Efficient procedure for the evaluation of multiple scattering and multiphonon corrections in inelastic neutron-scattering experiments

10 págs.; 7 figs.; 1 tab.We present a full set of procedures to evaluate the experimental corrections needed to derive physically meaningful quantities from the measured neutron intensities in inelastic neutron-scattering experiments. Multiple-scattering corrections are evaluated by means of a Monte Carlo code, in which a combination of experimental data and the Synthetic Model is used to account for neutron-molecule interactions. Multiphonon corrections are treated with an iterative scheme. To illustrate the procedure the densities of vibrational states of deuterated water and ice near room temperature are evaluated from data measured in a chopper spectrometer. ©1998 American Physical SocietyPeer Reviewe

Calibración con parámetros de los ítems fijos para la evaluación del funcionamiento diferencial del ítem en tests adaptativos informatizados

In computerized adaptive testing pretest items are presented in conjunction with operational items to renew the item bank. Pretest items are calibrated, and possible differential item functioning (DIF) is analyzed. Some difficulties arise due to the large amount of missing responses, which can be avoided by the use of fixed item parameter calibration (FIPC; Kim, 2006) methods. In this study, we applied the multiple weights updating and multiple EM cycles method, with response imputation (as suggested by Lei, Chen, & Yu, 2006) and without response imputation for non-applied items. The IRT likelihood ratio test (IRT-LRT) was used for DIF detection. The manipulated factors were type of DIF, DIF size, impact size, test length, and sample size. The results showed that the FIPC method is suitable for detecting large-size DIF in large samples. In the presence of impact the use of imputation led to a bias in the effect-size measure of the DIFEn tests adaptativos informatizados los ítems pretest se presentan junto con los ítems operativos para renovar el banco de ítems. Los ítems pretest se calibran y se analiza el posible funcionamiento diferencial de los ítems (FDI). Este análisis presenta algunos problemas debido a la gran cantidad de respuestas faltantes, una de las posibles soluciones es el uso de métodos de calibración con parámetros fijos (Kim, 2006). En este estudio, aplicamos el método de múltiples actualizaciones de los pesos y múltiples ciclos EM con imputación de respuestas (tal y como propusieron Lei, Chen, y Yu, 2006) y sin imputación de respuesta para los ítems no aplicados. Empleamos el test de razón de verosimilitudes de la TRI para la detección del FDI. Los factores manipulados fueron el tipo de FDI, el tamaño del FDI, el tamaño del impacto, la longitud del test, y el tamaño de las muestras. Los resultados señalan que el método de calibración con parámetros fijos es una alternativa adecuada para la detección de un FDI grande cuando se utilizaron muestras grandes. En presencia de impacto el uso de imputación de respuestas introdujo un sesgo en las medidas del tamaño del efecto del FDIThis research was partly supported by a grant from the Spanish Ministry of Education and Science [PSI2009-10341

A holistic methodology to correct heat transfer and bearing friction losses from hot turbocharger maps in order to obtain adiabatic efficiency of the turbomachinery

