5 resultados para MORA

em Repositório Científico do Instituto Politécnico de Lisboa - Portugal


Relevância:

20.00% 20.00%

Publicador:

Resumo:

O presente relatório diz respeito ao trabalho por mim realizado na empresa de construção H Tecnic, Lda., no âmbito do 2º Ano do Mestrado em Engenharia Civil – ISEL, e procura-o descrever sumariamente e de forma clara durante o período em que o mesmo decorreu (Janeiro de 2010 a Agosto de 2010). Não sendo para mim novidade o enquadramento e o funcionamento de uma Empresa de Construção Civil, estes 8 meses de trabalho obrigaram-me a uma maior atenção e consolidação de alguns conhecimentos adquiridos na Faculdade. A constante evolução das técnicas de construção e a descoberta de novos materiais obrigam-nos a uma constante actualização para nos mantermos competitivos num sector cada vez mais exigente. A recente crise financeira, com repercussões em toda a economia, teve como consequência que as empresas para sobreviver tenham de optimizar os seus recursos e rentabilizá-los ao máximo procurando através do seu conhecimento, qualidade, cumprimento dos prazos, etc., distinguir-se das demais. É com este espírito que tenho desenvolvido o meu trabalho na H Tecnic, Lda., procurando dia a dia melhorar a minha prestação.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A dissertação de mestrado subordinada ao tema das Relações Intergeracionais e as Sociedades Envelhecidas surgiu, no âmbito do Mestrado em Educação Social e Intervenção Comunitária, da Escola Superior de Educação de Lisboa e teve como ponto de partida saber se a participação em actividades intergeracionais promove o envelhecimento ativo de 8 mulheres com 65 e mais anos, residentes num território multigeracional de Lisboa Oriental. A abordagem concetual do envelhecimento social, do envelhecimento ativo, das relações intergeracionais e da participação conduziu o estudo, através da triangulação dos instrumentos de análise qualitativa de entrevistas de histórias de vida e de focus group. As mulheres entrevistadas têm entre 65 e 85 anos de idade cronológica, mas em média dizem sentir que têm menos 34 anos. Afirmam, ser jovens de espirito e por isso preferem ser chamadas de seniores. Manifestam que sempre foram e são, mulheres autónomas, livres, independentes, com poder de decisão, com auto-estima elevada e com qualidade de vida. Mulheres que ocupam o tempo em actividades da vida diária, em actividades de tempos livres, e voluntariado. Mulheres reivindicativas, proativas, frontais e determinadas que assumem um papel social ativo envolvendo-se socialmente em todas as actividades produtivas ou orientadas para a performance e em actividades colectivas e ou orientadas para a união, com vista alcançar objetivos comuns. Mulheres, que ganham prestígio e estatuto na comunidade por se envolverem socialmente no processo de tomadas de decisão, organização, execução e avaliação, com as gerações mais novas. São visionárias ancestrais de espirito jovem que abrem novas portas para a construção social da velhice nas sociedades neoliberais e desafiam os humanistas quando afirmam que as atividades produtivas na velhice dão sentido à própria existência. São histórias de mulheres que nos fazem acreditar que a participação social contribui espontaneamente para o diálogo entre as gerações, em todas as fases da vida. - Abstract A dissertation on the subject of Intergenerational Relationships and Societies Aged emerged within the Master of Education Social and Community Intervention, School of Education and Lisbon had as starting point whether participation promotes intergenerational activities on aging 8 active women aged 65 years and older, residing in the territory of Eastern Lisbon multigenerational. The conceptual approach of social aging, active aging, intergenerational relations and participation conducted the study through triangulation of instruments qualitative analysis of interviews and life stories focus group. The women interviewed are between 65 and 85 years of chronological age, but on average say they feel they are under 34 years old. They claim to be young in spirit and so they prefer to be called seniors. Demonstrate that have always been and are women autonomous, free, independent, decision-making, self-esteem and quality of life. Women who occupy the time in activities of daily life, in leisure activities, and volunteering. Women reivindicativas, proactive, front and determined to play an active social role by engaging in socially productive activities or any performance-oriented and collective activities and or targeted at the union in order to achieve common objectives. Women who gain prestige and status in the community by becoming involved socially in the process of decision making, organization, implementation and evaluation with the younger generations. They are young visionary spirit of ancestors that open new doors to the social construction of old age in neoliberal societies and challenge humanists say when productive activities in old age give meaning to their own existence. These are stories of women who have us believe that social participation contributes to spontaneous dialogue between generations, in all stages of life.