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En el presente Trabajo de Fin de Grado, desarrollado en el laboratorio de metalotecnia de la EII de la UVa, se ha dado continuidad a la propuesta llevada a cabo desde hace algunos años de crear laboratorios virtuales dedicados a la Ciencia e Ingeniería de los materiales. En este caso, se han creado los laboratorios virtuales de los ensayos tecnológicos de corrosión y desgaste. Para la digitalización se ha creado una página web en la que se engloban una serie de ensayos tecnológicos de corrosión y desgaste, todos ellos con un texto y un video explicativo de los equipos necesarios, procedimientos y resultados que se pueden obtener de cada uno de ellos. Además, para completar la página web se ha desarrollado una prueba de autoevaluación para que el alumno pueda comprobar el nivel de aprendizaje adquirido en los ensayos tecnológicos donde se indican las respuestas correctas, incorrectas y los comentarios explicativos de cada una de las preguntas para aclarar o afianzar conceptos., In this Final Degree Project, developed at the metallography laboratory of the EII in UVa, it has proceeded to the continuation of the proposal carried out since few years of creating a virtual laboratory dedicated to the materials science and engineering. In this case it has been created the virtual laboratories of technological test of corrosion and wear. For the digitized, it has created a web site where there are a part of this tecnológicas test, all of them with and explicative text and video which we may find the necessary tolls, methods y results that he may get from each one of this tests. Furthermore, to complete the web site it has developed an self-evaluation test which the student may prove his or her learning about technological test and which it shows correct and wrong answers and also some explicative commentaries of each cuestions with the purpose of clarify or strengthen the most important concepts., Departamento de Ciencias de los Materiales e Ingeniería Metalúrgica, Expresión Gráfica en la Ingeniería, Ingeniería Cartográfica, Geodesia y Fotogrametría, Ingeniería Mecánica e Ingeniería de los Procesos de Fabricación, Grado en Ingeniería Mecánica

Producción Científica, The objective of this work was to develop a methodology based on multiparametric methods (FTIR and a voltammetric e–tongue based on SPE) to evaluate simultaneously fourteen parameters related to the phenolic content of red wines. Eight types of Spanish red wines, elaborated with different grape varieties from different regions and with different aging, were analyzed with both systems. Input variables used for multivariate analysis were extracted from FTIR spectra and voltammograms using the kernel method. PCA analysis could discriminate wines according to their phenolic content with PC1, PC2 and PC3 explaining the 99.8% of the total variance between the samples for FTIR analysis and 85.8% for the e-tongue analysis. PLS calculations were used to establish regression models with phenolic content parameters measured by UV–Vis spectroscopy (TPI, Folin-Ciocalteu, CIELab and Glories) with high correlation coefficients (R2 > 0.85), and low RMSEs (<3.0) and number of factors (<4). Both, PCA and PLS, were carried out using the full cross validation method. As time is a critical factor in the food industry, the main advantage of these multivariate techniques is their capability to evaluate many parameters in a single experiment and in shorter time than using independent classical techniques., Ministerio de Educación y Formación Profesional (project RTI2018-097990-B-I00), Junta de Castilla y Leon (grants VA275P18 and BOCYL-D-24112015-9)

Producción Científica, A bioelectronic tongue (bioET) based on combinations of enzymes (tyrosinase and glucose oxidase) and polypyrrole (Ppy) or polypyrrole/AuNP (Ppy/AuNP) composites was build up and applied to the analysis and discrimination of musts and wines. Voltammetric responses of the array of sensors demonstrated the effectiveness of polymers as electron mediators and the existence of favorable synergistic effects between Ppy and the AuNPs. Using Principal Component Analysis and Parallel Factor Analysis it was possible to discriminate musts according to the °Brix and TPI (Total Polyphenol Index), and wines according to the alcoholic degree and TPI. Partial Least Squares provided good correlations between the bioET output and traditional chemical parameters. Moreover, Support Vector Machines permitted to predict the TPI and the alcoholic degree of wines, from data provided by the bioET in the corresponding grapes. This result opens the possibility to predict wine characteristics from the beginning of the vinification process., Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482-R), Junta de Castilla y León - Fondo Europeo de Desarrollo Regional (project VA275P18), Junta de Castilla y León (grant BOCYL-D-4112015-9)

