Tensile behavior of 3D printed polylactic acid (PLA) based composites reinforced with natural fiber

Eliana M Agaliotis BALTAZAR DAVID AKE CONCHA ALEJANDRO MAY PAT Juan Pablo Morales Arias Celina Bernal Alex Valadez González Pedro Jesús Herrera Franco Gwenaelle Proust JUAN FRANCISCO KOH DZUL José Gonzalo Carrillo Baeza Emmanuel Alejandro Flores Johnson (2022, [Artículo])

Natural fiber-reinforced composite (NFRC) filaments for 3D printing were fabricated using polylactic acid (PLA) reinforced with 1–5 wt% henequen flour comprising particles with sizes between 90–250 μm. The flour was obtained from natural henequen fibers. NFRCs and pristine PLA specimens were printed with a 0° raster angle for tension tests. The results showed that the NFRCs’ measured density, porosity, and degree of crystallinity increased with flour content. The tensile tests showed that the NFRC Young’s modulus was lower than that of the printed pristine PLA. For 1 wt% flour content, the NFRCs’ maximum stress and strain to failure were higher than those of the printed PLA, which was attributed to the henequen fibers acting as reinforcement and delaying crack growth. However, for 2 wt% and higher flour contents, the NFRCs’ maximum stress was lower than that of the printed PLA. Microscopic characterization after testing showed an increase in voids and defects, with the increase in flour content attributed to particle agglomeration. For 1 wt% flour content, the NFRCs were also printed with raster angles of ±45° and 90° for comparison; the highest tensile properties were obtained with a 0° raster angle. Finally, adding 3 wt% content of maleic anhydride to the NFRC with 1 wt% flour content slightly increased the maximum stress. The results presented herein warrant further research to fully understand the mechanical properties of printed NFRCs made of PLA reinforced with natural henequen fibers. © 2022 by the authors.

POLYLACTIC ACID (PLA) NATURAL FIBER HENEQUEN FIBER NATURAL FIBER REINFORCED COMPOSITE (NFRC) ADDITIVE MANUFACTURING 3D PRINTING MECHANICAL PROPERTY INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Análisis a escala atómica de interfases magnéticas con aplicaciones en espintrónica

Atomic scale analysis of magnetic interfases with spintronics applications

Rocio González Díaz (2023, [Tesis de maestría])

La espintrónica es un área de la nanociencia que tiene por cometido el estudio y manipulación del espín de los electrones para el desarrollo y mejoramiento de dispositivos electrónicos. De manera particular, se ha orientado a la búsqueda de materiales para la fabricación de memorias magnéticas de acceso aleatorio (MRAM), diseñadas a partir de uniones túnel magnéticas (MTJ). Dichas uniones son heteroestructuras construidas a partir de un material aislante en cuya capa superior e inferior se dispone un compuesto ferromagnético. Una de las características de estos dispositivos es que presentan una anisotropía magnética perpendicular (PMA) y un efecto de torque por transferencia de espín (STT). Recientemente, un estudio experimental señala que la heteroestructura B2-CoAl/L10-MnAl es un candidato idóneo para la fabricación de MRAM, pues presenta PMA y STT. Sin embargo, en el trabajo experimental no se reporta un análisis de la estabilidad termodinámica de la heteroestructura. Dicho lo anterior, en este trabajo se hizo un estudio de la estabilidad termodinámica y estructural de B2-CoAl/L10-MnAl usando la teoría del funcional de la densidad (DFT). Se propusieron diferentes modelos de interfaz CoAl/MnAl y se determinó a través de un análisis energético cuál es la interfaz más estable. Los resultados obtenidos indican que la interfaz más estable sucede entre la última capa de Al del CoAl y la primera capa de Mn del MnAl. Además, se comprobó un efecto PMA en la heteroestructura B2-CoAl/L10-MnAl y se determinó que este comportamiento se origina esencialmente debido a la naturaleza ferromagnética de MnAl, pues CoAl no presenta características ferromagnéticas.

