Diseño de una llanta dinamométrica para vehículos ligeros

[ES] La simulación dinámica y el control avanzado son dos áreas que se están ganando importancia en al campo del diseño y producción industrial. La simulación dinámica es una herramienta ya consolidada y comúnmente usada en industrias como la del automóvil y todas las relacionadas con esta debido a que puede reemplazar las caras pruebas con prototipos. Así, los resultados que se puede obtener de las herramientas de simulación como las técnicas avanzadas de control dependen en gran medida de la calidad de los datos con los que el modelo dinámico es generado. La medida directa de los parámetros físicos (tales como la masa, localización de los centros de gravedad, tensores de inercia, parámetros de fricción, etc) resulta problemático en sistemas que están siendo diseñados. También debe considerarse que estos parámetros pueden cambiar significativamente a los largo de la vida del sistema mecánico. La alternativa a la medida directa es la identificación de estos parámetros de forma experimental a través de datos obtenidos directamente durante la operación de los sistemas mecánicos. La propuesta de este trabajo es el diseño de una llanta dinamométrica capaz de determinar las fuerzas y los momentos que son transmitidos al eje de la rueda durante el funcionamiento del vehículo. La instrumentación necesaria ha sido diseñada usando técnicas de extensometría y el del estudio de las deformaciones asociadas a los diferentes esfuerzos que actúan en ella. El estudio de las deformaciones se realizó mediante la técnica de elementos finitos considerando los diferentes tipos de fuerzas que actúan sobre la llanta. Modelando el comportamiento de las deformaciones de la llanta, y simulando una instrumentación apropiada basándose en los resultados provistos por el análisis de elementos finitos se desarrollará un procedimiento adecuado para determinar la instrumentación necesaria para obtener las medidas deseadas[EN] Dynamic simulation and advanced control are two areas that are becoming important in the field of design and industrial production. Dynamic simulation is a design tool now consolidated and commonly used in industries such as automobile and the related ones because it replaces the expensive tests with prototypes. Well, the results can provide simulation tools such as advanced control techniques critically depend on the quality of the data from which the mechanical model systems are generated. Direct measurement of these data or physical parameters (mass, location of centers of gravity, inertia tensors, friction parameters, etc) is problematic in systems that are being designed. We also have to consider that these parameters may change significantly over the life of the mechanical system. The alternative measurement is the identification of these parameters from experimental data acquired during the operation of mechanical systems. The actual proposal of this work is to design a wheel rim for light vehicle able to determinate the forces and moments that are transmitted to the axis of the vehicle wheel during use. The necessary instrumentation is designed using extensometry techniques, and the design process focuses on the study of the wheel rim deformations associated with the different forces acting on it. The study of strain performed on models analyzed by finite element techniques considering the different types of forces acting on the rim. Modeling the deformations behavior of the wheel rim, and doing a proper instrumentation based on the FEM analysis the results will be develop the procedure for the instrumentation of the rim to obtain the desired measurements. (inglés)Blasco Llopis, J. (2013). Diseño de una llanta dinamométrica para vehículos ligeros. http://hdl.handle.net/10251/35244Archivo delegad

Creación de una guía para la aplicación del nivel básico, medio y alto del Reglamento de Protección de Datos para microempresas

