ABSTRACT Tree crops, such as Arabica coffee (Coffea arabica L.), present enormous technical challenges in terms of pesticide application. The correct deposition and distribution of the active ingredient throughout the aerial part of these plants depends on knowledge of the canopy volume, but manually determining this volume is time consuming and imprecise. The objectives of this study were to develop a method to determine the vegetation volume of coffee crops from digital images captured by camera onboard unmanned aerial vehicles and to compare this approach with traditional vegetation volume estimation (tree row volume (TRV) method). Manual measurements of the canopy volume of four coffee cultivation areas were compared with data obtained using the method presented in this paper. It was concluded that the vegetation volume of coffee trees, a highly important variable in defining pesticide application techniques (in addition to other uses), could be determined in a practical and precise way by digitally processing the images captured by unmanned aerial vehicles. The method is fast and permits the assessment of large areas. Furthermore, estimates based on this method and the traditional TRV method were not significantly different.
ABSTRACT: The remotely piloted aircraft (RPA) have great applicability in agriculture. Although it is a technology that has been developed for many years, in the field of agriculture it passed unnoticed for a long time. The high cost of acquisition is still a limiting factor for small and medium-sized farmers. In this way, this study had as objective to develop a low cost RPA for agriculture application. In the present study, the development and the assembly of an RPA prototype of a quadcopter type is presented, consisting of four engines and of vertical propulsion, capable of moving without human intervention, that is, autonomous flight, applied to agriculture and low cost investment. In it was boarded a data control and processing system collected from sensors and cameras, using hardware and software from a free platform (Open Source). The assembly equipment showed to be robust, with a payload of approximately 1,000 grams, with an acquisition cost (R$ 2,393.16), included the camera module, much lower than those commercially available and suitable for the agricultural application, as acquisition, processing and interpretation of digital images, due to the quality of the images obtained.
The use of waste tire in blends with thermoplastics enables the formation of new materials. In this paper the use of waste tire was characterized with a complete 2³ factorial design with central point, in blends with polypropylene (PP), in the development of new thermoplastic elastomers vulcanized dynamically (TPVs) and containing recycled material. The factors used in this study were: waste tire, dicumylperoxide and bismaleimides in three levels, one being the central point. The factorial design was built to evaluate the effects of the factors (and their interaction) in the responses of tensile, elongation and oil swelling. The results showed that the level of waste tire is predominant to improve the performance of TPV. The swelling resistance is approximately 150% higher in some formulations.
O uso do pó de pneu em misturas com termoplásticos possibilita a formação de novos materiais. Nesse trabalho o uso do pó de pneu foi caracterizado pelo planejamento fatorial completo 2³, com ponto central, em misturas com polipropileno (PP), para desenvolvimento de novos elastômeros termoplásticos vulcanizados dinamicamente (TPVs), contendo material reciclado. Os fatores utilizados neste estudo foram, pó de pneu, peróxido de dicumila e bismaleimida (em três níveis, sendo um deles, o ponto central). O planejamento foi construído para avaliar os efeitos dos fatores (principais e suas interações) nas respostas de tração, alongamento e inchamento em óleo. Os resultados mostraram que o teor de pó de pneu é predominante para melhorar o desempenho das misturas. A resistência ao inchamento é aproximadamente 150% superior em algumas formulações.