Periodic superlattices constitute ideal structures to modulate the transport properties of two-dimensional materials. In this paper, we show that the tunneling magnetoresistance (TMR) in phosphorene can be tuned effectively through periodic magnetic modulation. Deltaic magnetic barriers are arranged periodically along the phosphorene armchair direction in parallel (PM) and anti-parallel magnetization (AM) fashion. The theoretical treatment is based on a low-energy effective Hamiltonian, the transfer matrix method and the Landauer–Büttiker formalism. We find that the periodic modulation gives rise to oscillating transport characteristics for both PM and AM configurations. More importantly, by adjusting the electrostatic potential appropriately we find Fermi energy regions for which the AM conductance is reduced significantly while the PM conductance keeps considerable values, resulting in an effective TMR that increases with the magnetic field strength. These findings could be useful in the design of magnetoresistive devices based on magnetic phosphorene superlattices.

Based on a V-shaped microactuator with a pair of beams, modifications were made to the length and width of a microactuator to observe the effects. A theoretical approach and numerical characterization of the modified microactuator were performed. Its performance was compared to a similar microactuator with equal beam widths, and a V-shaped microactuator. The proposed microactuator, fed at 2 V, compared to the V-shaped actuator, showed a 370.48% increase in force, but a 29.8% decrease in displacement. The equivalent von Mises stress level increased (until 74.2 MPa), but was below the silicon ultimate stress. When the modified microactuator was applied to the proposed microgripper, compared to the case using a V-shaped actuator, the displacement between the jaws increased from 0.85 µm to 4.85 µm, the force from 42.11 mN to 73.61 mN, and the natural frequency from 11.36 kHz to 37.99 kHz; although the temperature increased, on average, from 42 °C up to 73 °C, it is not a critical value for many microobjects. The maximum equivalent von Mises stress was equal to 68.65 MPa. Therefore, it has been demonstrated that the new modified microactuator with damping elements is useful for the proposed microgripper of novel geometry, while a reduced area is maintained.

The effect of the galvanic corrosion process taking place between aluminium alloy (AA2024-T3) and carbon fiber reinforced plastic (CFRP) immersed in 0.05 M NaCl was studied using organic and inorganic compounds as corrosion inhibitors. Electrochemical approaches such as electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) were carried out to evaluate efficiencies of 1,2,4-triazole (C₂H₃N₃) and cerium nitrate hexahydrate (Ce(NO₃)₃·6H₂O) as corrosion inhibitors. The highest efficiency was reached for Ce(NO₃)3.6H₂O, with some improvement observed by adding C₂H₃N₃ in a mixed inhibitor solution. The noise resistance (R_n) and polarization resistance (R_p) values calculated from ENA and EIS data showed almost identical behavior with different magni­tudes but similar trends. Adsorption isotherm models estimated with fractional surface coverage (q) parameter were fitted better to Langmuir model for C₂H₃N₃ and Temkin model for Ce(NO₃)₃·6H₂O. The calculated values of Gibbs free energy suggested physi­sorption and chemisorption as spontaneous interactions between a metal surface and both inhibitors. Energy-dispersive X-ray spectroscopy (EDS) was carried out before and after immersing AA2024-T3 in the electrolyte, identifying rich zones in copper with cerium deposited over it and confirming the presence of rare-earth oxide deposition and oxide film products. The EDS analysis for CFRP revealed the deposition of Ce and Al particles over its surface after immersion in the electrolyte, especially in the areas rich in carbon.

This article presents an annual performance evaluation of single- and double-air-channel solar chimneys for natural ventilation induction under weather conditions in Mexico. The global energy balance method modeled both types of solar chimneys in an unsteady state. The case study evaluated five cities in Mexico. Experimental data of a single-air-channel chimney prototype evaluated under controlled conditions were used to validate the GEB numerical solution. Model validation considers climatic parameters to increase the accuracy of ventilation calculations, e.g., solar radiation, ambient temperature, wind speed, relative humidity, and atmospheric pressure. Experimental evaluation was performed considering the warmest and coldest days in each month of 2018. The modeling time to achieve the initial condition independence for each configuration was 72 h of the physical phenomenon. Results show that double-air-channel solar chimney tested configurations induced at least 70% more airflow than single-air-channel solar chimneys. Both solar chimney airflows were higher than the dwelling-unit ventilation for a space of 54 m${}^3$, and volumetric flows up to 120 m${}^3$h${}^{-1}$ were identified for two studied cities.

High-Voltage Direct Current (HVDC) systems are transforming the global energy landscape, distinguished by their efficiency, stability, and low impact on the electrical grid. One of the challenges of HVDC transmission line design is assessing the generated stray magnetic field, as it can have negative effects on human health and the environment. This study presents an analytical methodology for calculating the magnetic field density at any point along an HVDC line corridor. It considers the spatial configuration, the current per pole, and the location of the conductors. The equations allow for the calculation of the horizontal and vertical components of the field, as well as its total magnitude. A practical case study of a ±500 and ±600 kV HVDC two-pole transmission line is presented. The methodology was programmed in MATLAB^® version R2024a to calculate the magnetic field density, and the results are consistent with those obtained with the established methodology. The presented methodology can be applied to monopolar and two-pole HVDC overhead transmission lines, offering speed and accuracy.

The feasibility study is crucial for decision-making in the investment stage of photovoltaic systems projects. A cost–benefit analysis for a project should not be evaluated solely in terms of money in-flows and outflows; it is important to consider other characteristics such as climate, solar irradiation, and the hours of sunshine in different spaces, as well as the electricity rates of the electricity supply company. Therefore, analyzing and simulating the performance conditions, both technical and economic, of photovoltaic systems is key. The objective of this study was to analyze the investment models in two types of photovoltaic systems: one integrated into the construction and the other conventional in a building in the Mexican Republic, considering ideal conditions, thus evaluating the energy efficiency in cities, as they consume around two-thirds of the world’s energy and are responsible for 70% of global greenhouse gas emissions. The methodological proposal was to select a location, determine the predominant type of climate and collect data on solar radiation, the electricity supplier rates, the profitability for a cost–benefit analysis, and the inflation rates to determine the viability of a project that comprehensively covers the variables for decision-making.