Papers by José Gomes de Matos
An Enhanced Current Controller for Grid-Connected Inverters based on Capacitor Current Feedback Active Damping and Capacitor Voltage Decoupling
2023 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe)
Energies
One of the challenges faced by Brazilian distribution utilities to enable the connection and oper... more One of the challenges faced by Brazilian distribution utilities to enable the connection and operation of microgrids (MGs) is the absence of a solid set of technical standards in the country. An alternative has been to use and adapt existing standards applied to micro- and mini-distributed generation. In this context, this paper presents an analysis of the development status of norms, standards, and general requirements for the connection and operation of microgrids, as well as a proposal for the regulation and structuring of technical and operational requirements related to the implementation of microgrid projects. Some critical points highlighted in the paper include: the modes of operation, the minimum requirements for the different modes of operation, interoperability of systems, a conceptual model with attribution of responsible actors for the decentralized management of microgrids adapted to the institutional standards of the Brazilian sectorial model, a proposal for a standar...
Proceedings IX Simpósio Brasileiro de Sistemas Elétricos
This paper analyzes two alternatives of dispatchable generation sources applied to the context of... more This paper analyzes two alternatives of dispatchable generation sources applied to the context of microgrids, considering that the presence of renewable sources entails in an imbalance between electric energy generation and demand towards such electric system. However, if the microgrid is connected to the main grid, the surplus and/or deficit of energy is assumed by the main system. Although, if the situation becomes critical if the sum between load and generation is different than zero and the microgrid is isolated. Therefore, two microgrids scenarios were analyzed considering the possible applications of two dispatchable generation sources: diesel generators and gas generators. In the first case, the inexistence of gas pipelines made the application of the gas generator unfeasible and in the second case, with the help of HOMER software, an advantage of diesel generator in terms of fuel costs was perceived, but with the gas generator being advisable for cogeneration applications. Resumo: Neste artigo analisa-se dois tipos de fontes despacháveis aplicadas ao contexto de microrredes, visto que a presença das fontes renováveis insere um desbalanço entre a geração e a demanda de energia elétrica a um sistema elétrico deste tipo. Entretanto, se a microrrede está conectada à rede principal, o superavit e/ou déficit de energia é assumido pelo sistema principal. Porém, a situação torna-se crítica se a soma entre carga e geração é diferente de zero e a microrrede está isolada. Desta maneira, considera-se para o estudo dois casos de microrredes considerando a aplicação de dois tipos de fontes despacháveis: o gerador a gás, e o gerador a diesel. No primeiro caso, a inexistência de gasodutos inviabiliza a utilização do gerador a gás e no segundo caso, com auxílio do software HOMER, foi percebida uma vantagem do gerador a diesel quanto aos custos de combustível, mas com o gerador a gás sendo aconselhável para aplicações em que se considera a cogeração.
Este trabalho propoe uma nova estrategia para controle da potencia gerada em uma microrrede isola... more Este trabalho propoe uma nova estrategia para controle da potencia gerada em uma microrrede isolada, que opera em corrente alternada e que dispoe de geradores e bancos de baterias distribuidos ao longo da mesma. Embora nao haja restricoes quanto ao tipo de gerador a ser conectado a microrrede, neste estudo a aplicabilidade da estrategia proposta e analisada considerando a fonte de potencia como sendo uma turbina eolica acoplada a um gerador sincrono a imas permanentes. A microrrede estudada e composta de um conversor eletronico bidirecional, alimentado por um banco de baterias, que tem a funcao de formar a microrrede; um conversor eletronico ligado ao gerador da turbina eolica e que funciona como alimentador da microrrede; alem das cargas e demais sistemas perifericos de controle e manobra. O principal objetivo dessa estrategia e controlar a tensao terminal dos bancos de baterias abaixo de um determinado valor limite, mesmo quando momentaneamente a potencia demandada pela carga cone...
Ao longo deste trabalho pude contar com o apoio e contributo de muitos, aos quais desejo expressa... more Ao longo deste trabalho pude contar com o apoio e contributo de muitos, aos quais desejo expressar aqui os meus sinceros agradecimentos. Ao meu orientador, Professor Veloso Gomes, por todo o apoio prestado durante a realização deste trabalho, pelos conselhos e orientação, pelo sentido crítico das suas intervenções, e pela boa disposição com que sempre me recebeu nas reuniões semanais. Aos Professores Nuno Formigo e Alexandre Leite e à Dª. Maria Assunção Araújo (Professora Catedrática da FLUP) os meus sinceros agradecimentos pela partilha de conhecimentos e material de apoio à realização da presente dissertação e, principalmente, pela imediata disponibilidade a prestar apoio. Gostaria de agradecer, também, ao Dr. Henrique Alves por me ter recebido nas instalações do Parque Biológico de Vila Nova de Gaia e pelo interesse que demonstrou em discutir o tema de estudo.
