230 resultados para Inelastic collision
Resumo:
The contribution of the total dose due to deposition of secondary energy particles caused by nuclear inelastic processes (n, 2H, 3H, 3He and ) in proton therapy is an opened problem and in discussion. In the calculations of plans implemented for routine treatment, the paid dose is calculated whereas that the proton loses energy by ionization and or coulomb excitement. The contribution of inelastic processes associated with nuclear reactions is not considered, mainly due to the difficulty of processing targets consisting of various materials. In this sense, there are only estimates for pure materials or simple composition (water, for example).This work presents the results of simulations by the Monte Carlo method employing the code MCNPX v2.50 (Monte Carlo N-Particle eXtended) of the contribution to the total dose of secondary particles. The study was implemented in a cylindrical phantom composed by compact bone, for monochromatic beams of protons between 100 and 200 MeV with pencil beam form
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Pós-graduação em Engenharia Civil - FEIS
Resumo:
The objective of this work is to present an analysis of the results of a study about the reading practices of a group of teachers from the public school, discussing how these practices constitute themselves since the initial formation until the teaching period. The selected teachers had their formation between the end of the 60’s and the beginning of the 80’s, remaining as teachers of the public school for the next twenty years. Using as methodology the narrative research, we are going to discuss how the reading appears in the lives of these professionals, what their representations about it are and how the reading permeates their lives and their actuations in the school, passing through the first contacts with the books until the collision between theory and practice, observed in the speech of the teachers who were interviewed, always taking into account the teaching formation.
Resumo:
The purpose of the present study was to analyze the visual control of braking a bicycle when the cyclist is surprised by an obstacle in his way. According to Lee (1976), visually controlled braking based on time to collision information utilizes the optic variables tau and its first derivative in time, tau-dot, to initiating the braking action and regulating its intensity. Seven young adults performed a bicycle braking task in curvilinear trajectory under distinct velocity (high, medium, and low) and uncertainty (certainty and uncertainty) conditions. Results showed that, independently of velocity and uncertainty levels, participants utilized tau and tau-dot to initiating and regulating the braking action, avoiding collision with the obstacle. Cognitive, attentional, and other psychological factors resulting from both increased velocity and uncertainty were not capable of altering the use of time to collision information, corroborating the tested hypothesis
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)