T.09 - Dinâmica de engrenagens

Neste documento aborda-se o tema da dinâmica de engrenagens, o qual é lecionado no âmbito da unidade curricular Órgãos de Máquinas II, do curso de Mestrado Integrado em Engenharia Mecânica da Universidade do Minho. Com efeito, inicia-se este assunto com uma breve abordagem ao conceito de diagrama do corpo livre e nomenclatura em dinâmica de engrenagens. Seguidamente apresenta-se a análise dinâmica de engrenagens cilíndricas de dentes retos e inclinados, engrenagens cónicas e de parafuse sem-fim. Finalmente, termina-se este documento com uma breve lista de questões de revisão de conhecimentos, assim como uma lista de referências bibliográficas.info:eu-repo/semantics/publishedVersio

Experimental validation of the electro-thermal model of a PV paneil

The use of solar energy to generate electricity by photovoltaic (PV) cel Is is increasng, in response to the warld energy needs and environmental constraints. Hawever, most of the incident radiation on conventional PV ceUs is not converted into electricity being wasted through heat dissipation and responsable for rising the ceUs temperatura and lowering even more the already low efficiency of photovottaic energy converters. Á way to maintain the efficiency higher is to cantrol the temperature of the cells. To understand the vaflatian of PV efficiency, specific modais are needed, that incarparate electric, thermal and cUmotic porameters. This papar presents a dynamic modal of a PV cal? and evaluatas its thermal and electrical performance. Simulation and experimental results are presented and campared to validara the modal

Anterior Slope Correction-Flexion Osteotomy in Traumatic Genu Recurvatum

A decreased posterior tibial slope has been associated with an increased risk of posterior cruciate ligament failure, anterior knee pain, and premature knee osteoarthritis. Trauma is a common cause of osseous genu recurvatum. Surgical management is recommended to correct the tibial slope and prevent knee pain and osteoarthritis progression. This article discusses our preferred treatment using a proximal tibial opening-wedge osteotomy for surgical management of genu recurvatum secondary to significant anterior tibial slope.info:eu-repo/semantics/publishedVersio

Cervical abscess in an immunocompetent patient with Mycobacterium malmoense pulmonary disease

BACKGROUND: Mycobacterium malmoense is a nontuberculous mycobacteria seen mainly in two age groups and with different clinical presentations. Most patients are male adults presenting clinical symptoms and signs similar to those of pulmonary tuberculosis. The second group is formed by immunocompetent children with localized cervical lymphadenitis. Although cervical adenitis is the main extrapulmonary manifestation of M. malmoense, virtually all cases of cervical disease were documented in children. Disseminated disease is rare and has been reported in patients with severely impaired immunity. CASE REPORT: We report a case of a 47-year-old immunocompetent man with a cervical abscess, in whom we identified a M. malmoense pulmonary disease with multiple cervical, thoracic and abdominal adenopathies. CONCLUSION: Extrapulmonary infection due to M. Malmoense needs to be considered on the differential diagnosis of cervical masses and adenopathies, not only in pediatric patients but also in adults with no impaired immunity. A high index of suspicion for nontuberculous mycobacteria is essential for the diagnosis and prognosis

First Results of the Phase II SIMPLE Dark Matter Search

We report results of a 14.1 kgd measurement with 15 superheated droplet detectors of total active mass 0.208 kg, comprising the first stage of a 30 kgd Phase II experiment. In combination with the results of the neutron-spin sensitive XENON10 experiment, these results yield a limit of |a_p| < 0.32 for M_W = 50 GeV/c2 on the spin-dependent sector of weakly interacting massive particle-nucleus interactions with a 50% reduction in the previously allowed region of the phase space formerly defined by XENON, KIMS and PICASSO. In the spin-independent sector, a limit of 2.3x10-5 pb at M_W = 45 GeV/c2 is obtained.Comment: 4 pages, 4 figures; PRL-accepted version with corrected SI contour (Fig. 4

Propagação vegetativa de pitaia vermelha em resposta a profundidade de plantio e dominância apical.

A produção de mudas de qualidade é condição fundamental para o sucesso de uma boa produção agrícola, o que justifica o estudo da propagação por estaquia, para facilitar o estabelecimento em novas áreas cultivadas

Estaquia de pitaia vermelha com remoção da gema apical submetida a profundidades de plantio diferentes.

Assim, este estudo foi conduzido com o objetivo de avaliar os efeitos da profundidade de plantio em estacas de pitaia e da quebra da dominância apical na formação das brotações, e a partir dessas técnicas identificar qual o melhor método de condução da cultura

Influence of annealing conditions on formation of regular lattices of voids and Ge quantum dots in amorphous alumina matrix

In this work, the influence of air pressure during the annealing of Ge quantum dot (QD) lattices embedded in an amorphous Al2O3 matrix on the structural, morphological and compositional properties of the film is studied. The formation of a regularly ordered void lattice after performing a thermal annealing process is explored. Our results show that both the Ge desorption from the film and the regular ordering of the QDs are very sensitive to the annealing parameters. The conditions for the formation of a void lattice, a crystalline Ge QD lattice and a disordered QD lattice are presented. The observed effects are explained in terms of oxygen interaction with the Ge present in the film.This study has been partially funded through the projects (i) FEDER funds through the COMPETE program ‘Programa Operacional Factores de Competitividade’ and by Portuguese funds through the Portuguese foundation for Science and Technology (FCT) in the frame of the project PTDC/FIS/70194/2006 and PEst-C-FIS/UI607/2011–2012; (ii) ELETTRA Synchrotron Radiation Center through the European Community’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no 226716. SRCP is grateful for financial support through the FCT grant SFRH/BPD/73548/2010 and JMS is grateful for financial support through the Spanish CSIC JAE-DOC program. MB acknowledges support from the Croatian Ministry of Science, Higher Education and Sport (project number 098-0982886-2859).We thank Dr Anabela Rolo and Engineer Jos´e Santos for all the valuable discussions and the sample preparation