Submitted by Jos? Henrique Henrique (jose.neves@ufvjm.edu.br) on 2017-01-04T14:03:51Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ivana_pires_sousa_baracho.pdf: 881653 bytes, checksum: 116255ef5aa789c8ed97b09f4b8417c8 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2017-01-31T16:57:04Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ivana_pires_sousa_baracho.pdf: 881653 bytes, checksum: 116255ef5aa789c8ed97b09f4b8417c8 (MD5) / Made available in DSpace on 2017-01-31T16:57:04Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) ivana_pires_sousa_baracho.pdf: 881653 bytes, checksum: 116255ef5aa789c8ed97b09f4b8417c8 (MD5) Previous issue date: 2016 / Funda??o de Amparo ? Pesquisa do Estado de Minas Gerais (FAPEMIG) / Objetivou-se com este trabalho avaliar o efeito da compacta??o do solo e diferentes doses de nitrog?nio no desenvolvimento, produtividade e qualidade de esp?cies forrageiras e nos atributos f?sicos do solo. Foram montados tr?s experimentos independentes em casa de vegeta??o com um delineamento em blocos casualizados, em um esquema fatorial duplo. Os experimentos foram com as tr?s esp?cies forrageiras - Bachiaria ruzizienses, Brachiaria brizantha cv. MG-5 Vit?ria e Panicum maximum cv. momba?a; os tratamentos: quatro Graus de Compacta??o (GC) ? 65%; 75%; 85% e 95% e quatro dose de adubo nitrogenado ? 0; 200; 250 e 300 Kg de N ha-1), com quatro repeti??es. O experimento foi conduzido em vasos em casa de vegeta??o localizada na UFVJM campus JK, em Diamantina-MG. No local de coleta do solo utilizado no experimento, foram coletadas amostras de aproximadamente 5 kg para a realiza??o do ensaio de Proctor normal, determinando-se a Densidade do solo e a Umidade para cada corpo de prova. Uma vez estipulado o GC, conhecendo a Densidade m?xima do solo e o volume do vaso, foi poss?vel calcular a massa de solo a ser colocada dentro dos vasos referente a cada GC. As amostras foram coletadas 90 dias ap?s semeadura, para realiza??o das avalia??es em laborat?rio. As vari?veis analisadas nas plantas foram: produ??o de massa verde (MV) e massa seca (MS) da parte a?rea, altura, volume da raiz, prote?na bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ?cido (FDA) e lignina. Para a realiza??o do ensaio de Resist?ncia do solo ? penetra??o (RP), as amostras indeformadas foram trabalhadas e saturadas por um per?odo de 48 h, em seguida deu-se in?cio ?s leituras de RP. Realizou-se tamb?m a avalia??o de RP em vasos contendo solo compactado com GC de 95%, antes da semeadura; a modelagem foi feita ajustando um modelo exponencial de RP x umidade e foram comparados estatisticamente por um teste de identidade de modelos. Concluiu-se que a MV, MS da parte a?rea, a altura de plantas e o teor de prote?na bruta aumentaram linearmente com a aplica??o de nitrog?nio em todas as forrageiras estudadas. ? medida que se aumentam as doses de nitrog?nio, os teores de FDN e FDA em todas as forrageiras estudadas diminu?ram. Para o volume da raiz, a Brachiaria brizantha cv. MG-5 Vit?ria respondeu linearmente e positivamente ?s crescentes doses de nitrog?nio no solo compactado. Na avalia??o dos atributos f?sicos do solo, o solo cultivado com Brachiaria ruziziensis foi o que apresentou uma maior RP na umidade na capacidade de campo no grau de compacta??o de 95%. As tr?s esp?cies forrageiras t?m capacidade de al?vio da estrutura do solo compactado; por?m, a Brachiaria brizantha cv. MG-5 Vit?ria demonstrou ser a mais eficiente. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Produ??o Vegetal, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2014. / The objective of this study was to evaluate the effect of soil compaction and different doses of nitrogen, in the development, productivity and quality of forage species and in soil physical properties. Three independent experiments were performed in a greenhouse with a randomized block design, in a double factorial. The experiments were with three forage species Bachiaria ruzizienses, Brachiaria brizantha cv. MG-5 Vit?ria and Panicum maximum cv. momba?a: the treatments: Four Degrees of Compaction (GC) ? 65%; 75%; 85% and 95% and four doses of nitrogen fertilizer? 