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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Vibration Transmissibility of the Coffee Fruit-Peduncle System: a Forced Vibration Study of High Frequency Aiming Mechanical Harvesting(Associação Brasileira de Engenharia Agrícola, 2023-01-30) Villibor, Geice P.; Santos, Fábio L.; Queiroz, Daniel M.; Khoury Junior, Joseph K; Pinto, Francisco A. C.Semi-mechanized and mechanized harvesting use machines that promote the transference of vibrational energy and impact to achieve the detachment of coffee fruits. The aim of this study was to evaluate the vibration transmissibility in coffee fruit-peduncle systems, using high-speed cameras, submitted to high frequency harmonic excitation in different combinations between frequency and amplitude of vibration, identifying working ranges suitable to perform selective harvesting. Vibration transmissibility was determined for the coffee fruit-peduncle systems, for the maturation stages unripe and ripe that were subjected to a sinusoidal harmonic displacement, in which the input parameters were frequency (35, 45 and 55 Hz) and peak-to-peak amplitude (3.5, 5.0 and 6.5 mm). An experiment was used to study the effect of frequency and amplitude on vibration transmissibility in a completely randomized design in a factorial scheme 3 x 3 x 2, with three replications. The frequency of 35 Hz, associated with the amplitudes 3.5-6.5 mm, was the one that most influenced the results of vibration transmissibility. For the frequency of 55 Hz and amplitude of 6.5 mm, in the ripe maturation stage, the vibration transmissibility was higher than 1.0, which could be a suitable combination for selective coffee harvesting.Item Spatial variability of apparent electrical conductivity and soil properties in a coffee production field(Associação Brasileira de Engenharia Agrícola, 2014-11) Valente, Domingos S. M.; Queiroz, Daniel M. de; Pinto, Francisco de A. de C.; Santos, Fábio L.; Santos, Nerilson T.Precision agriculture based on the physical and chemical properties of soil requires dense sampling to determine the spatial variability of these properties. This dense sampling is often expensive and time-consuming. One technique used to reduce sample numbers involves defining management zones based on information collected in the field. Some researchers have demonstrated the importance of soil electrical variables in defining management zones. The objective of this study was to evaluate the relationship between the spatial variability of the apparent electrical conductivity and the soil properties in the coffee production of mountain regions. Spatial variability maps were generated using a geostatistical method. Based on the spatial variability results, a correlation analysis, using bivariate Moran’s index, was done to evaluate the relationship between the apparent electrical conductivity and soil properties. The maps of potassium (K) and remaining phosphorus (P-rem) were the closest to the spatial variability pattern of the apparent electrical conductivity.Item Preservation of roasted and ground coffee during storage. Part 2: Bulk density and intergranular porosity(Departamento de Engenharia Agrícola - UFCG, 2016-07) Corrêa, Paulo C.; Oliveira, Gabriel H. H. de; Vasconcelos, Wander L.; Vargas-Elías, Guillermo A.; Santos, Fábio L.; Nunes, Eduardo H. M.The determination of physical properties is an important factor in the design of machinery and the scaling of post-harvest operations. The present study evaluates the influence of the level of roasting and the size of grinding on the physical properties of coffee during storage. The following physical properties were evaluated: true and bulk density, and intergranular porosity. Raw coffee beans (Coffea canephora and Coffea arabica), hulled and dried, were roasted to two different levels: medium light (SCAA#65) and moderately dark (SCAA#45). The beans were then grinded into three different sizes: fine (0.59 mm), medium (0.84 mm) and coarse (1.19 mm). An additional coffee lot was kept whole. Following grinding, samples were stored at two different temperatures (10 and 30 oC) and analyzed after five different storage durations (0, 30, 60, 120 and 180 days). The medium light roast had