This is the author¿s version of a work that was accepted for publication in International Journal of Engine Research. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published as https://doi.org/10.1177/1468087419834194[EN] Turbocharger performance maps provided by manufacturers are usually far from the assumption of reproducing the isentropic performance. The reason being, those maps are usually measured using a hot gas stand. The definition of the effective turbocharger efficiency maps include the mechanical losses and heat transfer that has occurred during the gas stand test for the turbine maps and only the heat transfer for the compressor maps. Thus, a turbocharger engine model that uses these maps provides accurate results only when simulating turbocharger operative conditions similar to those at which the maps are recorded. However, for some critical situations such as Worldwide harmonized Light vehicles Test Cycles (WLTC) driving cycle or off-design conditions, it is difficult to ensure this assumption. In this article, an internal and external heat transfer model combined with mechanical losses model, both previously developed and calibrated, has been used as an original tool to ascertain a calculation procedure to obtain adiabatic maps from diabatic standard turbocharger maps. The turbocharger working operative conditions at the time of map measurements and geometrical information of the turbocharger are necessary to discount both effects precisely. However, the maps from turbocharger manufacturers do not include all required information. These create additional challenges to develop the procedure to obtain approximated adiabatic maps making some assumptions based on SAE standards for non-available data. A sensitivity study has been included in this article to check the validity of the hypothesis proposed by changing the values of parameters which are not included in the map data. The proposed procedure becomes a valuable tool either for Original Equipment Manufacturers (OEMs) to parameterize turbocharger performance accurately for benchmarking and turbocharged engine design or to turbocharger manufacturers to provide much-appreciated information of their performance maps.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: This work has been partially supported by FEDER and the Government of Spain through Grant No. TRA2016-79185-R.Serrano, J.; Olmeda, P.; Arnau Martínez, FJ.; Samala, V. (2020). A holistic methodology to correct heat transfer and bearing friction losses from hot turbocharger maps in order to obtain adiabatic efficiency of the turbomachinery. International Journal of Engine Research. 21(8):1314-1335. https://doi.org/10.1177/1468087419834194S13141335218Sirakov, B., & Casey, M. (2012). Evaluation of Heat Transfer Effects on Turbocharger Performance. Journal of Turbomachinery, 135(2). doi:10.1115/1.4006608Payri, F., Serrano, J. R., Fajardo, P., Reyes-Belmonte, M. A., & Gozalbo-Belles, R. (2012). A physically based methodology to extrapolate performance maps of radial turbines. Energy Conversion and Management, 55, 149-163. doi:10.1016/j.enconman.2011.11.003Chesse, P., Chalet, D., & Tauzia, X. (2011). Impact of the Heat Transfer on the Performance Calculations of Automotive Turbocharger Compressor. Oil & Gas Science and Technology – Revue d’IFP Energies nouvelles, 66(5), 791-800. doi:10.2516/ogst/2011129Serrano, J. R., Olmeda, P., Arnau, F. J., Reyes-Belmonte, M. A., & Tartoussi, H. (2015). A study on the internal convection in small turbochargers. Proposal of heat transfer convective coefficients. Applied Thermal Engineering, 89, 587-599. doi:10.1016/j.applthermaleng.2015.06.053Tanda, G., Marelli, S., Marmorato, G., & Capobianco, M. (2017). An experimental investigation of internal heat transfer in an automotive turbocharger compressor. Applied Energy, 193, 531-539. doi:10.1016/j.apenergy.2017.02.053Serrano, J., Olmeda, P., Arnau, F., & Dombrovsky, A. (2014). General Procedure for the Determination of Heat Transfer Properties in Small Automotive Turbochargers. SAE International Journal of Engines, 8(1), 30-41. doi:10.4271/2014-01-2857Payri, F., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2014). External heat losses in small turbochargers: Model and experiments. Energy, 71, 534-546. doi:10.1016/j.energy.2014.04.096Serrano, J. R., Olmeda, P., Tiseira, A., García-Cuevas, L. M., & Lefebvre, A. (2013). Theoretical and experimental study of mechanical losses in automotive turbochargers. Energy, 55, 888-898. doi:10.1016/j.energy.2013.04.042SAE International. Turbocharger gas stand test code, SAE J1826. Technical Report, Society of Automotive Engineers Inc, Warrendale, PA, 1995.SAE International. Supercharger testing standard, SAE J1723. Technical Report, Society of Automotive Engineers Inc, Warrendale, PA, 1995.Serrano, J. R., Olmeda, P., Páez, A., & Vidal, F. (2010). An experimental procedure to determine heat transfer properties of turbochargers. Measurement Science and Technology, 21(3), 035109. doi:10.1088/0957-0233/21/3/03510

