Viabilidade De Implantação De Um Buffet De Eventos Especializado Em Churrasco Em São José - Sc

TCC (graduação) - Universidade Federal de Santa Catarina, Centro Sócio Econômico, Curso de Administração.Este trabalho consiste na elaboração de um Plano de Negócios com o intuito de verificar a viabilidade de implantação de um Buffet de churrasco em domicílio no município de São José-SC

Determinação experimental e simulação das curvas de distribuição de tempo de residência no processo de extrusão de polímeros.

A medida da Distribuição do Tempo de Residência (DTR) em tempo real durante o processo de extrusão permite realizar uma análise global do desempenho do equipamento (extrusora), proporcionando um melhor conhecimento do comportamento do fluxo do material durante todo o processo. Neste trabalho foi desenvolvido um sistema ótico (hardware e software) para detecção de curvas DTR em tempo real durante a extrusão de polímeros. O sistema de detecção teve sua eficiência validada. Os resultados obtidos sugeriram que o sistema foi capaz de detectar as curvas de DTR com um elevado número de pontos, bem como se mostrou sensível a variação na concentração e no tipo de traçador utilizado; além disso, foi possível confirmar a boa reprodutibilidade das medições o que qualificou o sistema para o levantamento das curvas de DTR em tempo real. Posteriormente, foram avaliados os efeitos nas alterações das variáveis de processamento sobre a forma e os parâmetros das curvas de DTR. Foi possível confirmar que a variação na taxa de alimentação possui uma maior influência sobre as curvas DTR do que a velocidade da rosca, fato este corroborado com a literatura. também constatou-se que as alterações no Índice de Fluidez do material de fluxo afetaram a dispersão (capacidade de mistura) nas curvas de DTR. A eficiência energética do processo de extrusão também foi analisada através do levantamento da energia mecânica dissipada e da energia mecânica especifica, foi apresentada uma correlação destes parâmetros energéticos com o tempo de residencia médio. Neste trabalho também foi utilizado uma ferramenta computacional (WinTXS™) para simular as condições de processamento experimentais; a partir daí realizou-se a comparação entre os dados medidos experimentalmente e os simulados, de modo a estabelecer um grau de concordância entre os mesmos. Os resultados obtidos permitiram comprovar que medição da DTR e a simulação computacional unidimensinal são ferramentas importantes no estudo do processo de extrusão de polímeros.The measurement of Residence Time Distribution (RTD) in real time during the extrusion process allows a comprehensive analysis of equipment performance (extruder), providing a better understanding of the material flow behavior throughout the process. This work developed an optical system (hardware and software) to detect RTD curves in real time during the extrusion of polymers. The efficiency in the detection system was validated. The results obtained suggest that the system it was able to detect the RTD curves with a large number of points, and is sensitive to variations in the concentration and type of tracer used; furthermore, it was possible to confirm the good reproducibility of the measurements which qualify the system for lifting the RTD curves in real time. subsequently, we evaluated the effects of changes in processing variables on the form and parameters of the RTD curves. It was confirmed that the variation in feed rate has a larger influence on cornering RTD than the speed of the screw, a fact corroborated by the literature. It was also found that the change in Melt Index affect the flow of material dispersion (mixing capacity) in the RTD curves. The energy efficiency of the extrusion process was also analyzed by surveying the dissipated mechanical energy and mechanical energy specifies a correlation is presented these energy parameters with the average residence time. This work also used a computational tool (WinTXS ™) to simulate the processing conditions; there after it conducted a comparison between the experimentally measured and simulated data to establish the degree of agreement there between. Results show evidence that measurement of RTD and unidimensinal computer simulation is important tools in the study of polymer extrusion process

