Estudo preliminar do potencial de alguns asteroides

A survey we conducted, and bring expressed in this text is a preliminary study on the shape of asteroids and allowed us to understand a little more the dynamics around these bodies, in order that the images we have of asteroids are the most irregular possible. In this work, the asteroid is modeled by the method of the polyhedron, which provides a very good accuracy of the irregular shape of the body. Through study of models for non-spherical gravitational potential bodies, implementation of computational algorithms and numerical simulations a preliminary analysis was performed in relation to the shape of asteroids 4179 Toutatis, 6489 Golevka, 2063 Bacchus, 1620 Geographos and 1998 ML14, as well as regions of stability instability, we compute the coefficients of the gravitational potential. The work not only enables expansion for the case of asteroids, but also for other non-spherical bodies, contributing to the development of targeted studies the origin and evolution of the solar system, and perhaps the origin of the earth, and new technologies for modeling and mapping of non-spherical bodies. The main results were obtained by analyzing the graphics format and planning of asteroids, which confirmed how these bodies are irregular and show how distribution of non-homogeneous mass. Observe the behavior of the curves of zero velocity and equipotential curves as well as their respective surfaces. Also, compute some values of the gravitational potential and the spherical harmonic coefficients of each object. Furthermore, we find possible equilibrium points of asteroids except 4179 Toutatis, and analyze its stability

Dispositivo de microdescargas em gases na pressão atmosférica

Neste trabalho foi desenvolvido um dispositivo de microdescargas em gases à pressão atmosférica para geração de plasma a fim de ser utilizado no tratamento de superfícies. O trabalho foi baseado em um estudo de iniciação científica que aconteceu em duas etapas. Na introdução apresentam-se as motivações do estudo, o dispositivo desenvolvido na primeira etapa do trabalho bem como os primeiros resultados e propostas de melhorias. Definem-se os objetivos da segunda etapa, que contemplam modificações no dispositivo de descarga e na fonte de alimentação. Em seguida são explanados os métodos utilizados para confecção do dispositivo, construção da fonte de alimentação e circuito de fotodetecção para observar as descargas. Apresenta-se o modelo e configurações dos experimentos, os resultados obtidos são expostos e debatidos brevemente. Colocam-se as conclusões do trabalho e novas propostas de investigação e melhoramentos para o estudo das microdescargas. Seguem-se os agradecimentos aos envolvidos no projeto e, por fim, a bibliografia utilizada

Crescimento de apatita na superfície da liga Ti-25Ta empregando dois tipos de tratamento de superfície: biomimético e deposição de polímero por eletrofiação

Titanium and its alloys has been widely used as materials for metallic biomaterials implants are usually employed to restore the hard tissue function, being used for artificial joints and bones, synthetic plates, crowns, dental implants and screws . Objective of this work was the surface modification of Ti-alloy 25Ta from biomimetic surface treatment of employment and deposition of polymer by electrospinning. The league was obtained from the fusion of the pure elements in the arc furnace with controlled atmosphere. The ingots were subjected to heat treatment, cold forged and sectioned discs with 13 mm diameter and 3 mm thick. Two surface treatments was evaluated, biomimetic and electrospinning with PCL fiber. The biomimetic treatment was performed involving alkaline treatment for three molarities 1.5M, 3M and 5M with immersion in SBF. The electrospinning was performed using PCL polymer alloy surface after the alkali treatment Ti25Ta 1M. For this group the polymer coated surfaces were immersed in calcium phosphate containing solution for immobilization of apatite. The results were compared with previous studies using surface treatment group to verify hydroxyapatite formation on the sample surface and it is concluded that the best condition is biomimetic treatment with 5M alkali treatment and heat treatment at 80 ° C for 72 hours

Estudo e aplicação de diferentes métodos de resolução para problemas dinâmicos não-lineares em presença de atrito

The friction phenomena is present in mechanical systems with two surfaces that are in contact, which can cause serious damage to structures. Your understanding in many dynamic problems became the target of research due to its nonlinear behavior. It is necessary to know and thoroughly study each existing friction model found in the literature and nonlinear methods to define what will be the most appropriate to the problem in question. One of the most famous friction model is the Coulomb Friction, which is considered in the studied problems in the French research center Laboratoire de Mécanique des Structures et des Systèmes Couplés (LMSSC), where this search began. Regarding the resolution methods, the Harmonic Balance Method is generally used. To expand the knowledge about the friction models and the nonlinear methods, a study was carried out to identify and study potential methodologies that can be applied in the existing research lines in LMSSC and then obtain better final results. The identified friction models are divided into static and dynamic. Static models can be Classical Models, Karnopp Model and Armstrong Model. The dynamic models are Dahl Model, Bliman and Sorine Model and LuGre Model. Concerning about nonlinear methods, we study the Temporal Methods and Approximate Methods. The friction models analyzed with the help of Matlab software are verified from studies in the literature demonstrating the effectiveness of the developed programming

Caracterização de plasmas a partir do monômero digime através da espectrometria de massa: deposição polimérica

Pós-graduação em Engenharia Mecânica - FEG

Processo de reparo ósseo diante de três tipos de superfície de titânio: análise histomorfométrica e por microscopia eletrônica de varredura associada ao EDS: estudo experimental

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo do efeito do processo de shot peening na taxa de propagação de trinca por fadiga na liga aeronáutica 2024 - T3

Pós-graduação em Engenharia Mecânica - FEG

Análise do processo de fresamento de MDF em centro de usinagem CNC

Pós-graduação em Engenharia Mecânica - FEG

Implantes nanotopograficamente modificados pela ação do laser Yb-YAG

Titanium has proven its suitability as an implant material in surgery over many years. Excellent biocompatibility and corrosion resistance are outstanding features. Implant surfaces always causes concern and interest in scientific communities, due to its close relationship with the time required for osseointegration. Surface modification can be performed by several methods, being laser irradiation one of them. Titanium implants with two different surfaces were inserted in rabbits: Group I (G-I: machined surface, control group), and group II (G-II: laser irradiated, test group) being processed 30 and 60 days after surgery for histological analysis. Surface characterization was performed with SEM-EDS, contact angle measurement, and mean roughness (Ra) parameters. Surface analysis in the GII group showed a nanomorphology affected by melt and quick solidification zones following laser irradiation (SEM), as well as total wettability and Ra mean values significantly higher than in the G-I group. The laser treatment resulted in a homogenized, porous surface, with increased surface area and volume. Histological analysis of bone-implant contact linear extension (BIC) showed better results in G-II at 30 days (39.26 ± 18.23 and 68.41 ± 13.68 for G-I and G-II groups, respectively). Titanium implants modified by laser irradiation showed important features that may accelerate early osseointegration.

Efeito da limpeza pós-condicionamento e do tratamento térmico do silano na resistência de união de um cimento resinoso à cerâmica

Pós-graduação em Odontologia - FOA

Determinação do tempo de vida de restaurações totalmente cerâmicas (y-tzp/porcelana) com incidência da carga em diferentes regiões de contato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação histopatológica da cápsula posterior associada ao implante intraocular com superfície modificada: estudo experimental em coelhos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fatores indutores e supressores da eritropoiese em caninos doentes renais crônicos

Pós-graduação em Cirurgia Veterinária - FCAV

Carbono tipo diamante em componentes de implantes dentários: avaliação das propriedades antimicrobianas e de adesão de Escherichia coli

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Cana-de-açúcar em bacias hidrográficas experimentais irrigadas

Pós-graduação em Agronomia (Ciência do Solo) - FCAV