El desarrollo de nuevos métodos de análisis para caracterizar los alimentos es de vital importancia para mejorar los actuales sistemas de control de calidad de los productos alimenticios. Dentro de este campo, el concepto de lengua electrónica (ETs o e-tongues) ha crecido rápidamente en los últimos años debido a su gran potencial. Estos dispositivos se basan en sensores electroquímicos combinados con análisis de datos multivariantes. De acuerdo con la IUPAC (Unión Internacional de Química Pura y Aplicada), una lengua electrónica es un sistema multisensor, que consiste en un número de sensores de baja selectividad y utiliza procedimientos matemáticos avanzados para el procesamiento de señales basados en el reconocimiento de patrones (PARC) y/o análisis multivariante [redes neuronales artificiales (RNA), análisis de componentes principales (PCA), etc.]. Por lo tanto, las ETs son sistemas holísticos que proporcionan información global y cualitativa acerca de la muestra en lugar de datos cuantitativos acerca de compuestos específicos. Sin embargo, si la matriz de datos obtenida por estos sistemas se analiza con herramientas de procesamiento quimiométrico adecuadas, se podría extraer información descriptiva o predictiva de parámetros específicos. Existe un término más reciente en el campo de las lenguas electrónicas, ampliamente denominado lengua bioelectrónica (bioET), que incluye el uso de uno o varios biosensores implementados en las ETs. Durante esta investigación se han aplicado ETs y bioETs para estudiar las uvas tintas y los vinos con el fin de predecir mejor el momento óptimo de la vendimia de uvas, así como los parámetros de calidad de interés en los vinos., Departamento de Química Física y Química Inorgánica, Doctorado en Física

Este Trabajo de Fin de Grado ha consistido en el empleo de una lengua potenciométrica para diferenciar entre los cinco sabores básicos y analizar leche de vaca, con y sin adulteración, y mezcla de leche de vaca con leche de cabra. Además, la lengua potenciométrica se ha modificado con la enzima β- galactosidasa para obtener un sistema de lengua biopotenciométrica, con el fin de mejorar la respuesta del dispositivo en las medidas de galactosa. Por último, se han utilizado diferentes análisis estadísticos multivariantes sobre los datos obtenidos con la lengua potenciométrica. Así, el Análisis de Componentes Principales (PCA), se utilizó para estudiar la capacidad de discriminación de la lengua potenciométrica en el estudio de los sabores y muestras de leche. Por otro lado, el Análisis de Mínimos Cuadrados Parciales (PLS), se llevó a cabo para establecer modelos de predicción que permitan correlacionar los datos obtenidos con la lengua potenciométrica y los datos químicos obtenidos., Departamento de Química Física y Química Inorgánica, Grado en Ingeniería Química

En el presente TFG se han desarrollado nuevos sensores y biosensores nanoestructurados basados en la técnica de Layer by Layer (LbL) para la detección de catecol, un componente fenólico de interés para la industria alimentaria. Para la fabricación de las películas LbL se utilizaron una nanoarcilla de aluminosilicato, polietilenimina y ftalocianina de cobre, que es un material sensible con propiedades electrocatalíticas. La nanoarcilla se ha utilizado con el objetivo de mejorar la adhesión entre las películas. Se ha comparado la respuesta electroquímica de los sensores, con y sin nanoarcilla en su estructura, con el fin de estudiar si la presencia de este material mejora la fijación de la ftalocianina de cobre en las películas LbL. Además, a partir de los sensores LbL fabricados se ha desarrollado un biosensor basado en una enzima oxidorreductasa para mejorar la respuesta electroquímica de los sensores LbL. Los sensores exhibieron excelentes prestaciones frente a catecol con LDDs de 0,987 μM para el sensor LbL con presencia nanoarcilla y de 1,16 μM para el sensor LbL sin nanoarcilla. Para el biosensor LbL con nanoarcilla desarrollado se obtuvo un LDD de 0,938 μA, similar al obtenido con respecto a su análogo no enzimático. Los sensores LbL se caracterizaron mediante técnicas de espectroscopía UVVis y FTIR. La técnica electroquímica de voltametría cíclica se ha aplicado para estudiar la reproducibilidad, repetitividad, límites de detección y comportamiento dinámico de los sensores y el biosensor desarrollados., Departamento de Química Física y Química Inorgánica, Grado en Ingeniería Química