Computer vision component to environment scanning

Dissertação de mestrado em Engenharia de InformáticaComputer vision is usually used as the perception channel of robotic platforms. These platforms must be able of visually scanning the environment to detect specific targets and obstacles. Part of detecting obstacles is knowing their relative distance to robot. In this work different ways of detecting the distance of an object are analyzed and implemented. Extracting this depth perception from a scene involves three different steps: finding features in an image, finding those same features in another image and calculate the features’ distance. For capturing the images two approaches were considered: single cameras, where we capture an image, move the camera and capture another, or stereo cameras, where images are taken from both cameras at the same time. Starting by SUSAN, then SIFT and SURF, these three feature extraction algorithms will be presented as well as their matching procedure. An important part of computer vision systems is the camera. For that reason, the procedure of calibrating a camera will be explained. Epipolar geometry and the fundamental matrix are two important concepts regarding 3D reconstruction which will also be analyzed and explained. In the final part of the work all concepts and ideas were implemented and, for each approach, tests were made and results analyzed. For controlled environments the relative distance of the objects is correctly extracted but with more complex environment such results are harder to obtain.A visão por computador é, normalmente, usada como o canal de percepção do mundo em plataformas robóticas. Estas plataformas têm de ser capazes de rastrear, visualmente, o ambiente para detectar objectivos e obstáculos específicos. Parte da detecção de obstáculos envolve saber da sua distância relativa ao robot. Neste trabalho, são analisadas e implementadas diferentes formas de extrair a distância de um objecto. A extracção desta noção de profundidade de uma cena envolve três passos diferentes: encontrar características numa imagem, encontrar estas mesmas características numa imagem diferente e calcular as suas distâncias. Para a captura de imagens foram considerados dois métodos: uma única câmara, onde é tirada uma imagem, a câmara é movida e é tirada a segunda imagem; e câmaras estéreo onde as imagens são tiradas de ambas as câmaras ao mesmo tempo. Começando pelo SUSAN, depois o SIFT e SURF, estes três algoritmos de extracção de características são apresentados, assim como os seus métodos de emparelhamento de características. Uma parte importante dos sistemas de visão por computador é a câmara, por este motivo, o procedimento de calibrar uma câmara é explicado. Geometria Epipolar e matriz fundamental são dois conceitos importantes no que refere a reconstrução 3D que também serão analisados e explicados. Na parte final do trabalho, todos os conceitos e ideias são implementados e, para cada método, são realizados testes e os seus resultados são analisados. Para ambientes controlados, a distância relativa é correctamente extraída mas, para ambientes mais complexos, os mesmos resultados são obtidos com mais dificuldade

The influence of noise emitted by vehicles on pedestrian crossing decision-making: a study in a virtual environment

When crossing a road, pedestrians must detect traffic, combine data coming from different perceptual modalities, evaluate the time envelope for safely cross the street, and monitor the position of oncoming vehicles to perform corrective actions if needed. This study analyzed the influence of noise emitted by vehicles, or its absence, on pedestrians’ crossing decision-making. Experiments were performed in a virtual environment using two road scenarios. Participants were presented with stimuli of approaching vehicles that varied regarding speed, movement patterns, and auditory condition: one concerning the approaching of an electric vehicle, another regarding the approaching of a gasoline combustion vehicle, and, finally, a condition regarding the absence of auditory cues. Participants were tasked with indicating the moment when they decided to cross the street. The results show that, despite the noise variations caused by the type of vehicle and its speed pattern, the participants’ decision to cross was mostly based on vehicle distance. When a vehicle approaches the crosswalk from a short distance and with no occlusion to the pedestrian’s visibility, the sound does not seem to influence the pedestrians’ crossing decision-making.The authors acknowledge the support of the research project: Nutraceutica come supporto nutrizionale nel paziente oncologico, CUP: B83D18000140007. E.B. Souto acknowledges the sponsorship of the projects M-ERA-NET-0004/2015-PAIRED and UIDB/04469/2020 (strategic fund), receiving support from the Portuguese Science and Technology Foundation, Ministry of Science and Education (FCT/MEC) through national funds, and co-financed by FEDER, under the Partnership Agreement PT2020

Plantas eléctricas híbridas offshore con energía eólica, fotovoltaica y almacenamiento de energía

