The objective of this article is to measure through intelligent techniques, the quality of university life in a university population. In this investigation, a dependent variable called quality of university life is taken, as well as 10 independent variables: Academic load, economic resources, relationship with classmates, relationship with professors, curriculum, extracurricular activities, current housing, family relationships, emotional state and university environment. In the samplings of these variables, 127 surveys were carried out on university students of a public university located in the central region of Colombia. Subsequently, the most relevant variables were selected throughout statistical techniques, in order to establish a file to be analyzed through the decision tree classification algorithm J48from the Weka platform. The results show, with over an 80 % effectiveness, that the most influential variables in the quality of life of a university student are: University environment, current housing, emotional state, and relationships with professors. Finding a lot of times that the quality of university life can also depend of external variables to the university such as: Current housing and emotional state. These results are of great importance in the design of new university policies.

In this work, solar cells with Mo/CuInSe2/CdS/n+–ZnO structure were deposited and experimentally characterized by the I-V curve. From these results, the electrical parameters were estimated fitting, theoretically, the curve to determine the most important variables. The estimation was carried
out using the single and double diode models and comparing the curve that best fits. The estimated variables were photogenerated current (Iph), dark current of the diode (Is), series resistance (Rs), shunt resistance (Rp) and diode ideality factors (a1 and a2) according to each model of circuit taken for optimization. The adjustment of the current-voltage (I-V) and power-voltage (P-V) curves achieved with the double diode
model indicates that in the manufactured solar cells, interfacial states are present in the p-n junction, which decreases the efficiency of the device.

Soil salinization is one of the main constraints for food production. These processes occur mainly in irrigated areas, due to natural conditions and inadequate fertilization and irrigation practices. The objective of this article was to generate a model to identify and spatialize the levels of vulnerability to soluble phase salinization in the irrigation districts of Colombia as a complementary tool for the management of soil salinization risk. Two tools were integrated to achieve the objective. On the one hand, the multi-criteria
analysis method called Analytic Hierarchy Process (AHP) was applied to assign weights to the analysis parameters and build the Soil Vulnerability to Salinization Index (SVSS), and on the other hand, geographic information systems (GIS) were applied to spatialize the analysis parameters and the SVSS, as well as to define the homogeneous vulnerability zones. Finally, the model was applied to a case study. The resulting model considered vulnerability parameters. The most important are Aridity Index, Soil Texture and Fertilization Practices. On a second level are Drainage Infrastructure and Depth of the Water Level. Other factors considered were Slope of the land, Irrigation Water Application Efficiency and Irrigation Water Distribution Pattern. In the case study it was found that 71.8 % of the territory presents Medium Vulnerability and 27.9 % High Vulnerability. The determining parameters of these results were the low efficiencies of irrigation water application, inadequate fertilization practices, clayey textures and lack of subsurface drainage systems.

In this work, the char morphology from coal-sugarcane bagasse with concentrations of 0, 25, 50, 75 and 100 % w/w and particle sizes -0.25 mm and -20 mm was evaluated. The samples were fed to a devolatilization process at 900 °C in a tubular drop reactor (-0.25 mm) and a batch-type fixed bed reactor (-20 mm). The morphology of the char was determined through image analysis. The surface area was evaluated by BET analysis for particle size -0.25 mm. The results showed that for particle sizes -20 mm synergistic effects were obtained towards the generation of reactive morphologies (thin walls + thick walls) with the increase in bagasse concentration. It was found that coal generated a higher concentration of thick and solid wall morphologies.

This paper aims to make a bibliographic literature review about the current and potential uses of geothermal energy within the food industry, which uses a third of the world’s energy during production in all the processes involved. Fossil fuels are the most common sources for generating electrical energy for the food industry. However, it is known that they cause adverse environmental effects such as atmospheric pollution, ecosystem disturbances and natural resource depletion. Due to the lack of published studies about this subject, this review was carried out using different databases. Of the 77 documents published between 2010 and 2020, more than 70 % of them were written in English by researchers from 67 institutions from around the world. These documents allow us to analyze a sample of countries where the implementation of geotermal energy has a greater advance in processes implementing geothermal energy in the food industry; such as heating and cooling systems for the drying of fruits and vegetables, and producing various foods, achieving energy coverage close to 10 % in this industry.