Producción Científica, The maturity of grapes is usually monitored by means of the sugar concentration. However, the assessment of other parameters such as the phenolic content is also important because the phenolic maturity has an important impact on the organoleptic characteristics of wines. In this work, voltammetric sensors able to detect phenols in red grapes have been developed. They are based on metal oxide nanoparticles (CeO2, NiO, and TiO2,) whose excellent electrocatalytic properties toward phenols allows obtaining sensors with detection limits in the range of 10−8 M and coefficients of variation lower than 7%. An electronic tongue constructed using a combination of the nanoparticle-based sensors is capable to monitor the phenolic maturity of red grapes from véraison to maturity. Principal Component Analysis (PCA) can be successfully used to discriminate samples according to the ripeness. Regression models performed using Partial Least Squares (PLS-1) have established good correlations between voltammetric data obtained with the electrochemical sensors and the Total Polyphenolic Index, the Brix degree and the Total Acidity, with correlation coefficients close to 1 and low number of latent variables. An advantage of this system is that the electronic tongue can be used for the simultaneous assessment of these three parameters which are the main factors used to monitor the maturity of grapes. Thus the electronic tongue based on metal oxide nanoparticles can be a valuable tool to monitor ripeness. These results demonstrate the exciting possible applications of metal oxide nanoparticles in the field of electronic tongues., Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-67482- R), Junta de Castilla y Leon - Fondo Europeo de Desarrollo Regional (project VA011U16), Junta de Castilla y León (grant BOCYL-D-24112015-9)

En este Trabajo de Fin de Grado se ha analizado el contenido polifenólico de vinos tintos mediante diferentes técnicas de análisis multivariante: Lengua electrónica, espectroscopía FTIR, coordenadas CIELab y parámetros Glories, y se han comparado los resultados obtenidos entre las distintas técnicas. Para ello, se analizaron vinos tintos en diferente estado de maduración (Joven, Roble, Crianza, Reserva y Gran Reserva). Además, se ha medido el índice polifenólico de los vinos mediante métodos oficiales tradicionales de análisis químico (IPT280 y Folin-Ciocalteu). Se han realizado diferentes tratamientos estadísticos de los resultados obtenidos: Análisis de componentes principales (PCA) para discriminar las muestras de vino, Regresión de mínimos cuadrados parciales (PLS-1) para comprobar la correlación entre los métodos de análisis y los parámetros químicos del contenido polifenólico y Máquinas de vectores soporte (SVM-R) para elaborar modelos de regresión capaces de predecir los índices IPT280 y Folin-Ciocalteu de los vinos., Departamento de Química Física y Química Inorgánica, Grado en Ingeniería Química

Producción Científica, An array of electrochemical quartz crystal electrodes (EQCM) modified with nanostructured films based on phthalocyanines was developed and used to discriminate musts prepared from different varieties of grapes. Nanostructured films of iron, nickel and copper phthalocyanines were deposited on Pt/quartz crystals through the Layer by Layer technique by alternating layers of the corresponding phthalocyanine and poly-allylamine hydrochloride. Simultaneous electrochemical and mass measurements were used to study the mass changes accompanying the oxidation of electroactive species present in must samples obtained from six Spanish varieties of grapes (Juan García, Prieto Picudo, Mencía Regadío, Cabernet Sauvignon, Garnacha and Tempranillo). The mass and voltammetric outputs were processed using three-way models. Parallel Factor Analysis (PARAFAC) was successfully used to discriminate the must samples according to their variety. Multi-way partial least squares (N-PLS) evidenced the correlations existing between the voltammetric data and the polyphenolic content measured by chemical methods. Similarly, N-PLS showed a correlation between mass outputs and parameters related to the sugar content. These results demonstrated that electronic tongues based on arrays of EQCM sensors can offer advantages over arrays of mass or voltammetric sensors used separately., Ministerio de Economía, Industria y Competitividad – FEDER (Grant CICYT AGL2012-33535), Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA-032U13), University of Valladolid (PIF-UVa)

