In this work, a comparison of the microwave absorption properties of Opuntia ficus-indica cladodes, Agave atrovirens branches, and Cocos nucifera L. husk samples was performed. The study was carried out by inserting dry and powdered samples of these organic materials transversely and in the middle of a rectangular waveguide, for which scattering parameters S₂₁ and S₁₁ were measured to estimate the absorption coefficient. These measurements were compared to determine the material that behaves the best as a microwave absorber with a view to develop future low-cost and eco-friendly products by reusing agricultural waste. Specifically, Agave atrovirens sample showed the best performance, having an average value of absorption coefficient of 0.4218, while its maximum was 0.5792 at 9.706 GHz within the range from 8.005 to 13 GHz.

Stevia rebaudiana Bertoni Morita II, a perennial plant native to Paraguay and Brazil, is also widely cultivated in the state of Colima, Mexico, for its use as a sweetener in food and beverages. The optimization of soil parameters is crucial for maximizing biomass production and stevioside levels in stevia crops. This research presents the development and implementation of a monitoring system to track essential soil parameters, including pH, temperature, humidity, electrical conductivity, nitrogen, phosphorus, and potassium. The system employs a wireless sensor network to collect quasi-real-time data, which are transmitted and stored in a web-based platform. A Mamdani-type fuzzy logic model is utilized to process the collected data and provide farmers an integrated assessment of soil quality. By comparing the quality data output of the fuzzy logic model with a linear regression model, the system demonstrated acceptable performance, with a determination coefficient of 0.532 for random data and 0.906 for gathered measurements. The system enables farmers to gain insights into the soil quality of their stevia crops and empowers them to take preventive and corrective actions to improve the soil quality specifically for stevia crops.

Currently, the smart grid concept represents the modern vision of an automated and highly adaptable electrical grid. Supervisory control and data acquisition (SCADA) systems are a fundamental component of a smart grid, enabling communication between field equipment and digital environments. For this purpose, they require industrial frameworks, among which IEC 61850 stands out. IEC 61850 has become a widely adopted standard for substation automation systems (SASs). However, despite its widespread adoption, IEC 61850 faces significant implementation challenges, including the potential complexity of data modeling, which often leads to discrepancies in semantic interpretation and, consequently, different readings among SAS configuration users. A disparity in the semantic interpretation of a process can negatively affect SAS operation, leading to execution errors or interoperability issues. Translating and analyzing SAS configurations can identify and resolve semantic interpretation discrepancies across these systems. The purpose of this research was to determine the degree to which a user interface was perceived as useful to support the translation and analysis of SAS configurations based on the IEC 61850 standard. To this end, a software tool was proposed as the central artifact to address the socio-technical dimension of a custom-built SCADA system at a Latin American state enterprise. The tool serves as the local, intelligent, and real-time operational layer in that system and was rated by users experienced with IEC 61850 as highly usable. The consistently obtained results suggest potential support for those performing the SAS configuration.

A microstrip second-iteration square Koch dipole fractal antenna is presented. This meandered antenna has a total length of 56.56 cm including its feed gap and was printed on the diagonal of a 100 mm × 100 mm PCB card that acts as CubeSat face. The antenna that was designed to optimize space shows acceptable performance at its resonance frequency of 455 MHz within the 70-centimeter band, a band that is commonly used for TTC CubeSat subsystems. The designed fractal antenna shows a reflection coefficient below −20 dB, a VSWR below 1.2, a −10 dB bandwidth of 50 MHz, and impedance magnitude of 56 Ω, while the average maximum gain around its resonance frequency is 2.14 dBi. All these parameters make this designed antenna suitable for small satellite applications at a band where a linear λ/2 dipolar antenna working at 455 MHz would be about 32.97 cm long, which does not fit within the largest dimension of a CubeSat face corresponding to 14.14 cm.

In this article, the design and the integral implementation of a satellite ground station connected to the Internet of Things is presented. The communication system is based on long-range wireless technology, with the objective of receiving telemetry packets from a network of low-arth orbit satellites that transmit at frequencies around 433 MHz. The design covers mechanical design aspects, the control system, the antenna system, and the receiver. The ground station is oriented with respect to the elevation and azimuth coordinates obtained from a web page. This web page contains a console that shows the telemetry packets that have been received, as well as the satellite from which they came. The ground station is a low-cost proposal since commercial ground stations could be purchased at prices much higher than 2 orders of magnitude. All these aspects implied in this easy-to-replicate ground station are especially relevant in educational terms and for amateur radio enthusiasts.