The present study shows a characterization and evaluation of clays from sterile of mining phospha... more The present study shows a characterization and evaluation of clays from sterile of mining phosphate concentrated in the micro region of Araxá, MG, as pozzolanic addition. Three clays of distinct shades where used: yellow clay (AA), red clay (AV) and intermediate clay (AI), the samples were collected in natural conditions in different excavation depth levels in the phosphate extraction mine. At first, a physical characterization was performed to know the size distribution, the liquidity and plasticity limit. Next step, the clay samples were treated by an improvement process being grinded up and passed through a 0,075mm(200#) opening sieve, used in a characterization by X-Ray diffraction (XRD), thermal analysis (DTA), thermo gravimetric analysis (TGA), X-Ray fluorescence spectroscopy by dispersive energy (EDX), and scanning electronic microscopy (SEM). Second step, the clay samples were calcined in an electric oven furnace muffle type, then they were submitted to three temperatures (680, 760 and 840ºC) calcination conditions. The pozzolanic activity levels of the calcined clays where measured through electric conductivity variation in saturated solution of Ca(OH) 2 , and the resistance to compression of mortars with the 35% of the cement volume by the calcined material. The results were that the calcined clays presented a high level of pozzolanic activity so that they can be used as partial substitution of portland cement, in this way showing that they can be one of the possibilities of advantage of this material considered sterile.
Computerization and automation currently represent an asset recognized by major global constructi... more Computerization and automation currently represent an asset recognized by major global construction companies to add quality in the realization of their projects. However, the extracted information is not always managed used properly, causing lack of management time and adding extra costs in carrying out construction projects. The BIM concept -"Building Information Modeling" is a recent investment of construction companies to address their challenges with regard to information management. BIM is largely based on the integration of physical and functional information of a building or project into a single digital model. BIM allows the design and review of projects even before construction. This model provides architects, enginers and builders the possibility to better collaborate and develop projects from the beginning to the end of the life cycle of buildings. The starting point for this thesis is based on the need to understand how the world's big companies apply BIM in their projects. To archieve this objective, the autor of this dissertation was with in the service Etudes de Prix and Méthodes of a large French company called Bouygues Bâtiment Ile-de-France Habitat Social at its headquarters in the Parisian region. This work describes the ambitions of the company's managers in the use of BIM tools represent the way for realization of construction projects at national and internacional level. The process of implementing BIM is relatively new for the company but already ambitious targets were set for the future use of this technology. This study explains the area of intervention where the author was present, called Etudes de Prix and Méthodes service, inside the enterprise Bouygues, and intends to identify their functions and their methods of work. The use of BIM based software for the company Bouygues will be explained in this dissertation with the completion of various BIM activities made by the service Etudes de Prix and Méthodes at the stage of design and site preparation for the construction of a building to be held in the Parisian region.
Dyna, Oct 1, 2012
El objetivo de este trabajo fue evaluar y caracterizar el comportamiento mecánico en desgaste del... more El objetivo de este trabajo fue evaluar y caracterizar el comportamiento mecánico en desgaste del acero API 5L X65, revestido con niobio en comparación al desempeño del revestimiento de la aleación de inconel 625 empleados en la industria de petróleo y gas. El revestimiento de niobio fue obtenido por el proceso de aspersión térmica a plasma de arco no transferido y el revestimiento inconel 625 por soldadura con electrodo revestido. La resistencia al desgaste por abrasión fue evaluada según la norma Petrobras N-2568, en un tribómetro CTER, la rugosidad y el volumen de material desgastado se determinó a través de perfilometría y la dureza de los revestimientos por microscopia Vickers. Los revestimientos obtenidos fueron caracterizados respecto a su morfología por microscopia electrónica de barrido (MEB) y microscopía óptica (MO). La mayor dureza del revestimiento con niobio obtenido puede haber contribuido a reducir la tasa de desgaste en comparación con el revestimiento de inconel 625.
As extraordinárias virtualidades disponibilizadas pelas Tecnologias da Informação e da Comunicaçã... more As extraordinárias virtualidades disponibilizadas pelas Tecnologias da Informação e da Comunicação trazem consigo potenciais riscos, se usadas de forma abusiva ou indevida. O estudo a que nos reportamos neste texto insere-se nesse potencial de riscos e conflitos focalizando-se na análise do fenómeno do cyberbullying sobre os professores. O tema apresentou-se como relevante e inovador, no contexto português, pela gravidade das repercussões no quotidiano emocional e social dos professores e na organização escolar onde estão inseridos. Com o presente estudo, de caráter exploratório e descritivo, pretendemos contribuir para desocultar o fenómeno, fazer uma aproximação à sua dimensão e características, perceber qual é o seu impacto sobre as vítimas e percecionar o interesse que suscita. Os dados foram recolhidos através dum inquérito por questionário, online, ao qual responderam 3 426 professores. Para além da clarificação de múltiplos aspetos do fenómeno, registe-se, como principal conclusão, o facto de cerca de um terço dos professores ter declarado já ter sido alvo de cyberbullying.