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study evaluates the dosimetric impact caused by an air cavity located at 2 mm depth from the top surface in a PMMA phantom irradiated by electron beams produced by a Siemens Primus linear accelerator. A systematic evaluation of the effect related to the cavity area and thickness as well as to the electron beam energy was performed by using Monte Carlo simulations (EGSnrc code), Pencil Beam algorithm and Gafchromic EBT2 films. A home-PMMA phantom with the same geometry as the simulated one was specifically constructed for the measurements. Our results indicate that the presence of the cavity causes an increase (up to 70%) of the dose maximum value as well as a shift forward of the position of the depthedose curve, compared to the homogeneous one. Pronounced dose discontinuities in the regions close to the lateral cavity edges are observed. The shape and magnitude of these discontinuities change with the dimension of the cavity. It is also found that the cavity effect is more pronounced (6%) for the 12 MeV electron beam and the presence of cavities with large thickness and small area introduces more significant variations (up to 70%) on the depthedose curves. Overall, the Gafchromic EBT2 film measurements were found in agreement within 3% with Monte Carlo calculations and predict well the fine details of the dosimetric change near the cavity interface. The Pencil Beam calculations underestimate the dose up to 40% compared to Monte Carlo simulations; in particular for the largest cavity thickness (2.8 cm).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Monte Carlo (MC) dose calculation algorithms have been widely used to verify the accuracy of intensity-modulated radiotherapy (IMRT) dose distributions computed by conventional algorithms due to the ability to precisely account for the effects of tissue inhomogeneities and multileaf collimator characteristics. Both algorithms present, however, a particular difference in terms of dose calculation and report. Whereas dose from conventional methods is traditionally computed and reported as the water-equivalent dose (Dw), MC dose algorithms calculate and report dose to medium (Dm). In order to compare consistently both methods, the conversion of MC Dm into Dw is therefore necessary. This study aims to assess the effect of applying the conversion of MC-based Dm distributions to Dw for prostate IMRT plans generated for 6 MV photon beams. MC phantoms were created from the patient CT images using three different ramps to convert CT numbers into material and mass density: a conventional four material ramp (CTCREATE) and two simplified CT conversion ramps: (1) air and water with variable densities and (2) air and water with unit density. MC simulations were performed using the BEAMnrc code for the treatment head simulation and the DOSXYZnrc code for the patient dose calculation. The conversion of Dm to Dw by scaling with the stopping power ratios of water to medium was also performed in a post-MC calculation process. The comparison of MC dose distributions calculated in conventional and simplified (water with variable densities) phantoms showed that the effect of material composition on dose-volume histograms (DVH) was less than 1% for soft tissue and about 2.5% near and inside bone structures. The effect of material density on DVH was less than 1% for all tissues through the comparison of MC distributions performed in the two simplified phantoms considering water. Additionally, MC dose distributions were compared with the predictions from an Eclipse treatment planning system (TPS), which employed a pencil beam convolution (PBC) algorithm with Modified Batho Power Law heterogeneity correction. Eclipse PBC and MC calculations (conventional and simplified phantoms) agreed well (<1%) for soft tissues. For femoral heads, differences up to 3% were observed between the DVH for Eclipse PBC and MC calculated in conventional phantoms. The use of the CT conversion ramp of water with variable densities for MC simulations showed no dose discrepancies (0.5%) with the PBC algorithm. Moreover, converting Dm to Dw using mass stopping power ratios resulted in a significant shift (up to 6%) in the DVH for the femoral heads compared to the Eclipse PBC one. Our results show that, for prostate IMRT plans delivered with 6 MV photon beams, no conversion of MC dose from medium to water using stopping power ratio is needed. In contrast, MC dose calculations using water with variable density may be a simple way to solve the problem found using the dose conversion method based on the stopping power ratio.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Previous Monte Carlo studies have investigated the multileaf collimator (MLC) contribution to the build-up region for fields in which the MLC leaves were fully blocking the openings defined by the collimation jaws. In the present work, we investigate the same effect but for symmetric and asymmetric MLC defined field sizes (2×2, 4×4, 10×10 and 3×7 cm2). A Varian 2100C/D accelerator with 120-leaf MLC is accurately modeled fora6MVphoton beam using the BEAMnrc/EGSnrc code. Our results indicate that particles scattered from accelerator head and MLC are responsible for the increase of about 7% on the surface dose when comparing 2×2 and 10×10 cm2 fields. We found that the MLC contribution to the total build-up dose is about 2% for the 2×2 cm2 field and less than 1% for the largest fields.