Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Fabrication of low-Cost SnO2 anodes on silicon for the electrochemical degradation of organic pollutants in water(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-10) Díaz Gallegos, Juan José; García Farrera, Brenda; emipsanchez; Karthik Tangirala, Venkata Krishna; Reyna González, Juan Manuel; Barrios Pérez, José Antonio; School of Engineering and Sciences; Campus Estado de México; Cano Quiroz, AnaidIndirect anodic oxidation is a promising electrochemical advanced oxidation process (EAOP) that has demonstrated high efficiency in oxidating organic pollutants in water. The effectiveness of this process depends critically on anode’s ability to generate hydroxyl radicals while minimizing radical adsorption and resisting corrosion under high oxidative stress. Therefore, scaling up this technology demands electrode fabrication methods that are not only effective but also scalable, reproducible, and cost-effective. As an alternative to extrinsic dopants, depositing SnO2 films onto silicon substrates creates a p-n heterojunction that induces sufficient electronic conductivity and thus anodic activity without intentional doping. This work investigates two scalable manufacturing routes, reactive magnetron sputtering and ultrasonic spray pyrolysis to deposit SnO2 thin films on silicon, as well as the optimization of their performance as anodic oxidation electrodes. Comprehensive electrochemical characterizations including linear sweep voltammetry, cyclic voltammetry, and dye-removal assays are used to link each film’s electrochemical performance with its morphology and composition. Physicochemical analyses such as scanning electron microscopy (SEM) for surface morphology, atomic force microscopy (AFM) for topography and roughness, energy-dispersive X- ray spectroscopy (EDS) for elemental mapping, and X-ray diffraction (XRD) for phase identification are used to provide deeper insights into the impact of fabrication parameters on film structural properties and long-term stability. Magnetron sputtered films suffered from incomplete oxidation, revealing metallic Sn peaks, poor adhesion, and low corrosion resistance, highlighting reactor design limitations and indicating that, with the current reactor configuration, full SnO2 stoichiometry via PVD cannot be achieved without substrate pre-heating, cyclic voltammograms showed that these films had SnO2 like behavior but their reproducibility was compromised by its low mechanical stability during the electrochemical characterization. In contrast, films fabricated via ultrasonic spray pyrolysis formed rutile phase SnO2. The Si/SnO2 film exhibited an oxygen evolution potential of 1.93 V vs. Ag/AgCl, which increased to 2.21 V after annealing, and a significant decrease in their charge-transfer resistance. Both samples, with and without annealing, exhibited excellent methylene blue color removal (>95%), with the annealed samples demonstrating superior mechanical stability and corrosion resistance under electrooxidation stress. Finally, this thesis reviews the testing protocols implemented to refine both physicochemical and electrochemical characterizations, elucidating how each fabrication parameter impacts film properties and their subsequent performance in electrochemical evaluations, thus providing guidance for further optimization toward cost-effective, scalable manufacturing of SnO2 anodes for advanced water treatment applications.
- Digital light processing additive manufacturing for accessible blood-brain barrier organ-on-a-chip fabrication(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06) Lagunes Nava, Daniel; García Farrera, Brenda; emimmayorquin; Magaña Aguirre, Jonathan Javier; García Aguirre, Ian Alain; Cano Quiroz, Anaid; School of Engineering and Sciences; Campus Estado de México; Solis Cordova, José de JesúsOrgan-on-a-Chip (OoC) technologies represent a promising alternative to traditional preclinical models and their actual limitations, yet their widespread adoption remains limited by cost, fabrication complexity, and accessibility. This thesis presents the development of an economically viable microfluidic platform designed to mimic the Blood-Brain Barrier (BBB) using Digital Light Processing (DLP) additive manufacturing. By leveraging the geometric freedom and rapid prototyping capabilities of DLP, a series of chips were fabricated and systematically evaluated through both structural characterization and functional assays. The platform’s performance was assessed via passive diffusion experiments using sodium chloride, providing a quantifiable readout of molecular transport across the chip interface. Particular emphasis was placed on the role of channel geometry in shaping diffusion behavior. Comparative analysis of square and circular layouts demonstrated that structural configuration alone can influence transport dynamics, even under equivalent flow conditions, an observation reinforced by simplified computational simulations. These findings call into question the extent to which current chip designs, often simplified because of the nature of the techniques, truly replicate physiologically relevant transport. Results revealed that the square chip exhibited faster and more direct fluid penetration through the interface, while the circular design induced more distributed flow with attenuated velocity vectors. This divergence also reflected in the diffusion curves, challenges the conventional assumption that greater surface area alone enhances transport, and emphasizes the need to reevaluate geometric decisions in microfluidic design. Beyond functionality, the fabrication process itself validated the feasibility of low-cost and reproducible production of complex microfluidic architectures. Together, these findings reaffirm the potential of DLP printed devices as accessible tools for biomedical research and establish a foundation for more physiologically relevant Organ-on-a-Chip systems.
- Caracterización de propiedades mecánicas de estructuras flexibles basadas en TPMS manufacturadas aditivamente(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022-11-28) Manrique Moreno, Víctor José; García Farrera, Brenda; puemcuervo, emipsanchez; Rojo Valerio, Alejandro; Elias Espinosa, Milton Carlos; Escuela de Ingeniería y Ciencias; Campus TolucaEn esta Tesis se presenta las propiedades mecánicas efectivas de una geometría reticulada basado en superficies mínimas triplemente periódicas (TPMS) tipo Diamond, caracterizadas experimentalmente mediante probetas cubicas de 50 mm de lado, fabricadas por manufactura aditiva con tecnología Fused deposition modeling (FDM) utilizando poliuretano termoplástico (TPU) de dureza 95A. Como resultado del estudio del estado del arte, se identificó la estructura Diamond como una de las que exhibe mayor resistencia a la compresión respecto a otras geometrías TPMS. Este comportamiento de resistencia a la compresión fue caracterizado experimentalmente bajo lineamientos de ISO 844, y presenta tres zonas claramente diferenciadas: 1) zona elástica, 2) zona de meseta, y 3) zona de densificación. Una vez descomprimido, este material recupera hasta un 95% de su altura inicial, y minutos más tarde hasta el 98-99% y no presenta fracturas ni separación o desprendimiento de las capas de impresión. Después de diez ciclos de compresión, su resistencia máxima se reduce en un 67%. Las probetas base diseñadas tienen una porosidad de 86,5% (está compuesto en un 13.5% por TPU) y tiene una densidad de 154 kg/m3 y una resistencia máxima ingenieril (σy) de 156 kPa al 10% de compresión y módulo de elasticidad (E) de 2.25 MPa. La TPMS Diamond tiene una resistencia hasta un 70% mayor que la Gyroid y un 214% mayor que Schwarz, en relación con su peso. Estos resultados permiten confirmar la hipótesis bajo la cual se seleccionó la TPMS Diamond. Además, exhibe un comportamiento casi isotrópico, a pesar de que la manufactura aditiva por FDM es un proceso de fabricación inherentemente anisotrópico. Las propiedades mecánicas (resistencia y módulo de elasticidad) de la estructura TPMS Diamond se relacionan con la densidad relativa en el intervalo 0.1 a 0.64 de acuerdo con el modelo de Gibson-Ashby, con los coeficientes presentados en esta Tesis. Las probetas con gradiente de espesor presentan un comportamiento diferente a las probetas de espesor uniforme. En este caso, la curva esfuerzo – deformación no presenta una zona de meseta definida, sino varios puntos de esfuerzo máximo qué aparecen de forma escalonada y se pueden relacionar con los respectivos puntos máximos de las curvas de las probetas de espesor uniforme.