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

[EN] Growing interest has arisen to adopt Variable Valve Timing (VVT) technology for automotive engines due to the need to fulfill the pollutant emission regulations. Several VVT strategies, such as the exhaust re-opening and the late exhaust closing, can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to simulate several VVT strategies and develop a control system to actuate over the valves timing in order to increase diesel oxidation catalyst efficiency and reduce the exhaust pollutant emissions. A transient operating conditions comparison, taking the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC) as a reference, has been done by analyzing fuel economy, HC and CO pollutant emissions levels. The results conclude that the combination of an early exhaust and a late intake valve events leads to a 20% reduction in CO emissions with a fuel penalty of 6% over the low speed stage of the WLTC, during the warm-up of the oxidation catalyst. The same set-up is able to reduce HC emissions down to 16% and NO(x)emission by 13%.This research has been partially funded by the Spanish government under the grant agreement TRA2017-89894-R ("Mecoem"). Angel Aunon was supported through the "Apoyo para la investigacion y Desarrollo (PAID)" grant for doctoral studies (FPI S2 2018 1048) by Universitat Politecnica de Valencia.Serrano, J.; Arnau Martínez, FJ.; Martín, J.; Auñón-García, Á. (2020). Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine. Energies. 13(17):1-26. https://doi.org/10.3390/en13174561S1261317Arnau, F. J., Martín, J., Pla, B., & Auñón, Á. (2020). Diesel engine optimization and exhaust thermal management by means of variable valve train strategies. International Journal of Engine Research, 22(4), 1196-1213. doi:10.1177/1468087419894804Luján, J. M., Serrano, J. R., Piqueras, P., & García-Afonso, Ó. (2015). Experimental assessment of a pre-turbo aftertreatment configuration in a single stage turbocharged diesel engine. Part 2: Transient operation. Energy, 80, 614-627. doi:10.1016/j.energy.2014.12.017Lancefield, T., Methley, I., Räse, U., & Kuhn, T. (2000). The Application of Variable Event Valve Timing to a Modern Diesel Engine. SAE Technical Paper Series. doi:10.4271/2000-01-1229Gonzalez D, M. A., & Di Nunno, D. (2016). Internal Exhaust Gas Recirculation for Efficiency and Emissions in a 4-Cylinder Diesel Engine. SAE Technical Paper Series. doi:10.4271/2016-01-2184Serrano, J. R., Piqueras, P., Navarro, R., Gómez, J., Michel, M., & Thomas, B. (2016). Modelling Analysis of Aftertreatment Inlet Temperature Dependence on Exhaust Valve and Ports Design Parameters. SAE Technical Paper Series. doi:10.4271/2016-01-0670Siewert, R. M. (1971). How Individual Valve Timing Events Affect Exhaust Emissions. SAE Technical Paper Series. doi:10.4271/710609Tomoda, T., Ogawa, T., Ohki, H., Kogo, T., Nakatani, K., & Hashimoto, E. (2010). Improvement of Diesel Engine Performance by Variable Valve Train System. International Journal of Engine Research, 11(5), 331-344. doi:10.1243/14680874jer586Benajes, J., Reyes, E., & Luján, J. M. (1996). Modelling Study of the Scavenging Process in a Turbocharged Diesel Engine with Modified Valve Operation. Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 210(4), 383-393. doi:10.1243/pime_proc_1996_210_210_02Deppenkemper, K., Özyalcin, C., Ehrly, M., Schoenen, M., Bergmann, D., & Pischinger, S. (2018). 1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications. SAE Technical Paper Series. doi:10.4271/2018-01-0163Zammit, J. P., McGhee, M. J., Shayler, P. J., Law, T., & Pegg, I. (2015). The effects of early inlet valve closing and cylinder disablement on fuel economy and emissions of a direct injection diesel engine. Energy, 79, 100-110. doi:10.1016/j.energy.2014.10.065Pan, X., Zhao, Y., Lou, D., & Fang, L. (2020). Study of the Miller Cycle on a Turbocharged DI Gasoline Engine Regarding Fuel Economy Improvement at Part Load. Energies, 13(6), 1500. doi:10.3390/en13061500Guan, W., Pedrozo, V. B., Zhao, H., Ban, Z., & Lin, T. (2019). Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine. International Journal of Engine Research, 21(4), 578-591. doi:10.1177/1468087419846031Guan, W., Zhao, H., Ban, Z., & Lin, T. (2018). Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine. International Journal of Engine Research, 20(4), 381-392. doi:10.1177/1468087418755586Maniatis, P., Wagner, U., & Koch, T. (2018). A model-based and experimental approach for the determination of suitable variable valve timings for cold start in partial load operation of a passenger car single-cylinder diesel engine. International Journal of Engine Research, 20(1), 141-154. doi:10.1177/1468087418817119Kim, J., & Bae, C. (2015). An investigation on the effects of late intake valve closing and exhaust gas recirculation in a single-cylinder research diesel engine in the low-load condition. