Comportamento dinâmico não-linear em fenômenos de colheita de energia usando dispositivos baseados em materiais piezoelétricos em estruturas aporticadas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento de dispositivos eletrônico-orgânicos e sua aplicação como sensores em meio aquoso

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Análise dos processos de infiltração, percolação, retenção e evaporação em solos arenoso e residuais utilizando lisímetro

The mobility of water in the soil is a difficult process to be quantified. During precipitation, there is a portion of the water that infiltrates, which is very important for recovering the groundwater balance. This work studies the mobility of water in sandy soils with different textures and residual soils through experiments mounted in lysimeters. The lysimeters were mounted on acrylic cylinder with 11.3 cm diameter and 25.0 cm in length. The sand was deposited using the process sand rain. In the tests it was maintained a hydraulic head of two centimeters above the surface with the aid of a Mariotte flask. The portions of water were controlled in the experiments using relations between weight and volume measurements over time. The data were obtained by monitoring the input and output volumes of water through calibrated reservoir and system weight by an electronic balance. The infiltration front was monitored with the aid of a digital camera. The results indicate that the smaller the particle size of the sand, the lower the speed of the saturation front, the higher the retained volume, the smaller the basic rate of infiltration and the lowest speed of percolation. Moreover, the rate of water loss in the evaporation process indicated no significant difference with variation of the particle size of the samples

Desenvolvimento de objeto de aprendizagem para dispositivos móveis explorando os sensores internos do sistema operacional Android

The traditional model of teaching little is modernized in recent decades. When in contact with this system, it is normal that the new-generation students feel unmo tivated in carrying out the proposed activities in the classroom. Considers Prensky (2001) these students, called Digital Natives, born with a modern way of thinking and learn and feel encouraged and motivated with activities that invite to interact. For this reason, it has been proposed the development of an object of learning in the form of application for Android tablets, exploring the internal sensors available in them, with the purpose of offering an interactive activity to students on the physical concepts involved in the process of photosynthesis in plants. For the construction, informational texts written in didactic language and easy to understand, illustrative images and animations were employed. In addition, we used the light sensor in the interactive activity on the process of photosynthesis so that the student could observe and understand how the environment is able to interfere with this process

Avaliação da liberação, permeação e retenção na mucosa vaginal in vitro de formulação proposta para o tratamento da candidíase vaginal

A pesquisa de novas substâncias com atividade anti-Candida é importante devido à ocorrência de resistência por parte de algumas destas espécies aos antifúngicos usuais. Araújo e colaboradores (2009) comprovaram a atividade antifúngica do extrato de Syngonanthus nitens e torna-se relevante a proposta de formulações e o estudo destas. O objetivo geral deste trabalho foi a avaliação da liberação, permeação e retenção na mucosa vaginal in vitro de formulação (creme) contendo o extrato de Syngonanthus nitens, em comparação com outra formulação proposta (gel), para averiguar qual das formulações apresenta mais vantagens para o tratamento da candidíase. Foi validado um método analítico para quantificação do extrato de S. nitens por espectrofotômetro UV-VIS utilizando o padrão luteolina. Os parâmetros analíticos utilizados para avaliar a credibilidade do método analítico foram: seletividade e especificidade, linearidade, limite de quantificação, precisão, exatidão e robustez. O método analítico proposto mostrou-se satisfatório: apresentou seletividade e especificidade; linearidade (os pontos obtidos nas concentrações de 5 a 30 µg/mL apresentaram-se lineares e com um ótimo coeficiente de correlação linear: 0,99996); precisão e exatidão; robustez; e o limite de quantificação foi de 0,5 µg/mL, com coeficiente de variação menor que 5%. Além disso, foram realizados testes de estabilidade preliminar e estudos reológicos, e a formulação creme apresentou resultados adequados para o uso proposto e também apresentou estabilidade. Os ensaios de liberação demonstraram que ambas as formulações apresentam cinética de liberação conforme o modelo de Higuchi, ou seja, a velocidade de liberação do fármaco da matriz do sistema se dá por difusão controlada. Os resultados mostram que as duas formulações apresentam perfil de liberação muito... (Resumo completo, clicar acesso eletrônico abaixo)

Desenvolvimento de um sistema para caracterização de dispositivos eletroluminescentes

The materials designed to be used in electroluminescent (EL) devices construction are studied and improved since 1936. Great interests in the development of this kind of devices are mainly due to its low power consumption, flexibility, low cost and easy processing. One class of ELs devices with these characteristics are produced by employing a organic-polymeric/inorganic composite from a conductive polymer blend and an inorganic electroluminescent material (Zn2SiO4:Mn) dispersed in the polymeric matrix. This kind of device operates in d.c. or a.c. potentials, with EL of hundreds candela in the green region of the visible spectrum. However, few studies on the light emission were performed for these devices. In order to characterize devices made from composites, in this work is proposed a method of characterizing the electroluminescence associated with the impedance spectroscopy technique. To implement the technique of impedance spectroscopy was employ an experimental setup consisting of a source of a.c. voltage, an oscilloscope, and a reference resistor. Associated with this system, was use a photo diode and an analog electrometer to characterize the emitted light signal from the sample. The system was implemented allows characterization by impedance spectroscopy in the frequency range from 0.2 Hz up to 2 MHz and voltage amplitudes of 5 mV up to 20 kV. This system permits, at the same time, measurement of the RMS value of the luminance for devices in frequency range from 20 Hz up to 2 MHz. To test the system efficiency, an EL device was characterized showing analogous results to those reported in literature. By doing this, was demonstrated the efficiency of the system for electroluminescence characterization associated with the electrical characterization by impedance spectroscopy, for devices

