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Precision agriculture is the use and application of new technologies in big and small surface units, taking into account the diversity of the soil, the environmental environment and the needs of the plants in order to manage and optimize the application of inputs (seeds, fertilizers, phytosanitary products, irrigation...) to obtain profitable, quality and environmentally friendly production. About 20 years ago or so, applications of the GPS system (Global Positioning System) were achieved in agriculture to obtain the position using coordinates and the production obtained at each of those points. With the preparation of this data, the first yield maps were represented, and the use of these new systems began to be called "Precision Agriculture." In recent years, with technological advances in computing and new communication networks, very important advances have been obtained, being able to control positioning with errors of less than 1 meter, through DGPS and GIS (Geographic Information Systems). This technology in Cuba is in a completely experimental phase, but it is a fact that performance maps are being obtained and this information can be used by equipment that can be mounted on tractors. [ABSTRACT FROM AUTHOR]

Population growth has led to an exponential demand for agricultural products, to meet this demand it is necessary to improve management and achieve efficient use of resources without compromising the sustainability of ecosystems, particularly agricultural ones. One of the technologies that facilitate these tasks is precision agriculture (PA), which focuses on the optimization of resources and inputs based on the compilation of precise and timely geo-information of variables of agricultural interest with high spatio-temporal variability, obtained through remote sensors of three types: images captured by satellites or airplanes, images obtained from manned and unmanned aerial vehicles (UAVs) and specific information with sensors mounted on machinery or in the field. These limitations were overcome by using multispectral images, which has increased applications for agricultural purposes. Currently, multispectral images allow quantifying soil moisture, monitoring the presence of droughts and the degree of crop water stress, estimating the temporal and spatial variability of evapotranspiration, monitoring phenology, detecting nutritional deficiencies, estimating the degree of weed infestation. and insects, calculate organic carbon and soil salinity, and estimate yields and agricultural production. The use of geospatial technologies in the PA has changed the paradigm of agriculture and today constitutes a viable alternative to face the challenges that food production demands in a world with high climate variability. [ABSTRACT FROM AUTHOR]

The research belongs to a project approved by the National Energy Program. The objective of the work is to evaluate the protection effect that windbreak curtains can provide to a photovoltaic field located in a rural area, in the face of hurricane force winds, applying Computational Fluid Dynamics (CFD) tools. A windbreaker of Bugambilia (Bougainvillea spectabilis) of 2 and 3 m in height and porosities of 0.56 and 0.79 is simulated. The distribution of wind speeds in the environment of a photovoltaic field sector composed of ten batteries, made up of 10 photovoltaic modules each with an arrangement of 5x2 panels, are determined for different intensities and direction of the winds. Likewise, the aerodynamic loads and the Von Mises stresses acting on the panels are determined. As a result, it is obtained that the curtain provides effective protection to the entire photovoltaic field, preserving the integrity of the solar panels, due to the fact that the maximum dynamic tensions reached do not exceed the permissible loads for winds of up to 56 m / s (200 km / h) coinciding with the upper limits of the wind speed in category III hurricanes of the Saffir Simpson scale. [ABSTRACT FROM AUTHOR]

On an international scale, the broadcast distribution of mineral fertilizers is carried out fundamentally with the use of centrifugal disk spreaders with blades, due to their high distribution capacity and their constructional and operational simplicity. In spite of these advantages, a high demand in the correct selection of the parameters of the working process of these organs is required, to guarantee a high uniformity of fertilizer distribution in the field and consequently, the corresponding productive requisites. A model to determine the characteristics of the movement of the fertilizer particles on the spreading disk with inclined blades in relation to the radial direction is presented in this work. The analysis was carried out by obtaining the differential equation of the dynamics of a particle's motion by applying the laws of classical Newtonian mechanics. The equations obtained from the solution of the differential equation of motion were programmed using the Mathcad software, version 2000 Professional. It allowed evaluating the model with specific data and obtaining the output speed and angle of the fertilizer based on parameters of input such as: inclination angle of blades, coefficient of friction between the fertilizer and the disk and blades material, dimensions and rotation speed of the disk and coordinates of the zone of the fertilizer fall from the mouth of the hopper. [ABSTRACT FROM AUTHOR]

As a result of the development of a sorting table for agricultural products for the selection of tomatoes, potatoes or other products with approximately spherical shape, a mechanical-mathematical model and software were developed that make it possible to determine and adjust the design parameters of that sorting table. The model interrelates a set of parameters such as the coordinates of the drop point of the fruits or tubers on the conveyor belt and the angle of transverse inclination of the conveyor belt. In addition, it interrelates the rolling friction angle of the product with respect to the conveyor surface, the components of the falling speed and the linear speed of the conveyor belt, among others. The modeling was carried out applying the laws of Newtonian mechanics. The development of the software was carried out on the basis of the Mathcad 2000 Professional software. [ABSTRACT FROM AUTHOR]