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 230(6), 771-787. doi:10.1177/0954407015595149Zhou, X., Liu, E., Sun, D., & Su, W. (2018). Study on transient emission spikes reduction of a heavy-duty diesel engine equipped with a variable intake valve closing timing mechanism and a two-stage turbocharger. International Journal of Engine Research, 20(3), 277-291. doi:10.1177/1468087417748837Gosala, D. B., Ramesh, A. K., Allen, C. M., Joshi, M. C., Taylor, A. H., Van Voorhis, M., … Stretch, D. (2017). Diesel engine aftertreatment warm-up through early exhaust valve opening and internal exhaust gas recirculation during idle operation. International Journal of Engine Research, 19(7), 758-773. doi:10.1177/1468087417730240Parvate-Patil, G. B., Hong, H., & Gordon, B. (2004). Analysis of Variable Valve Timing Events and Their Effects on Single Cylinder Diesel Engine. SAE Technical Paper Series. doi:10.4271/2004-01-2965Piano, A., Millo, F., Di Nunno, D., & Gallone, A. (2017). Numerical Analysis on the Potential of Different Variable Valve Actuation Strategies on a Light Duty Diesel Engine for Improving Exhaust System Warm Up. SAE Technical Paper Series. doi:10.4271/2017-24-0024Payri, F., Arnau, F. J., Piqueras, P., & Ruiz, M. J. (2018). Lumped Approach for Flow-Through and Wall-Flow Monolithic Reactors Modelling for Real-Time Automotive Applications. SAE Technical Paper Series. doi:10.4271/2018-01-0954Martin, J., Arnau, F., Piqueras, P., & Auñon, A. (2018). Development of an Integrated Virtual Engine Model to Simulate New Standard Testing Cycles. SAE Technical Paper Series. doi:10.4271/2018-01-1413Serrano, J. R., Arnau, F. J., García-Cuevas, L. M., Dombrovsky, A., & Tartoussi, H. (2016). Development and validation of a radial turbine efficiency and mass flow model at design and off-design conditions. Energy Conversion and Management, 128, 281-293. doi:10.1016/j.enconman.2016.09.032Galindo, J., Tiseira, A., Navarro, R., Tarí, D., Tartoussi, H., & Guilain, S. (2016). Compressor Efficiency Extrapolation for 0D-1D Engine Simulations. SAE Technical Paper Series. doi:10.4271/2016-01-0554Serrano, J. R., Olmeda, P., Arnau, F. J., & Samala, V. (2019). A holistic methodology to correct heat transfer and bearing friction losses from hot turbocharger maps in order to obtain adiabatic efficiency of the turbomachinery. International Journal of Engine Research, 21(8), 1314-1335. doi:10.1177/1468087419834194Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2014). Analysis and Methodology to Characterize Heat Transfer Phenomena in Automotive Turbochargers. Journal of Engineering for Gas Turbines and Power, 137(2). doi:10.1115/1.4028261Serrano, J. R., Olmeda, P., Arnau, F. J., Dombrovsky, A., & Smith, L. (2015). Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes. Energy, 86, 204-218. doi:10.1016/j.energy.2015.03.130Arrègle, J., López, J. J., Martín, J., & Mocholí, E. M. (2006). Development of a Mixing and Combustion Zero-Dimensional Model for Diesel Engines. SAE Technical Paper Series. doi:10.4271/2006-01-1382Payri, F., Arrègle, J., López, J. J., & Mocholí, E. (2008). Diesel NOx Modeling with a Reduction Mechanism for the Initial NOx Coming from EGR or Re-entrained Burned Gases. SAE Technical Paper Series. doi:10.4271/2008-01-1188Broatch, A., Olmeda, P., Martin, J., & Salvador-Iborra, J. (2018). Development and Validation of a Submodel for Thermal Exchanges in the Hydraulic Circuits of a Global Engine Model. SAE Technical Paper Series. doi:10.4271/2018-01-0160Guardiola, C., Pla, B., Bares, P., & Mora, J. (2018). An on-board method to estimate the light-off temperature of diesel oxidation catalysts. International Journal of Engine Research, 21(8), 1480-1492. doi:10.1177/1468087418817965Russell, A., & Epling, W. S. (2011). Diesel Oxidation Catalysts. Catalysis Reviews, 53(4), 337-423. doi:10.1080/01614940.2011.596429Guardiola, C., Pla, B., Piqueras, P., Mora, J., & Lefebvre, D. (2017). Model-based passive and active diagnostics strategies for diesel oxidation catalysts. Applied Thermal Engineering, 110, 962-971. doi:10.1016/j.applthermaleng.2016.08.207Abdelghaffar, W. A., Osman, M. M., Saeed, M. N., & Abdelfatteh, A. I. (2002). Effects of Coolant Temperature on the Performance and Emissions of a Diesel Engine. Design, Operation, and Application of Modern Internal Combustion Engines and Associated Systems. doi:10.1115/ices2002-464Torregrosa, A. J., Olmeda, P., Martín, J., & Degraeuwe, B. (2006). Experiments on the influence of inlet charge and coolant temperature on performance and emissions of a DI Diesel engine. Experimental Thermal and Fluid Science, 30(7), 633-641. doi:10.1016/j.expthermflusci.2006.01.00

