Abstract The use of computational simulation techniques is an important tool for the coffee harvesting issues, particularly the finite element method. The method is widely used in the structural analysis of agricultural machinery, as well as in the analysis of the stresses and vibrations of coffee branches and peduncles during the harvesting process. The present study aimed to develop three-dimensional finite element models of the plagiotropic branches of the Catuaí Vermelho variety of Arabica coffee in different positions along the orthotropic branches of the plant; considering high-fidelity models. Additionally, by considering the branches’ experimental properties (physical-mechanical), the natural frequencies and vibration modes of the branches were determined by means of computer simulations. First, the geometric properties of the coffee branches were obtained by means of two images taken using a professional camera to obtain the input data of the virtual simulation. For the mechanical properties, it was used a semi-analytical digital scale, to obtain the mass of the specimens. The modulus of elasticity was determined using a universal testing machine. The variability in the simulated natural frequencies could be identified, which was on the order of 30% for the first frequency, regardless of the position of the branch in the plant. These values were lower for the other frequencies. Linear regression fits showed a coefficient of determination, and correlation tests were used to verify the relationship between the values obtained numerically and experimentally, which were validated by using experimental data using the modal analysis techniques.

ABSTRACT In family farming, mechanisation, when appropriate to the task and to the size of the property, can be one way of easing tiring and repetitive work, such as garlic harvesting. The present study is based on a model of harvester currently on the market, and proposes several improvements for mechanising the harvest on family farms, with an emphasis on sloping terrain, to reduce costs and increase productivity. Since the equipment currently on the market reduces the operational performance of these producers resulting in the high prices of commercial garlic, the aim of this study was to evaluate, using the Finite Element Method, the von Mises stresses and the displacement of a garlic harvester in different topographies. A structural analysis was carried out, and the vibration modules in the three main parts that make up the structure of the garlic harvester were checked: the structure supporting the scarifier point, the structure of the plant transport system, and the structure at the rear of the harvester. The structural modifications that were implemented corrected the initial high-stress conditions, showing improvements in stress concentration and areas of displacement. As such, the entire structure of the garlic harvester tends to withstand the proposed loads. From the results of the simulations, we conclude that the connecting support may undergo greater response from structural dynamics, and that frequencies greater than 45.7 Hz should be avoided since there are several natural frequencies above this range that might cause interference to the structure.

Resumo Dada a importância da suinocultura para o Brasil, é necessário entender o impacto ambiental gerado pelos materiais de construção empregados na produção das instalações rurais, em especial na construção dos biodigestores, visto que essas instalações têm um importante papel na sustentabilidade dos sistemas de produção. Diante da relevância do volume de concreto empregado no processo de construção de biodigestores para manejo e tratamento de resíduos da suinocultura, esta pesquisa avaliou as emissões de dióxido de carbono equivalente (CO2Eq.) em diferentes cenários de dosagens de concreto. Para isso, um modelo computacional ANFIS (Adaptive Neuro-Fuzzy Inference System) foi desenvolvido para predição e análise das emissões de CO2Eq. durante o ciclo de vida dos materiais adotados em concretos convencionais. Os resultados indicam que a escolha adequada da dosagem pode gerar redução nas emissões de CO2Eq. da ordem de 31,41% para concretos de 30 MPa a 40 MPa. Isso implica uma proposta promissora para a redução do impacto ambiental na produção de instalações em concreto, o que tem potencial paraimpulsionar novas pesquisas na área.

Abstract Due to the importance of swine production in Brazil, there is a need to understand the environmental impact generated by the construction materials used in the production of rural facilities, especially in the construction of biodigesters, as these facilities play an important role in the sustainability of production systems. Considering the relevance of the volume of concrete used in the construction of biodigesters for the management and treatment of swine waste, this research study sought to evaluate the emissions of carbon dioxide equivalent (CO 2 Eq.) in different concrete mix scenarios. For that purpose, a computational ANFIS (Adaptive Neuro-Fuzzy Inference System) model was developed to predict and analyse CO 2 Eq. emissions during the life cycle of materials adopted in conventional concrete. The results indicate that the proper choice of dosage can lead to a reduction of 31.41% in CO 2 Eq. emissions, for concrete from 30 to 40 MPa. This represents a promising proposal for reducing the environmental impact of the production of concrete constructions, which has the potential to stimulate further research in this area.

Resumo Com o aumento do processo de urbanização e da população das cidades, surge a necessidade de entender o custo energético para produção dos materiais de construção. Entre os instrumentos utilizados, o aporte de energia é um importante instrumento no monitoramento do uso de fontes de energia não renováveis para produção de concretos convencionais, o que demanda novas pesquisas na área. Neste trabalho, um modelo híbrido ANFIS (Adaptive Neuro-Fuzzy Inference System) foi desenvolvido para predição do aporte de energia, para a avaliação da demanda de energia necessária para cada um dos componentes na produção de concretos convencionais (cimento, água, agregado miúdo e agregado graúdo), mediante a utilização de 101 dosagens experimentais, 101 dosagens para validação e coeficientes energéticos disponíveis em literaturas. Identificou-se que a escolha adequada da dosagem pode gerar uma economia no custo energético para produção do concreto da ordem de 24,77%, mantendo a característica mecânica de resistência à compressão para construções convencionais.