Large centralized conventional power plants, although robust and reliable, have numerous disadvantages. The use of distributed generation has increased to fulfill the growing energy demand, and to reduce the distance between generation and consumption. Consequently, hybrid energy systems that combine several renewable energy sources are flowering, mainly in grid-connected configurations. The presence of this distributed generation in the electric grid changes its control and operation significantly. Therefore, special attention should be paid to the study of hybrid systems composed of wind turbines (WTs) and photovoltaic solar panels, due to their intermittent and fluctuation characteristics. Currently, a means of improving the connection of such systems to the electricity grid is to combine different energy sources with energy storage systems. Due to the development of storage technologies, they can be used in numerous applications, such as frequency regulation, system stabilization, reduction of transmission losses, increased reliability, load regulation or support for grid services, among others.The hybrid power generation systems used to date are mostly small-scale, with a rated power of tens or hundreds of kW. Another relevant aspect is that most hybrid power systems are located onshore. Nevertheless, a considerable growth of large-scale offshore wind farms is noticeable currently in Europe, mainly due to advances in WTs and foundation structures, which have improved their economic conditions and contributed to the implementation of offshore plants. It is expected that the installed capacity will continue to increase, since the European Union aims at reaching about 100 GW of offshore wind capacity by 2030. In this thesis, a detailed study evidencing this growth has been carried out. The most significant characteristics of 57 plants installed in Europe with a rated power above 150 MW and fully commissioned until 2019, as well as 11 plants authorized or under construction, are studied in detail, drawing relevant conclusions from the data collected. The results show the trends on WT size and capacity, turbine model, distance to shore, water depth, investment cost, type of foundation, transmission technology, and voltage array systems among others. This thesis gathers the latest information about the topic, deducing future trends from the evaluation of offshore wind farms fully commissioned, authorized or under construction.Furthermore, this thesis evaluates the performance of a hybrid power plant consisting of a WT, a solar photovoltaic (PV) power plant, and an energy storage system that share the same grid connection point. This hybrid power plant has a rated power in the range of several MW. Typically, permanent magnet synchronous generator-based WTs present a two-stage power converter topology based on a DC/DC boost converter and voltage source inverter. In the thesis, this configuration is substituted by a quasi-Z-source inverter, which is an attractive solution for boosting and converting the voltage from DC to AC in a single stage. A switched dynamic model of the quasi-Z-source inverter (including the modelling of all switches and firing pulses) is not recommended for steady-state stability studies, long-term simulations, or large electric power systems. For such studies, two averaged dynamic models are proposed in this thesis. Both models present the same control system as the switched dynamic model, except for the generation of the firing pulses, which is not necessary in the averaged models. The two models proposed are evaluated and compared with the switched dynamic model. Both proposed averaged models can substitute the switched dynamic model with satisfactory accuracy in terms of time-domain response in steady-state stability studies. In addition, two voltage sources emulating the terminals of C1 and C2 are added to enable the integration of PV and BES, respectively. The grid-connected hybrid power plant under study consists of a 1.5 MW WT, a 402 kW PV generator connected to the capacitor C2, and a 532 kW lithium-ion battery connected to capacitor C1, making a total 2.44 MW for the rated power of the hybrid plant. Moreover, a load of 1.2 MVA shares a common connection point with the hybrid power plant.After choosing the most suitable configuration for the connection of the WT, the photovoltaic power plant, and the energy storage system; a second objective of the thesis is the development of control strategies for the energy sources and their converters. Different control strategies are implemented and evaluated to regulate active and reactive power, and voltage levels. Finally, a third objective is the design of a supervisory control system for the hybrid power plant. This system must be able to manage and coordinate the energy flow between the devices in the hybrid system. For this purpose, some of the variables considered by the supervisory control system are the generation set point established by the grid operator, the instantaneous production of WTs and the photovoltaic panels, and the state of charge of the battery. Different control strategies have been developed for a proper energy management, and an adequate regulation of the electric parameters of the hybrid plant internally and at the point of connection to grid. Using widely recognized models for the components of the hybrid power plant, it has been possible to represent the behaviour of the system and to evaluate the original designs of this thesis through simulation under different operating conditions (changes in wind speed, solar radiation, or electricity generation of the grid, etc.). The simulation results have shown the adequate performance of the hybrid power plant through the control strategies implemented, which coordinate the renewable energy sources, the battery and the load using impedance source converters

SIMULAÇÃO DO GERADOR EÓLICO DUPLAMENTE ALIMENTADO QUANDO SUBMETIDO À VARIAÇÃO DA VELOCIDADE DO VENTO

A demanda de energia elétrica no mundo é crescente. A eletricidade é fundamentalmente importante para o desenvolvimento social e econômico de nações, tornando investimentos em energia altamente necessários. Com o aumento das turbinas eólicas ligadas à rede de energia e com o aumento de produtores independentes de energia renovável, estudos relacionados à melhor estratégia de controle se tornam indispensáveis. Este trabalho apresenta o comportamento do gerador de indução duplamente alimentado (GIDA) exposto à variação da velocidade do vento incidente em sua hélice. O trabalho é apresentado através de simulações utilizando MatLab/Simulink. O controle exemplificado no trabalho atua na angulação das pás do gerador

