No abstract

La detección adecuada de plagas y enfermedades en la producción de cultivos es fundamental para aumentar la producción agrícola de forma sostenible. Es por esta razón, que se incorpora el término Agricultura 4.0, la cual integra un conjunto de tecnologías, dispositivos, protocolos y paradigmas computacionales para mejorar los procesos agrícolas. La información sobre las condiciones climáticas, suelos, enfermedades, insectos, semillas, fertilizantes, constituye una importante contribución al desarrollo económico y sostenible de este sector. Las técnicas de procesamiento digital de imágenes son una herramienta que permite la identificación temprana de las plagas o enfermedades en los cultivos como: cereales, frutales, raíces, hojas y tubérculos; y de esta forma, mitigar pérdidas económicas en el sector agrícola. A nivel mundial, alrededor del 40% de los cultivos son desechados por diversas enfermedades y plagas. En la mayoría de los casos, las enfermedades de los cultivos producen síntomas y características visibles durante el crecimiento de las plantas. Debido a la escasez de tecnologías utilizadas en los cultivos, el diagnóstico de las enfermedades y plagas se soporta en gran parte en la inspección humana, generando errores ocasionados por la subjetividad de los individuos. La presente revisión de literatura se llevó a cabo con la finalidad de identificar diferentes técnicas de procesamiento digital de imágenes para la prevención de plagas y enfermedades en cultivos de los diferentes sectores agrícolas. Los resultados demostraron que el sistema de diagnóstico está compuesto de la adquisición de imágenes, preprocesamiento de imágenes, la segmentación, la extracción de características, la selección de características y la posterior clasificación de las plagas o enfermedades; asimismo, se presentan las tendencias y desafíos actuales en la temática.

This work presents the physical-mechanical properties of two types of H-10 blocks of six holes fabricated in two different companies in Norte de Santander, Colombia to provide a general visualization of the ceramic properties of masonry products base clay. Random samples of H-10 blocks were collected from the selected companies directly from the furnace as part of the experimental procedure, which was used to perform the physical-mechanical tests such as initial and final water absorption, morphology, resistance to compression, and flexion according to the NTC 4017 standard procedure, the results obtained were compared with the values established in the NTC 4205 standard procedure, used as non-structural masonry products for indoor or outdoor use. Finally, the SEM-EDS micrographs exposed the maincharacteristic chemical elements (Al, Si, O), defects on the surface of an H-10 block and the presence of typical phases (Quartz, Kaolinite, Illite, and Hematite) obtained by the XRD technique.

In the research the temperature acquisition was carried out inside and outside the wall an intermittent furnace and the evaluation of the energy loss on the wall during baking process, the first phase begins with the design, programming and implementation of an virtual instrument for data temperature acquisition and generation of temperatures profiles then, heat loss due to conduction on the furnace wall was determined considering one-dimensional heat flow, in radial direction and in a transitory state. The virtual instrument was programmed every 5 minutes and 1596 data were recorded, the input heat supplied to the furnace was 49.2x106 KJ and the energy losses due to the furnace wall were 5.2x106 KJ indicating the 10.57 percent of the supplied energy. Results of research have made it possible to establish trends in the temperature distribution, as well as identify thermal energy entering and leaving the furnace to propose improvements in performance of the furnace that increase its energy efficiency, reduce fuel consumption and gas emissions to the environment avoiding acute respiratory diseases.

It is presents the characterization of the clays from the algodonal formation and the mechanical properties of the products manufactured in brickyard “Hora”, located in Ocaña, Norte de Santander, Colombia.Tests of scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetry, initial rate of absorption, 24-hour immersion, compressive strength, and modulus of rupture were performed. The results indicate that the clay contains a considerable amount of silico-aluminate, while the products have low mechanical strength and high percentage of water absorption. The clays used present difficulty in the process of shaping and compacting the products. None of the samples comply with the values established in the standard and do not allow their use as non-structural masonry products for interior or exterior use.

It is presents the evaluation of water absorption and compressive and flexural strength in perforated blocks manufactured in a Hoffman-type kiln of brickworks Ocaña, Colombia. Combustion gases are reused in the firing process and the samples are directly exposed to fire. Standardized non-destructive quality control tests such as dimensional, initial absorption rate and 24-hour immersion, and destructive tests such as compressive strength and modulus of rupture were performed. The firing process with higher fire exposure on the samples showed values of compressive and flexural strength and water absorption percentage according to current regulations. The samples comply with the values established in the standard and allow their use as non-structural masonry products for interior or exterior use.

En vista de la preocupación mundial por el aumento del consumo energético, así como, la aplicación de alternativas viables que permitan un mejor aprovechamiento de las fuentes energéticas disponibles, los residuos térmicos surgen como una alternativa energética en aplicaciones industriales en las cuales se generan.  En este sentido, el presente trabajo analiza el potencial energético de los gases de combustión emitidos por una estación de compresión, los cuales pueden utilizarse como fuente de calor para un ciclo Rankine de potencia el cual opera con varios fluidos de trabajo incluyendo nueve de tipo orgánico y el dióxido de carbon (CO2). Las simulaciones demostraron la capacidad de los fluidos de trabajo para incrementar la eficiencia energética de la instalación a partir de los gases de escape de la estacion de compresión, siendo que el tolueno y el CO2 se destacan por presentar los mayores niveles de eficiencia, 21 y 20%, respectivamente. Con el objetivo de generación de potencia del ciclo, se concluye que los fluidos refrigerantes considerados en el análisis no son aptos para el ciclo en los niveles de temperatura evaluados.

This paper presents the use of calcium carbonate as an additive in the manufacturing process of ceramic bricks, in order to reduce the temperature and sintering time of the clays and to improve the quality of the products. In the study, samples of solid bricks with two different proportions were made. One was composed of 100% clay and the other of 70% clay and 30% calcium carbonate, which were fired in an intermittent kiln. The temperatures of the firing process were recorded using a virtual instrument. The samples manufactured were tested for water absorption and strength. The addition of calcium carbonate brought advantages such as an 8.66% decrease in fuel consumption, a 23.88% decrease in firing time, a 12.11% and 26.67% decrease in the firing temperature and gases released into the environment, respectively, as well as improvements in the quality of the product. The use of calcium carbonate as an additive decreased the time and temperature of ceramic firing and fuel consumption and increased energy efficiency, productivity and product quality, as well as reduced gas emissions into the environment.