As part of a research project aimed at determining the effect of extreme winds on agricultural economic objectives, through the application of simulation methods based on Computational Fluid Dynamics and finite elements analysis, some experimental runs were carried out to validate that simulation method and the criteria used during the formation of the models and the characteristics of the finite element meshing to be applied. For the experimental measurements, a wind tunnel built in the Agricultural Mechanization Center of the Agrarian University of Havana was used, which was modeled in 3D with the SolidWork 2018 computational tool and the simulation was carried out through the "Flow Simulation" module. For the experimental application of the simulation models used, the results of experimental measurements of the pressures within the wind tunnel were compared with the pressures determined by simulation. A variable pressure field in the space was achieved by interposing an obstacle to air circulation, aimed at achieving different pressure levels in different sections of the tunnel. As a result of the comparison, a simulation prediction error was obtained that ranged between 0.53 and 2.07%, which was extremely satisfactory. [ABSTRACT FROM AUTHOR]

An important soil variable is mechanical resistance, a feature that interacts with other soil properties such as bulk density, texture, moisture content and porosity. Hence a number of experimental investigations have been conducted to obtain a probe of better correlation with volumetric density and resistance to penetration. However, so far, there is no precise information on the technical requirements for the design of probes. The objective of this scientific research was determining the type of probe that ensures the correlation levels between volumetric density and resistance to penetration under different moisture conditions for a Ferrallitic Red Lixiviate soil, typical of Cuba. To meet this objective, eight types of probes (five cone-shaped and three wedge-shaped) with different geometric dimensions were designed and an experimental design of 2x3 factorial nature was executed, setting humidity, intermediate (28%) and high (35%), and three levels of volumetric density (1; 1,1 and 1,2 g·cm-3). As a result of the experimentation, it was obtained that the wedge-shaped prismatic probe with 30o and base area of 520 mm², presented the highest levels of correlation with the ASAE index (R² = 0.95) and the volumetric density (R² = 0.84), for moisture of 28%, resulting in the most accurate geometric form for estimating soil compaction. [ABSTRACT FROM AUTHOR]

The dynamic load coefficients allow obtaining the tensile and deformational states in parts and structures subjected to dynamic loads with an acceptable degree of accuracy. In the present investigation, the dynamic load coefficients are determined and a structural evaluation is carried out on an agricultural trailer axle, subjected to a static vertical load of 20 kN. The energy method was used to determine the dynamic load coefficients and the simulation by the finite element method was performed to determine static stresses and deformations. Applying this method, the structural evaluation of the agricultural trailer axle subjected to impact loads was achieved, with a low computational requirement. For a free fall height of the trailer of 200 mm, with a load of 20 kN on each axle, if the wheels were rigid, an excessively high dynamic load coefficient would occur. It would cause exceeding the elastic limit of the axis material more than five times, while an impact height of that same level, can be damped by the tires, without using other damping means (springs), with a safety coefficient of 2.5. [ABSTRACT FROM AUTHOR]

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Copyright of RICYDE. Revista Internacional de Ciencias del Deporte is the property of Revista Internacional de Ciencias del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Ingeniería Agrícola is the property of Instituto de Investigaciones de Ingenieria Agricola and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Nowadays, it is interest of Cuban sugarcane agriculture, the introduction of conservationist methods during the preparation of soils for sugarcane sowing. Localized soil preparation, done exclusively in the area of root growth of the seedlings, is a viable alternative, both, from the point of view of soil conservation, as well as from point of view of economy of energy resources that are dedicated to the preparation of large areas of land. In this sense, a tillage implement having four staggered shanks with "V"- shaped blades has been developed, leaving a trapezoidal profile in the transverse plane of the soil removed, according to the demands of sowing. In the design process of this equipment, it was necessary to carry out certain analyses related to suction and stability, developing an analytical method and software that facilitates these analyses, avoiding the use of cumbersome traditional graphic methods, based on the construction of force polygons and rays, which make it difficult to evaluate multiple variants. The application of this method to the aggregate formed by an YTO-1604 tractor and a the tillage implement with four staggered shanks, made it possible to determine the most suitable position for the support wheel, as well as for the instantaneous center of rotation of the tractor suspension mechanism. It was also possible to evaluate the incidence of the wedge angle on the conditions of suction and stability. [ABSTRACT FROM AUTHOR]

The objective of this paper is to determine the design parameters required for a system of transportation of banana clusters in mountainous areas. A theoretical model was elaborated with the application of the classical mechanics methods that allows rationalizing the design of the transport systems of banana bunches harvested on slopes using cableways. The model makes it possible to select, taking into account the productivity requirements, the speed of transport and the distance between clusters along the cable via, which guarantee the non-physical interference between the clusters, starting from the knowledge of the angle of the slope and the physical properties of bunches of bananas transported. Based on the functional relationships obtained from modeling, a software was developed that facilitates the obtaining of graphs and tables useful for the selection of the design parameters of the transportation system. The input data to the software for the model evaluation were determined in a banana zone in the state of Trujillo, Venezuela, characterized by the production of bananas on mountain slopes. [ABSTRACT FROM AUTHOR]