The present study exhibits the behavior of ABS polymer (acrylonitrile butadiene styrene) subjected to mechanical compression tests considering two filling patterns, rectangular and hexagonal; these patterns have been selected due to the geometric arrangement of their internal structure improves the mechanical properties of 3D printed parts, in addition to the increase in tensile strength. The specimens were developed by molten deposition modeling (FDM) under the ASTM D695 standard in 2015, so five samples of each pattern were made; they have an 80% filler material. This is due to the demanding mechanical requirement in engineering applications. The results obtained show that the rectangular fill pattern at 0° and 90° registered the highest compressive strength obtaining as a result an average compression strength of 4 179.92 N, likewise a percentage of deformation of 5.96% and a maximum compressive strength of 33.147 MPa. Because of the evidenced data, the rectangular pattern is useful for engineering and industrial applications, including substituting car parts, machinery or household appliances.

The utilization of agroindustrial residues, such as avocado peel, as a source of bioactive compounds with antioxidant properties has garnered significant attention. In this study, we investigated the antioxidant potential using the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ORAC (oxygen radical absorbance capacity) methods, along with the antimicrobial activity of phenolic compounds extracted from Hass avocado peel. These soluble polyphenols were quantified and identified using high-performance liquid chromatography (HPLC). The research focused on their effects against three fungal pathogens, Verticillium theobromae, Colletotrichum musae, and Aspergillus niger, which significantly impact banana crops, an essential agricultural commodity in Ecuador. The results have revealed that the application of 80% ethanol as an organic solvent led to increased soluble polyphenol content compared to 96% ethanol. Extraction time significantly influenced the phenolic content, with the highest values obtained at 90 min. Interestingly, despite substantial mycelial growth observed across all extract concentrations, the antifungal effect varied among the pathogens. Specifically, V. theobromae exhibited the highest sensitivity, while C. musae and A. niger were less affected. These results underscore the importance of considering both antioxidant and antimicrobial properties when evaluating natural extracts for potential applications in plant disease management.

Bimetallic Pd-Pt/HY catalysts prepared by the co-impregnation method with an atomic variation of Pd/Pd+Pt were studied to convert toluene and methylcyclohexane. The catalysts were characterized by the BET method, chemisorption of CO by the pulse method, programmed temperature reduction (H2-TPR), and programmed ammonia thermo-desorption (NH3TPD). Results of chemisorption of CO and H2-TPR for Pd-Pt/HY catalysts suggest the existence of a strong interaction between Pd and Pt. The NH3-TPD showed that incorporating metals influences the percentage of relative distribution of weak/strong acid sites presented in decreasing order of acidity: Pd0Pt100/HY>Pd100Pt0/HY>Pd33Pt67/HY. Atomic composition Pd/Pd+Pt equal to 0.33, and relative distribution of weak/strong acid sites equal to 2, favor hydrogenation of toluene to methylcyclohexane in metal sites and subsequent skeletal isomerization in the acidic sites through dimethylcyclopentane intermediate and ring-opening in the metal sites, leading to increased formation of n-heptane relative to iso-heptane. Bimetallic Pd-Pt/HY catalysts prepared by the co-impregnation method with an atomic variation of Pd/Pd+Pt were studied to convert toluene and methylcyclohexane. The catalysts were characterized by the BET method, chemisorption of CO by the pulse method, programmed temperature reduction (H2-TPR), and programmed ammonia thermo-desorption (NH3TPD). Results of chemisorption of CO and H2-TPR for Pd-Pt/HY catalysts suggest the existence of a strong interaction between Pd and Pt. The NH3-TPD showed that incorporating metals influences the percentage of relative distribution of weak/strong acid sites presented in decreasing order of acidity: Pd0Pt100/HY>Pd100Pt0/HY>Pd33Pt67/HY. Atomic composition Pd/Pd+Pt equal to 0.33, and relative distribution of weak/strong acid sites equal to 2, favor hydrogenation of toluene to methylcyclohexane in metal sites and subsequent skeletal isomerization in the acidic sites through dimethylcyclopentane intermediate and ring-opening in the metal sites, leading to increased formation of n-heptane relative to iso-heptane.

