1,150 research outputs found
Contribución al modelado termofluidodinámico de filtros de partículas Diesel de flujo de pared
Pese al desarrollo de los filtros de partículas Diesel en la década de los 80, no ha sido hasta la actualidad cuando se ha generalizado el uso de estos sistemas como solución tecnológica para la reducción de la emisión de partículas. Las razones hay que encontrarlas en la creciente presión de las normativas anti-contaminantes presentes y futuras, cercanas al límite tecnológico de otro tipo de soluciones basadas en el control del proceso de combustión.
Este renovado interés por los filtros de partículas Diesel requiere por parte de los investigadores iniciar estudios experimentales y teóricos para optimizar tanto las prestaciones del filtro como su acoplamiento con el motor. Desde el punto de vista teórico, este doble objetivo puede ser alcanzado con el uso de una única herramienta de cálculo unidimensional, los modelos de acción de ondas. Comúnmente utilizados para el estudio de la renovación de la carga de los motores de combustión interna alternativos, su extensión al análisis de sistemas de post-tratamiento requiere del desarrollo de herramientas específicas para su plena adaptación; el transporte de especies químicas a través de todo el motor o la optimización de la metodología de cálculo para reducir el coste computacional haciendo independiente el asociado a cada elemento del modelo son los principales aspectos tratados. Se converge así a un modelo de acción de ondas con capacidad de acometer el cálculo de todos los procesos físico-químicos de los sistemas de post-tratamiento.
Por otra parte, un aspecto clave ha de ser alcanzar la capacidad de flexibilizar el modelo al análisis de cualquier arquitectura de la línea de escape garantizando una adecuada interacción del filtro de partículas con el resto de componentes del motor. Para ello resulta conveniente que en el filtro de partículas se trate al flujo como no-estacionario, unidimensional, compresible y no-homoentrópico. Con estas características se presenta el modelo propuesto en este trabajo.Piqueras Cabrera, P. (2010). Contribución al modelado termofluidodinámico de filtros de partículas Diesel de flujo de pared [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/7341Palanci
Seguimiento longitudinal de la evolución en la condición aeróbica en jóvenes futbolistas
El objetivo del presente estudio fue determinar el comportamiento de los principales factores condicionantes de la condición aeróbica en jóvenes futbolistas (15–18 años)
Documenting Paintings with Gigapixel Photography
[EN] Digital photographic capture of pictorial artworks with gigapixel resolution (around 1000 megapixels or greater) is a novel technique that is beginning to be used by some important international museums as a means of documentation, analysis, and dissemination of their masterpieces. This line of research is extremely interesting, not only for art curators and scholars but also for the general public. The results can be disseminated through online virtual museum displays, offering a detailed interactive visualization. These virtual visualizations allow the viewer to delve into the artwork in such a way that it is possible to zoom in and observe those details, which would be negligible to the naked eye in a real visit. Therefore, this kind of virtual visualization using gigapixel images has become an essential tool to enhance cultural heritage and to make it accessible to everyone. Since today's professional digital cameras provide images of around 40 megapixels, obtaining gigapixel images requires some special capture and editing techniques. This article describes a series of photographic methodologies and equipment, developed by the team of researchers, that have been put into practice to achieve a very high level of detail and chromatic fidelity, in the documentation and dissemination of pictorial artworks. The result of this research work consisted in the gigapixel documentation of several masterpieces of the Museo de Bellas Artes of Valencia, one of the main art galleries in Spain. The results will be disseminated through the Internet, as will be shown with some examples.This research was carried out within the Research Project entitled Captura fotografica de resolucion gigapixel para la documentacion y divulgacion del patrimonio pictorico (01/01/19-01/01/21), reference SP20180066. Project funded with the help of Primeros Proyectos de Investigacion (PAID-06-18), Vicerrectorado de Investigacion,Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Valencia, Spain.Cabezos Bernal, PM.; Rodríguez Navarro, P.; Gil Piqueras, T. (2021). Documenting Paintings with Gigapixel Photography. Journal of imaging. 7(8):1-20. https://doi.org/10.3390/jimaging70801561207
Documenting Paintings Using Gigapixel SfM Photogrammetry
[EN] Capturing paintings with gigapixel resolution (resolution around 1000 megapixels or greater) is an innovative technique that is starting to be used by some important international museums for documenting, analysing, and disseminating their masterpieces.
This line of research is extremely interesting, not only for art curators and scholars, but also for the general public. The results can be disseminated through online virtual tours, offering a detailed interactive visualization. These virtual tours allow the viewer to delve into the artwork, in such a way, that it is possible to zoom in and observe those details, which would be negligible to the naked eye in a real visit. Therefore, this kind of virtual visualization using gigapixel images becomes an essential tool to enhance this cultural heritage and to make it accessible to everyone.
