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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- Analysis of the linearity limitations of Jacobs working curve for stereolithography (SLA) additive manufacturing and exploration of potential alternatives through scaling analysis(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-06-12) Celis Guzmán, Angel; Aguirre Soto, Héctor Alán; mtyahinojosa, emipsanchez; Hernández Aranda, Raúl Ignacio; Beigi Boroujenji, Saeed; Killgore, Jason; School of Engineering and Sciences; Campus MonterreyPhotopolymerization-based Additive Manufacturing (PAM) has grown in the last few years due to its capability to create parts that have complex geometries that are difficult or impossible to produce with non-additive methods. However, PAM requires a harmonious control of chemical reaction kinetics, mechanical actuation, and optical instrumentation to achieve optimum results. Therefore, a framework that connects these systems is crucial to understand how to match the chemistry of a resin to the mechanical and optical parameters of the printer. To date, the only available theoretical framework to achieve this is the so-called Jacobs Working Curve (WC). The Jacobs WC explains the connection between key printing parameters that must be properly set as a function of every resin, for example the penetration depth (Dp) and the critical dose (Ec) as a function of the cure depth (Cd), writing speed, linewidth, etc. The problem is that the Jacobs Working Curve is affected by a significant used-dependent variability and that alleged linearity stems from an oversimplification of the polymerization-based printing process. Notably, no standardized method to perform a working curve measurement has been done. Therefore, Dp and Cd values can vary by several factors and magnitudes from on user to another. Furthermore, even amongst data from a single user, a linear dependence between the incident radiant exposure (E0) and the Cd is seldom obtained. On the contrary, it is more common to obtain multiple linear regimes and uncertainty about whether absolute Dp and Cd values could be estimated from this method. In this work, we discuss a potential route to capture the inherent non-linearity of VAT photopolymerization using scaling analysis and dimensionless numbers along with a comprehensive characterization of the reaction kinetics of several SLA resins. We employed a coupled UV-Vis and NIR customed-built set-up to obtain the required kinetic data for the polymerization of commercial and in-house resins to establish correlations to the results that one would obtain with the standard Jacobs equation as compared to the analysis through adapted dimensionless numbers for the prediction of the critical dose.
- Development of a framework towards the analysis of the enzymatic degradation of post-consumer polyethylene terephthalate using a photo-modulated PETase(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-02) Gómez Pérez, Leonardo Sebastián; Aguirre Soto, Héctor Alán; puemcuervo, emipsanchez; Rodríguez Macías, Fernando Jaime; García Cuéllar, Alejandro Javier; Contreras Cruz, David Atahualpa; Beigi-Boroujeni, Saeed; School of Engineering and Sciences; Campus Estado de MéxicoIn 2016 Yoshida, et al. discovered the enzyme PETase which has the highest natural activity on PET. To date, several studies about its structure, mechanism of action and enzyme kinetics have been carried out to elucidate the whole series of reactions that involve its catalytic performance. Furthermore, different research groups have tried to modify its stability, catalytic activity, and binding intending to condition the enzyme for scaling up and industrial application. Even though the modifications have been achieved positive results regarding the performance of the wild-type PETase, one of the biggest problems in the enzymatic hydrolysis of PET remains in the low bioavailability of the polymer to be attached in the binding site. To expand the comprehension of the binding process of PETase, the present work comprises the development of a framework for further modulation of PETase architecture using photo-switch based on azobenzene conjugated by thiol-ene click reaction as a novel strategy to reveal key dynamic regions in the binding process of the enzyme. Current results from molecular simulations support the application of a hinge-like structure to enlarge the cavity and enhance contact between the enzyme and the substrate, also a non-specific binding site unreported is defined and related to previous experimental data results.
