94 research outputs found
El controlador KUKA youBot
En nuestros días, muchas placas base y PCBs presentan fallos debido al fin de su vida útil o a
errores en el proceso de producción. En muchos de estos casos, su clasificación se realiza
mediante operaciones manuales, llevando a los empleados a una posible exposición a
elementos tóxicos. Debido a ello, este proyecto se propone detectar dichos fallos con
el procesamiento de imágenes tomadas por una cámara Siemens MV440 mediante el programa
GNU Octave, así como la clasificación de las mismas gracias a la programación de un robotbrazo
KUKA youBot dentro del entorno Linux conocido Robot Operating System o ROS. Previa a
la programación de dicho robot, se simulará su comportamiento dentro del programa Gazebo.Vilnius Gediminas Technical University. Faculty of Electronics. Department of Electrical EngineeringGrado en Ingeniería en Electrónica Industrial y Automátic
Consequence analysis of an explosion by simple models: Texas refinery gasoline explosion case
Accidents in petrochemical plants and oil refineries are quite destructive, due to the high reactivity of chemicals involved in them. An accident that occurred in the Texas City refinery, on March 23rd 2005, consisting on a vapour cloud explosion (VCE) that followed a gasoline release and caused 15 deaths, has been studied in terms of people vulnerability to overpressure and thermal radiation. With this aim, simple models (TNT, TNO Multi-Energy, BST) have been used in order to evaluate the effects of the explosion.Moreover, a thermal radiation model was used to estimate the damage caused by the heat released as consequence of the explosion. Finally, the Probit methodology was used to evaluate the vulnerability of persons. Although differences between the data derived from each of them existed, they all reproduced actual damages with a reasonable accuracy. The results reached let us say that the TNO and BST models predict with a reasonable accuracy the effects of the explosion that occurred. Furthermore, the use of simplified empirical models can be used for risk assessment
Chloralkali low temperature PEM reversible electrochemical cells
This work demonstrates the viability of MEAs based on Nafion membranes for being used in reversible electrochemical cells for the chloralkali process. It also shows the effect of the operation temperature, from room temperature up to 80 °C, and humidification of the chlorine stream on the performance of these cells as fuel cell. Results demonstrate that these cells can be operated in reversible mode, yielding a current density of approximately12 mA cm−2 at a cell potential of 0.5 V, when operating as fuel cells fed with gaseous chlorine and hydrogen. The maximum power density achieved is 7.0 mW cm−2, which is much higher than that obtained with the same system fed with hydrogen and chlorine dissolved into liquid electrolytes. It is important to operate at room temperatures because efficiency decreases dramatically with temperature in an irreversible way, affecting the electrode. Humidification is necessary for the hydrogen stream and convenient for the chlorine stream, although it does not solve the irreversible cell damage caused by operation at high temperatures. Current efficiency of chlorine production is above 95 %, when operating as electrolyzer feeding a solution containing 2.0 M of NaCl. The rate of production of chlorine was 45.4 mmol h−1 at 100 mA cm−2 and the Cl2/O2 molar ratio is 9.54, which is much higher than the values obtained in previous works which are between 3 and 5.Este trabajo demuestra la viabilidad de los MEA basados en membranas de Nafion para ser utilizados en celdas electroquímicas reversibles para el proceso de cloro-álcali. También se muestra el efecto de la temperatura de operación, desde temperatura ambiente hasta 80 °C, y la humidificación de la corriente de cloro sobre el desempeño de estas celdas como pila de combustible. Los resultados demuestran que estas celdas pueden operar en modo reversible, produciendo una densidad de corriente de aproximadamente 12 mA cm- 2 a un potencial de celda de 0,5 V, cuando operan como celdas de combustible alimentadas con cloro gaseoso e hidrógeno. La máxima densidad de potencia alcanzada es de 7,0 mW cm −2, que es muy superior a la obtenida con el mismo sistema alimentado con hidrógeno y cloro disueltos en electrolitos