99 resultados para 220106 Ondas de choque


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This work presents a partial analysis of the implementation of a didactic sequence aimed at undergraduate students of quantum chemistry. The sequence develops on some fundamental concepts to understand the behavior of the objects particles and waves in the doubleslit experiment. The analysis is based on the didactic transposition theory, proposed by Yves Chevallard, which allows reflection upon the scientific knowledge reorganized to be used in teaching contexts. Our interest in this study lays on the dynamics of transposition of knowledge-to-be-taught into knowledge-taught, particularly the importance of making concepts more comprehensible. Results showed that the communication of knowledge by the students is presented with interruptions, gaps and colloquial language. The analysis allowed the identification of needs and possibilities of learning, as well as a turn in the teacher practice, through a dynamic process of action and reflection.

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In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on condition. P. taeda L wood (43 years old trees) from Horto Florestal of Manduri (latitude 230 00’ south, longitude 400 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better ju regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, cons right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences between the velocity of stress waves at juvenile wood, mature wood and pith regions. Keywords: stress wave method, velocity 17 destrutivos de propagação da propagação de ondas de tensão em toras e madeira serrada de taeda L. Hernando Alfonso Lara Palma - Universidade Estadual Paulista Faculdade de Ciências Agronômicas – FCA/UNESP – Botucatu - SP, e-mail: awballarin@fca.unesp.br Luiz Antonio Vasques Hellmeister - Universidade Estadual Paulista - Faculdade de Arquitetura, FAAC/UNESP – Bauru - SP, e-mail: hellmeister@faac.unesp.br Este trabalho teve como objetivo analisar a influência do tipo de lenho, da posição da tora ao longo do fuste e das dimensões das peças desdobradas, na velocidade de as de tensão (Stress wave method), na condição de madeira verde. P. taeda L., originária de árvores de plantio do Horto Florestal de SP., com idade aproximada de 43 anos, pela facilidade de identificação dos anéis imento e demarcação das regiões de madeira adulta e madeira juvenil. Foram amostradas 6 árvores distintas, escolhidas ao acaso do talhão selecionado. De cada árvore foram retiradas 4 toras com comprimento de 2,5 m cada. Foram demarcadas nas toras a ha central (8 cm de espessura) e 4 tábuas laterais (espessura comercial de 2,5 cm), sendo duas à esquerda e duas à direita da prancha central. Foram avaliadas as relações existentes entre as velocidades de propagação das ondas de tensão na madeira íntegra (toras) e desdobrada (pranchas e tábuas), na condição de madeira verde, nas três regiões distintas do lenho: medula, madeira adulta e madeira juvenil. A análise comparativa dos resultados revelou a concordância entre as velocidades antes e após o desdobr madeira. Houve diferenciação estatisticamente significativa entre as velocidades de propagação das ondas de tensão nos lenhos adulto, juvenil e na medula. -destrutivos, método das ondas de tensão, Pinus taeda stress wave tests on green logs and lumber of Pinus taeda In this paper it was evaluated the influence of the relative position of logs on the trees, the type of wood (juvenile and mature wood and pith) and the dimension of sawed wood elements on the velocity of propagation of stress waves into the material on L wood (43 years old trees) from Horto Florestal of Manduri (latitude 19’ west and altitude de 700 m) São Paulo State, Brazil were used, considering its easy growth rings visualization and the better juvenile and mature wood regions definition. Six trees were randomly chosen in the plantation. Trees were sawed into 4 logs (2,5 m long each. In each log it was delimited the central board (80mm tick) region and the lateral boards (25mm tick) regions, considering 2 boards on the left and 2 at the right hand. It were evaluated relation between velocity of stress waves on logs and the correspondent lumber (central and lateral boards), on green condition, on the three main region of the elements (mature wood, juvenile wood and pith). Comparative analyses of results obtained revealed the concordance between velocities of stress waves in the material before and after the its mechanical processing. It was also revealed statistical differences ty of stress waves at juvenile wood, mature wood and pith regions

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This paper proposes an extension of the personal experience of the listener through radio. The radio, because it is a medium of reaching, disseminating and having considerable accessibilities towards the production of its contents, and if exploited, could very well combine functionality with aesthetics in the production and broadcasting of programs, something that makes the radio not only a means for transmission of information. In the production of dramatic art, for example, the use of other elements, such as sound effects, may suggest form and consistency to the object described during the practice of radio utterance. The proper combination of function and aesthetic in music, sound effects and voiceover radio can change the mood of the listener and even promote their creativity.

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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This study evaluated the use of hipoosmotic swelling test (HOST) with deionized water (0 mOsmol), as a method of post thaw ram semen evaluation and correlate their findings with different techniques of semen evaluation. Therefore, twenty semen samples of 20 different adult rams were assessed as for kinetic sperm parameters through computerized system (IVOS 12, Hamiton Thorn Biosciences, Beverly, MA, EUA) and subjective analysis. The sperm membranes viability was carried out by the association of fluorescent probes (propidium iodide, JC-1 and FITC-PSA). The structural integrity of the plasma membrane was also studied through supravital test with eosin and the functional integrity of membrane evaluated by doing the hipoosmotic swelling test with deionized water (0 mOsmol), in the following proportions: One part of semen for 10 (HOST 10), 50 (HOST 50) and 100 (HOST 100) parts of water. After semen dilution in the different proportions it was fixed in formalin-buffered saline and analyzed with regard to percentage of HOST reactive sperm (bent/coiled). The percentage of reaction obtained for HOST 10 (33,1%); HOST 50 (32,8%) and HOST 100 (31,8%) did not differ significantly. HOST 10 presented positive correlation with the plasma membrane integrity by the EOS (r = 0,80; p < 0,05). Positive correlations between HOST 50 and HOST 100 with sperm subpopulation with membrane integrity by fluorescence were observed (r = 0,83 and r = 0,85; p < 0,01). The findings suggest that the HOST with deionized water can provide additional information for post thawing ram sperm viability evaluation.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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It is important to ensure smoothly operation of a transmission line, sending energy to the consumption centers with minimal interruptions and safer. With this necessity, the fault location techniques have grown, in order to mitigate the impact of the fault and its correction can be more quickly and accurately. This paper presents a comparison between two different techniques of fault location, the fault location by impedance method, which uses the line parameters, the impedance per distance, voltage and current signals, and the other is the traveling wave method, which uses only a very fast analysis of time, synchronization and length between the line ends, do not using voltage and current values, but the temporal perception of the fault. Using travelling waves fault detection makes the previous knowledge of line parameters obsolete, which helps a lot network technicians and engineers with a quick and easy analysis. The methods are simulated in ATP Draw software, so both algorithms can be evaluated for their effectively and accuracy