[ES] El presente trabajo de fin de grado sirve de guía para aplicar la Ley Orgánica de Protección de Datos paso a paso en empresas pequeñas. Esta desarrollado forma que sea inteligible por personal no especializado y pueda ser aplicado con facilidad, celeridad y sin un coste económico elevado. Durante el trascurso del proyecto abarcaremos las diferentes etapas necesarias para la adaptación a la legislación vigente en materia de protección de datos. El proyecto comienza con una explicación sobre qué es la protección de datos y porque resulta fundamental. Seguidamente se explican los niveles de seguridad existentes y se proporciona un breve resumen de los pasos que van a seguirse para llevar a cabo la adaptación. Para un mayor entendimiento se propone un ejemplo ficticio de una microempresa para ayudar al usuario a tener una mejor comprensión de las medidas necesarias. Sobre este ejemplo se aplicarán los pasos descritos en cada apartado del presente trabajo. Veremos las diferentes fases para llevar a cabo la adaptación, desde un primer análisis de la empresa que nos ayude a diferenciar la información necesaria, pasando por las medidas de seguridad que se deben adoptar o como tratar los datos personales y terminando con el desarrollo de un documento que recoja todas las medidas desarrolladas. El proyecto está apoyado por una aplicación móvil, desarrollada para dispositivos con sistema operativo Android, que sirve para tener un mayor control sobre las fases completadas.[EN] This thesis provides guidance for applying the Organic Law on Data Protection step by step in small businesses. The thesis is developed in a way that can be understandable by nonspecialists and can be applied easily, quickly and without a high cost. During the course of the project we will cover the different necessary stages to adapt to the current legislation on data protection. The project starts with an explanation of what is data protection and because it is fundamental. Then, the security levels are explained and a brief summary of the steps that will be followed to perform the adaptation provided. For a better understanding a fictional example of a small business is given to help the user to have a better understanding of the necessary measures proposed. The steps in each section of this thesis will apply on this example. We'll see the different phases to carry out adaptation, from a first analysis of the company to help us differentiate the necessary information. through security measures to be taken or process personal data and ending with the development of a document containing all developed measures. The project is supported by a mobile application, developed for devices with Android operating system, to have more control over the completed phases.Llopis Ferriol, J. (2016). Creación de una guía para la aplicación del nivel básico, medio y alto del Reglamento de Protección de Datos para microempresas. http://hdl.handle.net/10251/68612.TFG

Improvements in CO2 Booster Architectures with Different Economizer Arrangements.

CO2 transcritical booster architectures are widely analyzed to be applied in centralized commercial refrigeration plants in consonance with the irrevocable phase-out of HFCs. Most of these analyses show the limitations of CO2 cycles in terms of energy e ciency, especially in warm countries. From the literature, several improvements have been proposed to raise the booster e ciency in high ambient temperatures. The use of economizers is an interesting technique to reduce the temperature after the gas cooler and to improve the energy e ciency of transcritical CO2 cycles. The economizer cools down the high pressure’s line of CO2 by evaporating the same refrigerant extracted from another point of the facility. Depending on the extraction point, some configurations are possible. In this work, di erent booster architectures with economizers have been analyzed and compared. From the results, the combination of the economizer with the additional compressor allows obtaining energy savings of up to 8.5% in warm countries and up to 4% in cold countries with regard to the flash-by-pass arrangement and reduce the volumetric displacement required of the MT compressors by up to 37%

Experimental determination of the optimum working conditions of a transcritical CO2 refrigeration plant with integrated mechanical subcooling

Subcooling methods for transcritical CO2 plants are being studied in order to improve their behavior. Among them, the Integrated Mechanical Subcooling system is one of the most promising owing that performs with high efficiency and it is a total-CO2 system. This work presents the experimental determination of the optimum working conditions of a transcritical CO2 plant working with an integrated mechanical subcooling system. The plant was tested at different pressure and subcooling conditions in order to optimize the COP of the plant and determine the optimal conditions for three ambient temperatures 25.0 °C, 30.4 °C and 35.1 °C and evaporation levels between −15.6 °C and −4.1 °C. Optimum operating conditions were determined and two correlations are proposed to determine the optimal pressure and subcooling as function the gas-cooler outlet temperature and the evaporation level