Spintronics is nanoscience area whose aim is the study and manipulation of electrons spin to development and improvement of electronic devices. In a particular way, the spintronics has focused to search of new materials to fabrication of magnetic random-access memory (MRAM), which are designed from devices call magnetic tunnel junctions (MTJ). This devices are heterostructures built from an insulating material with a ferromagnetic compound on top and bottom layers and characterized by the perpendicular magnetic anisotropy and spin-transfer torque (STT) effects prensent on it. Recently, an experimental study indicates the B2-CoAl/L10-MnAl heterostructure is a suitable candidate for the fabrication of MRAM based on MTJ devices. Nevertheless, the thermodynamic stability of the heteroestructure is not reported in the experimental work. Therefore, in this work a study of the thermodynamic and structural stability of B2-CoAl/L10-MnAl was performed using density functional theory (DFT). Different CoAl/MnAl interface models were proposed and the most stable interface was determined by an energy analysis. The results obtained, indicate that the most stable interface occurs between the last Al layer of CoAl and the first Mn layer of MnAl. In addition, a PMA effect in the B2-CoAl/L10-MnAl heterostructure was demonstrated and it was determined that this behaviour is essentially due to the ferromagnetic nature of MnAl, since CoAl does not present ferromagnetic characteristics.

simulaciones computacionales, interfases magnéticas, estabilidad termodinámica computational simulation, magnetic interfaces, termodinamic stability INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Effect of the noble metals addition on the oxidation behavior of Ni3Al

Jose Juan Ramos-Hernandez JESUS PORCAYO-CALDERON Jan Mayen Chaires GABRIEL ANGEL LARA RODRIGUEZ victor salinas JOSE-GONZALO GONZALEZ-RODRIGUEZ Lorenzo Martínez Gómez (2018, [Artículo])

This paper discusses the e1ect of the addition of noble metals on the microstructure, mechanism, and oxidation kinetics of the Ni3Al intermetallic alloy. Ni3Al was doped with 1% (atomic percent) of Au, Ag, Pd, and Pt. Oxidation behavior of the alloys was evaluated at 900, 1000, and 1100°C in O2 for 24 hours. XRD analysis showed that the addition of noble metals favored the oxide growth on preferential crystallographic planes. In addition, the preferential substitution of the noble metals in the Ni3Al structure modi>es the surface composition by increasing the Al/Ni ratio. It was observed that most of the alloys showed a subparabolic behavior, and only the intermetallic base and the alloy doped with Ag show a parabolic behavior at 900°C. ,e developed oxides were analyzed both super>cially and in cross section by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA). It was evident that only the intermetallic base showed the formation of a duplex oxide scale (Al2O3/NiO). ,e alloys doped with noble metals showed the oxide growth practically of pure Al2O3. ,is was due to a decrease in the di1usion of the Ni cations because of the presence of the noble metals in the crystalline structure.

Financial support from Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico) (Project no. 159898 and Ph.D. scholarship to J. J. Ramos-Hernandez, Registration no. 202898) is gratefully acknowledged.

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Thermal and mechanical properties of PLA-based multiscale cellulosic biocomposites

MIGUEL ANGEL RUZ CRUZ Pedro Jesús Herrera Franco Emmanuel Alejandro Flores Johnson MARIA VERONICA MORENO CHULIM LUCIANO MIGUEL GALERA MANZANO Alex Valadez González (2022, [Artículo])

In this work polylactic acid (PLA) based multiscale cellulosic biocomposites were prepared with the aim to evaluate the effect of the incorporation of cellulose nanocrystals (CNCs) on the PLA biocomposites reinforced with cellulose microfibers (MFCs). For this, PLA composite materials reinforced with both MFCs and with a combination of MFCs and CNCs were prepared, while keeping the content of cellulosic reinforcements constant. The thermal and mechanical properties of these multiscale PLA biocomposites were characterized by thermogravimetry (TGA), differential scanning calorimetry (DSC), flexural mechanical and, dynamic mechanical (DMA) tests. Likewise, they were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results show that the replacement of MFCs by CNCs in the 1–5% range appreciably modifies the thermal and mechanical properties of multiscale compounds. For example, they increase the thermal stability of the materials, modify the PLA crystallization process and play the role of adhesion promoters since the mechanical properties in flexure increase in the order of 40% and the storage modulus increases in the order of 35% at room temperature. Also, the addition of CNCs increases the relaxation temperature of the material from 50 to 60 °C, thereby expanding the temperature range for its use. © 2022 The Author(s)

MULTISCALE BIOCOMPOSITES CELLULOSE MICROFIBER CELLULOSE NANOCRYSTALS HIERARCHICAL STRUCTURE PROPERTIES INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

Las cáscaras de naranja: ¿Desechos de la agricultura o riqueza farmacéutica?

