Discrete choice models of labour suppluy, behavioural microsimulation and the Spanish tax reform

In this paper, we demonstrate the potential of behavioural microsimulation models as powerful tools for the ex ante evaluation of public policies. The subject of our analysis is the impact of recent Spanish Income Tax reforms on efficiency and household and social welfare. We also analyze the likely effects of some basic income - flat tax and vital minimum - flat tax schemes. The analysis is carried out using a microsimulation model in which labour supply is explicitly taken into account. Instead of following the traditional continuous approach (Hausman 1981, 1985a, and 1985b), we estimate the direct utility function using the methodology proposed by Van Soest (1995). Our data come from a sample of Spanish individuals in the 1995 wave of the EC Household Panel. We show that in the Spanish case, the redistribution policies considered have only little impact on the efficiency of the economy. On the contrary, they strongly affect social welfare.microsimulation models ; evaluation of public policies

Discrete choice models of labour suppluy, behavioural microsimulation and the Spanish tax reform

In this paper, we demonstrate the potential of behavioural microsimulation models as powerful tools for the ex ante evaluation of public policies. The subject of our analysis is the impact of recent Spanish Income Tax reforms on efficiency and household and social welfare. We also analyze the likely effects of some basic income - flat tax and vital minimum - flat tax schemes. The analysis is carried out using a microsimulation model in which labour supply is explicitly taken into account. Instead of following the traditional continuous approach (Hausman 1981, 1985a, and 1985b), we estimate the direct utility function using the methodology proposed by Van Soest (1995). Our data come from a sample of Spanish individuals in the 1995 wave of the EC Household Panel. We show that in the Spanish case, the redistribution policies considered have only little impact on the efficiency of the economy. On the contrary, they strongly affect social welfare.Dans cet article, on démontre le potentiel des modèles de microsimulation avec comportements dans l'évaluation ex ante des politiques publiques. Le sujet de notre analyse est l'impact sur l'efficacité et sur le bien-être des ménages, des réformes récentes de l'impôt sur les revenus implémentées en Espagne. On analyse aussi les effets de certains scénarios de réforme inspirés de la logique du revenu minimum - impôt linéaire. L'analyse est effectuée à l'aide d'un modèle de microsimulation avec réactions d'offre de travail. Au lieu de suivre l'approche traditionnelle à la Hausman (1981, 1985a, 1985b), on estime directement les paramètres de la fonction d'utilité en employant la méthodologie proposée par Van Soest (1995). Les données ont été récupérées à partir de la vague 1995 du Panel européen des ménages (ECHP). On démontre que, dans le cas espagnol, les politiques redistributives implémentées ont des effets mineurs sur l'efficacité économique, par contre, elles augmentent de façon importante le bien-être social

Efecto del número de indicadores por factor sobre la identificación y estimación en modelos aditivos de análisis factorial confirmatorio

La matriz multirrasgo-multimétodo (MRMM) es un diseño de investigación de larga tradición en Psicología. Las técnicas de análisis de datos adecuadas para una correcta extracción de conclusiones han estado sujetas a controversia. Parece, no obstante, que diversos modelos de análisis factorial confirmatorio resultan muy adecuados. De entre los diversos modelos, dos de ellos han recibido gran atención, el modelo completo, que apareció primero en la literatura, y el de unicidades correlacionadas, que parece una alternativa razonable a los problemas que aparecen en el primero. Los resultados de ambos modelos en la literatura se refieren a situaciones con un solo indicador por combinación rasgo-método. La presente investigación simula datos de matrices MRMM para múltiples indicadores por combinación rasgo-método y somete a prueba la adecuación de las estimaciones de ambos modelos. Los resultados apuntan a un mejor comportamiento del modelo completo, si bien los sesgos, aunque triviales en cuantía, aumentan conforme aumenta la correlación entre los métodos

Soot temperature characterization of spray a flames by combined extinction and radiation methodology