Water scarcity in areas with abundant rainfall due to drought is, in a sense, contradictory; however, the effects of such a situation can have dramatic consequences on the productivity and development of communities. This work, derived from a finished research and financed with resources of the authors, evaluated the threat by drought in the department of Cordoba, Colombia, by means of the Standardized Index of Precipitation (SPI), for a critical scenario defined by the maximum intensities of events with occurrence of two years of return, using the information of 40 meteorological stations; evaluating the SPI to scales of 3 and 6 months and characterizing this index in terms of intensity, duration, frequency and magnitude. The results show the occurrence of droughts of moderate intensity, with frequency of 58 % and 56 % in quarterly and semestral scale respectively, resulting in threat by drought in medium and high categories for some areas of the department; which indicates that, although on the study area there are registered abundant rainfalls, it can be presented scarcity of the resource in the long term caused by droughts.

A LAN network is considered as a scenario in which the nodes regularly have the need to transmit, which generates a constant dispute to access the medium, and BPL (Broadband Power Line) networks are no exception. BPL technology is characterized by using the electrical network as a means of transmission and for this it makes use of several standards, IEEE 1901 among them, due to its wide acceptance. Based on the growth in the demand for new services and to offer acceptable levels of QoS (Quality of Service), IEEE 1901 operates a hybrid medium access mechanism, supported by CSMA/CA and TDMA. However, this strategy has shown little efficiency when increasing the number of nodes in the network, because only one of the nodes can transmit at a time. This article proposes a medium access mechanism on OFDMA (Orthogonal Frequency-Division Multiple Access), based on weighted voting game theory and supported by the Deegan-Packel power index, in order to optimize access. in the time and frequency domain, improving network performance and allowing multiple nodes to transmit simultaneously.

Induction motors have played a central role in the techno-economic development of modern industries and electric power generation. However, the presence of recurring failures hinders a cost-effective performance and leads to catastrophic damage. Therefore, the present study proposed an assessment to investigate the influence of two types of failures in induction motors, namely failure due to broken bars in the rotor and defects in the connection between the rotor bars and the end ring. Accordingly, a three-phase induction motor was evaluated under different failure conditions that modified the operational torque and rotational speed. The results indicated that both types of failures magnify both the core and copper power losses by up to 13.3 % and 8 %, respectively, compared to the healthy condition. On the other hand, an efficiency reduction
between 1.94 % to 3.41 % is an indication of failure progression. Finally, the appearance of harmonics 3 and 7, and the intensified magnitude of harmonic 5, represent a clear sign of failure occurrence related to rotor bars
and defects in the connection to the end ring. In conclusion, the proposed methodology proved to be an adequate tool to predict failure appearance, which has a direct impact on extending the lifetime of induction motors.

Cr₂O₃ coatings were deposited on carbon steel through the flame spraying technique using two types of flames (neutral and oxidizing). The protective and morphological characteristics of the coatings were determined. The coatings had layer thickness values of 114 and 214µm for oxidizing and neutral samples, respectively. Porosity percentages of 4.5 % and 2.5 % were determined, where the neutral sample presented the greatest porosity due to the insufficient fusion of the oxide particles during the process, resulting in the formation of a heterogeneous and less compact layer. Microcracks and pores were found on the surface and cross-section of the coatings, due to the thermal expansion generated during the solidification process. The coating protective capacity was evaluated by electrochemical techniques over 672 hours in a 3.5 %wt NaCl saline solution. The results evidenced that the coatings manufactured with the oxidizing flame presented more corrosion resistance compared to those prepared with the neutral flame. The corrosion products were more evident in the neutral flame coatings, because of the diffusion mechanisms from the substrate to the surface coating through the interconnected pores. Finally, the wettability of the sodium chloride solution in the Cr₂O₃ coatings was measured by the contact angle technique, finding that the oxidizing flame coatings exhibited a higher angle contact value (64.8°) in contrast to the neutral flame coatings (35°).