Bárbara Denicol do Amaral Rodriguez

Determination of the exposure build-up factor in a slab using the LTSN method

Abstract In this paper an exposure build-up factor formulation is reported by solving the photon transport equation in a heterogeneous slab by the LTSN method, assuming the Klein-Nishina scattering kernel as the scattering differential cross section as well as the multigroup model in the wavelength variable. Numerical simulations and comparisons with available results in the literature are presented for different compositions containing water, iron and lead.

A solution for the two-dimensional transport equation for photons and electrons in a rectangular domain by the Laplace transform technique

In the first part of this paper, we describe a review in the Laplace transform technique applied to SN two-dimensional transport equation in a rectangular domain considering Compton scattering. In Compton scattering the incident photon interacts with an electron of the irradiated medium, giving the electron kinetic energy, and also producing a scattered photon. In order to track that electron, in the second part of this paper, we apply the PN approximation to X,Y-geometry electron transport problems. In this derivation, the energy deposited by the free electron is taken into account. To reach this objective we solve two model problems: the first one for the transport of photons, assuming the Klein-Nishina scattering kernel as the scattering differential cross-section as well as the multigroup model in the energy variable; and the second one for the transport of free electrons considering the screened Rutherford scattering kernel. The results are presented under absorbed energy form in several points of interest. We report numerical simulations and comparisons with results obtained by using the Geant4 version 9.1 program which applies the Monte Carlos technique to low energy libraries for both two-dimensional problems.

The exposure buildup factor formulation in a slab and rectangle geometry by the LTSN method

In this paper, we report a formulation for the exposure buildup factor by solving the one-dimensional photon transport equation in a heterogeneous slab by the LTSN method, assuming the Klein-Nishina scattering kernel as the scattering differential cross-section as well as the multigroup model in the wavelength variable. We present numerical simulations and comparisons with available results in the literature for a multilayered slab composed of water, iron and lead. We also report an analytical solution to the exposure buildup factor by solving the photon transport equation in a rectangle applying the LTSN nodal method.

Gráfico de Função polinomial: Uma Discussão Sobre Dificuldades dos Alunos no Ensino Superior

Este artigo apresenta e discute dificuldades de alunos do primeiro ano de cursos de Ciencias Exatas e Engenharias da Universidade Federal do Rio Grande (FURG) no que diz respeito a leitura e compreensao de um grafico de uma funcao polinomial. A partir de um estudo qualitativo dos dados obtidos e das atividades propostas, pretende-se identificar algumas lacunas na aprendizagem e analisar a falta de dominio dos conteudos envolvidos. Muitas vezes, os alunos nao estao aptos e nao avancam nas disciplinas da graduacao, pois nao possuem os pre-requisitos necessarios para dar continuidade ao processo de ensino-aprendizagem. Atraves de um teste de sondagem, foi possivel investigar alguns conhecimentos matematicos previos e as principais duvidas dos alunos. Os resultados deste trabalho permitem tracar uma estrategia inicial para dar continuidade e complementar a formacao basica do aluno. Portanto, propoem-se atividades utilizando o software GeoGebra para trabalhar os conceitos envolvidos e auxiliar na transicao do Ensino Medio para o Ensino Superior. Ao final, ainda discute-se a aplicacao de uma das atividades propostas em uma turma.

ANALYZING APPLIED MATHEMATICS GRADUATION STUDENTS’ PROFILE: DISCUSSING THE REASONS OF THE LOW ACADEMIC RESULTS DURING THE FIRST SEMESTER AT THE UNIVERSITY

This paper aims to show and justify a relation between the number of new students and egress of Applied Mathematics course. Analyzing qualitative data, we intend to discuss learning problems related to the subjects of the course’s first semester, such as the lack of mastery of the mathematics studied during elementary and high school. In this case, students are not prepared and do not approve the graduation subjects, as they have significant gaps in their academic fundamental training which is required to learning. By means of a survey, we collect data referring to elementary school, prior knowledge and students’ main doubts. The results allow defining a student profile and suggest the need of adding alternative ways to complement their basic education.