Desenvolvimento de projetos: um trabalho para a integração universidade/escola técnica

In this article we present a research work developed with the groups of the mechanics students of the High School to explore the projects pedagogical practices. For the technical students too It is necessary to give opportunities for qualifies them to create, to judge and to development any project, since your original idea, until the operation of the products. Thus, we worked the mechanics of the harmonic motions under the softened and forced oscillations conditions, and several technological applications. These problems are precariously explored in the didactic books and laboratories. Like this, we proposed to project and to make a prototype of an oscillator that allows to explorer all the relationship of the variables and the dynamic situations which the subject to can provide for understanding the sciences of the mechanical oscillations. The work was realized by including since its conception on the general plan, and the dimensional shipping of the parts, and drawings in Auto-CAD software, until the operation of the mechanisms. The work still included the making of the mechanical components. The oscillator constructed is a mass-spring system, with backup for the operation. It allows to study, since the simple harmonic motion until the effects of the external forces to the under-critical, the critical and the super-critical attenuation. The results allows to correlate the different variables and respective scientific-technological meanings, associating the physical parameters with the consensual mathematical models. The essence of this proposal was to present the challenge for learning sciences from the technological projects developments.No presente artigo, apresentamos resultados de pesquisa em extensão, desenvolvida com grupos de alunos de Mecânica de uma Escola Técnica Profissionalizante explorando a pedagogia de projetos. Ao técnico também é necessário dar-lhes oportunidades para obter um desenvolvimento profissional que os capacite a criar e a julgar um projeto, desde a sua idealização até a operação de um produto final. Com estes objetivos, propusemos um trabalho com abordagens teórica/experimental da mecânica de movimentos harmônicos. Este tema é precariamente apresentado em livros e em laboratórios didáticos. Assim, propusemos projetar e desenvolver um protótipo de um sistema que permita estudar as inúmeras variáveis e situações dinâmicas que o assunto pode oferecer a partir de registros de dados experimentais. Foram idealizados, dimensionados os componentes e os desenhos feitos em Auto-CAD, incluindo os detalhes técnicos para operação dos mecanismos e confecção dos componentes em oficinas. O sistema construído foi um oscilador mecânico tipo massa-mola, versátil, contando com opções para estudar, desde o MHS, algumas oscilações sob ação de uma força alternada externa, até investigar oscilações com amortecimentos crítico, sub-crítico e supercrítico, tópicos fundamentais em diversas aplicações tecnológicas. Os dados constituídos permitem correlacionar diferentes variáveis e seus respectivos significados científico-tecnológicos, contextualizando os parâmetros físicos envolvidos e associando-os aos modelos matemáticos consensuais, alcançando a essência da proposta e que representaram o grande desafio de aprender ciências a partir do desenvolvimento de projetos tecnológicos com conceitos da física e de engenharia

Desenvolvimento de projetos: um trabalho para a integração universidade/escola técnica

In this article we present a research work developed with the groups of the mechanics students of the High School to explore the projects pedagogical practices. For the technical students too It is necessary to give opportunities for qualifies them to create, to judge and to development any project, since your original idea, until the operation of the products. Thus, we worked the mechanics of the harmonic motions under the softened and forced oscillations conditions, and several technological applications. These problems are precariously explored in the didactic books and laboratories. Like this, we proposed to project and to make a prototype of an oscillator that allows to explorer all the relationship of the variables and the dynamic situations which the subject to can provide for understanding the sciences of the mechanical oscillations. The work was realized by including since its conception on the general plan, and the dimensional shipping of the parts, and drawings in Auto-CAD software, until the operation of the mechanisms. The work still included the making of the mechanical components. The oscillator constructed is a mass-spring system, with backup for the operation. It allows to study, since the simple harmonic motion until the effects of the external forces to the under-critical, the critical and the super-critical attenuation. The results allows to correlate the different variables and respective scientific-technological meanings, associating the physical parameters with the consensual mathematical models. The essence of this proposal was to present the challenge for learning sciences from the technological projects developments.No presente artigo, apresentamos resultados de pesquisa em extensão, desenvolvida com grupos de alunos de Mecânica de uma Escola Técnica Profissionalizante explorando a pedagogia de projetos. Ao técnico também é necessário dar-lhes oportunidades para obter um desenvolvimento profissional que os capacite a criar e a julgar um projeto, desde a sua idealização até a operação de um produto final. Com estes objetivos, propusemos um trabalho com abordagens teórica/experimental da mecânica de movimentos harmônicos. Este tema é precariamente apresentado em livros e em laboratórios didáticos. Assim, propusemos projetar e desenvolver um protótipo de um sistema que permita estudar as inúmeras variáveis e situações dinâmicas que o assunto pode oferecer a partir de registros de dados experimentais. Foram idealizados, dimensionados os componentes e os desenhos feitos em Auto-CAD, incluindo os detalhes técnicos para operação dos mecanismos e confecção dos componentes em oficinas. O sistema construído foi um oscilador mecânico tipo massa-mola, versátil, contando com opções para estudar, desde o MHS, algumas oscilações sob ação de uma força alternada externa, até investigar oscilações com amortecimentos crítico, sub-crítico e supercrítico, tópicos fundamentais em diversas aplicações tecnológicas. Os dados constituídos permitem correlacionar diferentes variáveis e seus respectivos significados científico-tecnológicos, contextualizando os parâmetros físicos envolvidos e associando-os aos modelos matemáticos consensuais, alcançando a essência da proposta e que representaram o grande desafio de aprender ciências a partir do desenvolvimento de projetos tecnológicos com conceitos da física e de engenharia

