TecnoLógicas

Journal Information
ISSN / EISSN : 0123-7799 / 2256-5337
Published by: Instituto Tecnológico Metropolitano (10.22430)
Total articles ≅ 535
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Published: 20 September 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2384

Abstract:
The objective of this study, reflected in this document, was to implement a rectenna for 2.45 GHz and 5.38 GHz wireless local area applications. For this purpose, the antenna dimensions were set to 18 mm × 44 mm, which is simulated using the optimization software CST Studio, manufactured on FR4 substrate with a thickness of 1.6 mm, where the conductive material has a thickness of 0.035 mm. Likewise, the rectangular slot technique was used to improve the bandwidth of the antenna; this technique consists of inserting slots in the structure to modify the displacement of the surface current. The above presented a gain of 2.49 dB at the 2.45 GHz frequency and 4.01 dB at the 5.38 GHz frequency. The proposed antenna for RF energy harvesting applications exhibits a dipole type radiation pattern, which enhances the capture of RF energy from various directions. The triple slotted-band rectifier with T-shaped impedance matching network was designed in FR4, using a Schotkky HSMS-286C diode for AC to DC RF control switching. A tp-link TL-WR940N wireless router was used as the RF emitting source at 30 cm separation between it and the proposed rectenna. The DC output of the rectenna is 3 volts with a generated signal power of 20 dBm at 2.4 GHz. The low-cost rectenna can be used for power-charging applications in the Internet of things (IoT) systems.
Published: 20 September 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2381

Abstract:
Milk powder is a highly demanded food that is used in various ways, both in the industrial area and in everyday life. In the present work, an innovative and unprecedented techno-economic evaluation of a technological proposal for a skimmed milk powder production plant with an annual capacity of 700 tons was carried out through the use of the SuperPro Designer® simulator, in order to know its main economic and profitability indicators under the current economic conditions in Cuba. For economic performance evaluation, the total capital investment, unit production cost, internal rate of return (IRR), net present value (NPV) and project payback time (PT) among other indicators, were determined. A sensitivity study was also accomplished, to determine from what value of the fluid milk unit cost the proposed skimmed milk powder plant begins to be unprofitable. A total capital investment of USD 22 744 000, an annual operating cost of USD 9 884 000, a working capital of USD 647 000 and a unit production cost of USD 352.95 per 25 kg bag were obtained. From the techno-economic results obtained, it can be concluded that the evaluated skimmed milk powder production plant is profitable and feasible due to the values of NPV (USD 14 475 000), IRR (18.98 %) and PT (4.46 years) obtained. The proposed production plant becomes unprofitable from a value of the fluid milk unit cost of USD 1.32/L.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2505

Abstract:
El modelo de producción actual, basado en una economía lineal de “Extraer, Fabricar, Consumir, Desechar”, hace que la cantidad de residuos que se generan sea cada vez mayor. Según la Organización de las Naciones Unidas, cada año se recolectan en el mundo una cantidad estimada de 11.200 millones de toneladas de residuos sólidos y, según el Banco Mundial, los desechos a nivel global crecerán un 70 % para 2050, a menos que se adopten medidas urgentes [1, 2]. Solo por poner algunos ejemplos, cada minuto se compran en el mundo 1.000.000 de botellas plásticas, y al año se usan en el planeta 5 billones de bolsas de plástico de usar y tirar [1]. Además, de todo el plástico producido en la historia, solo se ha reciclado el 9 %, y aproximadamente un 12 % se ha incinerado. Por lo tanto, el 79 % restante se ha acumulado en vertederos, basureros o en el medio ambiente. Afortunadamente, la conciencia sobre el tratamiento de los residuos plásticos está aumentando, debido en parte a visibilidad de éstos en zonas como mares, playas y ríos.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2376

Abstract:
High lightning activity sites have been characterized using methodologies based on the spatial occurrence of lightning through parameters such as Ground Flash Density, GFD. This work found the areas with the highest number of lightning strikes (hotspots) in some Colombian cities through a methodology based on the temporal occurrence of lightning. Likewise, the influence of elevated structures on lightning activity in these regions is determined. Polygons of 600 meters on each side were located on the surface of the study cities. Based on lightning information (strokes) provided by the Colombian Network of Total Lightning Detection with LINET technology between 2016 and 2018, the number of impacts per polygon was determined, making it possible to identify the areas in which the incidence of lightning is recurrent. Elevated structures were located in each of the study cities to determine which of them corresponded to hotspots. The results showed that the main hotspots are far from urban areas and that most of these sites coincide with elevated structures. Possible causes of these lightning strikes are also explained, such as meteorological variables, relief, precipitation, and charge distributions in storm clouds. Urbanism is found to have a marked influence on the determination of hotspots and that urbanism and elevated structures increase lightning activity in the study areas.  
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2265