líquidos. Es importante operar a temperatura ambiente porque la eficiencia disminuye drásticamente con la temperatura de manera irreversible, afectando al electrodo. La humidificación es necesaria para la corriente de hidrógeno y conveniente para la corriente de cloro, aunque no soluciona el daño irreversible de las celdas causado por la operación a altas temperaturas. La eficiencia actual de producción de cloro es superior al 95 %, cuando opera como electrolizador alimentando una solución que contiene 2,0 M de NaCl. La tasa de producción de cloro fue de 45,4 mmol h -1 a 100 mA cm -2 y el Cl 2 /O 2relación molar es de 9,54, muy superior a los valores obtenidos en trabajos anteriores que se sitúan entre 3 y 5
Improving stability of chloralkaline high-temperature PBI-PEMFCs
This work focuses on the production of electricity using chloralkaline high temperature PEM fuel cells (HT-PEMFC) comparing, within the range 120–180 °C, the performance of a cell equipped with a cathode containing a novel Ru/Pt catalyst manufactured at mild temperature conditions with another cell which contains a conventional Ru based catalyst (Ru0.75Pt0.25O2). Performance of the cell equipped with the conventional electrode at 120 °C is much better, but this situation reverses at higher operation temperatures, where the novel catalyst outperforms the conventional Ru0.75Pt0.25O2 in terms of production of electricity. In addition, the new catalyst allows to operate even at 180 °C, temperature at which the cell equipped with the conventional electrode is completely deteriorated. Results pointed out that materials are the bottleneck for the chloralkaline HT-PEMFC technology but opens the window for the search of new materials that help to improve their future development.Este trabajo se centra en la producción de electricidad utilizando pilas de combustible PEM de alta temperatura cloralcalinas (HT-PEMFC) comparando, en el rango de 120-180 °C, el rendimiento de una pila equipada con un cátodo que contiene un catalizador novedoso de Ru/Pt fabricado a temperatura templada. condiciones de temperatura con otra celda que contiene un catalizador basado en Ru convencional (Ru 0.75 Pt 0.25 O 2 ). El desempeño de la celda equipada con el electrodo convencional a 120 °C es mucho mejor, pero esta situación se revierte a temperaturas de operación más altas, donde el nuevo catalizador supera al convencional Ru 0.75 Pt 0.25 O 2en términos de producción de electricidad. Además, el nuevo catalizador permite operar incluso a 180 °C, temperatura a la que la celda equipada con el electrodo convencional se deteriora por completo. Los resultados señalaron que los materiales son el cuello de botella para la tecnología cloroalcalina HT-PEMFC pero abren la ventana para la búsqueda de nuevos materiales que ayuden a mejorar su desarrollo futuro
Storage of energy using a gas-liquid H2/Cl2 fuel cell: A first approach to electrochemically-assisted absorbers
In this work, the use in fuel cell mode of three electro-absorbers is evaluated for the chloralkaline process and performance is compared with that of a conventional PEMFC operated at the same operation conditions (room temperature). To do this, four cells have been in-house manufactured and compared, in order to determine which electrolyte (solution containing the active species or the membrane) is the best and which is the influence of the absorption stage on the operation of the cell. Because of the high solubility of chlorine, only the hydrogen absorption has been considered in order to evaluate relevant differences in the performance. Results demonstrate that design of the cell has a superb significance on the performances obtained. Cells with membrane-electrode assemblies are more efficient than those in which the membrane is used only as an electrodic compartment separator and utilization of devices which produce tiny bubbles of gas into the electrolyte is also very advantageous in order to obtain higher efficiencies. Results are of a great significance for the design of electro-absorbers and this paper is a first approach to face the design of reversible electrochemical cells for the chloralkaline process
First approaches for hydrogen production by the depolarized electrolysis of SO2 using phosphoric acid doped polybenzimidazole membranes