Producción Científica, Two different methods were used to obtain polypyrrole/AuNP (Ppy/AuNP) composites. One through the electrooxidation of the pyrrole monomer in the presence of colloidal gold nanoparticles, referred to as trapping method (T), and the second one by electrodeposition of both components from one solution containing the monomer and a gold salt, referred to as cogeneration method (C). In both cases, electrodeposition was carried out through galvanostatic and potentiostatic methods and using platinum (Pt) or stainless steel (SS) as substrates. Scanning electron microscopy (SEM) demonstrated that in all cases gold nanoparticles of similar size were uniformly dispersed in the Ppy matrix. The amount of AuNPs incorporated in the Ppy films was higher when electropolymerization was carried out by chronopotentiometry (CP). Besides, cogeneration method allowed for the incorporation of a higher number of AuNPs than trapping. Impedance experiments demonstrated that the insertion of AuNPs increased the conductivity. As an electrochemical sensor, the Ppy/AuNp deposited on platinum exhibited a strong electrocatalytic activity towards the oxidation of catechol. The effect was higher in films obtained by CP than in films obtained by chronoamperometry (CA). The influence of the method used to introduce the AuNPs (trapping or cogeneration) was not so important. The limits of detection (LOD) were in the range from 10−5 to 10−6 mol/L. LODs attained using films deposited on platinum were lower due to a synergy between AuNPs and platinum that facilitates the electron transfer, improving the electrocatalytic properties. Such synergistic effects are not so pronounced on stainless steel, but acceptable LOD are attained with lower price sensors., Ministerio de Economía, Industria y Competitividad – FEDER (Grant CICYT AGL2012-33535), Junta de Castilla y León (programa de apoyo a proyectos de investigación - Ref. VA-032U13), University of Valladolid (PIF-UVa)

[EN] This research investigates the impact of heat treatment on the microstructure, hardness, and corrosion resistance of 17-4 PH SS (stainless steel) processed by Selective Laser Manufacturing (SLM) in Phosphate Buffer Solution (PBS) and compared to its commercial wrought counterparts. The SLM process produced a segregated microstructure with significant variations in composition and phases. Post-process heat treatment resulted in a uniform and reproducible microstructure in the SLM samples with a significant improvement in corrosion resistance in the solubilised samples and a remarkable hardening in the solubilised and aged samples. Additionally, heat-treated SLM samples showed no relevant release of metallic elements to PBS electrolyte after 75 days of immersion, indicating its potential use as a biomaterial. The study concludes that the manufacturing process used to produce SS have a significant impact on its properties, moreover, post-build treatment improve microstructure providing uniformity which positively impact in the corrosion resistance. The electrochemical results also suggest that, after homogenization, the additively produced 17-4 PH SS shows a better behaviour in biological environment than the wrought 17-4 PH SS.

Producción Científica, The sensing properties of electrodes chemically modified with PEDOT/PSS towards catechol and hydroquinone sensing have been successfully improved by combining layers of PEDOT/PSS with layers of a secondary electrocatalytic material such as gold nanoparticles (PEDOT/PSS/AuNPs), copper phthalocyanine (PEDOT/PSS/CuPc) or lutetium bisphthalocyanine (PEDOT/PSS/LuPc2). Layered composites exhibit synergistic effects that strongly enhance the electrocatalytic activity as indicated by the increase in intensity and the shift of the redox peaks to lower potentials. A remarkable improvement has been achieved using PEDOT/PSS/LuPc2, which exhibits excellent electrocatalytic activity towards the oxidation of catechol. The kinetic studies demonstrated diffusion-controlled processes at the electrode surfaces. The kinetic parameters such as Tafel slopes and charge transfer coefficient (α) confirm the improved electrocatalytic activity of the layered electron mediators. The peak currents increased linearly with concentration of catechol and hydroquinone over the range of 1.5 × 10−4 to 4.0 × 10−6 mol·L−1 with a limit of detection on the scale of μmol·L−1. The layered composite hybrid systems were also found to be excellent electron mediators in biosensors containing tyrosinase and laccase, and they combine the recognition and biocatalytic properties of biomolecules with the unique catalytic features of composite materials. The observed increase in the intensity of the responses allowed detection limits of 1 × 10−7 mol·L−1 to be attained., 2220-12-31, Financial support by MINECO-FEDER (AGL2015-67482-R)., Junta de Castilla y Leon FEDER (VA-011U16)., Celia Garcia-Hernandez would also like to thank Junta de Castilla y León for a grant (BOCYL-D-4112015- 9).