Gerenciador de estudos para dispositivos móveis: aplicativo do aluno

The project is a platform for education that provides a way where teachers can create and share educational content for their classes, and students can download that content to refer to it at any time. The solution is based on two Windows Phone 7 Apps: Kookaburra Teachers, where teachers can add content to their classes, and Kookaburra Students, where students can download and view the content of classroom. To realize the communication between these two applications, we use a Windows Azure server, that server is also responsible for processing some conversions, enabling real-time translation. In addition to storing all the content that is generated during the lessons

Equações de taxa aplicadas na modelagem de dispositivos fotodetectores baseados em poços quânticos

In this work, it is presented a novel method for calculating some intrinsic parameters such as capture mean time, thermic emission mean time, capture probability and noise gain on quantum well infrared photodetectors. Such devices are built by depositing layers of semiconductors of different energy gap, forming quantum wells. The present method uses rate equations to describe the occupation of discrete states of the quantum wells, that together with noise gain equations given in literature, are solved self consistently. The input data of the method is experimental measurement of dark current (current measured with no relevant incident photon) versus applied bias. In order to validate this approach, the values obtained were compared with results from literature

Colheita de energia usando dispositivos baseados em materiais piezoelétrico

Recently, research on energy harvesting has increased substantially. Many researchers have concentrated their efforts to find the best configuration for these systems and to optimize their output power. In the process of energy harvesting, the electric energy is obtained by converting mechanics energy created by an environment vibration source by a transducer, for example, a thin piezoceramic film. That vibration source is, for example, a beam suffering some mechanic force able to generate a vibration in it, an oscillating beam is the best properly used example. Different mechanisms of electromechanical coupling have been developed to harvesting devices, and a particular interest has been given to the use of models that transform the mechanical vibration into electrical current using a piezoelectric element. In this paper we propose a model to energy harvesting from vibrations, from an oscillating beam, including non-linearities in the piezoelectric coupling and a non-ideal excitation in the material. From this model, it was developed a system to obtain some results about the harvested power by the material. It was demonstrated that the power captured was influenced by the effect of the nonlinearities of the piezoelectric coupling, modifying the system dynamic behavior

Análise do nível de retenção de aprendizagem de idosos em relação aos socorros de urgência

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Caracterização e aplicação da Blenda PEDOT : PSS/PVA na construção de eletrodos transparentes e dispositivos eletroluminescentes

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da quantidade de dentifrício e concentração de fluoreto na retenção intrabucal de fluoreto em crianças

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Síntese de 14-aril-14h-dibenzol[a,j]xantenos e 4-aril-3,4-di-hidrobenzo[f]cumarinas promovida pelo pentacloreto de nióbio, com potencial aplicação na preparação de corantes sensibilizadores para utilização em dispositivos de Grätzel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Entre o corpo e a escola: estudo sobre alguns dispositivos de colonização

We present some results of our studies on the relationship between educational processes and subjective processes. The object of our research is the body inserted in the school context in which we analyze tenderness as a field colonized by the dynamics of power. We have observed in the educational process both signs of capture as well as rupture facing the mechanisms of control coming from the market. We identified the implications of the body in the educational process in order to propose the aesthetic paradigm as a reference for educational action.

Alternativa de tratamento simplificado e integrado da retenção intraóssea de incisivo central superior, associada a odontoma: relato de caso

Permanent teeth impaction is highly prevalent among brazilian people. Its etiology is related to local and general factors association. Permanent teeth retention compromises dental occlusion and when anterior teeth are involved, it also brings esthetics impairments which lead to psychological disturbance. Early diagnosis and adequate treatment are extremely important to solve not only occlusal problems but also psychological aspects. Orthodontic traction of impacted teeth can be conducted by using fixed or removable appliances. Although it depends on patient compliance the use of removable appliances provides an anchorage based on the teeth and the palate reducing undesirable side effects. This paper describes the case of a fourteen years old female patient whose right maxillary central incisor was adequately tractioned with a removable orthodontic appliance. Removable orthodontic devices were used at first to reposition teeth in maxillary anterior area what provided adequate space to allow the placement of the impacted incisor and after were also used to traction and position this tooth. The procedure described seemed to be effective, non expensive and a viable treatment to be performed even on the scope of public health services, extending orthodontic treatment to a higher number of patients.