Cashew nutshells from the northern region of Colombia were prepared to assess their potential use as a filler in polymer matrix filaments for 3D printing. After drying and grinding processes, cashew nutshells were characterized using scanning electron microscopy (SEM), attenuated total reflectance Fourier-transform infrared (ATR-FTIR), and thermogravimetric analyses (TGA). Three different filaments were fabricated from polylactic acid pellets and cashew nutshell particles at 0.5, 1.0, and 2.0 weight percentages using a single-screw extruder. Subsequently, single-filament tensile tests were carried out on them. SEM images showed rough and porous particles composed of an arrangement of cellulose microfibrils embedded in a hemicellulose and lignin matrix, the typical microstructure reported for natural fibers. These characteristics observed in the particles are favorable for improving filler–matrix adhesion in polymer matrix composites. In addition, their low density of 0.337 g/cm³ makes them attractive for lightweight applications. ATR-FTIR spectra exhibited specific functional groups attributed to hemicellulose, cellulose, and lignin, as well as a possible transformation to crystalline cellulose during drying treatment. According to TGA analyses, the thermal stability of cashew nutshell particles is around 320 °C. The three polylactic acid–cashew nutshell particle filaments prepared in this work showed higher tensile strength and elongation at break when compared to polylactic acid filament. The characteristics displayed by these cashew nutshell particles make them a promising filler for 3D printing filaments.

Dissimilar welded joints of AISI 430 and AISI 316L stainless steel were produced by the GMAW process using two different shielding gas mixtures composed of 97Ar-3N2 and 80Ar-19He-1O2. The microstructure of the heat-affected zone was characterized by optical and scanning electron microscopy, and Vickers microhardness measurements were carried out along the cross-section of the specimens. The dissimilar welded joints were submitted to immersion corrosion test in a 10%v/v hydrochloric acid solution for 24 and 72 hours. Afterward, yields strength, tensile strength, and elongation percentage were measured using tensile tests according to ASTM E8 standard. Non-immersed welded joints were used for comparison purposes. An analysis of variance was developed to evaluate the influence of immersion time and shielding gas mixture on yielding strength and tensile strength. The microstructure characterization showed that the heat-affected zone on AISI 430 side was the widest, and it was observed a significant presence of acicular ferrite, martensite, and coarsened ferritic grains. In contrast, on the heat-affected zone on AISI 316L side was not observed coarsening nor refinement of austenite grains. The AISI 430 heat-affected zone showed the maximum hardness values and higher susceptibility to corrosion damage. Tensile tests results evidenced that immersion corrosion tests did not change significantly ultimate strength in comparison to non-immersed specimens while yielding strength and elongation percentage were drastically decreased due to immersion time. According to the p-value, the immersion time is the most influencing factor on yielding strength and tensile strength of the dissimilar welded joints.

El departamento de Córdoba cuenta con zonas rurales que no hacen parte del sistema interconectado nacional. Esto crea un problema para sus habitantes ya que, no pueden conservar alimentos. Sin embargo, la alta disponibilidad de radiación solar durante todo el año, ofrece una alternativa para preservar alimentos utilizando equipos de refrigeración por absorción solar. El objetivo de este trabajo fue simular y analizar un sistema de refrigeración por absorción solar, usando el software ASPEN Hysys. Se obtuvo un coeficiente de desempeño (COP) máximo de 1,0 a 93°C y 1547 kPa, teniendo en cuenta el efecto de distintas variables.

This study explores the use of banana pseudostem fibers from Córdoba, Colombia, as reinforcement in polymer composites manufactured through vacuum-assisted resin transfer molding (VARTM). The fibers were decorticated, oven-dried at 40 °C, and subjected to mercerization and epoxy coating treatments. Plain-weave fabrics were produced using continuous yarns composed of 10 and 15 fibers, both treated and untreated. Experimental analyses included pull-out tests, thermogravimetric analysis, fourier-transform infrared spectroscopy, winding speed, surface twist angle, and tensile strength tests for yarns, as well as tensile load, adhesion, and permeability tests for fabrics and tensile and flexural strength tests for composites. Treated yarns exhibited a slight increase in diameter and a lower extraction (25%) compared to untreated yarns (33%). Although treated fabrics showed enhanced permeability and improved resin infiltration, untreated fabrics demonstrated superior mechanical performance, with a tensile load of 2.33 kN in comparison to 1.37 kN for treated yarns. The highest tensile strength of 76.56 MPa was achieved in composites reinforced with three layers of untreated fabric, while the best flexural strength of 86.93 MPa was observed in single-layer composites with the same configuration. These results emphasize the potential of untreated banana fiber fabrics as promising reinforcement in structural composite applications.