0; 200; 250 e 300 Kg de N ha-1), with four replications. The experiment was conducted in pots in a greenhouse located at UFVJM JK campus, Diamantina-MG. At the site of the soil sampling used in the experiment, samples of 5kg approximately were collected to perform the normal Proctor test, determining soil density and humidity for each specimen. Once stipulated the GC, knowing the maximum density of the soil and the pot volume, it was possible to calculate the mass of soil to be placed in the pots for each GC. The samples were collected 90 days after sowing, to carry out evaluations in the laboratory. The variables analyzed in plants were: green mass production (MV) and dry matter (MS) of the shoot, height, root volume, crude protein (PB), neutral detergent fiber (FDN), acid detergent fiber (FDA) and lignin. To carry out the soil penetration resistance test (RP), the undisturbed soil samples were worked and saturated for a period of 48 h, next we started the RP readings. It was also performed the evaluation of RP in pots containing compacted soil with a 95% GC, before sowing and the modeling was performed by adjusting an exponential model of RP x humidity and they were compared statistically by an identity test of models. It was concluded that the MV, MS of the shoot, height of plants and crude protein content increased linearly with the application of nitrogen in all the studied forages. As it increases the nitrogen levels, the levels of FDN and FDA in all studied forages decreased. For the root volume, the Brachiaria brizantha cv. MG-5 Vit?ria responded linearly and positively to increasing doses of nitrogen in compacted soil. In the evaluation of soil physical properties, the soil cultivated with Brachiaria ruziziensis was the one that presented a higher RP in humidity at field capacity in the degree of compaction of 95%. The three forage species have relief capacity of the compacted soil structure, however, the Brachiaria brizantha cv. MG-5 Vit?ria proved to be the most efficient one.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-10-02T23:37:04Z No. of bitstreams: 1 EvandroAilsonDeFreitasNunes_DISSERT.pdf: 2832434 bytes, checksum: fbd09520d8dfca43784e60b088545e00 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-10-07T00:23:58Z (GMT) No. of bitstreams: 1 EvandroAilsonDeFreitasNunes_DISSERT.pdf: 2832434 bytes, checksum: fbd09520d8dfca43784e60b088545e00 (MD5) / Made available in DSpace on 2017-10-07T00:23:58Z (GMT). No. of bitstreams: 1 EvandroAilsonDeFreitasNunes_DISSERT.pdf: 2832434 bytes, checksum: fbd09520d8dfca43784e60b088545e00 (MD5) Previous issue date: 2017-06-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Atualmente, os incentivos ? gera??o de energia el?trica a partir da fontes consideradas limpas v?m aumentando consideravelmente devido ? escassez dos combust?veis f?sseis, at? ent?o utilizados em abund?ncia. Em paralelo, unidades de gera??o distribu?da que utilizam fontes renov?veis tamb?m ganha for?a com a diminui??o dos impostos aplicados sobre os componentes constituintes dos sistemas de gera??o que utilizam este tipo de fonte de energia. No entanto, a qualidade da energia el?trica tem sido severamente afetada pelo aumento do n?mero desses sistemas ligados ?s redes de distribui??o de baixa tens?o. Com base nisso, nesta disserta??o s?o avaliados os impactos na rede de distribui??o de energia el?trica decorrentes da conex?o de instala??es fotovoltaicas, em v?rios n?veis de penetra??o. Nesse intuito, ? realizado um estudo de caso que consiste em operar uma planta fotovoltaica de 9 kWp conectada ao ponto de acoplamento comum de uma subesta??o com pot?ncia nominal de 15 kVA. O sistema fotovoltaico utilizado, se divide em: i) sistema trif?sico fixo de 8 kWp e ii) sistema monof?sico fixo de 1 kWp. A avalia??o ? feita com base nos indicadores da qualidade da energia el?trica, que indicam as caracter?sticas de pot?ncia, harm?nicos de tens?o e corrente, desequil?brios entre fases do sistema e regula??o do fator de pot?ncia. A partir da an?lise desses indicadores, obtidos com aux?lio da transformada discreta de Fourier, ? realizada uma an?lise do impacto gerado pela planta fotovoltaica no ponto de conex?o com a rede el?trica. Por meio de resultados experimentais, os indicadores s?o estimados durante a opera??o do sistema fotovoltaico e s?o analisados e comparados com o padr?o internacional estabelecido pelo IEEE (do ingl?s, Institute of Electrical and Electronics Engineers). / Currently, incentives for clean energy