Non-linear Analysis of Slender High Strength Concrete Column

[EN] This article shows the influence of axial force eccentricity on high strength concrete columns design. The behavior of columns made of normal, middle and high strength concrete with slenderness values between 20 and 60 under an eccentric axial force has been studied. Structural analysis has been developed by means of software which considers both geometrical and mechanical non-linearity. The sequence of points defined by increasing values of axial force and bending moment produced by eccentricity has been represented on the cross-section interaction diagram until failure for each tested column. Then, diagrams depicting the relationship between failure axial force and column's slenderness have been drawn. The loss of bearing capacity of the member for normal and middle strength columns when compared with the bearing capacity of their cross-section is more noticeable as axial force eccentricity assumes higher values. However, this situation reverses for high strength columns with high slenderness values. On the basis of results obtained, the accuracy level for the moment magnifier method was checked. Despite the good concordance in most of the cases, it was verified that the moment magnifier method leads to excessively tight results for high strength concrete columns with high slenderness values. In these specific cases, a coefficient which amends the column rigidity is proposed so as to obtain safer values.This work was supported by Universitat Politecnica de Valencia, Spain.Fenollosa Forner, EJ.; Cabrera Fausto, I.; Llopis-Pulido, V.; Alonso Durá, A. (2019). Non-linear Analysis of Slender High Strength Concrete Column. The Open Civil Engineering Journal. 5(7):1440-1451. https://doi.org/10.28991/cej-2019-03091343S144014515

Second-order Effects in Steel-Concrete Composite Columns of the Unbraced Frames

[EN] An unbraced frame is regarded as the one without a bracing system to avoid the horizontal displacement of its nodes. These displacements progressively increase due to their interaction with axial load (second-order effects) reducing the column¿s resistant capacity and can lead to the global frame instability. At the present work the Eurocodes criteria related to the way to approach its design will be displayed. Different iterative processes that take into account second-order effects will be exposed as well as a non-linear procedure based on an incremental load application. This procedure will be applied over an unbraced frame under gravity and wind loads with reinforced concrete beams and steel-concrete composite columns. Two geometrical models will be used: one of them starts from geometry without deformation and the other one takes into account the initial imperfections. The results comparison regarding first-order linear analysis will show that bending moments at the critical section of the columns will increase by nearly 50% when their initial imperfections are taken into account.Fenollosa Forner, EJ.; Cabrera Fausto, I.; Alonso Durá, A.; Llopis-Pulido, V. (2016). Second-order Effects in Steel-Concrete Composite Columns of the Unbraced Frames. Journal of Civil Engineering and Construction. 5(1):42-55. http://hdl.handle.net/10251/107341S42555

Experimental analysis of R-450A and R-513A as replacements of R-134a and R-507A in a medium temperature commercial refrigeration system

This work presents the experimental evaluation of R-513A (GWP = 573) and R-450A (GWP = 547) as R-134a (GWP = 1301) drop-in replacements and as R-507A (GWP = 3987) retrofits in a commercial direct expansion refrigeration system for medium temperature applications (2 °C). The evaluation covered 24-hour tests using a single-stage cycle with semi-hermetic compressor, an electronic expansion valve customized for each refrigerant and a commercial vertical cabinet with doors placed inside a climatic chamber. The tests were performed at three water dissipation temperatures (23.3, 32.8 and 43.6 °C). Experimental results indicate that R-513A and R-450A can operate with R-134a plants, with increments in energy consumption between −1.6 to +1.2% for R-513A and from +1.3 to +6.8% for R-450A, whereas in comparison with R-507A, R-513A offered reductions in energy consumption between 4.4 to 8.2% and R-450A between 0 to 3.3%. The paper analyzes the modification of the operating pressures/temperatures and the energy indicators using the four refrigerants

Energy assessment of an R134a refrigeration plant upgraded to an indirect system using R152a and R1234ze(E) as refrigerants

In this work the experimental results obtained from a direct expansion refrigerating plant converted into an indirect plant, are presented and discussed in terms of energy consumption for a commercial refrigerating unit plugged to a medium temperature cabinet. Refrigerants used in the analysis are R134a for direct system, and R134a, R152a and R1234ze(E) for indirect system. The evaluation has been performed at laboratory conditions using three different heat rejection levels: 43.6, 32.8 and 23.3 °C keeping constant the environmental conditions in the cabinet (25 °C; 55%). From the experimental tests performed during 24 h, it has been demonstrated that the adoption of an indirect configuration results in an increment of the total energy consumption of the refrigerating plant regardless the refrigerant adopted. The average increment registered was 21.8% for R134a, 18.7% for R152a and finally 27.2% for R1234ze(E). The adoption of an indirect system also reduces the refrigerant mass charge of the facility up to 62% depending on the refrigerant used