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URI permanente desta comunidadehttps://thoth.dti.ufv.br/handle/123456789/3352
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Item Detachment efficiency of fruits from coffee plants subjected to mechanical vibrations(Escola de Agronomia - UFG, 2015) Coelho, Andre Luiz de Freitas; Santos, Fábio Lúcio; Pinto, Francisco de Assis de Carvalho; Queiroz, Daniel Marçal deO desenvolvimento de máquinas eficientes para a colheita mecanizada do cafeeiro exige a utilização de parâmetros vibracionais adequados. Assim, para um menor desprendimento de frutos verdes, repasse, quebra de galhos e desfolha, devem ser utilizados magnitudes de frequência, amplitude e tempo de vibração adequados. Objetivou-se analisar a eficiência de derriça de frutos de cafeeiro, em função de parâmetros vibracionais e estádio de maturação. Cachos de frutos foram amostrados nos estádios de maturação verde e cereja e submetidos à vibração, utilizando-se um sistema composto por um gerador de sinais, um amplificador e uma máquina vibratória eletromagnética. Os ensaios foram realizados combinando-se diferentes frequências (16,4 Hz; 20,3 Hz; 24 Hz; 25,6 Hz; 30,0 Hz; e 33,0 Hz), amplitudes (5,0 mm; 7,0 mm; e 9,0 mm) e tempos de vibração (10,0 s e 20,0 s). Os tempos de vibração empregados não influenciaram na eficiência de derriça. Houve tendência de a eficiência de derriça dos frutos cerejas ser superior à dos frutos verdes. A eficiência de derriça aumentou à medida que se aumentou a frequência e a amplitude de vibração.Item Definition of management zones in coffee production fields based on apparent soil electrical conductivity(Escola Superior de Agricultura "Luiz de Queiroz", 2012-05) Valente, Domingos Sárvio Magalhães; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de Carvalho; Santos, Nerilson Terra; Santos, Fábio LúcioFertilizer application at variable rates requires dense sampling to determine the resulting field spatial variability. Defining management zones is a technique that facilitates the variable-rate application of agricultural inputs. The apparent electrical conductivity of the soil is an important factor in explaining the variability of soil physical-chemical properties. Thus, the objective of this study was to define management zones for coffee (Coffea Arabica L.) production fields based on spatial variability of the apparent electrical conductivity of the soil. The resistiv- ity method was used to measure the apparent soil electrical conductivity. Soil samples were collected to measure the chemical and physical soil properties. The maps of spatial variability were generated using ordinary kriging method. The fuzzy k-means algorithm was used to delimit the management zones. To analyze the agreement between the management zones and the soil properties, the kappa coefficients were calculated. The best results were obtained for the management zones defined using the apparent electrical conductivity of the soil and the digital elevation model. In this case, the kappa coefficient was 0.45 for potassium, which is an element that is associated with quality coffee. The other variable that had a high kappa coefficient was remaining phosphorous; the coefficient obtained was 0.49. The remaining phosphorus is an important parameter for determining which fertilizers and soil types to study.Item Analysis of the coffee harvesting process using an electromagnetic shaker(Editora da Universidade Estadual de Maringá - EDUEM, 2010-07) Santos, Fábio Lúcio; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de Carvalho; Santos, Nerilson TerraHarvesting is one of the most important operations in coffee production systems. This operation has a high cost and impact on the final quality of the product. To reduce production costs, producers are looking for ways to mechanize this operation. Harvesting machines generally detach fruits from the coffee plant by vibration and/or impact. The objective of this work was to study the effect of the amplitude and frequency of vibration on the efficiency of coffee fruit harvesting. Vibration tests of coffee branches were performed in a laboratory using an electromagnetic shaker. The tests were performed using amplitudes in the range of 3.75 to 7.50 mm and frequencies from 13.33 to 26.67 Hz. Coffee branches from two different varieties were used for evaluation, Catuaí Vermelho and Mundo Novo. It was verified that harvesting efficiency is directly related to the acceleration reached by the fruits during the harvesting process. The frequencies of 23.33 and 26.67 Hz and amplitudes of 6.25 and 7.50 mm resulted in the highest harvesting efficiency of ripe coffee cherries for both varieties. However, the harvesting efficiency for the Mundo Novo variety was higher than that of the Catuaí Vermelho variety at the studied frequency and amplitude ranges in this work.Item Characterization and delimitation of the terroir coffee in plantations in the municipal district of Araponga, Minas Gerais, Brazil(Universidade Federal do Ceará, 2014-01) Silva, Samuel de Assis; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de Carvalho; Santos, Nerilson TerraDifferentiating coffees through the notion of terroirs allows us to determine potential areas for specialty coffee production and to characterize the type of coffee in these areas, exploring their potential. The objective of this work was to study spatial variability quality and to characterize and delimit terroirs in coffee crop production in Araponga municipality, Minas Gerais State, Brazil, using sensorial evaluation. The data were collected from four crops, from altitudes ranging from 770 to 1270 m, with the extract increasing from low to high. In each plot of crops, samples of cherry fruits were collected, dried, benefited, subjected to sensorial analysis and given grades ranging from 0 to 100 points for the global drink quality and relative characteristics of honey, body, acidity, flavor and equilibrium. The spatial variability of the quality was analyzed using the Moran Index. To define coffee production terroirs, average quality grades were compared through separation tests and the individual values of the plots were subjected to an analysis of groupings. The study was efficient in identifying terroirs for mountain coffee culture, therefore allowing coffees to be differentiated as a function of their production locations. Araponga has more than one coffee production terroir characterized by two distinct altitude extracts.Item Dynamic behavior of the coffee fruit-stem-branch system using stochastic finite element method(Editora UFLA, 2016-01) Coelho, Andre Luiz de Freitas; Santos, Fábio Lúcio; Queiroz, Daniel Marçal de; Pinto, Francisco de Assis de CarvalhoThe development of an efficient machine for harvesting coffee requires comprehensive knowledge of the dynamic behavior of the plant and its parts. The finite element method is a numerical approach used to determine natural frequencies and mode shapes. However, the stochastic finite element method has not been employed for the analysis of the dynamic behavior of coffee. The aim is to determine the natural frequencies and mode shapes for the coffee fruit-stem-branch system. The natural frequencies and the mode shapes were determined by employing the stochastic finite element method, in which the elastic modulus and the specific mass were treated as random variables, and the variation in the natural frequency was obtained as a function of the variability of these properties. The natural frequencies were reduced according to the evolution of the ripening process of the fruit and stem or due to the increase in the total weight of the system due to an increase in the number of fruits attached to the stem. The natural frequencies increased with an increase in the elastic modulus or with a reduction in the specific mass.