Ecossistema startup na visão de seus agentes / Startup ecosystem in the view of its agents

O objetivo do estudo foi identificar a visão, conhecimentos e perspectiva que os agentes têm em relação ao ecossistema startup Buriti Valley em Boa Vista – RR. Realizou-se uma pesquisa exploratória-descritiva, de natureza qualitativa. O instrumento de coleta foi um questionário estruturado com doze perguntas fechadas e uma aberta. Os resultados revelaram que 89,47% dos respondentes concordam totalmente com a afirmação de que o ecossistema startup é uma estratégica fundamental de desenvolvimento tecnológico, social e econômico. Mostrou, ainda, falta de conhecimento do que realmente é o Buriti Valley. Conclui-se que o ecossistema local precisa buscar formas de incentivar o envolvimento dos agentes

EGFR oligomerization organizes kinase-active dimers into competent signalling platforms

Epidermal growth factor receptor (EGFR) signalling is activated by ligand-induced receptor dimerization. Notably, ligand binding also induces EGFR oligomerization, but the structures and functions of the oligomers are poorly understood. Here, we use fluorophore localization imaging with photobleaching to probe the structure of EGFR oligomers. We find that at physiological epidermal growth factor (EGF) concentrations, EGFR assembles into oligomers, as indicated by pairwise distances of receptor-bound fluorophore-conjugated EGF ligands. The pairwise ligand distances correspond well with the predictions of our structural model of the oligomers constructed from molecular dynamics simulations. The model suggests that oligomerization is mediated extracellularly by unoccupied ligand-binding sites and that oligomerization organizes kinase-active dimers in ways optimal for auto-phosphorylation in trans between neighbouring dimers. We argue that ligand-induced oligomerization is essential to the regulation of EGFR signalling

The architecture of EGFR's basal complexes reveals autoinhibition mechanisms in dimers and oligomers

Our current understanding of epidermal growth factor receptor (EGFR) autoinhibition is based on X-ray structural data of monomer and dimer receptor fragments and does not explain how mutations achieve ligand-independent phosphorylation. Using a repertoire of imaging technologies and simulations we reveal an extracellular head-to-head interaction through which ligand-free receptor polymer chains of various lengths assemble. The architecture of the head-to-head interaction prevents kinase-mediated dimerisation. The latter, afforded by mutation or intracellular treatments, splits the autoinhibited head-to-head polymers to form stalk-to-stalk flexible non-extended dimers structurally coupled across the plasma membrane to active asymmetric tyrosine kinase dimers, and extended dimers coupled to inactive symmetric kinase dimers. Contrary to the previously proposed main autoinhibitory function of the inactive symmetric kinase dimer, our data suggest that only dysregulated species bear populations of symmetric and asymmetric kinase dimers that coexist in equilibrium at the plasma membrane under the modulation of the C-terminal domain

Role of the Mitochondria in Immune-Mediated Apoptotic Death of the Human Pancreatic β Cell Line βLox5