[EN] Even though different optical techniques have been applied on 'Spray A' in-flame soot quantification within Engine Combustion Network in recent years, little information can be found for soot temperature measurement. In this study, a combined extinction and radiation methodology has been developed with different wavelengths and applied on quasi-steady Diesel flame to obtain the soot amount and temperature distribution simultaneously by considering self-absorption issues. All the measurements were conducted in a constant pressure combustion chamber. The fuel as well as the operating conditions and the injector used were chosen following the guidelines of the Engine Combustion Network. Uncertainty caused by wavelength selection was evaluated. Additionally, temperature-equivalence ratio maps were constructed by combining the measurements with a 1D spray model. Temperature fields during the quasi-steady combustion phase show peak temperatures around the limit of the radiation field, in agreement with a typical diffusion flame structure. Effects of different operating parameters on soot formation and temperature were investigated. Soot temperature increases dramatically with oxygen concentration, but it shows much less sensitivity with ambient temperature and injection pressure, which on the other hand have significant effects on soot production. (C) 2019 The Combustion Institute. Published by Elsevier Inc. All rights reserved.This study was partially funded by the Ministerio de Economia y Competitividad from Spain in the frame of the CHEST Project (TRA2017-89139-C2-1-R) and China Postdoctoral Science Foundation (2018M642176). This study was also partially supported by State Key Laboratory of Engines, Tianjin University.Xuan, T.; Desantes J.M.; Pastor, JV.; García-Oliver, JM. (2019). Soot temperature characterization of spray a flames by combined extinction and radiation methodology. Combustion and Flame. 204:290-303. https://doi.org/10.1016/j.combustflame.2019.03.02329030320

Effect of laser induced plasma ignition timing and location on Diesel spray combustion

[EN] An experimental study about the influence of the local conditions at the ignition location on combustion development of a direct injection spray is carried out in an optical engine. A laser induced plasma ignition system has been used to force the spray ignition, allowing comparison of combustion's evolution and stability with the case of conventional autoignition on the Diesel fuel in terms of ignition delay, rate of heat release, spray penetration and soot location evolution. The local equivalence ratio variation along the spray axis during the injection process was determined with a 1D spray model, previously calibrated and validated. Upper equivalence ratios limits for the ignition event of a direct injected Diesel spray, both in terms of ignition success possibilities and stability of the phenomena, could been determined thanks to application of the laser plasma ignition system. In all laser plasma induced ignition cases, heat release was found to be higher than for the autoignition reference cases, and it was found to be linked to a decrease of ignition delay, with the premixed peak in the rate of heat release curve progressively disappearing as the ignition delay time gets shorter. Ignition delay has been analyzed as a function of the laser position, too. It was found that ignition delay increases for plasma positions closer to the nozzle, indicating that the amount of energy introduced by the laser induced plasma is not the only parameter affecting combustion initiation, but local equivalence ratio plays a major role, too. (C) 2016 Elsevier Ltd. All rights reserved.The authors acknowledge that this research work has been partly funded by the Government of Spain under the project HiR-eCo TRA2014-58870-R and grant BES-2015-072119. The equipment used in this work has been partially supported by FEDER project ICTS-2012-06, framed in the operational program of unique scientific and technical infrastructure of the Ministry of Science and Innovation of Spain.Pastor, JV.; García-Oliver, JM.; García Martínez, A.; Pinotti, M. (2017). Effect of laser induced plasma ignition timing and location on Diesel spray combustion. Energy Conversion and Management. 133:41-55. https://doi.org/10.1016/j.enconman.2016.11.054S415513

Optimization of spray break-up CFD simulations by combining Sigma-Y Eulerian atomization model with a response surface methodology under diesel engine-like conditions (ECN Spray A)