Abstract:
La agroindustria genera gran cantidad de residuos de tipo orgánico, los cuales son considerados una biomasa apta para aprovechamiento energético. Una de las tecnologías de conversión termoquímica que permite obtener un producto de alto valor energético es la carbonización hidrotermal, la cual puede ser asistida por microondas o por horno convencional. El objetivo de este artículo fue recopilar información sobre la influencia que tienen los parámetros operativos en la obtención de mayores rendimientos y contenidos de carbono del hidrochar en el proceso de carbonización hidrotermal asistida por microondas (MAHTC) y, a su vez, demostrar tal influencia de los parámetros mediante un metaanálisis. Para el metaanálisis se tomó la información bibliográfica recopilada y se evaluó a través de un modelo lineal generalizado tipo mixto. Los resultados del modelo evidenciaron que la temperatura y el tiempo ejercen influencia en el contenido de carbono, mientras que el rendimiento estaría influenciado, principalmente, por el tiempo de reacción. En términos generales, se resalta al parámetro de la temperatura de reacción como el factor más importante en la carbonización hidrotermal, ya que determina las propiedades fisicoquímicas del hidrochar, es decir que con la información aquí presentada se pretende incentivar el aprovechamiento de los residuos agroindustriales para ser transformados en productos de alto valor energético y, de este modo, brindar una solución a la problemática de cambio climático, propiciando el desarrollo sostenible del sector agrícola.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2352

Abstract:
Several studies have analyzed the integration of energy-saving strategies in buildings to mitigate their environmental impact. These studies focused mainly on a disaggregated analysis of such strategies and their effects on the building's energy consumption and thermal behavior, using energy engine simulation software (EnergyPlus, TRNSYS, and DOE2) or graphical interface software (DesignBuilder, eQuest, and ESP-r). However, buildings are complex systems whose energy behavior depends on the interaction of passive (e.g., location and construction materials) and dynamic (e.g., occupation) components. Therefore, this study proposes a composite indicator Building’s Energy Performance (BEP) as an alternative to deal with this complex and multidimensional phenomenon in a simplified way. This indicator considers energy efficiency and thermal comfort. The Electrical Engineering Building (EEB) of the Universidad Industrial de Santander was selected to verify the performance of the BEP indicator. In addition, a sensitivity analysis was performed for different mathematical aggregation methods and weighting values to test their suitability to reproduce the building behavior. Different simulation scenarios modeled with DesignBuilder software were proposed, in which the energy-saving strategies integrated with the building was individually analyzed. The results confirmed that the integration of the building's energy-saving strategies improved the BEP indicator by approximately 16%. It has also been possible to verify that the BEP indicator adequately reproduces the building’s energy behavior while guaranteeing comfort conditions. Finally, the Building Energy Performance indicator is expected to contribute to the integration of sustainability criteria in the design and remodeling stages of buildings.
Jimilgton Enrique Soto Sogamoso, ,
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2348

Abstract:
El objetivo de este artículo fue analizar las principales técnicas y estrategias de visión artificial utilizadas en sistemas diseñados para la identificación automática de hongos formadores de micorrizas arbusculares, abordando aspectos generales de las micorrizas y su clasificación taxonómica. Las micorrizas son asociaciones simbióticas entre las raíces de las plantas y determinados grupos de hongos, se caracterizan por generar grandes beneficios al suelo circundante, a las plantas y a los procesos productivos derivados. El trabajo se desarrolló con una metodología de recolección de información especializada a partir de criterios de búsqueda específicos, seleccionando publicaciones relevantes, en un rango de tiempo entre el año 2014 y 2021, en las bases de datos de Scopus, Scielo, Dialnet y Google Académico. Los resultados del estudio revelaron que la morfología matemática difusa es una técnica importante en la segmentación de las esporas de hongos y, en general, los estudios desarrollados se basan en una identificación binaria de las esporas, donde la transformada de Hough y las redes neuronales artificiales son las técnicas combinadas que reportan mejores resultados. El presente estudio permitió concluir que es posible auxiliar el proceso de identificación de hongos formadores de micorrizas arbusculares a partir de técnicas de visión artificial, y contribuye indicando un vacío de información respecto de sistemas de clasificación no binaria, los cuales son importantes y se deben tener en cuenta para apoyar procesos de clasificación avanzados, de acuerdo con la cantidad de familias y géneros reportados en la literatura.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2269