Assessment of a methodology to mesh the spatial domain in the proximity of the boundary conditions for one-dimensional gas dynamic calculation

[EN] Solution of governing equations for one-dimensional compressible unsteady flow has been performed traditionally using a homogenously distributed spatial mesh. In the resulting node structure, the internal nodes are solved by applying a shock capturing finite difference numerical method whereas the solution of the end nodes, which define the boundary conditions of the pipe, is undertaken by means of the Method of Characteristics. Besides the independent solution of every method, the coupling between the information obtained by the method of characteristics and the finite difference method is key in order to reach a good accuracy in gas dynamics modeling. The classical spatial mesh could provide numerical problems leading the boundary to generate lack of mass, momentum and energy conservation because of the interpolation methodology usually applied to draw the characteristics and path lines from its departure point at calculation time to the end of the pipe during the next time-step. To deal with this undesirable behavior, in this work a modification of the traditional grid including an extra node close to the boundary is proposed in order to explore its ability to provide numerical results with higher conservation fulfillment. © 2010 Elsevier Ltd.J.R. Serrano; Arnau Martínez, FJ.; Piqueras, P.; Reyes Belmonte, MA. (2011). Assessment of a methodology to mesh the spatial domain in the proximity of the boundary conditions for one-dimensional gas dynamic calculation. Mathematical and Computer Modelling. 54:1747-1752. doi:10.1016/j.mcm.2010.11.073S174717525

Cisatracurio

El cisatracurio es uno de los 10 isómeros que forman la mezcla racémica de atracurio (el 51W89 o 1R-cis, 1’Rcis atracurio). Se caracteriza por ser 3 veces más potente que el atracurio y por su estabilidad hemodinámica debido a la escasa liberación de histamina. Se hidroliza básicamente por la vía de Hofmann (77%) y en menor proporción se metaboliza de modo órgano-dependiente (fundamentalmente por el riñón [16%]). Debido a esto, apenas precisa modificaciones de la dosificación en caso de enfermedad hepática, renal o cardiovascular, o en los pacientes ancianos. La dosis eficaz 95 se ha calculado en 0,05 mg•kg-1 (0,04 mg•kg-1 en los niños), aunque clínicamente se utiliza de 2-4 veces esta dosis para reducir el tiempo necesario para la intubación traqueal debido a su lento inicio del bloqueo, especialmente si se compara con el rocuronio. Al incrementar la dosis se prolonga el período de bloqueo profundo (sin respuesta a la neuroestimulación), pero al iniciarse la recuperación cursa de forma dosis-dependiente, con índices de recuperación similares. La utilización del cisatracurio en cuidados intensivos ha resultado ser útil por su estabilidad hemodinámica, equiparable a los derivados esteroides, pero con recuperación más rápida del bloqueo al suspender su administración, y por su metabolismo predominante mediante la vía de Hofmann, con menor formación de laudanosina que el atracurio. El cisatracurio se perfila corno un miorrelajante no despolarizante de elección en procedimientos quirúrgicos de duración media-larga, en los pacientes hemodinámicamente inestables o con enfermedad renal o hepática y en el bloqueo neuromuscular en cuidados intensivos

