PACIENTES COM E SEM LESÕES CAVITÁRIAS.

Introdução: Baseado na hipótese de que a variabilidade genética de Mycobacterium tuberculosis (MTB) pode influenciar a virulência e a gravidade da doença os perfis genéticos de isolados clínicos de MTB foram avaliados para detectar associação entre diversidade genética e gravidade da doença. Objetivos: Analisar características genéticas de isolados de MTB e verificar sua possível associação com a gravidade da TB pulmonar. Métodos: Estudo retrospectivo, caso controle, conduzido em Vitória-ES, utilizando isolados de MTB (2003 a 2006, n=214) de pacientes com TB pulmonar, cavitária (127) e não cavitária (87). Realizou-se genotipagem por meio de RFLP-IS6110, Spoligotyping, MIRU-VNTR 24 loci, e a análise de deleções e inserções, como RDRio, RD174 utilizando PCR multiplex, bem como a detecção do Ag85C103. Realizou-se análise estatística, para verificação dos padrões de distribuição das variáveis, seguida de análises bivariadas para verificação de associações entre elas, empregando-se os teste exato de Fisher ou Chi-quadrado, ambos com 95% de intervalo de confiança e nível de significância (&#61554;) < 0,05. Resultados: Após a regressão logística, as variáveis que contribuíram no modelo explicativo da doença foram baciloscopia (ORajust = 5,96; IC= 2,58-13,73) e produção de escarro (ORajust = 4,55; IC= 1,28-16,12). Não houve associação estatisticamente significativa com o restante das variáveis.A família LAM foi a mais frequente entre os dois grupos analisados, representando 65 (62%) dos isolados no grupo cavitário e 40 isolados (38%) do grupo não cavitário. Não houve diferença estatisticamente significativa entre os grupos em relação à deleção RDRio (p=0,65) e com relação à deleção RD174 (p=0,65). Dentre os 205 isolados analisados, 25 (12%) isolados do grupo não cavitário e 43 (21%) do grupo cavitário, estavam em cluster. não houve diferença estatisticamente significativa entre a quantidade de clusters e os grupos analisados (p= 0,4). Conclusões: Foi determinado o perfil genotípico dos isolados de pacientes com doença pulmonar, cavitária e não cavitária. Não houve associação entre a presença de cavidade e os genótipos encontrados. Não houve associação do genótipo com nenhum dos marcadores moleculares avaliados. Palavras Chaves: Mycobacterium tuberculosis, genotipagem molecular, RFLP- IS6110, MIRU-VNTR 24 loci , Spoligotyping

NO COTIDIANO DA INOVAÇÃO E A INOVAÇÃO NO COTIDIANO DA PRÁTICA PEDAGÓGICA EM EDUCAÇÃO FÍSICA

NO COTIDIANO DA INOVAÇÃO E A INOVAÇÃO NO COTIDIANO DA PRÁTICA PEDAGÓGICA EM EDUCAÇÃO FÍSIC

Recent Developments of Planar Printed Circuit Board (PCB) Transformer Technology

Rapid developments of planar magnetics in recent years have prompted new applications of planar transformers in electronic industry. The low-profile features of planar magentics make them attractive in many electronic systems that have stringent thickness requirements. In this article, some recent progress of planar PCB transformers and their applications are described. Comparisons of conventional and planar transformers are reviewed. New trend of integrated electronic packaging in power electronic systems is briefly discussed.link_to_subscribed_fulltex