Ring closing metathesis by Hoveyda–Grubbs catalysts: A theoretical approach of some aspects of the initiation mechanism and the influence of solvent
Inorganica Chimica Acta, 2015
Abstract Olefin metathesis is a type of chemical reaction with a wide range of applications. Desp... more Abstract Olefin metathesis is a type of chemical reaction with a wide range of applications. Despite intense study, the mechanism of this reaction and the effects of solvent are still poorly understood. The full RCM catalytic cycle of N-tosyldiallylamine and a Hoveyda–Grubbs catalyst were examined using density functional theory. We considered two different possibilities for the initiation step, and the pathway that included interconversion of the 14 electron structure was found to be the most stable. Important solvent influences were revealed using the PCM method, as the reaction was found to be much more favourable in all of the solvents studied herein. We did not detect any significant differences between the solvents considered by this approach, but we did find that dichloromethane and methanol are better than water for this reaction, as was expected. Classical Monte Carlo simulations of the solvation process revealed that water is a poor solvent, but solvation became better with addition of methanol. Also, the Monte Carlo simulations showed that dichloromethane is the best solvent of those analysed followed very closely by methanol.
Pseudodictyopsella jurassica N. gen., n. sp., a new foraminifera from the early middle Jurassic of the Musandam Peninsula, N. Oman mountains; sedimentological and stratigraphical context
Revue de Micropaléontologie, 1998
A new genus of foraminifera Pseudodictyopsella n. gen., type species P. jurassica n. sp. is descr... more A new genus of foraminifera Pseudodictyopsella n. gen., type species P. jurassica n. sp. is described in the Middle Jurassic of the Musandam limestone Group in the Wadi Naqab section (North Oman Mountains). Its trochospiral coiling and the presence of a valvular tooth plate places the new genus in the family Valvulinidae emended. The presence of exoskeletal hypodermic radial partitions
RESUMO -Este trabalho teve como objetivo estudar a ocorr&lcia e flutuação populacional do pulgão ... more RESUMO -Este trabalho teve como objetivo estudar a ocorr&lcia e flutuação populacional do pulgão Brachycaudus (Appelia) schwartzi (Bômer, 1931) (Homoptera: Aphididae), em pessegueiro, no município de Jacul, MCi, sob a influência dos fatores climáticos e da fenologia da planta, bem como verificar • proporção de formas durante o período amostrado. Foram amostrados quinzenalmente (agosto/1994 • julho/1995), três ramos apicais, de aproximadamente 25 cm de comprimento, por planta em 10 plantas. Durante todo o período de amostragem constatou-se a presença de B. schwartzi, mas com maiores picos durante o período de agosto/1994 a dezembro/1994. O pico máximo ocorreu em setembro/1994, quando as plantas encontravam-se na fase vegetativa e a população de pulgões mostrou-se correlacionada positivamente com a temperatura e negativamente com a umidade relativa. A população de ninfas de primeiro e segundo instares foi maior em relação às demais, representando 62,68% do total de individuos amostrados. A fenologia do pessegueiro foi um fator de grande importância na flutuação populacional de B. schwartzt Termos para indexação: fator climático, fenologia. ABSTRACT -This work intended to study both occurrence and population fluctuation of the aphid Brachycaudus (Appelia) schwartzi, (Bõrner, 1931) (Homoptera: Aphididae), on peach tree in the city ofJacui, MCi, under the influence of climate factors and phenology ofthe plant, as well as to veri' the ratio of forms over the period sampled. Three apical twigs about 25 cm long were sampled fortnightly per plant in 10 plants. Throughout the sampling period, the presence ofB. schwartzi was found, but the highest peaks were registered from August, 1994 to December, 1994. The maximum peak occurred in September, 1994, where its population proved to be positively correlated with temperature and negatively with relative humidity and the plants were in the vegetative phase. 'fie population of nymphs offirst and second instars was greater ia relation to the others, standing for 62.68% of the total of individuais sampled. The phenology of the peach tree was a factor of great importance in the population fluctuation of B. schwartzi. Index terms: climate factors, fenology. Aceito para publicação em 26 de agosto de 1997. Extraido da Dissertação de Mestrado em Fitossanidade, apresentada pelo primeiro autor à Universidade Federal de Lavras, Lanas, MCI. Trabalho financiado pelo CNPq.
Revista Brasileira de Ciências da Saúde - USCS, 2012
doutor em Ciências do Desporto, pela Utad; professor associado com Agregação da Utad.