ROLFFY RUBEN ORTIZ ANDRADE JESUS ALFREDO ARAUJO LEON Gregoreo Centeno Hoil MICHELLE SANSORES CHUC (2023, [Artículo])

México se encuentra entre los diez primeros países con la mayor producción de cítricos, siendo Yucatán uno de los principales estados productores, en particular, de naranjas. Actualmente, la producción de cítricos se utiliza para la extracción de jugo para alimentos y bebidas. Sin embargo, las cáscaras de naranjas son desechadas o subutilizadas. En este ensayo abordamos una perspectiva del potencial médico y económico que existe en las cáscaras de naranja y que podrían ser una riqueza farmacéutica por su alto contenido de flavonoides, moléculas que han sido objeto de estudio para la prevénción de la diabetes, hipertensión y la obesidad.

CITRUS SINENSIS DIABETES HESPERIDINA HIPERTENSION NARINGENINA OBESIDAD BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA VEGETAL (BOTÁNICA) EXPLOTACIÓN DE LOS CULTIVOS EXPLOTACIÓN DE LOS CULTIVOS

MLN disease diagnostics, MLN disease-free seed production and MLN disease management

Suresh L.M. (2022, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DISEASES DISEASE MANAGEMENT SEED PRODUCTION MAIZE NECROSIS YIELD LOSSES ECONOMIC IMPACT SURVEILLANCE SYSTEMS TRAINING

A Novel Technique for Classifying Bird Damage to Rapeseed Plants Based on a Deep Learning Algorithm.

Ali Mirzazadeh Afshin Azizi Yousef Abbaspour_Gilandeh José Luis Hernández-Hernández Mario Hernández Hernández Iván Gallardo Bernal (2021, [Artículo])

Estimation of crop damage plays a vital role in the management of fields in the agricultura sector. An accurate measure of it provides key guidance to support agricultural decision-making systems. The objective of the study was to propose a novel technique for classifying damaged crops based on a state-of-the-art deep learning algorithm. To this end, a dataset of rapeseed field images was gathered from the field after birds¿ attacks. The dataset consisted of three classes including undamaged, partially damaged, and fully damaged crops. Vgg16 and Res-Net50 as pre-trained deep convolutional neural networks were used to classify these classes. The overall classification accuracy reached 93.7% and 98.2% for the Vgg16 and the ResNet50 algorithms, respectively. The results indicated that a deep neural network has a high ability in distinguishing and categorizing different image-based datasets of rapeseed. The findings also revealed a great potential of Deep learning-based models to classify other damaged crops.

rapeseed classification damaged crops deep neural networks INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE LOS ALIMENTOS

Fabricación de nanopartículas de oro dentro de óxido de aluminio (γ-Al2O3) nanoestructurado con cavidades esféricas

Manufacturing of Gold Nanoparticles within Nanostructured Aluminum Oxide (γ-Al2O3) with Spherical Cavities

Mariela de Jesús Franco Gallegos (2023, [Tesis de maestría])

Los catalizadores basados en nanopartículas de oro han generado gran interés, gracias a su capacidad de ser selectivos en la promoción de reacciones específicas o en la producción de productos deseados, minimizando la formación de productos secundarios no deseados; sus propiedades electrónicas únicas; y su utilización bajo condiciones ambientales. Sin embargo, la desventaja principal de los catalizadores de oro es la sinterización de las nanopartículas debido a su baja temperatura de fusión, lo que provoca la pérdida de actividad catalítica y la desactivación del catalizador. Una de lassoluciones que ofrece el uso de la nanociencia y la nanotecnología es la utilización de soportes nanoestructurados que den mejor estabilidad a las nanopartículas y las protejan de la desactivación. En este trabajo se sintetizaron catalizadores basados en nanopartículas de oro soportados y encapsulados en alúmina macroporosa, por un método de impregnación húmeda asistida por ultrasonido; un método sencillo, rápido y ecológico. El desempeño catalítico de materiales sintetizados se analizó mediante espectroscopía UV-Visible in-situ en la reducción de 4-Nitrofenol a 4-Aminofenol. Así mismo, se presentan las caracterizaciones por TEM, SEM, FT-IR, espectroscopía UV-Visible, y XRD de catalizadores obtenidos. Se obtuvieron catalizadores altamente activos con alto rendimiento gracias al uso de un soporte nanoestructurado.