This article will describe an affordable methodology, based on SfM photogrammetry techniques, with which it will be possible to achieve a very high level of detail and chromatic fidelity, when documenting and disseminating pictorial artworks. As a practical example, there will be shown a case study of the altarpiece, from the Museo de Bellas Artes de Valencia (Spain), entitled Virgen de las fiebres, painted around 1500 by Bernardino di Benedetto di Biagio, nicknamed `Il Pinturicchio' (Perugia, ca. 1454 ¿ Siena, 1513).This research was carried out within the Research Project entitled Captura fotográfica de resolución gigapíxel para la documentación y divulgación del patrimonio pictórico (01/01/19- 01/01/21), reference SP20180066. Project funded with the help of Primeros Proyectos de Investigación (PAID-06-18), Vicerrectorado de Investigación,Innovación y Transferencia de la Universitat Politècnica de València (UPV), València, SpainCabezos Bernal, PM.; Rodríguez Navarro, P.; Gil Piqueras, T. (2021). Documenting Paintings Using Gigapixel SfM Photogrammetry. International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. 93-100. https://doi.org/10.5194/isprs-archives-XLVI-M-1-2021-93-20219310
Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications
[EN] The increasingly restrictive legislation on pollutant emissions is involving new homologation procedures driven to be representative of real driving emissions. This context demands an update of the modelling tools leading to an accurate assessment of the engine and aftertreatment systems performance at the same time as these complex systems are understood as a single element. In addition, virtual engine models must retain the accuracy while reducing the computational effort to get closer to real-time computation. It makes them useful for pre-design and calibration but also potentially applicable to on-board diagnostics purposes. This paper responds to these requirements presenting a lumped modelling approach for the simulation of aftertreatment systems. The basic principles of operation of flow-through and wall-flow monoliths are covered leading the focus to the modelling of gaseous emissions conversion efficiency and particulate matter abatement, i.e. filtration and regeneration processes. The model concept is completed with the solution of pressure drop and heat transfer processes. The lumped approach hypotheses and the solution of the governing equations for every sub-model are detailed.
While inertial pressure drop contributions are computed from the characteristic pressure drop coefficient, the porous medium
effects in wall-flow monoliths are considered separately. Heat transfer sub-model applies a nodal approach to account for heat
exchange and thermal inertia of the monolith substrate and the external canning. In wall-flow monoliths, the filtration and
porous media properties are computed as a function of soot load applying a spherical packed bed approach. The soot oxidation mechanism including adsorption reactant phase is presented. Concerning gaseous emissions, the general scheme
to solve the chemical species transport in the bulk gas and washcoat regions is also described. In particular, it is finally
applied to the modelling of CO and HC abatement in a DOC and DPF brick. The model calibration steps against a set of
steady-state in-engine experiments allowing separate certain phenomena are discussed. As a final step, the model performance is assessed against a transient test during which all modelled processes are taking place simultaneously under
highly dynamic driving conditions. This test is simulated imposing different integration time-steps to demonstrate the model’s potential for real-time applications.This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R and by the European Union’s Horizon 2020 Framework Programme for research, technological development and demonstration under grant agreement number 723976.Payri, F.; Arnau Martínez, FJ.; Piqueras, P.; Ruiz Lucas, MJ. (2018). Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications. SAE Technical Papers. https://doi.org/10.4271/2018-01-0954
Impact on Reduction of Pollutant Emissions from Passenger Cars when Replacing Euro 4 with Euro 6d Diesel Engines Considering the Altitude Influence
[EN] The impact of Euro 4 compression ignition engines over the air quality in Europe has been analyzed in this work by comparing them with Euro 6d emissions regulation. The Euro 6d diesel engine has been chosen as the preferred replacement according to its advantages in global warming potential (GWP) emissions, like methane hydrocarbons (MHC) and CO2, with respect to Euro 6d petrol-based powertrains. The motivation for this study is that the effects of the emissions reduction policies, as the implementation of the regulation Euro 6d, are necessarily limited due to the great number of passenger cars still in circulation that were homologated under Euro 4 or older standards. To address the impact of the old vehicle pool, a Worldwide harmonized Light-vehicles Test Cycle (WLTC) has been used to analyze the performance and pollutant emissions of a Euro 4 diesel engine in altitude conditions. This driving cycle and engine are considered as a baseline for the subsequent discussion, where the altitude plays a key role because of the European geography. It forces passenger cars to drive over sea level during a significant number of trips. Thus, an analysis of how significant would be the impact of energy policies promoting the substitution of the pre-Euro 5 diesel fleet (>10 years old) by modern Euro 6d engines in the short term on the pollutants and GWP emissions reduction is presented.This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R.Serrano, J.; Piqueras, P.; Abbad Andaloussi, A.; Tabet, R.; Bender, S.; Gómez-Gil, J. (2019). Impact on Reduction of Pollutant Emissions from Passenger Cars when Replacing Euro 4 with Euro 6d Diesel Engines Considering the Altitude Influence. Energies. 