Efeito da época da queima na dinâmica de campo sujo de Cerrado

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Colunas de Winogradsky com águas contaminadas por petróleo e derivados monitoradas por ensaios ecotoxicológicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A germinação de espécies de Vellozia é afetada pelo fogo do cerrado?

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

Nanopartículas de Pd suportadas em compósitos óxido-carbono: influência das interações metal-suporte na oxidação de etanol em meio básico

Fuel cells powered directly with ethanol (Direct Ethanol Fuel Cell-DEFC) are very attractive for the possibility of using a renewable fuel in the generation of clean energy. However, it is still necessary to deepen the understanding of catalytic processes and their dependence on the catalytic properties. This work proposes to study the catalytic activity of ethanol oxidation in an alkaline medium of Pd nanoparticles supported in carbon oxide hybrids using various transition metal oxides (MoO3, TiO2, WO3 and ZrO2). The materials prepared were characterized by techniques such as X-ray diffraction, transmission electron microscopy (TEM) and X-ray dispersive spectroscopy (EDX) to verify the structure, the distribution of particles in the supports and the presence of Pd on particles oxide. Experiments of X-rays absorption spectroscopy were carried out using soft X-rays (SXS) to evaluate the changes in the electronic properties of the Pd particles caused by interactions with different oxides. Measurements of cyclic voltammetry and potential sweeps of adsorbed CO oxidation allowed evaluating general aspects of the catalysts' electrochemical behavior and determining the electrochemically active area thereof. The catalytic performances of ethanol oxidation in alkaline medium were evaluated by electrochemical techniques (potential scan and chronoamperometry), and showed an improvement in activity with the addition of oxides in material containing only carbon, which was most pronounced for the catalyst containing TiO2. This improvement was predominantly associated with the electronic effects caused by the interaction of Pd on the support, causing a vacancy in the 4d band of Pd which, in turn, produces variations in adsorption energies of the species...

Termometria em chamas utilizando a técnica de espalhamento Rayleigh

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estimativa do potencial de acréscimo da oferta de energia no setor sucroalcooleiro paulista a partir de cogeração e gaseificação do bagaço de cana-de-açúcar com utilização de ciclo combinado

This work evaluates the existing potential in the state of Sao Paulo for the generation of electrical energy using the sugar cane bagasse as fuel. As the bagasse is a by-product of the sugarcane and alcohol industry and it is produced in large scale in the country, mainly in the state of Sao Paulo, it is important to develop researches that aim the best utilization of this input. In order to determine its potential, at first, a study was conducted considering the utilization of the cogeneration, which is a common practice in the plants of the sector. However, it was concluded that the cogeneration could provide a higher quantity of energy if more modern technologies and more efficient processes were used. Another study to estimate the potential considered a system of gasification of the sugar cane bagasse integrated with the combined cycle (BIG/GTCC). It was concluded that this technology can provide a considerable increase in the electrical supply. In this work it was also developed an energetic study based on real data from a plant located in the state of Sao Paulo. A thermodynamic analysis was done in the existing equipment of the cogeneration section of the plant. And another analysis was done considering the implementation of the BIG/GTCC technology to the cogeneration system. Comparing the results of both settings, it was concluded that the utilization of the sugar cane bagasse integrated to a combined cycle increased considerably the efficiency in the generation of electricity of the plant, increasing more than six times its production capacity of electrical energy

Projeto de adaptação do sistema de injeção do túnel transônico para ensaios em bocais de foguete

In this work, the project of a new experimental facility to be installed at the Aerodynamics Division of the Institute of Aeronautics and Space is presented. This new facility will provide means to perform experimental campaigns to analyze the flow behavior at different rocket nozzle concepts using cold gas that will be obtained from a modification of the Pilot Transonic Wind Tunnel air system. The new installation will enable less expensive experiments in a more secure environment, since the cold gas experimental procedures do not demand fuel storage and burn and security procedures are much less severe. Furthermore, experiments can be carried with different types of sensors, commonly used in wind tunnel tests. Also, the optical access is facilitated enabling the use of optical techniques for the characterization of flow properties inside the nozzles, such as pressure and temperature sensitive painting. The full project design and the operation conditions will be showed, as also some technical considerations about the flor behavior in the facility

Utilização de trocadores de calor de placas em espiral em processos da indústria siderúrgica

Stricter environmental policies are shown necessary to ensure an effective pollutant emission control. It is expected for the present year of 2015, that Brazil will assume, at the 21th United Nation's Climate Change Conference (COP21), implementation of commitment to a low carbon economy. This positioning affects the industrial environment, so that is deemed necessary to search for new technologies, less aggressive to the environment, so the adequacies to the new emission policies do not cause a negative effect on production. Almost all of the processes performed in the steel industry demand burning fuel and, therefore, flue gases are sent to the atmosphere. In this present work is discussed the utilization of heat exchangers so, by recovering part of the available heat from the flue gases of certain industrial process, the combustion air is preheated. The combustion air preheat results in less energy requirement, i.e., less need of fuel consumption and, in addition, minor amount of pollutants to be emitted. Due to better fitting to the process, it is studied the utilization of spiral plate heat exchangers. The heat exchanger dimensioning is made by an iterative method implemented in the software Microsoft Excel. Subsequently are analyzed the gains in terms of process's thermal efficiency improvement and the percentage of fuel saving. The latter implies in reduction of the same percentage of greenhouse gases emission

Pesquisa, projeto e construção de um sistema de ignição sem distribuidor

This work intends to know the most types of ignition systems, studying its history, the way it works, applications and some examples. The assembly of a distributor less ignition system is also required. All vehicles powered by internal combustion engines need an ignition system that allows this engine to ignite the air-fuel mixture using its ignition system in the best possible manner. The main goal of an ignition system is to obtain a spark having enough energy to start the chemical reaction of the oxygen and the fuel. It took a study dealing with the various types of ignition systems since their creation at the beginning of the last century until 2015. The work starts studying the high tension magneto ignition system and later together with the low tension ignition system, going on with the conventional ignition system and finally accomplishing with the various types of electronic ignition systems. It was studied and implemented an electronic circuit to power a double spark ignition system also known as wasted spark ignition system. This circuit was assembled with an electric pulse generator and powered mechanically by a dc electric motor of the variable rpm type