[EN] This work evaluates the performance of the Sigma-Y Eulerian atomization model at reproducing the internal structure of a diesel spray with a special focus on Sauter Mean Diameter (SMD) predictions. Modeling results have been compared to x-ray radiography measurements [21,24,38] which provided unique data within dense spray region. The first step corresponds to accurately reproduce the large scale spray dispersion. Among different RANS turbulence models, the standard k-s with the round jet corrected CIE value (1.60), has shown the best performance, as shown in [12]. Then, the study is devoted to the application and optimization of the predicted interphase surface density (E). In this work, a combination of CFD modeling and the statistical Design of Experiments (DOE) technique known as Response Surface Method (RSM) is applied in order to improve Sauter Mean Diameter (SMD) predictions from E equation compared to experimental measurements. In the investigation, two different optimizations are conducted for the three modeling parameters involved in the equation, following a Central Composite Design (CCD), leading to 15 simulations for each one. After that, both optimum sets of values are validated to assure the accuracy of the method and it is decided the best choice. Finally, different injection and ambient conditions are simulated, with those selected values, providing a remarkable improvement in the modeling performance.Authors acknowledge that part of this work was possible thanks to the Programa de Ayudas de Investigacion y Desarrollo (PAID 2013 3198) of the Universitat Politecnica de Valencia. Also this study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF (TRA2014-59483R) project.Pandal-Blanco, A.; Payri, R.; García-Oliver, JM.; Pastor Enguídanos, JM. (2017). Optimization of spray break-up CFD simulations by combining Sigma-Y Eulerian atomization model with a response surface methodology under diesel engine-like conditions (ECN Spray A). Computers & Fluids. 156:9-20. doi:10.1016/j.compfluid.2017.06.022S92015

Local habitat and landscape influence high predation of bird nests on afforested Mediterranean cropland

Afforestation programs such as the one promoted by the EU Common Agrarian Policy have contributed to spread tree plantations on former cropland. Nevertheless these afforestations may cause severe damage to open habitat species, especially birds of high conservation value. We investigated predation of artificial bird nests at young tree plantations and at the open farmland habitat adjacent to the tree plantations in central Spain. Predation rates were very high at both tree plantations (95.6%) and open farmland habitat (94.2%) after two and three week exposure. Plantation edge/area ratio and development of the tree canopy decreased predation rates and plantation area and magpie (Pica pica) abundance increased predation rates within tree plantations, which were also affected by land use types around plantations. The area of nearby tree plantations (positive effect), distance to the tree plantation edge (negative effect), and habitat type (mainly attributable to the location of nests in vineyards) explained predation rates at open farmland habitat. We conclude that predation rates on artificial nests were particularly high and rapid at or nearby large plantations, with high numbers of magpies and low tree development, and located in homogenous landscapes dominated by herbaceous crops and pastures with no remnants of semi-natural woody vegetation. Landscape planning should not favour tree plantations as the ones studied here in Mediterranean agricultural areas that are highly valuable for ground-nesting bird species.Ministerio de Ciencia y EducaciónComunidad de Madri

Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy

[EN] Multiple injection strategies have increased their capabilities along with the evolution of injection system technologies up to the point that nowadays it is possible to inject eight different pulses, permitting to improve the engine performance, and consequently, emissions. The present work was realized for two simplified strategies: a pilot-main and a main-post, in order to analyze the influence of an auxiliary pulse on the main and otherwise, in reactive conditions for two pilot/post quantities and four hydraulic dwell times. The study was carried out by employing two optical techniques: diffused back-illumination with flame bandpass chemiluminescence for measuring soot, represented by soot-maps distribution, and single-pass schlieren for ignition delay (ID). Furthermore, a novel methodology for decoupling the start of combustion (SOC) of the second pulse was developed and successfully validated. From the ignition delay results, it was found for all test points that the pilot injection enhanced conditions, which promote a faster ignition of the main pulse, also at higher chamber temperatures, all conditions presented a separate combustion event for each injection. In emission terms, soot increased in the pilot-main strategies compared to its single injection case, as well as, in conditions that promote faster-premixed combustion.This research has been partially funded by Spanish "Ministerio de Ciencia, Innovacion y Universidades" through project RTI2018-099706-B-100. Additionally, the experimental hardware was purchased through FEDER and Generalitat Valenciana under project IDIFEDER/2018/037.Payri, R.; García-Oliver, JM.; Mendoza, V.; Viera, A. (2020). Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy. Energies. 13(13):1-22. https://doi.org/10.3390/en13133505S1221313Musculus, M. P. B., Miles, P. C., & Pickett, L. M. (2013). Conceptual models for partially premixed low-temperature diesel combustion. Progress in Energy and Combustion Science, 39(2-3), 246-283. doi:10.1016/j.pecs.2012.09.001Han, S., Kim, J., & Bae, C. (2014). Effect of air–fuel mixing quality on characteristics of conventional and low temperature diesel combustion. Applied Energy, 119, 454-466. doi:10.1016/j.apenergy.2013.12.045Mingfa, Y., Hu, W., Zunqing, Z., & Yan, Y. (2009). Experimental Study of Multiple Injections and Coupling Effects of Multi-Injection and EGR in a HD Diesel Engine. SAE Technical Paper Series. doi:10.4271/2009-01-2807Schöppe, D., Stahl, C., Krüger, G., & Dian, V. (2012). Servo-Driven Piezo Common Rail Diesel Injection System. ATZautotechnology, 12(2), 42-47. doi:10.1365/s35595-012-0107-yO’Connor, J., & Musculus, M. (2013). Post Injections for Soot Reduction in Diesel Engines: A Review of Current Understanding. SAE International Journal of Engines, 6(1), 400-421. doi:10.4271/2013-01-0917Samuel J, J., & A, R. (2018). A physics-based model for real-time prediction of ignition delays of multi-pulse fuel injections in direct-injection diesel engines. International Journal of Engine Research, 21(3), 540-558. doi:10.1177/1468087418776876Siebers, D. L., & Higgins, B. (2001). Flame Lift-Off on Direct-Injection Diesel Sprays Under Quiescent Conditions. SAE Technical Paper Series. doi:10.4271/2001-01-0530Benajes, J., Payri, R., Bardi, M., & Martí-Aldaraví, P. (2013). Experimental characterization of diesel ignition and lift-off length using a single-hole ECN injector. Applied Thermal Engineering, 58(1-2), 554-563. doi:10.1016/j.applthermaleng.2013.04.044Payri, R., Salvador, F. J., Manin, J., & Viera, A. (2016). Diesel ignition delay and lift-off length through different methodologies using a multi-hole injector. Applied Energy, 162, 541-550. doi:10.1016/j.apenergy.2015.10.118Higgins, B., Siebers, D. L., & Aradi, A. (2000). Diesel-Spray Ignition and Premixed-Burn Behavior. SAE Technical Paper Series. doi:10.4271/2000-01-0940O’Connor, J., & Musculus, M. (2013). Effects of exhaust gas recirculation and load on soot in a heavy-duty optical diesel engine with close-coupled post injections for high-efficiency combustion phasing. International Journal of Engine Research, 15(4), 421-443. doi:10.1177/1468087413488767Baert, R. S. G., Frijters, P. J. M., Somers, B., Luijten, C. C. M., & de Boer, W. (2009). Design and Operation of a High Pressure, High Temperature Cell for HD Diesel Spray Diagnostics: Guidelines and Results. SAE Technical Paper Series. doi:10.4271/2009-01-0649Payri, R., Gimeno, J., Martí-Aldaraví, P., & Viera, A. (2020). Measurements of the mass allocation for multiple injection strategies using the rate of injection and momentum flux signals. International Journal of Engine Research, 22(4), 1180-1195. doi:10.1177/1468087419894854Payri, R., Salvador, F. J., Abboud, R., & Viera, A. (2020). Study of evaporative diesel spray interaction in multiple injections using optical diagnostics. Applied Thermal Engineering, 176, 115402. doi:10.1016/j.applthermaleng.2020.115402Tschöke, H., & Marohn, R. (Eds.). (2017). 