972 resultados para Thermodynamics
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This work research and analyses the formulations and concepts of heat and temperature presented in Physics textbooks. These issues are deemed important because students often have difficulties differentiating and understanding such concepts, which compromises their education. The goal is to show that well-established relationships between Physical quantities such as energy, pressure, heat and temperature, even in different theories of Classical and Quantum Physics are not enough to define either temperature or heat. It also presents simple experiments that complement the teaching and learning of these concepts
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The technological advances of recent decades combined with digital inc1usion in Brazil sparked the country's population to the constant use of computers to perform tasks in many different natures. Whether it's for communication, entertainment, work or school, computers are tools with increasing numbers in Brazilian homes. Along with this evolution the Brazilian Physics teaching should be aware of the use of teaching tools that relate directly to the computer to student learning. Highlighting in this work we have scanned the contents of the Wikipedia community, a wide variety of educational videos placed on YouTube, educational games that try to teach the player in a fun way and a variety educational softwares placed on the World Wide Web. It is with special attention to educational softwares as tools for teaching physics, which describe some strategies for use of these software, combined with the textbooks, to illustrate some ways to introduce the use of educational softwares directly in the classroom
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The reason of this work is perform a study about using of electrical energy to identify the opportunities through rational use of electrical energy. For that it was necessary perform an analysis of hired energy against consumption. Based in a guide of energy analysis were found the main consumers and verified the main problems, which generate excessive use of electrical energy in a plastic injection factory. It was also analyzed the painting line because there are some thermal equipment that use electrical energy. Based on the data obtained will be proposed ways to reduce the needless consumption and energy use of rationally and efficiently, in addition to re-evaluate the contracted demand based on the new policy of supplying and charging.It were also proposed thermodynamics solutions to reduce the energy consumed in thermal process
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Química - IBILCE
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Microemulsions of hexadecyltrimethylammonium bromide (HTAB)/n-butanol/hexadecane/water catalyze the intramolecular degradation of cephaclor. The rate increase is a sensitive function of the microemulsion volume fraction and salt concentration. The effects of microemulsions, analyzed quantitatively using a pseudophase ion-exchange model, assumed that the extent of ion dissociation from the microemulsions varies with volume fraction. Comparison of micellar and microemulsion effects on the same reaction shows that microemulsions are less effective catalysts. Acceleration decreased significantly by increasing the relative proportion of n-butanol ratio in microemulsions and by addition of n-butanol in HTAB micelles. Comparison of the activation parameters of the reaction in aqueous solution, microemulsions, and micelles suggests that catalysis by both aggregates is driven mainly by entropic contributions.
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An electrical model able to decouple the electron pathway from microbial cell machinery impedance terms is introduced. In this context, capacitance characteristics of the biofilm are clearly resolved. In other words, the model allows separating, according to the advantage of frequency and spectroscopic response approach, the different terms controlling the performance of the microbial biofilm respiratory process and thus the directly related electricity production process. The model can be accurately fitted to voltammetry measurements obtained under steady-state conditions and also to biofilm discharge amperometric measurements. The implications of biological aspects of the electrochemical or redox capacitance are discussed theoretically in the context of current knowledge with regard to structure and physiological activity of microbial Geobacter biofilms.
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Pós-graduação em Engenharia Mecânica - FEG
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The conditions under which cosmologies driven by time-varying cosmological terms can be described by a scalar field coupled to a perfect fluid are discussed. An algorithm to reconstruct potentials dynamically and thermodynamically analogous to given phenomenological λ models is presented. As a working example, the deflationary cosmology which evolves from a pure de Sitter vacuum state to a slightly modified Friedmann-Robertson-Walker cosmology is considered. It is found that this is an example of nonsingular warm inflation with an asymptotic exponential potential. Differences with respect to other scalar field descriptions of decaying vacuum cosmologies are addressed and possible extensions are indicated.
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Pós-graduação em Física - IGCE
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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The objective of this paper is to realize the preliminary cogeneration project, to be applied on the output of a float glass furnace, aiming the energetic use of the furnace's by-products in other relevant applications on the site. It was analyzed the main points where the cycle could be installed and also the available technologies to energy recovery. After, it was chosen the installation point and the technology to be projected, evaluated the electric power generated and the cycle efficiency. Finally it was evaluated economical indicators in order to verify the project's economical feasibility
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The objective of this paper is to realize the preliminary cogeneration project, to be applied on the output of a float glass furnace, aiming the energetic use of the furnace's by-products in other relevant applications on the site. It was analyzed the main points where the cycle could be installed and also the available technologies to energy recovery. After, it was chosen the installation point and the technology to be projected, evaluated the electric power generated and the cycle efficiency. Finally it was evaluated economical indicators in order to verify the project's economical feasibility