generation have been increasing considerably due to the limitation of fossil fuels, until then used in abundance. In parallel, distributed generations increase with the reduction of the taxes of the embedded components of the renewable energy sources. However, the power quality (PQ) has been severely affected by the increasing number of these types of energy sources connected to low voltage distribution networks. In this dissertation, the impact on the utility grid will be evaluated under varying levels of a photovoltaic system penetration. A 9 kWp photovoltaic plant, composed of three system topologies connected to a 15 kVA substation common coupling point, will be carried out: a 8 kWp three-phase fixed topology and a 1 kWp fixed single phase. These photovoltaic systems are power electronics based devices, such as inverters constructed from semiconductor switches, which, due to their construction and operation, affect the waveform of the electrical voltage and current, deteriorating the PQ. From the analysis of PQ indices, obtained by means of discrete Fourier transform, for power characteristics, voltage and current harmonics, imbalanced levels among system phases and power factor regulation, an analysis of the impact generated by the photovoltaic plant at its point of connection with the utility grid will be performed. The indices will be analyzed and compared to the standards established by the Institute of Electrical and Electronics Engineers (IEEE) in order to evaluate the impact caused by the connection of the photovoltaic system at the PCC.

Made available in DSpace on 2014-12-17T14:55:52Z (GMT). No. of bitstreams: 1 BezalielASP_DISSERT.pdf: 2307069 bytes, checksum: aa5ddc5e2ae2722d27d66e85a1e511f1 (MD5) Previous issue date: 2011-08-03 / This work develops a methodology for defining the maximum active power being injected into predefined nodes in the studied distribution networks, considering the possibility of multiple accesses of generating units. The definition of these maximum values is obtained from an optimization study, in which further losses should not exceed those of the base case, i.e., without the presence of distributed generation. The restrictions on the loading of the branches and voltages of the system are respected. To face the problem it is proposed an algorithm, which is based on the numerical method called particle swarm optimization, applied to the study of AC conventional load flow and optimal load flow for maximizing the penetration of distributed generation. Alternatively, the Newton-Raphson method was incorporated to resolution of the load flow. The computer program is performed with the SCILAB software. The proposed algorithm is tested with the data from the IEEE network with 14 nodes and from another network, this one from the Rio Grande do Norte State, at a high voltage (69 kV), with 25 nodes. The algorithm defines allowed values of nominal active power of distributed generation, in percentage terms relative to the demand of the network, from reference values / Neste trabalho, prop?e-se uma metodologia para defini??o dos valores m?ximos de pot?ncia ativa a serem injetados em barras pr?-definidas das redes de distribui??o estudadas, considerando a possibilidade de m?ltiplos acessos de unidades geradoras. A defini??o desses valores m?ximos se obt?m a partir de um estudo de otimiza??o, no qual as novas perdas n?o superam as do caso base, ou seja, sem a presen?a da gera??o distribu?da. No estudo atendem-se as restri??es de carregamentos nos ramos e tens?es do sistema. Para tratar o problema, prop?e-se um algoritmo baseado no m?todo num?rico de otimiza??o nuvem de part?culas, ou particle swarm optimization PSO, aplicado ao estudo de fluxo de carga convencional CA e ao fluxo de carga ?timo para maximiza??o da penetra??o da gera??o distribu?da. Tamb?m se incorporou o m?todo de Newton-Raphson, como alternativa, para a resolu??o do fluxo de carga. Realiza-se a programa??o computacional no software SCILAB. Testa-se o algoritmo proposto com os dados da rede IEEE-14 barras e de uma rede de distribui??o em alta tens?o (69 kV) do Estado do Rio Grande do Norte, com 25 barras. O algoritmo determina valores permitidos de pot?ncia ativa nominal de gera??o distribu?da, em termos percentuais relativos ? demanda da rede, a partir de valores de refer?ncia