Abstract Anincreasingprocess of urbanisation anda growing urban population heighten the need to understand the energy costsof the production of building materials. One of the most importanttoolsapplied to monitor the use of non-renewableenergyresources in the production of conventionalconcretes is energy input, intowhichfurther research is needed. In this study, an ANFIS (adaptive neuro-fuzzy inference system) hybrid model was developed to predict energy input in order to evaluate the energy demand required for each component of the production of conventional concrete (cement, water, fine aggregate and coarse aggregate) using 101 experimental dosages, 101 validation dosages and energy coefficients available in literature. The resultsshowedthatan adequate dosage can generate energy cost savingsof 24.77% in the production of concrete, while still maintaining the mechanical characteristics of compressive strength for conventional constructions.

Resumo Otimização por Enxame de Partículas (PSO) é uma técnica de inteligência artificial (AI), que pode ser usada para encontrar soluções aproximadas para problemas numéricos de maximização e minimização extremamente difíceis. Neste trabalho, utilizou-se um algoritmo PSO para comparar os deslocamentos sofridos por uma amostra de córnea humana submetida à uma pressão interna de 45 mmHg com resultados de simulações numéricas e identificar valores otimizados para propriedades hiperelásticas da córnea (µ e α). Por meio dos resultados das simulações via análise inversa pelo Método dos Elementos Finitos (MEF), em conjunto com o algoritmo PSO, foram encontrados valores otimizados de µ = 0,047 e α = 106,7. Quando comparado com resultados otimizados por meio de um software comercial, foram encontrados erros de aproximadamente 0,15%. Por meio dos resultados obtidos, verificou-se ainda que, variando os valores dos coeficientes de inércia da partícula no algoritmo PSO, os resultados podem sofrer ligeira melhoria, o que demonstra potencial uso do PSO em conjunto com análise inversa do MEF para caracterização de materiais hiperelásticos, utilizando modelos geométricos simplificados

Abstract Particle Swarm Optimization (PSO) is an artificial intelligence technique (AI) that can be used to find approximate solutions to numerical problems of maximization and minimization. In this study, it was used a PSO algorithm to compare displacements from human cornea sample subjected to internal pressure of 45 mmHg with Results of numerical simulations were provided which identified optimized values for hyperelastic properties of the cornea (µ and α). By means of the results from numerical simulations via inverse analysis by the Finite Element Method (FEM), in conjunction with the PSO algorithm, optimized values of µ = 0.047 and α = 106.7 were found. When compared with optimized results from commercial software, errors around 0.15% were found. Results showed that, varying the values of particle inertia coefficients in the PSO algorithm, simulated displacements have improved when compared to experimental data. This demonstrates the potential use of PSO algorithm in conjunction with the FEM inverse analysis for hyperelastic materials characterization, using simplified geometrical models

RESUMO: Este artigo apresenta as principais aplicações de veículos elétricos no meio rural, apontanto as tendências e mudanças futuras. O trabalho discute também as condições tecnológicas e dificuldades enfrentadas pelo setor industrial para a inserção do veículo elétrico no mercado. São apresentados os principais pesquisadores da área com propostas para superar os problemas da implementação dos tratores elétricos, tais como abastecimento e armazenamento de energia elétrica. As comparações técnicas e econômicas entre tratores convencionais, a combustão interna, e tratores elétricos são apresentadas e discutidas. A revisão mostra a existência de barreiras para a implantação dos veículos elétricos no meio rural, como a necessidade de evolução tecnológica das baterias, que apresentam alto custo e ainda são pesadas para este propósito, mas mostra também que já existem sistemas que podem minimizar a dependência de compubstíveis fóceis do setor e aumentar o uso de energia sustentável.

ABSTRACT: This paper presents the main applications of electric vehicles in rural areas, pointing out the trends and challenges for the future. Technological conditions and difficulties faced by the industry for a wide dissemination of this technology are discussed. The paper described the main researches with proposals to overcome the problems of implementing electric tractors, as supply and electricity storage. Technical and economic comparisons between conventional internal combustion tractors and electric tractors are also presented and discussed. The paper showed the existence of barriers to the implementation of electric vehicles in rural areas, as well as the need for batteries technological evolution, which have high costs and for that reason they are very heavy for these purposes, but there are already systems that can be applied to minimize dependence of fossil fuels in this sector and increase the use of sustainable energy.