La investigación estudia la fragilización de los aceros inoxidables dúplex SAF 2205 y SAF 2507 sometidos a tratamientos de envejecimiento artificial. Las probetas de tracción e impacto Charpy en V fueron sometidas a tratamiento de envejecimiento artificial que constó de dos fases, primero se realizó la solubilización a temperaturas entre 1100 °C y 1200 °C con tiempos entre 1 h y 2 h, y segundo el envejecimiento artificial fue realizado a temperaturas de 475 °C, 700 °C, 850 °C, 870 °C y 900 °C. Existen varios factores que afectan a las características mecánicas de los aceros inoxidables, por ejemplo, la existencia de micro segregaciones y la precipitación de fases secundarias, que pueden tener lugar durante la solidificación, conformado, tratamiento térmico, operaciones de soldadura, entre otros. El estudio realizado permitió la construcción de curvas que muestran los cambios en el comportamiento mecánico de los aceros dúplex SAF 2205 y SAF 2507, donde se observa que a medida que incrementa el tiempo de envejecimiento, se reduce la ductilidad, resistencia mecánica y tenacidad de impacto. En la microestructura se observó la precipitación de fases secundarias sigma y Chi.

The purpose of this study is the development of a composite material composed of a main layer of polydimethylsiloxane (PDMS) and a reinforcement of polytetrafluoroethylene (PTFE), to be used later in human prosthesis coatings. A mass ratio of the main layer consisting of PDMS:Tetraethyl orthosilicate (TEOS):Di-n-butyl tin dilaurate (DBTL) in the range of 33:1:0.5; 25:1:0.5; 10:1:0.5, and the mass ratio of the composite material (PTFE:PDMS) with a range was evaluated of 1:9; 1:1; 2:3. Obtaining the following results: Tensile strength of 0.085 MPa based on the ratio of 33:1:0.5 - 1:9 and 0.59 MPa with respect to the ratio of 10:1:0.5 - 2:3, evidencing an increase in tensile strength by decreasing the weight of PDMS and increasing the weight of PTFE. On the other hand, the composite material obtained is hydrophobic, insoluble in ethanol and water, has a cross-linking percentage of 98.74 % and 99.66 % respectively, also has a minimum permeance of 5.24x10^-7 (g Pa^-1 s^-1 m^-2). With which it is concluded that the treatment whose properties resemble the human skin is the combination 10:1:0.5 - 1:1 that allowed to obtain an average tensile strength of 0.66 MPa, average modulus of elasticity of 6.56 MPa, similar to the dermis of a 43 year old person.

Post-consumer polypropylene (PP) waste is a growing environmental liability in developing economies with limited recycling infrastructure. This study presents an integrated kinetic-to-reactor approach for the catalytic pyrolysis of three compositionally distinct post-consumer PP streams, combining a moderate vacuum (0.45 bar absolute) with a regenerated fluid catalytic cracking (FCC) catalyst to produce diesel-range fuel while valorising two industrial waste streams. The activation energies derived from thermogravimetric analysis (β = 30 °C min⁻¹, N₂) using the Coats–Redfern method were 178.3 kJ mol⁻¹ for the near-pure isotactic PP feedstock, consistent with random chain scission, and 209.2 and 351.9 kJ mol⁻¹ for the UV-stabilised and PP/HDPE streams, respectively, reflecting the feedstock composition; the DTG profile informed the selection of 450 °C as the reactor set point. At the best condition within the studied domain (Cat/PP = 0.03 g g⁻¹, 2 h, 450 °C), the regenerated FCC catalyst achieved 75.10 wt% liquid yield, a 50% improvement over thermal pyrolysis, with a low aromatic content of 1.69 area%,attributed primarily to the moderate acidity of the regenerated catalyst, versus the 10–25 wt% typical of atmospheric zeolitic pyrolysis. Vacuum distillation yielded a diesel fraction that mainly complies with the ASTM D975 Grade 2-D S15 parameters (cetane index 68.92, sulphur 14.1 ppm) without hydrotreatment, demonstrating a technically viable waste-to-fuel pathway where post-consumer polyolefins and refinery FCC by-products are simultaneously abundant.