Renewable energy storage and conversion is nowadays a major target for the scientific community. Their conversion into hydrogen is a clear and clean alternative for their storage. This work shows, for the first time, the results of the SO2 depolarized electrolysis for hydrogen production at high temperature (120–170 °C) using phosphoric acid doped polybenzimidazole (PBI) membranes. A standard and a thermally cure PBI membrane doped with phosphoric acid were used for manufacturing the MEA of two electrolyzers. The benefit of the temperature was demonstrated but an unexpected behavior occurs at voltages higher than 0.8 V when temperature increases. Moreover, the thermally cured membrane shows a superior performance as compared with the standard one. Production of sulfur by reduction of SO2 becomes an important drawback and advices not operating above 130 °C. Results show that PBI membranes doped with phosphoric acid are suitable for high temperature operation for the sulfur dioxide depolarized electrolysis. Increasing temperature is beneficial up to a certain value of potential, showing a considerable influence in the charge transfer resistance of the system.El almacenamiento y conversión de energía renovable es hoy en día un objetivo importante para la comunidad científica. Su conversión en hidrógeno es una alternativa clara y limpia para su almacenamiento. Este trabajo muestra, por primera vez, los resultados de la electrólisis despolarizada con SO 2 para la producción de hidrógeno a alta temperatura (120-170 °C) utilizando ácido fosfóricoMembranas de polibencimidazol dopado (PBI). Se utilizaron una membrana PBI estándar y una de curado térmico dopada con ácido fosfórico para fabricar el MEA de dos electrolizadores. Se demostró el beneficio de la temperatura pero se presenta un comportamiento inesperado a voltajes superiores a 0.8 V cuando la temperatura aumenta. Además, la membrana curada térmicamente muestra un rendimiento superior en comparación con la estándar. La producción de azufre por reducción de SO 2 se convierte en un inconveniente importante y aconseja no operar por encima de 130 °C. Los resultados muestran que las membranas de PBI dopadas con ácido fosfórico son adecuadas para operaciones a alta temperatura para la electrólisis despolarizada con dióxido de azufre . El aumento de la temperatura es beneficioso hasta cierto valor de potencial, mostrando una influencia considerable en laresistencia de transferencia de carga del sistema
Enhancement of Electrode Stability Using Platinum–Cobalt Nanocrystals on a Novel Composite SiCTiC Support
PtCo alloy catalysts for high temperature PEMFCs (protonic exchange membrane fuel cells) were synthesized on a novel noncarbonaceous support (SiCTiC) using the impregnation method with NaBH4 as the reducing agent at different synthesis temperatures to evaluate the effect of this variable on their physicochemical and electrochemical properties. The catalysts were characterized by inductively coupled plasma optical emission spectrometry, scanning electron microscopy–energy dispersive X-ray spectroscopy, X-ray diffraction, transmission electron microscope–energy dispersive X-ray,and temperature-programmed reduction. In addition, the electrochemical characterization (i.e., cyclic voltammetry, oxygen reduction reaction, and chronoamperometry) was carried out with a rotating disk electrode. For the cyclic voltammetry investigation, 400 cycles were performed in hot phosphoric acid and a half-cell to evaluate the stability of the synthesized catalysts. The catalyst synthesized on SiCTiC exhibited excellent durability compared to the catalyst synthesized on a Vulcan support. In addition, all synthesized catalysts exhibited better catalytic activity than that of the PtCo/C catalysts. The best results were observed for the catalyst synthesized at 80 °C due to its shorter Pt–Pt nearest-neighbor and higher alloy degree. Finally, a preliminary stability test was conducted in an HT-PEMFC, and promising results in terms of stability and performance were observed.Se sintetizaron catalizadores de aleación de PtCo para PEMFC (pilas de combustible de membrana de intercambio protónico) de alta temperatura en un novedoso soporte no carbonoso (SiCTiC) utilizando el método de impregnación con NaBH 4como agente reductor a diferentes temperaturas de síntesis para evaluar el efecto de esta variable sobre sus propiedades fisicoquímicas y electroquímicas. Los