10. Tagung Diesel- und Benzindirekteinspritzung 2016. Proceedings. doi:10.1007/978-3-658-15327-4Payri, R., Bracho, G., Marti-Aldaravi, P., & Viera, A. (2017). Nozzle Geometry Size Influence on Reactive Spray Development: From Spray B to Heavy Duty Applications. SAE Technical Paper Series. doi:10.4271/2017-01-0846Payri, R., Gimeno, J., Cardona, S., & Ayyapureddi, S. (2019). Experimental study of the influence of the fuel and boundary conditions over the soot formation in multi-hole diesel injectors using high-speed color diffused back-illumination technique. Applied Thermal Engineering, 158, 113746. doi:10.1016/j.applthermaleng.2019.113746Meijer, M., Somers, B., Johnson, J., Naber, J., Lee, S.-Y., Malbec, L. M., … Bazyn, T. (2012). ENGINE COMBUSTION NETWORK (ECN): CHARACTERIZATION AND COMPARISON OF BOUNDARY CONDITIONS FOR DIFFERENT COMBUSTION VESSELS. Atomization and Sprays, 22(9), 777-806. doi:10.1615/atomizspr.2012006083Ghandhi, J. B., & Heim, D. M. (2009). An optimized optical system for backlit imaging. Review of Scientific Instruments, 80(5), 056105. doi:10.1063/1.3128728Settles, G. S. (2001). Schlieren and Shadowgraph Techniques. doi:10.1007/978-3-642-56640-0Manin, J., Bardi, M., Pickett, L. M., & Manin, J. (2012). SP2-4 Evaluation of the liquid length via diffused back-illumination imaging in vaporizing diesel sprays(SP: Spray and Spray Combustion,General Session Papers). The Proceedings of the International symposium on diagnostics and modeling of combustion in internal combustion engines, 2012.8(0), 665-673. doi:10.1299/jmsesdm.2012.8.665Payri, R., Salvador, F. J., Bracho, G., & Viera, A. (2017). Differences between single and double-pass schlieren imaging on diesel vapor spray characteristics. Applied Thermal Engineering, 125, 220-231. doi:10.1016/j.applthermaleng.2017.06.140Payri, R., Gimeno, J., Bracho, G., & Vaquerizo, D. (2016). Study of liquid and vapor phase behavior on Diesel sprays for heavy duty engine nozzles. Applied Thermal Engineering, 107, 365-378. doi:10.1016/j.applthermaleng.2016.06.159Pastor, J. V., Payri, R., Garcia-Oliver, J. M., & Nerva, J.-G. (2012). Schlieren Measurements of the ECN-Spray A Penetration under Inert and Reacting Conditions. SAE Technical Paper Series. doi:10.4271/2012-01-0456Siebers, D. L. (1998). Liquid-Phase Fuel Penetration in Diesel Sprays. SAE Technical Paper Series. doi:10.4271/980809Skeen, S. A., Manin, J., Pickett, L. M., Cenker, E., Bruneaux, G., Kondo, K., … Hawkes, E. (2016). A Progress Review on Soot Experiments and Modeling in the Engine Combustion Network (ECN). SAE International Journal of Engines, 9(2), 883-898. doi:10.4271/2016-01-0734Payri, R., García-Oliver, J. M., Xuan, T., & Bardi, M. (2015). A study on diesel spray tip penetration and radial expansion under reacting conditions. Applied Thermal Engineering, 90, 619-629. doi:10.1016/j.applthermaleng.2015.07.042Wu, G., Zhou, X., & Li, T. (2019). Temporal Evolution of Split-Injected Fuel Spray at Elevated Chamber Pressures. Energies, 12(22), 4284. doi:10.3390/en12224284Maes, N., Bakker, P. C., Dam, N., & Somers, B. (2017). Transient Flame Development in a Constant-Volume Vessel Using a Split-Scheme Injection Strategy. SAE International Journal of Fuels and Lubricants, 10(2), 318-327. doi:10.4271/2017-01-0815Park, C., & Busch, S. (2017). The influence of pilot injection on high-temperature ignition processes and early flame structure in a high-speed direct injection diesel engine. International Journal of Engine Research, 19(6), 668-681. doi:10.1177/1468087417728630Kozlov, A., Grinev, V., Terenchenko, A., & Kornilov, G. (2019). An Investigation of the Effect of Fuel Supply Parameters on Combustion Process of the Heavy-Duty Dual-Fuel Diesel Ignited Gas Engine. Energies, 12(12), 2280. doi:10.3390/en12122280Desantes, J. M., García-Oliver, J. M., García, A., & Xuan, T. (2018). Optical study on characteristics of non-reacting and reacting diesel spray with different strategies of split injection. International Journal of Engine Research, 20(6), 606-623. doi:10.1177/1468087418773012Jorques Moreno, C., Stenlaas, O., & Tunestal, P. (2017). Influence of Small Pilot on Main Injection in a Heavy-Duty Diesel Engine. SAE Technical Paper Series. doi:10.4271/2017-01-0708Ameen, M. M., & Abraham, J. (2014). RANS and LES Study of Lift-Off Physics in Reacting Diesel Jets. SAE Technical Paper Series. doi:10.4271/2014-01-1118Pickett, L. M., & Siebers, D. L. (2004). Soot in diesel fuel jets: effects of ambient temperature, ambient density, and injection pressure. Combustion and Flame, 138(1-2), 114-135. doi:10.1016/j.combustflame.2004.04.006Wu, T., Yao, A., Yao, C., Pan, W., Wei, H., Chen, C., & Gao, J. (2018). Effect of diesel late-injection on combustion and emissions characteristics of diesel/methanol dual fuel engine. Fuel, 233, 317-327. doi:10.1016/j.fuel.2018.06.063Peraza, J. E., Payri, R., Gimeno, J., & Bazyn, T. (2017). Spray/wall interaction analysis on an ECN single-hole injector at diesel-like conditions through Schlieren visualization. Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems. doi:10.4995/ilass2017.2017.4709Zhao, L., Torelli, R., Zhu, X., Naber, J., Lee, S.-Y., Som, S., … Raessi, M. (2018). Evaluation of Diesel Spray-Wall Interaction and Morphology around Impingement Location. SAE Technical Paper Series. doi:10.4271/2018-01-027