Abstract:
The intensive use of fossil fuels contributes significantly to global warming and the growing world energy crisis. Thus, it is necessary to develop alternative energy sources that make the energy matrix more flexible and reduce environmental impacts. An outstanding option is the conversion of residual biomass into energy because it produces a low-emission fuel in terms of CO2. Therefore, this study aimed to improve the physicochemical properties of two residual biomasses (i.e., pine sawdust and spent coffee ground, SCG) through a torrefaction process. Biomass valorization was carried out in a bench-scale screw reactor (2.8 kg/h). The effect of temperature was evaluated between 200 °C and 300 °C, and the torrefied biomasses were characterized by instrumental techniques: calorific value, infrared spectroscopy analysis, thermogravimetric analysis, and scanning electron microscopy. Both biomasses exhibited an increase in calorific value when the process temperature was raised. This behavior is associated with the thermal degradation of the hemicellulose fraction and the increase in fixed carbon. In addition, the infrared analysis showed a decrease in OH and H-O-H signals associated with polar functional groups. These results show the high potential of the valorization of these two biomasses thanks to the decrease in polar groups, which have a great affinity with water, and the obtaining of calorific values close to those of fossil fuels such as lignite or sub-bituminous coal.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2386

Abstract:
En la actualidad, diversos estudios han demostrado que la luz roja favorece el crecimiento de la biomasa, mientras que, comúnmente, longitudes de ondas rojas y azules promueven la concentración y producción de ficobiliproteínas, lo cual depende del género o especie, y de las condiciones del medio, así como de sus condiciones nativas, pues este mecanismo se genera como respuesta de adaptación, por lo que se hace necesario indagar para comprender estos fenómenos. En este orden de ideas, el propósito de esta investigación fue dar a conocer la importancia del aprovechamiento de la luz, como mecanismo de utilización de las microalgas para la producción de ficobiliproteínas, como contribución a la biotecnología industrial, la cual brinda información sobre condiciones y parámetros cultivos. La metodología de estudio se basó en un análisis documental a través de VOSviewer, usando la base de datos Web of Science, en la cual se utilizaron las palabras “Microalgae Pigment Light effect”. Con base en lo anterior, se pudo determinar que existe una correlación de palabras enfocadas a la producción de biocombustibles, como carotenoides, antoxantina, betacarotenos y luteína, aprovechando el uso de la luz como factor determinante, teniendo en cuenta que las cepas que más se relacionan con estos estudios son: Spirulina plantesis, Chrorella vulgaris y Chlamydomonas reinhardtii. El conocimiento de la aplicación de estos pigmentos es amplio, por lo que el estudio de la producción de pigmentos a partir de microalgas, evaluando el efecto de la luz, se ha convertido en un tema de gran interés, en especial para el mercado de pigmentos.
Published: 16 June 2022
Journal: Tecnológicas
Tecnológicas, Volume 25; https://doi.org/10.22430/22565337.2223

Abstract:
In wet electrospinning, a natural or synthetic polymer solution is deposited on a non-solvent liquid coagulant used as collector. This technique can create 3D nanofiber scaffolds with better properties (e.g., porosity and high surface area) than those of traditional 2D scaffolds produced by standard electrospinning. Thanks to these characteristics, wet electrospinning can be employed in a wide range of tissue engineering and industrial applications. This review aims to broaden the panorama of this technique, its possible fields of action, and its range of common materials. Moreover, we also discuss its future trends. In this study, we review papers on this method published between 2017 and 2021 to establish the state of the art of wet electrospinning and its most important applications in cardiac, cartilage, hepatic, wound dressing, skin, neural, bone, and skeletal muscle tissue engineering. Additionally, we examine its industrial applications in water purification, air filters, energy, biomedical sensors, and textiles. The main results of this review indicate that 3D scaffolds for tissue engineering applications are biocompatible; mimic the extracellular matrix (ECM); allow stem cell viability and differentiation; and have high porosity, which provides greater cell infiltration compared to 2D scaffolds. Finally, we found that, in industrial applications of wet electrospinning: (1) additives improve the performance of pure polymers; (2) the concentration of the solution influences porosity and fiber packing; (3) flow rate, voltage, and distance modify fiber morphology; (4) the surface tension of the non-solvent coagulant on which the fibers are deposited has an effect on their porosity, compaction, and mechanical properties; and (5) deposition time defines scaffold thickness.
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