12(7):1-24. https://doi.org/10.3390/en12071278S124127Kim, J., & Bae, C. (2017). Emission reduction through internal and low-pressure loop exhaust gas recirculation configuration with negative valve overlap and late intake valve closing strategy in a compression ignition engine. International Journal of Engine Research, 18(10), 973-990. doi:10.1177/1468087417692680Vehicles in Use Europe https://www.acea.be/statistics/article/Report-Vehicles-in-UseRamos, A., Muñoz, J., Andrés, F., & Armas, O. (2018). NOx emissions from diesel light duty vehicle tested under NEDC and real-word driving conditions. Transportation Research Part D: Transport and Environment, 63, 37-48. doi:10.1016/j.trd.2018.04.018Bermúdez, V., Serrano, J. R., Piqueras, P., Gómez, J., & Bender, S. (2017). Analysis of the role of altitude on diesel engine performance and emissions using an atmosphere simulator. International Journal of Engine Research, 18(1-2), 105-117. doi:10.1177/1468087416679569Zama, Y., Ochiai, W., Furuhata, T., & Arai, M. (2011). EXPERIMENTAL STUDY ON SPRAY ANGLE AND VELOCITY DISTRIBUTION OF DIESEL SPRAY UNDER HIGH AMBIENT PRESSURE CONDITIONS. Atomization and Sprays, 21(12), 989-1007. doi:10.1615/atomizspr.2012004722Hiroyasu, H., Arai, M., & Tabata, M. (1989). Empirical Equations for the Sauter Mean Diameter of a Diesel Spray. SAE Technical Paper Series. doi:10.4271/890464Toff, W. D., Jones, C. I., Ford, I., Pearse, R. J., Watson, H. G., Watt, S. J., … Greaves, M. (2006). Effect of Hypobaric Hypoxia, Simulating Conditions During Long-Haul Air Travel, on Coagulation, Fibrinolysis, Platelet Function, and Endothelial Activation. JAMA, 295(19), 2251. doi:10.1001/jama.295.19.2251Galindo, J., Serrano, J. R., Piqueras, P., & Gómez, J. (2014). Description and Performance Analysis of a Flow Test Rig to Simulate Altitude Pressure Variation for Internal Combustion Engines Testing. SAE International Journal of Engines, 7(4), 1686-1696. doi:10.4271/2014-01-2582Broatch, A., Bermúdez, V., Serrano, J. R., Tabet-Aleixandre, R., Gómez, J., & Bender, S. (2018). Analysis of Passenger Car Turbocharged Diesel Engines Performance When Tested at Altitude and of the Altitude Simulator Device Used. Volume 2: Emissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical Development. doi:10.1115/icef2018-9549Cohen, J. E., & Small, C. (1998). Hypsographic demography: The distribution of human population by altitude. Proceedings of the National Academy of Sciences, 95(24), 14009-14014. doi:10.1073/pnas.95.24.14009The Delineation of European Mountain Areas https://ec.europa.eu/regional_policy/sources/docgener/studies/pdf/montagne/mount4.pdfBermúdez, V., Pastor, J. V., López, J. J., & Campos, D. (2014). Experimental correlations for transient soot measurement in diesel exhaust aerosol with light extinction, electrical mobility and diffusion charger sensor techniques. Measurement Science and Technology, 25(6), 065204. doi:10.1088/0957-0233/25/6/065204CO2 Emissions from New Passenger Cars in the EU: Car Manufacturer’s Performance in 2017 https://www.theicct.org/sites/default/files/publications/EU_manufacturers_performance_CO2_20180712.pdfNew Car CO2 Report 2018 https://www.smmt.co.uk/wp-content/uploads/sites/2/SMMT-New-Car-Co2-Report-2018-artwork.pdfEl Transporte Urbano y Metropolitano en España https://www.fomento.gob.es/recursos_mfom/transporteurbano.pdfTráfico de mercancías y viajeros por carretera (vehículos-kilómetro) por clase y tipo de vía http://observatoriotransporte.fomento.es/BDOTLE/visorBDpop.aspx?i=418Kampa, M., & Castanas, E. (2008). Human health effects of air pollution. Environmental Pollution, 151(2), 362-367. doi:10.1016/j.envpol.2007.06.012Thorpe, A., & Harrison, R. M. (2008). Sources and properties of non-exhaust particulate matter from road traffic: A review. Science of The Total Environment, 400(1-3), 270-282. doi:10.1016/j.scitotenv.2008.06.00
El Control Borroso: Una Metodología Integradora
[ES] En este trabajo se presentan las posibilidades que tiene la metodología de control basada en la lógica borrosa para integrar en el mismo marco un gran número de problemas de control. Junto a la posibilidad intrínseca de manejo de información de tipo aproximado, o con incertidumbre, se analiza la propiedad de un sistema borroso como aproximador universal de casi cualquier función. Igualmente, se discute la capacidad de implementar mediante controladores borrosos otro tipo de controladores diseñados mediante otras metodologías, incluyendo la capacidad de aprendizaje. Una aplicación agrícola ilustra algunas de estas ideas. El trabajo incluye algunas reflexiones personales sobre el tema tratadoAlbertos Pérez, P.; Sala Piqueras, A. (2010). El Control Borroso: Una Metodología Integradora. Revista Iberoamericana de Automática e Informática industrial. 1(2):22-31. http://hdl.handle.net/10251/146629OJS22311
Using drones under 250 g for documenting the architectural heritage
[EN] The emergence of drones in recent years has revolutionized the field of photogrammetry due to the advantages that their use entails. opening a new variety of possibilities, as the use of close-range aerial photogrammetry. Therefore, the main objective of this contribution is to analyse the legal limits for this kind of drones under 250 g and to determine the quality of the results that can be obtained when they are used for graphic surveying.