- Lab-scale modular platform to study coiled-flow inverters (CFI) as candidates for continuous-flow photoreactor units: A case study based on the oxidative degradation of fluorescein induced by visible light in the presence of ZnO-APTMS-Au micro/nano-particles in aqueous suspension(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-12-04) Tiwari, Chinmay Pramodkumar; Aguirre Soto, Héctor Alán; tolmquevedo; Gallo Villanueva, Roberto Carlos; Contreras Cruz, David Atahualpa; López Guajardo, Enrique Alfonso; School of Engineering and Sciences; Campus MonterreyVisible light-driven continuous-flow photochemistry has gained widespread recognition lately and is employed in many innovatively designed photoreactors. Out of the two main categories, slurry reactors are found to have a better reputation in terms of achieving competitive photon efficiencies when compared to immobilized catalyst type reactor designs. However, several obstacles had stalled the broad-scale implementation of this beneficial process. A few of the main imminent challenges include combating light attenuation by better mixing in continuous-flow of the suspension to allow the use of the higher photocatalyst content and require lower photon consumption. Also, the difficulties in the fabrication of intricate glass-based photoreactor designs are one of the significant challenges. An inherently better-designed reactor which deals with the common problems of conventional photoreactors is required. This thesis presents a flexible platform to study photoreactors, where a coiled flow inverter—a well-established static mixer design— is used as a micro/milli-fluidic device. The CFI is incorporated as a photoreactor for the first time for a continuous flow photodegradation study of an organic model pollutant, fluorescein, with ZnO catalyst functionalized with APTMS and Au nanoparticles to make it visible-light absorptive. Flow inversions leading to chaotic advection occurring in the CFI combats light attenuation. Due to superlative mixing coupled with a highly efficient visible light source, our photo-CFI stands to be in top slurry reactor designs as per the recently established PSTY benchmark, valued at 2.97×10^−2 (m^3 treated water day^-1 m^-3 reactor kW^-1). A brief study on the uni- and multi-axial light arrangement for complex geometries was used to analyze the effect of geometry/lighting arrangement and ensure uniform irradiation of the photo-CFI. A discussion of dye-degradation products surface interaction with photocatalyst was carried out to analyze possible explanations for an observed destabilization of the suspension during reaction, leading to depositions in the reactor. SLA based additive manufacturing is tested and projected to be a superior alternative for rapid prototyping of intricate transparent photoreactor designs in lieu of conventional glass blowing techniques of complex geometries such as those required for static mixers like the photo-CFI.
- Search for High-Molecular Weight Linear Polymers for the Formulation of Novel Solutions for the Fabrication of Micro-Fibers by Electromechanical Spinning(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-12-02) Katagiri Tanaka, Antonio Osamu; AGUIRRE SOTO, HECTOR ALAN; 322598; Aguirre Soto, Héctor Alán; tolmquevedo, emipsanchez; Bonilla Ríos, Jaime; School of Engineering and Sciences; Campus Estado de México; Medina Medina, Dora IlianaCarbon nano-wires are versatile structures composed of carbon chains with a wide range of applications due to their high chemical resistance and electric properties. Regardless of the high interest in the implementation of carbon nano-wires in energy, environmental and health-care applications, no feasible processes have been developed to fabricate carbon nano-wires with spatial control at a reasonable cost. Carbon nano-wires have been fabricated with the use of a photoresist, but little is known about polymers that can produce conductive carbon nano-wires after pyrolysis. Various polymer solutions have been tested in near field electrospinning (NFES) and photopolymerization separately, however, few have been tested for nano-wire fabrication purposes through the process of spatio-temporal deposition with NFES, photo-polymerization for cross-linking and pyrolysis. The intention behind the thesis proposal is to use rheological analyses of different polymer solutions to determine if they can be easily electrospun at low voltages and then fabricate nano-wires with them. This thesis work arises from the need to test a greater variety of polymer-solvent combinations with the goal of designing a polymer solution to fabricate carbon nano-wires with higher conductivity than the current SU-8 polymeric nano-fibers. The present work includes the design of polymer solutions that can be electrospun, with the hope that the selected high molecular weight polymers can be photo-polymerized, and then pyrolyzed into conducting carbon nanowires. The overarching goal is to contribute towards the development of novel designed polymer solutions to achieve mass scale manufacturing of conductive carbon nano-wires in an inexpensive, continuous, simple and reproducible manner as central components for nano-sensors.