A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines

[EN] The current investigation describes in detail a mass flow oriented model for extrapolation of reduced mass flow and adiabatic efficiency of double entry radial inflow turbines under any unequal and partial flow admission conditions. The model is based on a novel approach, which proposes assimilating double entry turbines to two variable geometry turbines (VGTs) using the mass flow ratio ( MFR ) between the two entries as the discriminating parameter. With such an innovative approach, the model can extrapolate performance parameters to non-measured MFR s, blade-to-jet speed ratios, and reduced speeds. Therefore, the model can be used in a quasi-steady method for predicting double entry turbines performance instantaneously. The model was validated against a dataset from two different double entry turbine types: a twin-entry symmetrical turbine and a dual-volute asymmetrical turbine. Both were tested under steady flow conditions. The proposed model showed accurate results and a coherent set of fitting parameters with physical meaning, as discussed in this paper. The obtained parameters showed very similar figures for the aforementioned turbine types, which allows concluding that they are an adequate set of values for initializing the fitting procedure of any type of double entry radial turbine.Vishnu Samala is partially supported through contract FPI-2017-S2-1256 of Programa de Apoyo para la Investigacion y Desarrollo (PAID) of Universitat Politecnica de Valencia. This work was partially funded by the 'Ayuda a Primeros Proyectos de Investigacion' (PAID-06-18), Vicerrectorado de Investigacion, Innovacion y Transferencia de la Universitat Politecnica de Valencia (UPV), Valencia, Spain.Serrano, J.; Arnau Martínez, FJ.; García-Cuevas González, LM.; Samala, V. (2020). A Robust Adiabatic Model for a Quasi-Steady Prediction of Far-Off Non-Measured Performance in Vaneless Twin-Entry or Dual-Volute Radial Turbines. Applied Sciences. 10(6):1-43. https://doi.org/10.3390/app10061955S143106Haq, G., & Weiss, M. (2016). CO2 labelling of passenger cars in Europe: Status, challenges, and future prospects. Energy Policy, 95, 324-335. doi:10.1016/j.enpol.2016.04.043Wang, S., Zhao, F., Liu, Z., & Hao, H. (2017). Heuristic method for automakers’ technological strategy making towards fuel economy regulations based on genetic algorithm: A China’s case under corporate average fuel consumption regulation. Applied Energy, 204, 544-559. doi:10.1016/j.apenergy.2017.07.076Kalghatgi, G. (2018). Is it really the end of internal combustion engines and petroleum in transport? Applied Energy, 225, 965-974. doi:10.1016/j.apenergy.2018.05.076Serrano, J. (2017). Imagining the Future of the Internal Combustion Engine for Ground Transport in the Current Context. Applied Sciences, 7(10), 1001. doi:10.3390/app7101001Kruiswyk, R. W. (2012). The role of turbocompound in the era of emissions reduction. 10th International Conference on Turbochargers and Turbocharging, 269-280. doi:10.1533/9780857096135.5.269Yang, M., Deng, K., Martines-Botas, R., & Zhuge, W. (2016). An investigation on unsteadiness of a mixed-flow turbine under pulsating conditions. Energy Conversion and Management, 110, 51-58. doi:10.1016/j.enconman.2015.12.007Zhu, D., & Zheng, X. (2017). Asymmetric twin-scroll turbocharging in diesel engines for energy and emission improvement. Energy, 141, 702-714. doi:10.1016/j.energy.2017.07.173Romagnoli, A., Copeland, C. D., Martinez-Botas, R., Seiler, M., Rajoo, S., & Costall, A. (2012). Comparison Between the Steady Performance of Double-Entry and Twin-Entry Turbocharger Turbines. Journal of Turbomachinery, 135(1). doi:10.1115/1.4006566Serrano, J. R., Arnau, F. J., Gracía-Cuevas, L. M., Samala, V., & Smith, L. (2019). Experimental approach for the characterization and performance analysis of twin entry radial-inflow turbines in a gas stand and with different flow admission conditions. Applied Thermal Engineering, 159, 113737. doi:10.1016/j.applthermaleng.2019.113737Watson, N., & Janota, M. S. (1982). Turbocharging the Internal Combustion Engine. doi:10.1007/978-1-349-04024-7Cerdoun, M., & Ghenaiet, A. (2016). Characterization of a Twin-Entry Radial Turbine under Pulsatile Flow Condition. International Journal of Rotating Machinery, 2016, 1-15. doi:10.1155/2016/4618298Winkler, N., Ångström, H.-E., & Olofsson, U. (2005). Instantaneous On-Engine Twin-Entry Turbine Efficiency Calculations on a Diesel Engine. SAE Technical Paper Series. doi:10.4271/2005-01-3887Fiaschi, D., Lifshitz, A., Manfrida, G., & Tempesti, D. (2014). An innovative ORC power plant layout for heat and power generation from medium- to low-temperature geothermal resources. 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Managing Group Decision Making criteria values using Fuzzy Ontologies