catalizadores se caracterizaron mediante espectrometría de emisión óptica de plasma acoplado inductivamente, microscopía electrónica de barrido-espectroscopía de rayos X de dispersión de energía, difracción de rayos X, microscopio electrónico de transmisión-rayos X de dispersión de energía y reducción programada por temperatura. Además, la caracterización electroquímica (es decir, voltamperometría cíclica, reacción de reducción de oxígeno y cronoamperometría) se realizó con un electrodo de disco rotatorio. Para la investigación de voltamperometría cíclica se realizaron 400 ciclos en ácido fosfórico caliente y media celda para evaluar la estabilidad de los catalizadores sintetizados. El catalizador sintetizado en SiCTiC exhibió una excelente durabilidad en comparación con el catalizador sintetizado en un soporte Vulcan. Además, todos los catalizadores sintetizados exhibieron una mejor actividad catalítica que la de los catalizadores de PtCo/C. Los mejores resultados se observaron para el catalizador sintetizado a 80 °C debido a su vecino más cercano Pt-Pt más corto y su mayor grado de aleación. Finalmente, se realizó una prueba de estabilidad preliminar en una HT-PEMFC y se observaron resultados prometedores en términos de estabilidad y rendimiento
Recent Progress in Catalysts for Hydrogen-Chlorine Regenerative Fuel Cells
The increasing energy demand and the subsequent climate change consequences are supporting the search for sustainable alternatives to fossil fuels. In this scenario, the link between hydrogen and renewable energy is playing a key role and unitized hydrogen-chlorine (H2-Cl2) regenerative cells (RFCs) have become promising candidates for renewable energy storage. Described herein are the recent advances in cell configurations and catalysts for the different reactions that may take place in these systems, that work in both modes: electrolysis and fuel cell. It has been found that platinum (Pt)-based catalysts are the best choice for the electrode where hydrogen is involved, whereas for the case of chlorine, ruthenium (Ru)-based catalysts are the best candidates. Only a few studies were found where the catalysts had been tested in both modes and recent advances are focused on decreasing the amount of precious metals contained in the catalysts. Moreover, the durability of the catalysts tested under realistic conditions has not been thoroughly assessed, becoming a key and mandatory step to evaluate the commercial viability of the H2-Cl2 RFC technology
Prediction and management of solar energy to power electrochemical processes for the treatment of wastewater effluents
A highly versatile software tool able to predict and manage the solar power coming from photovoltaic panels and to assess the environmental remediation of wastewater effluents has been developed. The prediction software tool is made up of four modules. The first one predicts the solar radiation by a phenomenological model. Secondly, an energy optimization algorithm manages the solar power towards the third and fourth modules, an environmental remediation treatment (electrooxidation) and an energy storage system (redox flow battery), respectively. The software tool is aimed to the best solar power management to obtain the highest remediation treatment. Results shows a daily solar radiation prediction with a high accuracy, attaining correlation coefficients of 0.89. Furthermore, the prediction of the removal of an organochlorinated compound from a wastewater effluent at different time of the year was studied. Different percentages of the total solar power are sent directly to the electrooxidation reactor and to the redox flow battery. At non-solar production hours, the electrooxidation reactor is powered by the redox flow battery in order to exploit the total solar power produced. The results show that, the higher the solar radiation, the higher the power percentage that must be directly sent to the electrooxidation treatment in order to attain the best energy management and the higher remediation. Thus, an 82.5% of the total solar power must be sent to the electrooxidation treatment in summer days in contrast to the 25% that have to be powered in winter days to attain the highest removal of pollutant.
Consequently, it is important to evaluate the connection between devices to get the best green energy management and the lower energy losses
- …