O Banco Regional de Desenvolvimento do Extremo Sul e a geração de empregos no Estado de Santa Catarina

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção

Oxide Free Wire Arc Sprayed Coatings—An Avenue to Enhanced Adhesive Tensile Strength

Conventionally, thermal spraying processes are almost exclusively carried out in an air atmosphere. This results in oxidation of the particles upon thermal spraying, and thus, the interfaces of the splats within the coating are oxidized as well. Hence, a full material bond strength cannot be established. To overcome this issue, a mixture of monosilane and nitrogen was employed in the present study as the atomising and environment gas. With this approach, an oxygen partial pressure corresponding to an extreme-high vacuum was established in the environment and oxide-free coatings could be realized. It is shown that the oxide-free particles have an improved substrate wetting behaviour, which drastically increases the adhesive tensile strength of the wire arc sprayed copper coatings. Moreover, the altered deposition conditions also led to a significant reduction of the coating porosity

Young’s Modulus and Residual Stresses of Oxide-Free Wire Arc Sprayed Copper Coatings

Conventional thermal spraying processes are almost exclusively carried out in an air atmosphere, resulting in the oxidation of the particle surfaces and interfaces within the coating and between the substrate and coating. Furthermore, the initial process of surface activation conventionally takes place in an air atmosphere, preventing an oxide-free interfacial transition. Consequently, the application of spraying materials with high oxygen affinity represents a major challenge. To overcome these issues, the present study utilized silane-doped inert gases to create an environment in which the oxygen concentration was equivalent to the residual oxygen content in an extreme high vacuum. By transferring the corundum blasting and coating process (wire arc spraying) to this environment, materials with a high oxygen affinity can be applied without oxidation occurring. For industrial use, this is an interesting prospect, e.g., for repair coatings, as the homogeneity of the composite is improved by a non-oxidized coating. Using the example of arc-sprayed copper coatings, the microstructure and mechanical properties of the coatings were analysed. The results showed that the oxide-free, wire arc sprayed copper coatings exhibited an improved wetting behaviour resulting in a significant reduction of the coating porosity. Moreover, the improved wetting behaviour and led to an increase in the bonding rate and apparent Young’s modulus. Contrary to expectations, the residual stresses decrease although relaxation mechanisms should be inhibited, and possible reasons for this are discussed in the paper

A Large-scale Synthesis and Characterization of Quaternary CuInₓGa₁₋ₓS₂ Chalcopyrite Nanoparticles via Microwave Batch Reactions

Various quaternary CuInxGa1-xS2 (0≤x≤1) chalcopyrite nanoparticles have been prepared from molecular single-source precursors via microwave decomposition. We were able to control the nanoparticle size, phase, stoichiometry, and solubility. Depending on the choice of surface modifiers used, we were able to tune the solubility of the resulting nanoparticles. This method has been used to generate up to 5g of nanoparticles and up to 150g from multiple batch reactions with excellent reproducibility. Data from UV-Vis, photoluminescence, X-ray diffraction, TEM, DSC/TGA-MS, and ICP-OES analyses have shown high reproducibility in nanoparticle size, composition, and bandgap

Simplified model to evaluate heat losses to the environment in the gasification zone of a downdraft reactor

La gasificación es uno de los procesos de termo conversión con mayores perspectivas de aplicación para la transformación de la biomasa en un combustible de mayor valor agregado y campo de aplicación. Dentro de las tecnologías que actualmente se utilizan, los gasificadores de flujo descendente son los más difundidos para instalaciones de pequeña capacidad. Durante la evaluación termodinámica de estos gasificadores, una de las pérdidas de energía a tener en cuenta son las pérdidas de calor al medio ambiente y dada variedad de los procesos de transferencia de calor que ocurren dentro del reactor, los métodos de cálculos resultan complejos. En el presente trabajo se desarrolla un modelo simplificado para evaluar estas pérdidas de calor al medio ambiente. El modelo permite desde la etapa de proyecto evaluar las pérdidas en función de las dimensiones del reactor, las propiedades térmicas de los materiales de construcción y la temperatura de trabajo del lecho con un error menor del 1% con respecto al método no simplificado.Gasification is one of the thermo conversion processes with the greatest application prospects for the transformation of biomass into a fuel with greater added value and field of application. Within the technologies currently in use, downdraft gasifiers are the most widely used for small capacity installations. During the thermodynamic evaluation of these gasifiers, one of the energy losses to take into account is the heat losses to the environment and given the variety of heat transfer processes that occur within the reactor, the calculation method are complex. In the present work, a simplified model is developed to evaluate these heat losses to the environment. The model allows from the project stage to evaluate the losses based on the dimensions of the reactor, the thermal properties of the construction materials and the working temperature of the bed with an error of less than 1% with respect to the non-simplified method.Fil: Lesme Jaen, René. Universidad de Oriente; CubaFil: Rodriguez Ortiz, Leandro Alexei. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Patagonia Confluencia. Instituto de Investigacion y Desarrollo En Ingenieria de Procesos, Biotecnologia y Energias Alternativas. Grupo Vinculado Instituto de Ingenieria Quimica | Universidad Nacional del Comahue. Instituto de Investigacion y Desarrollo En Ingenieria de Procesos, Biotecnologia y Energias Alternativas. Grupo Vinculado Instituto de Ingenieria Quimica.; Argentina. Universidad de Oriente; CubaFil: Lesme Jaen, Odalis. Universidad de Oriente; Cub