Efeito do ruído de tráfego na decisão de atravessamento dos peões

Para atravessar uma rua, os peões devem detetar o tráfego, combinar dados provenientes de diferentes fontes, auditivas e visuais, avaliar o tempo para atravessar com segurança e monitorizar a posição dos veículos que se aproximam. Este trabalho teve como objetivo avaliar a influência do ruído emitido pelos veículos na tomada de decisão de atravessamento dos peões. Realizou-se uma experiência em ambiente virtual que reproduziu condições reais de travessia, no que diz principalmente respeito aos estímulos dos veículos em aproximação com diferentes padrões de movimento e velocidades. Foi considerado o ruído de um veículo elétrico, um veículo de combustão a gasolina, e uma condição de referência sem pistas auditivas. Vários participantes indicaram o momento da sua decisão de atravessamento. A tomada de decisão dos participantes baseou-se sobretudo nas características do movimento de aproximação do veículo, indicando que, a baixa velocidade, o efeito do ruído do veículo na decisão dos peões é reduzido.To cross a street, pedestrians must detect traffic, combine data from different sources, auditory and visual, assess the time to cross safely and monitor the position of approaching vehicles. This work aimed to evaluate the influence of noise emitted by vehicles on pedestrians’ crossing decision. An experiment was carried out in a virtual environment that reproduced real crossing conditions, mainly regarding the presentation of stimuli concerning the approach of a vehicle with different movement patterns and speeds. The noise of an electric vehicle, a gasoline combustion vehicle, and a reference condition without auditory cues were considered. Several participants indicated the moment of their crossing decision. The participants’ decision-making was based mainly on the characteristics of the vehicle's movement, indicating that, at low speed, the effect of vehicle noise on pedestrians’ decision is reduced.Este trabalho enquadra-se nas atividades do projeto de investigação AnPeB – Análise do comportamento de peões com base em ambientes simulados e sua incorporação na modelação de risco (PTDC/ECM-TRA/3568/2014), foi financiado no âmbito do projeto Promover a Produção Científica e Desenvolvimento Tecnológico e a Constituição de Redes Temáticas (3599-PPCDT) e comparticipado pelo Fundo Comunitário Europeu FEDER. De referir ainda a Fundação para a Ciência e a Tecnologia devido ao financiamento da bolsa de doutoramento SFRH/BD/131638/2017

INFLUENCE OF FOREST COVERAGE IN THE SURFACE ALBEDO

The surface albedo controls the energy balance between the surface and the atmosphere, being a primordial variable to identify climatic variations. The objective of this study was to evaluate the changes of the surface albedo in different Land Use and Land Cover in the Atlantic Forest biome from images TM/Landsat 5 and OLI/Landsat 8, verifying its variation in 30 years. The images used were path-row 221-080, which covered the Floresta Nacional de São Francisco de Paula on the dates of 1987 and 2017. The albedo was obtained by the method of the Surface Energy Balance Algorithm for Land, while the mapping of Land Use and Land Cover was performed by the Bhattacharyya algorithm, identifying four thematic classes. Finally, the albedo was crossed with the thematic classes, evidencing their variation in function of the changes in the land cover. The surface albedo ranged from 6 to 22%, but the year 1987 concentrated albedo values higher than in 2017. The native forest presented superior albedo to the Forest Plantations in both dates due to the structure of the canopy of this class. The spatial analysis of the albedo exposes the relation of this climatic variable to the cover of the terrestrial surface. Thus changes in the vegetation cover cause alterations in the albedo, influencing changes in the radiation and atmospheric fluxes

USO DE IMAGENS DE MÉDIA RESOLUÇÃO ESPACIAL PARA O MONITORAMENTO DE DOSSÉIS DE Eucalyptus grandis

O objetivo desse estudo foi identificar plantios comerciais de Eucalyptus grandis com diferentes idades e estimar o volume total de madeira utilizando dados radiométricos do sensor OLI/Landsat 8. Demarcaram-se parcelas em povoamentos aos 4, 18 e 23 anos de idade, nas quais foi mensurado o volume total (m³/ha). A imagem OLI/Landsat 8 foi convertida para reflectância de superfície utilizando a correção radiométrica e, posteriormente gerados os índices de vegetação ARVI, DVI, GNDVI, MVI, NDVI, SAVIL=0,25, SAVIL=0,50 e SR. A diferenciação da idade dos dosséis foi estabelecida baseando-se na reflectância das bandas B4 e B5. Os dados espectrais e o volume total de madeira foram submetidos à análise de correlação e regressão múltipla baseada no método Stepwise. Os povoamentos foram diferenciados uma vez que o aumento da idade ocasionou a redução da reflectância na banda B5 e aumento na banda B4. Para a estimativa do volume total, apenas os povoamentos aos 4 anos de idade apresentaram bom ajuste, sendo o modelo composto pelo índice SAVI, explicando 74% da variabilidade do volume de madeira. Os dados espectrais extraídos de imagens OLI/Landsat 8 mostraram-se sensível às variações das características dos indivíduos nas diferentes fases de crescimento dos povoamentos, assim como na estimativa das variações do volume total