higher values for each of the measured physical properties. Finely ground samples had higher true and bulk densities, and porosities. It is concluded that the size of grinding, level of roasting and duration of storage significantly affect the physical properties of coffee.Item Preservation of roasted and ground coffee during storage Part 1: Moisture content and repose angle(Departamento de Engenharia Agrícola - UFCG, 2016-06) Corrêa, Paulo C.; Oliveira, Gabriel H. H. de; Oliveira, Ana P. L. R. de; Vargas-Elías, Guillermo A.; Santos, Fábio L.; Baptestini, Fernanda M.The present study evaluates the influence of the level of roasting and the grind size on the moisture content and repose angle of coffee during storage. Raw coffee beans (Coffea canephora and Coffea arabica), hulled and dried, were roasted to two different levels: medium light (SCAA#65) and moderately dark (SCAA#45). The beans were then ground into three different grind sizes: fine (0.59 mm), medium (0.84 mm) and coarse (1.19 mm). An additional coffee lot was kept whole. Following grinding, samples were stored at two different temperatures (10 and 30 oC) and analyzed after five different storage durations (0, 30, 60, 120 and 180 days). The moderately dark roast was found to have a lower moisture content. Finely ground samples had higher angles of repose. It is concluded that the grind size, level of roasting and duration of storage significantly affect the moisture content and angle of repose of coffee.Item Efeito da frequência e amplitude de vibração sobre a derriça de frutos de café(Departamento de Engenharia Agrícola - UFCG, 2010-04) Santos, Fábio L.; Queiroz, Daniel M. de; Pinto, Francisco de A. de C.; Resende, Ricardo C. deParâmetros de qualidade podem alterar significativamente o preço do café; entretanto, a colheita seletiva dos frutos é frequentemente associada à boa qualidade do produto, procedimento que pode ser realizado por meio de vibrações mecânicas. Desta forma, o estudo e a avaliação do efeito localizado de fatores como frequência, amplitude e grau de maturação dos frutos, são fundamentais para construção de máquinas adequadas a este tipo de prática. O trabalho foi desenvolvido com o objetivo de se avaliar os fatores frequência, amplitude, grau de maturação, direção de excitação e número de frutos por pedúnculo, na eficiência de derriça. Para a realização dos ensaios de vibração em laboratório utilizou-se uma máquina vibradora eletromagnética. Amplitudes na faixa de 3,75 a 7,50 mm e frequências na faixa de 13,33 a 26,67 Hz foram testadas para a variedade Mundo Novo, em que os resultados mostraram que a frequência de 26,67 Hz apresentou uma eficiência maior de derriça para os frutos cereja e a amplitude de 7,5 mm indicou maior eficiência de derriça. Verificou-se, também, que o número de frutos por pedúnculo influencia a eficiência de derriça dos frutos de café da variedade Mundo Novo.Item Determinação das propriedades geométricas, físicas e mecânicas do sistema fruto-pedúnculo-ramo do cafeeiro(Departamento de Engenharia Agrícola - UFCG, 2015-03) Coelho, Andre L. de F.; Santos, Fábio L.; Pinto, Francisco A. C.; Queiroz, Daniel M. deO método de elementos finitos tem sido empregado no projeto de máquinas e para o estudo do comportamento dinâmico do cafeeiro. Objetivou-se, neste trabalho, determinar as propriedades geométricas, físicas e mecânicas do sistema fruto-pedúnculo-ramo do cafeeiro. As dimensões foram determinadas por meio de processamento de imagens, as massas e os volumes mensurados utilizando-se balança e proveta, respectivamente. Os módulos de elasticidade foram determinados por meio de ensaios mecânicos de compressão, tração e flexão, para os frutos, pedúnculos e ramos, respectivamente. Os coeficientes de Poisson foram determinados a partir das deformações longitudinais e transversais dos frutos e pedúnculos. A razão de amortecimento foi determinada por meio das curvas de decaimento utilizando-se o método de decremento logaritmo. Concluiu-se que as dimensões e a massa dos frutos apresentaram tendência de aumento na medida em que seu estádio de maturação evoluiu. Os módulos de elasticidade dos frutos e dos pedúnculos no estádio de maturação verde foram superiores aos valores para o estádio de maturação cereja.