Stratigraphy and Sedimentation of the Middle Jurassic, U.A.E
Middle East Models of Jurassic/Cretaceous Carbonate System, 2000
Acceleration capacity in futsal and soccer players
Fitness & Performance Journal, 2008
ABSTRACT Introduction: Soccer and futsal present proper characteristics, with a complex variety o... more ABSTRACT Introduction: Soccer and futsal present proper characteristics, with a complex variety of factors that can influence the performance. The objective of this study was to analyze and compare the acceleration capacity between soccer and futsal players. ...
Fitness & Performance Journal, 2008
Introdução: O futebol de campo e o futsal apresentam características próprias, com complexa varie... more Introdução: O futebol de campo e o futsal apresentam características próprias, com complexa variedade de fatores que podem infl uenciar o desempenho. O objetivo deste estudo foi analisar e comparar a capacidade de aceleração entre jogadores de futebol de campo e futsal. Materiais e Métodos: Participaram deste estudo 37 voluntários, sendo 12 atletas da seleção mineira de futsal e 25 atletas de futebol de campo da categoria juvenil. Para análise da capacidade de aceleração foram utilizadas aparelhagens de fotocélulas com sensor fotoelétrico. As fotocélulas foram posicionadas no início do sprint e aos 10m. O nível de signifi cância estabelecido nesse estudo foi de p<0,05. Resultados: Os resultados no teste de velocidade de 10m indicaram diferença entre os dois grupos, com melhores resultados para os atletas de futsal. Discussão: Os jogadores de futsal foram mais velozes que os jogadores de futebol de campo. O resultado corrobora a literatura, verifi cando-se que arranques em alta intensidade acontecem com mais freqüência na modalidade de futsal em relação à modalidade de futebol de campo.
Studies on lanthanoid sulphites
Thermochimica Acta, 1985
Abstract Thermal behaviour of Er 2 (SO 3 ) 3 · 3H 3 O has been studied by means of TG, DTG, DTA, ... more Abstract Thermal behaviour of Er 2 (SO 3 ) 3 · 3H 3 O has been studied by means of TG, DTG, DTA, DSC and EGA techniques. Experimental conditions were also varied, viz. sample size, heating rate and the atmosphere. The dehydration starts slowly above 150°C but the release of water is rapid around 250°C. SO 2 gas is evolved slowly and simultaneously with H 2 O. The anhydrous sulphite is formed below 300°C after which it decomposes through several reactions accompanied by a release of mainly SO 2 , but also a small amount of SO 3 near 650°C. In air, there is a clear plateau in the TG curve between 600 and 800°C; the weight loss involved depends strongly on the sample size and heating rate, however. A plausible explanation for the plateau is the formation of a mixture of Er 2 (SO 4 ) 3 , Er 2 O(SO 4 ) 2 and Er 2 O 2 SO 4 . The next plateau around 900 – 1000°C corresponds to Er 2 O(SO 4 ) 2 and Er 2 O 2 SO 4 . In nitrogen atmosphere, the first plateau after the anhydrous sulphite appears later in the weight scale as compared to air. Although the position of the plateau corresponds to the sesquisulphide, it is according to X-ray diffraction results a mixture of Er 2 O 2 (SO 4 ) and Er 2 O 3 . In both air and nitrogen, the final reaction step above 1000°C is the formation of Er 2 O 3 .
Annals of Human Biology, 2010
Objective: To analyse the physical growth of a representative school population sample from the J... more Objective: To analyse the physical growth of a representative school population sample from the Jequitinhonha Valley, Minas Gerais, Brazil, in comparison with the reference proposed by the Centre for Disease Control and Prevention (CDC-2000). Methods: The sample was composed of 5100 individuals (2730 girls and 2370 boys), aged 6-18 years. Body weight-for-age and height-for-age percentiles were obtained using the LMS method. Statistical and graphical comparisons were made with the corresponding percentiles of the CDC-2000 reference, estimated using the same method. Results: Overall, the calculated values of the L (asymmetry) and the S (variability) parameters were quite similar to the CDC-2000 reference values. However, M (median) was substantially different from the reference used in the study, mainly in schoolchildren over 12-13 years of age of both genders. The magnitude of the deficits of height-for-age and body weight-for-age observed in the schoolchildren from the Jequitinhonha Valley, Minas Gerais, Brazil, varied from 4 to 6 cm and from 3 to 6 kg, respectively. The body weight-for-age and height-for-age percentiles of schoolchildren population in the Jequitinhonha Valley, Minas Gerais, Brazil differed substantially from those referenced.
Improved performance of wind turbines using a hybrid MPPT strategy
2023 25th European Conference on Power Electronics and Applications (EPE'23 ECCE Europe)
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Papers by José Gomes de Matos