Mitochondria are indispensable in the life and death of many types of eukaryotic cells. In pancreatic beta cells, mitochondria play an essential role in the secretion of insulin, a hormone that regulates blood glucose levels. Unregulated blood glucose is a hallmark symptom of diabetes. The onset of Type 1 diabetes is preceded by autoimmune-mediated destruction of beta cells. However, the exact role of mitochondria has not been assessed in beta cell death. In this study, we examine the role of mitochondria in both Fas- and proinflammatory cytokine-mediated destruction of the human beta cell line, βLox5. IFNγ primed βLox5 cells for apoptosis by elevating cell surface Fas. Consequently, βLox5 cells were killed by caspase-dependent apoptosis by agonistic activation of Fas, but only after priming with IFNγ. This beta cell line undergoes both apoptotic and necrotic cell death after incubation with the combination of the proinflammatory cytokines IFNγ and TNFα. Additionally, both caspase-dependent and -independent mechanisms that require proper mitochondrial function are involved. Mitochondrial contributions to βLox5 cell death were analyzed using mitochondrial DNA (mtDNA) depleted βLox5 cells, or βLox5 ρ0 cells. βLox5 ρ0 cells are not sensitive to IFNγ and TNFα killing, indicating a direct role for the mitochondria in cytokine-induced cell death of the parental cell line. However, βLox5 ρ0 cells are susceptible to Fas killing, implicating caspase-dependent extrinsic apoptotic death is the mechanism by which these human beta cells die after Fas ligation. These data support the hypothesis that immune mediators kill βLox5 cells by both mitochondrial-dependent intrinsic and caspase-dependent extrinsic pathways

Active control in flexible plates with piezoelectric actuators using linear matrix inequalities

The study of algorithms for active vibrations control in flexible structures became an area of enormous interest, mainly due to the countless demands of an optimal performance of mechanical systems as aircraft, aerospace and automotive structures. Smart structures, formed by a structure base, coupled with piezoelectric actuators and sensor are capable to guarantee the conditions demanded through the application of several types of controllers. The actuator/sensor materials are composed by piezoelectric ceramic (PZT - Lead Zirconate Titanate), commonly used as distributed actuators, and piezoelectric plastic films (PVDF-PolyVinyliDeno Floride), highly indicated for distributed sensors. The design process of such system encompasses three main phases: structural design; optimal placement of sensor/actuator (PVDF and PZT); and controller design. Consequently, for optimal design purposes, the structure, the sensor/actuator placement and the controller have to be considered simultaneously. This article addresses the optimal placement of actuators and sensors for design of controller for vibration attenuation in a flexible plate. Techniques involving linear matrix inequalities (LMI) to solve the Riccati's equation are used. The controller's gain is calculated using the linear quadratic regulator (LQR). The major advantage of LMI design is to enable specifications such as stability degree requirements, decay rate, input force limitation in the actuators and output peak bounder. It is also possible to assume that the model parameters involve uncertainties. LMI is a very useful tool for problems with constraints, where the parameters vary in a range of values. Once formulated in terms of LMI a problem can be solved efficiently by convex optimization algorithms

Experimental damage detection using observability grammian matrix

Structural Health Monitoring (SHM) has diverse potential applications, and many groups work in the development of tools and techniques for monitoring structural performance. These systems use arrays of sensors and can be integrated with remote or local computers. There are several different approaches that can be used to obtain information about the existence, location and extension of faults by non destructive tests. In this paper an experimental technique is proposed for damage location based on an observability grammian matrix. The dynamic properties of the structure are identified through experimental data using the eigensystem realization algorithm (ERA). Experimental tests were carried out in a structure through varying the mass of some elements. Output signals were obtained using accelerometers

Optimal placement of sensors/actuators in truss structures with known disturbances

An important stage in the solution of active vibration control in flexible structures is the optimal placement of sensors and actuators. In many works, the positioning of these devices in systems governed for parameter distributed is, mainly, based, in controllability approach or criteria of performance. The positions that enhance such parameters are considered optimal. These techniques do not take in account the space variation of disturbances. An way to enhance the robustness of the control design would be to locate the actuators considering the space distribution of the worst case of disturbances. This paper is addressed to include in the formulation of problem of optimal location of sensors and piezoelectric actuators the effect of external disturbances. The paper concludes with a numerical simulation in a truss structure considering that the disturbance is applied in a known point a priori. As objective function the C norm system is used. The LQR (Linear Quadratic Regulator) controller was used to quantify performance of different sensors/actuators configurations