Detachment efficiency of fruits from coffee plants subjected to mechanical vibrations

The development of efficient machines for the mechanical harvesting of coffee plants requires the use of appropriate vibrational parameters. Thus, in order to detach less unripe fruits and decrease reharvesting, branch breakage and defoliation, it is important to choose the appropriate frequency, amplitude and vibration time. This study aimed at analyzing the detachment efficiency of fruits from coffee plants according to vibrational parameters and ripening stage. Fruit bunches were sampled at the green and mature stages and subjected to vibration, using a system composed by a signal generator, an amplifier and an electromagnetic vibrating machine. Tests combined different frequencies (16.4 Hz, 20.3 Hz, 24 Hz, 25.6 Hz, 30.0 Hz and 33.0 Hz), amplitudes (5.0 mm, 7.0 mm and 9.0 mm) and vibration times (10.0 s and 20.0 s). The vibration times did not affect the detachment efficiency. There was a trend for higher detachment efficiency in mature fruits than in green fruits. The detachment efficiency increased with increasing vibration frequency and amplitude.O 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

Comportamento dinâmico do sistema fruto-pedúnculo-ramo do cafeeiro, usando método de elementos finitos estocástico

The 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.O desenvolvimento de máquinas eficientes para a colheita do cafeeiro exige conhecimentos sólidos sobre o comportamento dinâmico da planta. O método de elementos finitos é uma ferramenta numérica utilizada para determinar frequências naturais e modos de vibração. Porém não se tem empregado o método de elementos finitos estocástico para análise do comportamento dinâmico do cafeeiro. Assim, objetivou-se neste trabalho determinar as frequências naturais e modos de  vibração do sistema fruto-pedúnculo-ramo do cafeeiro. Foram determinadas as frequências naturais e os modos de vibração  empregando-se o método de elementos finitos estocástico, em que o módulo de elasticidade e a massa específica dos frutos, pedúnculo e ramos foram tratados como variáveis aleatórias, obtendo-se a variação das frequências naturais em função da variabilidade destas propriedades. As frequências naturais reduziram na medida em que se evolui o estádio de maturação dos frutos e pedúnculos ou se aumenta a massa total do sistema, dado pelo aumento do número de frutos solidários ao pedúnculo. As frequências naturais aumentaram na medida em que se elevou o módulo de elasticidade ou se reduziu a massa específica dos frutos, pedúnculos e ramos

Estudos de casos de classificação de áreas cultivadas com café por meio de descritores de textura

The objective of this work is to develop a system to identify areas cultivated with coffee using ANNs having as input variables descriptors Haralick. We used the training algorithm Back-propagation and Levenberg -Marquardt method. There were two cases of study: in the first step, the ANN was trained with representative samples of each class of interest (coffee, forest, water, bare soil, and urban area), thus verifying the potential to discriminate output classes; in the second step the objective was to classify the coffee plantations accordingly with the age. For the evaluation of the classification performance of ANNs was employed a reference map and land use through the Geographic Information System. The concordance between the thematic maps, classified by ANN, and the reference map was evaluated by Kappa index. It was verified that Kappa index for discriminating the coffee region of the other class of interest was 0,652 in the first case study, performance as very good. To classify the coffee plantations accordingly with the age, Kappa index was variable (0.675 to 0.4783), very good for Itatiaia farm and reasonable to Pedra Redonda farm.O objetivo neste trabalho foi desenvolver um sistema para identificar áreas cultivadas com café utilizando Redes Neurais Artificiais (RNAs) tendo como variáveis de entrada os descritores de textura de Haralick. Utilizou-se o algoritmo de treinamento do tipo retro-propagação do erro (backpropagation) e o método de Levenberg-Marquardt. Foram realizados dois estudos de casos: no primeiro, as RNAs foram desenvolvidas para discriminar entre as classes café, mata, água, solo exposto, pastagem e área urbana; no segundo, as RNAs foram desenvolvidas para classificar as plantações de café de acordo com a idade e com a data de recepa. Para a avaliação do desempenho de classificação das RNAs empregou-se um mapa de referência de uso e ocupação do solo elaborado por meio do Sistema de Informações Geográficas. A concordância entre os mapas temáticos, classificados pela RNA, e o mapa de referência foi avaliada pelo coeficiente Kappa. Verificou-se que o coeficiente Kappa para discriminar a região cafeeira das outras classes temáticas foi de 0,652 no primeiro estudo de caso, desempenho considerado muito bom. Para classificar os plantios de café em função da idade e data de recepa o índice Kappa foi variável (0,675 a 0,4783), sendo considerado muito bom para a fazenda Itatiaia e razoável para a fazenda Pedra Redonda

Development and evaluation of operational performance of macaw fruits semi-mechanized harvester by means mechanical vibrations principle

Macaw (Acrocomia aculeata) is a product of Brazilian socio-biodiversity and is an excellent source of oil for the cosmetics, food and fuel industry. One of the technical bottlenecks of macaw fruit production is the manual harvesting with rudimentary tools and the extractive system, which has a very large dependence on labor. The objective of this work was to develop the informational and conceptual design of a semi-mechanized harvesting system that can be used in adverse conditions of relief, also directed to the needs of family farmers. In this work the concept of a low cost macaw harvester is proposed, which works by the principle of mechanical vibrations, and is able to work efficiently in planted and natural plantations. From an adaptation of the Pahl and Beitz method for the development of machine designs, and the use of the evolution prototyping method, integration prototypes were constructed, which underwent a preliminary field test. Some modifications were made in portable coffee breakers, which constituted changes in the vibration signal generation system that were transmitted to macaw fruits at the head / plant interface. Only one of the built prototypes was considered effective and suitable for subsequent performance (product under patent registration). For the detailed design, CAD (Computer Aided Design) techniques were employed. Later, it was possible to observe the validation of efficiency of the macaw fruit harvest by the principle of mechanical vibrations. Under field conditions, field trials demonstrated that the average harvest efficiency for the proposed model with vibrating rods was 97.4% and the average harvesting capacity was 566.91 kg h-1

GVHD-derived plasma as a priming strategy of mesenchymal stem cells

Background: Mesenchymal stem cell (MSC) therapy is an important alternative for GVHD treatment, but a third of patients fail to respond to such therapy. Therefore, strategies to enhance the immunosuppressive potential of MSCs constitute an active area of investigation. Here, we proposed an innovative priming strategy based on the plasma obtained from GVHD patients and tested whether this approach could enhance the immunosuppressive capacity of MSCs. Methods: We obtained the plasma from healthy as well as acute (aGVHD) and chronic (cGVHD) GVHD donors. Plasma samples were characterized according to the TNF-α, IFN-γ, IL-10, IL-1β, IL-12p40, and IL-15 cytokine levels. The MSCs primed with such plasmas were investigated according to surface markers, morphology, proliferation, mRNA expression, and the capacity to control T cell proliferation and Treg generation. Results: Interestingly, 57% of aGVHD and 33% of cGVHD plasmas significantly enhanced the immunosuppressive potential of MSCs. The most suppressive MSCs presented altered morphology, and those primed with cGHVD displayed a pronounced overexpression of ICAM-1 on their surface. Furthermore, we observed that the ratio of IFN-γ to IL-10 cytokine levels in the plasma used for MSC priming was significantly correlated with higher suppressive potential and Treg generation induction by primed MSCs, regardless of the clinical status of the donor. Conclusions: This work constitutes an important proof of concept which demonstrates that it is possible to prime MSCs with biological material and also that the cytokine levels in the plasma may affect the MSC immunosuppressive potential, serving as the basis for the development of new therapeutic approaches for the treatment of immune diseases