Shallow convolutional network excel for classifying motor imagery EEG in BCI applications

Many studies applying Brain-Computer Interfaces (BCIs) based on Motor Imagery (MI) tasks for rehabilitation have demonstrated the important role of detecting the Event-Related Desynchronization (ERD) to recognize the user’s motor intention. Nowadays, the development of MI-based BCI approaches without or with very few calibration stages session-by-session for different days or weeks is still an open and emergent scope. In this work, a new scheme is proposed by applying Convolutional Neural Networks (CNN) for MI classification, using an end-to-end Shallow architecture that contains two convolutional layers for temporal and spatial feature extraction. We hypothesize that a BCI designed for capturing event-related desynchronization/synchronization (ERD/ERS) at the CNN input, with an adequate network design, may enhance the MI classification with fewer calibration stages. The proposed system using the same architecture was tested on three public datasets through multiple experiments, including both subject-specific and non-subject-specific training. Comparable and also superior results with respect to the state-of-the-art were obtained. On subjects whose EEG data were never used in the training process, our scheme also achieved promising results with respect to existing non-subject-specific BCIs, which shows greater progress in facilitating clinical applications

Monte Carlo dropout for uncertainty estimation and motor imagery classification

Motor Imagery (MI)-based Brain–Computer Interfaces (BCIs) have been widely used as an alternative communication channel to patients with severe motor disabilities, achieving high classification accuracy through machine learning techniques. Recently, deep learning techniques have spotlighted the state-of-the-art of MI-based BCIs. These techniques still lack strategies to quantify predictive uncertainty and may produce overconfident predictions. In this work, methods to enhance the performance of existing MI-based BCIs are proposed in order to obtain a more reliable system for real application scenarios. First, the Monte Carlo dropout (MCD) method is proposed on MI deep neural models to improve classification and provide uncertainty estimation. This approach was implemented using Shallow Convolutional Neural Network (SCNN-MCD) and with an ensemble model (E-SCNN-MCD). As another contribution, to discriminate MI task predictions of high uncertainty, a threshold approach is introduced and tested for both SCNN-MCD and E-SCNN-MCD approaches. The BCI Competition IV Databases 2a and 2b were used to evaluate the proposed methods for both subject-specific and non-subject-specific strategies, obtaining encouraging results for MI recognition

Carcinoma de las trompas de Falopio. Presentación de caso

Se reporta una paciente con diagnóstico histopatológico de adenocarcinoma tubulo-popilar moderadamente diferenciado con áreas de necrosis de la Trompa de Falopio Izquierda, operada en el Hospital Docente Ginecobstetrico “Manuel Fajardo” de Güines, constituyendo el único caso conocido en nuestro Hospital. Se completa el tratamiento remitiendo a la paciente al Instituto Nacional de Oncología y Radiología

Estudio físico-químico del proceso de construcción del Ladrillo de obra artesanal, para su utilización en la elaboración de una propuesta escultórica y su intervención pictórica en la conformación de proyectos artísticos, 2017

En esta investigación se desarrolla un estudio Físico-químico sobre el ladrillo de obra artesanal, para su determinación en la elaboración de piezas artísticas de carácter relieve mural cerámico y pictórico, en el que plantea una alternativa a partir de la experimentación en las nuevas tendencias artísticas, las cuales enfatizan la el uso de materiales alternos al rubro académico. Se sintetiza este proceso por medio del registro y elaboración de un manual, en el que se invita a un público amplio en el ejercicio plástico a través de materiales accesibles, además de contener la corroboración por medio de la ejecución de tres piezas a partir de estudios previamente hechos y en que combina diferentes disciplinas artísticas