182 resultados para Eletronica
Resumo:
The increasing demand for electro-electronic devices, with high performance and multi-functional and the rapid advances of the nanotechnology require the development of new methods and techniques for the production and characterization of nanostructure materials and phenomenological models to describe/to predict some of its properties. The demand for multifunctionality requires, at least, new materials, that can integrate ferroelectric and magnetic properties of high technological interest. Inside of this context, multiferroics material can be considered suitable to integrate two or more physical properties of high technological interest. It can also provides new challenges in the processes of synthesis of new materials, and development of new devices with controlling and simulation of its physical properties and modeling. For this Calcium (Ca)-doped bismuth ferrite (BiFeO3) thin films prepared by using the polymeric precursor method (PPM) were characterized by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), polarization and piezoelectric measurements.In order to study the behavior and determine which are the most important parameters to achieve the optimal property to be applied to a multiferroic materials
Resumo:
In this work is studied the fluid dynamic characteristics of sugarcane bagasse for gasification applications and use of syngas in the sugarcane sector. This is an experimental work, which is initially performed the particle size separation of sugarcane bagasse particles, using appropriate equipment. Through the experiment is possible to determine the average diameter of particles pomace typical sugarcane mill. The equipment used for the grading sieve separation assembly consists of several dimensions, arranged vertically and which shows adequate for good separation from the pulp. Later, it makes immediate analysis for the determination of moisture, ash, volatile materials and fixed carbon. The study also determines the gross calorific value and allows analysis of densities of particles of sugar cane bagasse. Also studied the bagasse morphology using electron microscopes, where it was possible to visualize the geometry of the particles of bagasse. The use of Electronic Scanning Microscopy (SEM) provided better understand the morphology and particle size measured by using photography methods. Two methods for determining the sphericity of the particles were also used. The experiments carried out using appropriate standards and specific equations, allowing compare the present results with the values found by several researchers. Subsequently, fluid dynamic simulations were performed for the determination of porosity and minimum fluidization velocity theoretical. It follows that the sphericity and porosity of the bagasse particles influence the minimum fluidization velocity of biomass
Resumo:
This work deals with the development of a switched-mode power supply circuit based on a Buck topology converter with a Boost Rectifier One-Cycle Control with Power Factor Correction developing, thus, a source of direct current for a module of 50 power LEDs that will be used in a lamp for public street lightning. It is presented, at first, some aspects about the most common technologies used in lamps of public street lightning in Brazil and a comparison with the White LED high power, which is the one that presents itself as the most promising among the existing market. Then it is presented the detailed development of the static converter switched PWM, consisting of a Boost rectifier with power factor correction and methodology of control One-Cycle Control associated with a Buck converter controlled by a PI method that operates as a direct current source . At the end of the simulation results of the circuit through the PSIM software are presented to verify the design behavior
Resumo:
Pós-graduação em Engenharia Mecânica - FEG
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Pós-graduação em Engenharia Mecânica - FEG
Resumo:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Resumo:
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Resumo:
In this work, RVC samples were treated by plasma immersion ion implantation (PIII) for electrodes production. High-voltage pulses with amplitudes of -3.0 kV or -10.0 kV were applied to the RVC samples while the treatment time was 10, 20 and 30 minutes. Nitrogen, atmospheric air and H2:N2 mixture were employed as plasma sources. The samples were characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The SEM images present an apparent enhancement of the surface roughness after the treatment probably due to the surface sputtering during the PIII process. This observation is in agreement with the specific electrochemical surface area (SESA) of RVC electrodes. An increase was observed of the SESA values for the PIII treated samples compared to the untreated specimen. Some oxygen and nitrogen containing groups were introduced on the RVC surface after the PIII treatment. Both plasma-induced process: the surface roughening and the introduction of the polar species on the RVC surface are beneficial for the RVC electrodes application
Resumo:
This project developed microstructural characterization technics of commercial dualphase and multi-phasic (TRIP) steels that were provided by the automotive industry and are currently used as the raw material for the production of automobiles. Inserted in this context, there is the development of the advanced high strength steels in consonance with the ULSABAVC project, which aims the production of safe, economically viable and efficient in terms of fuel consumption vehicles for the 21st century. The micro-structural characterization of biphasic and multiphase steels was done by the identification and quantification of the coexistent phases. In this item, a special attention was given to the technics that were performed using optic microscopy and scanning electron microscopy. An important contribution to this work was the utilization of different alternative chemical reagents (Beraha, Heat-Tinting technics) in addition to the classical ones (Nital and LePera)already used conventionally by the UNESP's Group of Mechanical, Microstructural and Fractografic Characterization of Materials. The revealed microstructures were correlated with the materials' mechanical properties determined through traction tests, such as ultimate tensile strengths, yield strength and stretching important since the material has structural application in the automotive industry. As a result, it was observed the superiority concerning the studied mechanical properties for the biphasic and multiphasic steels when compared to the conventional carbon steels. Besides, it was perceived a large potential for the industrial scale utilization of the Heat Tinting technics in this field, seen its differentiation of the existent phases and easy reproducibility
Resumo:
Pós-graduação em Engenharia Elétrica - FEIS
Resumo:
This article presents a reflection on the historical aspects and legislation on Distance Learning (DL). For this, a bibliographic and documentary research was performed with the goal of raising the necessary notes for discussion. The text begins with the characterization of the current society, the Information Society, which supports the modern distance education, which uses information and communication technologies (ICTs) to establish the process of learning teaching. Five stages of the EAD are identified. Later, the Brazilian legislation concerning the DL is punctuated, starting with the passage by Article 80 of the Guidelines and Bases Law-LBD (Law 9394/96) along with the critical analysis of Decree 5,622/05. Finally, in the final considerations is discussed the negative image that the DL carries by the Brazilian population and obstacles in the existing rules that hinder the democratization of access to education that aims DL.
Resumo:
The presented article discuss theoretical context and the practical impact reported in the bibliography about Continued Progression at São Paulo State schools. Such proceeding, oriented through Law of Basic Guidelines, LBG, from 1996, previses a restructuring in the Basic Education at the schools, primarily with respect to evaluations. Grades are replaced for cycles and reprobation only can happen if the student exceeds the limit of stated absences or for lowered acting at final of each cycle. The impact of educational public policy drafted through Continued Progression provoke transformations that need more attention, indicating a path of reflection turned to structural conditions in order that school offers the required reinforcement to students and assure quality education. It’s primordial understand, therefore, the endogenous and exogenous factors that leaded to adoption of such proceeding in the São Paulo State.
Resumo:
The main objective of this paper is to realize a review of literature about use of Interactive Digital Whiteboard, as a tool for improving the quality of education. We intend to show some results already reported in several studies in this area, and thus contribute to the systematization of knowledge about this resource. We found that the positive impacts of digital interactive whiteboards are specific and depend on the model followed in its implementation. Although the literature on this technology still emerging, there is evidences of good practice and positive results in all areas of the curriculum. The outcome of this research shows that to get potential benefits of digital whiteboard will be necessary, at first, to understand the process implementation and appropriation. If hardware and software of Interactive Digital Whiteboard not available and adequately used all their potential benefits not will take effect.