Meeting: 8th International Conference on Information Technology and Quantitative Management (ITQM) - Developing Global Digital Economy after COVID-19Most of the available Multi-criteria Group Decision Making methods that deal with a high number of elements usually focus on managing scenarios that have high number of alternatives and/or experts. Nevertheless, there are also cases in which the number of criteria values is difficult for the experts to tackle. In this paper, a novel Group Decision Making method that employs Fuzzy Ontologies in order to deal with a high number of criteria values is presented. Our method allows the criteria values to be combined in order to generate a reduced set of criteria values that the experts can comfortably deal with. (C) 2021 The Authors. Published by Elsevier B.V.The authors would like to thank the Spanish State Research Agency through the project PID2019-103880RB-I00 / AEI / 10.13039/501100011033

Thermo-economic analysis of an oxygen production plant powered by an innovative energy recovery system

[EN] Oxy-fuel combustion is considered an attractive alternative to reduce pollutant emissions, which uses high-purity oxygen mixed instead of air for combustion processes. However, purchasing large amounts of high-purity oxygen may be unprofitable for certain industrial sectors, discouraging its implementation. Considering this, the potential of an oxygen production cycle for factories using oxy-fuel combustion is studied by performing a thermo-economic analysis where high-purity oxygen, electricity, and natural gas prices are considered. Oxygen is produced by membrane means, where mixed ionic-electronic conducting membranes are used, which require high temperatures and pressure gradients to work properly. A set of turbochargers is implemented, chosen by scaling an off-the-shelf model, what introduces an innovative way of waste energy recovering for improving the performance of the cycle. The whole cycle is powered by waste heat from high temperature flue gases, and it is sized for a ceramic manufacturing factory. In this work, two cases are analysed, differentiated by considering additional heating and the vacuum generation method in the oxygen line. The first case exhibits smaller production levels, although better profitability (31¿€t¿1), whereas the second case displays higher production levels and production costs (33¿€t¿1). Both cases are competitive concerning the average price of high-purity oxygen, supposing an average of 50¿€t¿1 in wholesale markets, proving the potential of the proposed alternative for oxygen production.This research work has been supported by Grant PDC2021120821-I00 funded by MCIN/AEI/10.13039/501100011033 and by European Union NextGenerationEU/PRTR. This work has also been supported by Grant UPV-SOLGEN-79674 funded by the Vicerrectorado de Investigacion de la Universitat Politecnica de Valencia (PAID-11-21). The authors want to acknowledge the institution "Conselleria d'Educacio, Investigaci o, Cultura i Esport de la Generalitat Valenciana" and its grant program "Subvenciones para la contratacion de personal investigador de caracter predoctoral" for doctoral studies (ACIF/2020/246) funded by The European Union. Also, this work is part of grant number INNVA1/2021/38 funded by "Agencia Valenciana de la Innovacion (AVI)" and by "ERDF A way of making Europe".Serrano, J.; Arnau Martínez, FJ.; García-Cuevas González, LM.; Gutierrez, FA. (2022). Thermo-economic analysis of an oxygen production plant powered by an innovative energy recovery system. Energy. 255:1-18. https://doi.org/10.1016/j.energy.2022.12441911825