The methodology consisted in carrying out the survey of a renaissance courtyard, which is known as the Patio del Embajador Vich, one of the most relevant spaces in the city of Valencia that is currently integrated inside of the Museo de Bellas Artes de Valencia. The courtyard constitutes an excellent test bench due to the complexity of its sculptural forms and its combination with the large stucco panels. The photogrammetric survey was carried out with a DJI mini 2 drone, weighting less than 250 gr, equipped with a 1/2.3¿ CMOS sensor with a resolution of 12 Mp. In addition, a survey with a laser scanner Leica RTC 360 was also carried out to compare both of them and to estimate the precision of the photogrammetric survey.
Two types of photogrammetric surveys were carried out, the first of which was taken at a medium distance to achieve the restitution of part of the general volume, while the second consisted of a very close-range survey of one of the original capitals, in order to restore a more detailed model. The conclusions of this study, that arises from the comparison and study of the models obtained, will reveal the convenience of using this kind of drones and its application to architectural heritage surveying.This contribution is part of the R+D+i project / Grant PID2020-119469RB-I00, funded by the Ministry of Science and Innovation/ State Research Agency/10.13039/501100011033.Rodríguez Navarro, P.; Cabezos Bernal, PM.; Gil Piqueras, T.; Giménez Ribera, M. (2022). Using drones under 250 g for documenting the architectural heritage. DisegnareCon. 15(29):1-19. https://doi.org/10.20365/disegnarecon.29.2022.1119152
Efecto de un programa de iniciación a la natación basado en juegos motores acuáticos sobre la autoestima corporal y socio afectiva en niñas y niños de 5 y 6 años de edad
This study sought to examine the success of the application of two introductory swimming programmes in enhancing the body and socio-affective self-esteem of 5 and 6 year olds, and to determine which of these programmes was more effective in this improvement. Both programmes were administered over three months and were designed under the stageapproach of the Royal Spanish Swimming Federation. The first was implemented in the control group (31 girls and 27 boys), and the second in the experimental group (29 girls and 23 boys). The experimental group included the application of aquatic games designed to promote cooperative play and children’s knowledge of their own bodies. The results showed significant improvements in both types of self-esteem in the experimental group, while only body self-esteem improved in the control group. In the between-group comparison, the experimental group showed significantly more robust results in both types of self-esteem. No gender differences were found. We conclude that the use of motor games oriented towards collaborative games and knowledge of one's own body aremore effective in improving both types of self-esteem. Thus, their use is recommended in introductory swimming classes.Este estudio analizó si la aplicación de dos programas de iniciación a la natación conseguía mejorar la autoestima corporal y socio afectiva de alumnos de cinco y seis años, y conocer cuál era más efectivo en dicha mejora. Sendos programas se aplicaron durante tres meses. Los programas se diseñaron bajo el planteamiento de etapas de la Real Federación Española de Natación. El primero se estableció en el grupo control (31 niñas y 27 niños), y el segundo en el grupo experimental (29 niñas y 23 niños). El grupo experimental incluyó la aplicación de juegos motores acuáticos diseñados para fomentar el conocimiento del propio cuerpo y el juego cooperativo. Los resultados mostraron que en el grupo experimental se lograron mejoras significativas de ambas autoestimas, mientras que en el grupo control solo mejoró la autoestima corporal. En la comparación entre grupos, el grupo experimental fue significativamente más eficiente en ambas autoestimas. No se encontraron diferencias en función del sexo. Se concluye que la utilización de los juegos motores orientados al conocimiento del propio cuerpo, y los juegos cooperativos son más eficaces para la mejora de ambas autoestimas. De este modo es conveniente su uso en las clases de iniciación a la natación
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