A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model

[EN] An implementation and validation of the coupled Sigma-gamma ADF model is presented in this work for reacting Diesel spray CFD simulations under a RANS turbulence modeling approach. An Approximated Diffusion Flamelet (ADF) model Michel et al. (2008) implemented in the OpenFOAM CFD open-source library by Winklinger (2014)15 fed with the spray description, i.e. mixing formation process, provided by the Sigma-gamma Eulerian atomization model Garcia-Oliver et al. (2013). In the present investigation, the Engine Combustion Network Spray A reference configuration is used for validation. Specifically, the model can provide accurate predictions of typical reacting spray metrics, such as the ignition delay and the lift-off length. Moreover, the internal structure is also fairly reproduced in terms of quasi-steady spatial distribution of formaldehyde and OH, related with low and high temperature reactions respectively. Additionally, modeling results have been compared to recent Particle image velocimetry (PIV) measurements Garcia-Oliver et al. (2017) under both inert and reacting conditions. Flow response to heat release is quantitatively predicted by the model, both in terms of local velocity increase as well as radial dilation. The model has been used to understand combustion-induced reduction in entrainment, in particular around the lift-off length location. Flow confinement does not seem to influence the global flame behaviour, even though some changes in the local flow hint can be observed when moving from an open to a closed domain. (C) 2017 Elsevier Ltd. All rights reserved.Authors acknowledge that this work was possible thanks to the Programa de Ayudas de Investigation y Desarrollo (PAID-2013 3198) of the Universitat Politecnica de Valencia. Also this study was partially funded by the Spanish Ministry of Economy and Competitiveness in the frame of the COMEFF(TRA2014-59483-R) project. Authors thank Gilles Bruneaux from IFPEN for the interesting suggestions and discussions.Pandal-Blanco, A.; García-Oliver, JM.; Novella Rosa, R.; Pastor Enguídanos, JM. (2018). A computational analysis of local flow for reacting Diesel sprays by means of an Eulerian CFD model. International Journal of Multiphase Flow. 99:257-272. https://doi.org/10.1016/j.ijmultiphaseflow.2017.10.010S2572729