Catalysts -based on gold nanoparticles have recently gained interest due to their ability to selectively promote specific catalytic reactions or produce desired products, while minimizing the formation of unwanted byproducts, their unique electronic properties, and their utilization under ambient conditions. However, the main drawback of gold catalysts is the sintering of nanoparticles due to their low melting temperature, which leads to loss of catalytic activity and catalyst deactivation. One of the solutions offered by nanoscience and nanotechnology is the use of nanostructured supports that provide better stability to the nanoparticles and protect them from deactivation. In this work, gold nanoparticle-based catalysts supported and encapsulated in macroporous alumina were synthesized using a simple, fast, and eco-friendly method of ultrasound-assisted wet impregnation. The catalytic performance of synthetized materials was evaluated by in-situ UV-Visible spectroscopy in the reduction of 4-Nitrophenol to 4-Aminophenol. In addition, their characterization by TEM, SEM, FT-IR, UV Visible spectroscopy and XRD are presented. Highly active catalysts with high performance were obtained thanks to the use of a nanostructured supports.

nanopartículas de oro, alúmina macroporosa, impregnación, reducción 4-NF gold nanoparticles, macroporous alumina, impregnation, 4-NF reduction INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES

MLN disease diagnostics, surveillance, MLN disease-free seed production, and MLN disease management

Suresh L.M. (2022, [Objeto de congreso])

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA DISEASES DISEASE MANAGEMENT SEED PRODUCTION MAIZE NECROSIS YIELD LOSSES ECONOMIC IMPACT SURVEILLANCE SYSTEMS TRAINING

Periplos de mariachi. La modernización del mariachi como representación de "lo mexicano" en la política internacional mexicana (1938-1958)

Eduardo Martínez Muñoz (2019, [Tesis de maestría])

Instituto de Investigaciones Históricas. Facultad de Historia. Programa Institucional de Maestría en Historia

The musician-vocal ensemble called Mariachi, received in 2011 the nomination of Intangible Heritage of Humanity by UNESCO. This grouping of Mexican origin, from the Bajío-Occidente area of the country and an element of local, regional and national identity was projected by the cinema of the so-called Golden Age to its internationalization. In this work I show how the Mexican State through a cultural policy, shows the group and its music as representative of Mexico, making a worldwide presence through the lyric of its compositions, its costumes and the evocation of the feeling that It stereotyped and manifested itself as it was shown in the world, in a process of internationalization and in parallel to a process of appropriation by countries that was presented on the big screen and later in personal presentations. Government support was a cornerstone for Mariachi's presence in radio, film and advertising to promote the country. Governments from Álvaro Obregón, with José Vasconcelos in the SEP, Lázaro Cárdenas and even Miguel Alemán appear as presidents seeking elements of cohesion as part of the country's modernization, found in popular culture. South American countries were identified on the screen and adopted the luminaries such as Jorge Negrete, Pedro Infante, Luis Aguilar, etc., all representatives of Mexican-Jalisco music, without being tapatios. The Mariachi has been presented in countless scenarios in the world as the "typically Mexican", construct emanating from the intellectual and political elite groups, national and international.

El ensamble músico-vocal denominado Mariachi, recibió en el 2011 la nominación de Patrimonio Intangible de la Humanidad por parte de la UNESCO. Dicha agrupación de origen mexicano, del área del Bajío-Occidente del país y elemento de identidad local, regional y nacional fue proyectado por el cine de la llamada Época de Oro a su internacionalización. En este trabajo muestro cómo el Estado mexicano a través de una política cultural, muestra al grupo y su música como lo representativo de México, haciendo presencia en todo el mundo por medio de la lírica de sus composiciones, su vestuario y a la evocación del sentimiento que se fue estereotipando y manifestándose conforme se fue mostrando en el mundo, en un proceso de internacionalización y en paralelo a un proceso de apropiación por los países que se fue presentando en la pantalla grande y posteriormente en presentaciones personales. El apoyo gubernamental fue pieza angular para la presencia del Mariachi en la radio, el cine y publicidad para promover al país. Gobiernos desde Álvaro Obregón, con José Vasconcelos en la SEP, Lázaro Cárdenas y hasta Miguel Alemán aparecen como presidentes que buscan elementos de cohesión como parte de la modernización del país, encontrados en la cultura popular. Países sudamericanos se vieron identificados en la pantalla y adoptaron a las luminarias como Jorge Negrete, Pedro Infante, Luis Aguilar, etc., todos representantes de la música mexicana-jalisciense, sin ser tapatíos. El Mariachi se ha presentado en infinidad de escenarios en el mundo como lo "típicamente mexicano", constructo emanado desde los grupos de élite intelectual y política, nacional e internacional.

HUMANIDADES Y CIENCIAS DE LA CONDUCTA FH-M-2019-1690 Historiografía Teoría de los sentimientos Cine Hegemonía cultural