Re-Employment Probabilities for Spanish Men: What Role Does the Unemployment Benefit System Play?

We analyse the re-employment probabilities of almost 330,000 Spanish men aged 20-59 years who began a unemployment insurance (UI) spell between February 1987 and November 1991 using data derived from the national unemployment benefit administration database (SIPRE) and discrete time duration models with flexible baseline hazards. We show: (i) the level of UI benefits has a relatively small disincentive effect on re-employment rates; (ii) re-employment exit hazards increase as UI exhaustion approaches but, again, the effect is relatively small. (iii) Extensions to Unemployment Assistance eligibility lowered reemployment probabilities. Also (iv) there are clear seasonal and cyclical effects on reemployment rates, and (v) rates are much higher for those who enter UI from a fixed-term employment contract rather than permanent one, and (vi) for young workers. These results are consistent with other research drawing attention to the impact on unemployment of inflexibilities in Spanish labour market institutions, combined with low inter-regional mobility and reliance by many for support via their family.

Analysis of heavy-duty turbocharged diesel engine response under cold transient operation with a pre-turbo aftertreatment exhaust manifold configuration

Diesel particulate filters are the most useful technology to reduce particulate matter from the exhaust gas of internal combustion engines. Although these devices have suffered an intense development in terms of the management of filtration and regeneration, the effect of the system location on the engine performance is still a key issue that needs to be properly addressed. The present work is focused on a computational study regarding the effects of a pre-turbo aftertreatment placement under full and partial load transient operation at constant engine speed and low wall temperature along the exhaust line. The aim of the paper is to provide a comprehensive understanding of the engine response to define the guidelines of a control strategy that is able to get the standards of engine driveability during sudden accelerations under restraining thermal transient conditions governed by the aftertreatment thermal inertia. The proposed strategy overcomes the lack of temperature at the inlet of the turbine caused by the thermal transient by means of the boost and EGR control. It leads to a proper management of the power in the exhaust gas for the expansion in the turbine.This work was partially supported by the Universitat Politecnica de Valencia [grant number INNOVA 2011-3182].Bermúdez, V.; Serrano, J.; Piqueras, P.; García Afonso, Ó. (2013). Analysis of heavy-duty turbocharged diesel engine response under cold transient operation with a pre-turbo aftertreatment exhaust manifold configuration. International Journal of Engine Research. 14(4):341-353. https://doi.org/10.1177/1468087412457670S341353144Payri, F., Pastor, J. V., Pastor, J. M., & Juliá, J. E. (2006). Diesel Spray Analysis by Means of Planar Laser-Induced Exciplex Fluorescence. International Journal of Engine Research, 7(1), 77-89. doi:10.1243/146808705x27723Torregrosa, A. J., Broatch, A., Margot, X., Marant, V., & Beauge, Y. (2004). Combustion chamber resonances in direct injection automotive diesel engines: A numerical approach. International Journal of Engine Research, 5(1), 83-91. doi:10.1243/146808704772914264Serrano, J. R., Arnau, F. J., Dolz, V., & Piqueras, P. (2009). Methodology for characterisation and simulation of turbocharged diesel engines combustion during transient operation. Part 1: Data acquisition and post-processing. Applied Thermal Engineering, 29(1), 142-149. doi:10.1016/j.applthermaleng.2008.02.011Serrano, J. R., Climent, H., Guardiola, C., & Piqueras, P. (2009). Methodology for characterisation and simulation of turbocharged diesel engines combustion during transient operation. Part 2: Phenomenological combustion simulation. Applied Thermal Engineering, 29(1), 150-158. doi:10.1016/j.applthermaleng.2008.02.010Rakopoulos, C. D., Dimaratos, A. M., Giakoumis, E. G., & Rakopoulos, D. C. (2009). Evaluation of the effect of engine, load and turbocharger parameters on transient emissions of diesel engine. Energy Conversion and Management, 50(9), 2381-2393. doi:10.1016/j.enconman.2009.05.022Rakopoulos, C. D., Dimaratos, A. M., Giakoumis, E. G., & Rakopoulos, D. C. (2010). Investigating the emissions during acceleration of a turbocharged diesel engine operating with bio-diesel or n-butanol diesel fuel blends. Energy, 35(12), 5173-5184. doi:10.1016/j.energy.2010.07.049Ishikawa, N. (2012). A study on emissions improvement of a diesel engine equipped with a mechanical supercharger. International Journal of Engine Research, 13(2), 99-107. doi:10.1177/1468087411434885Desantes, J. M., Luján, J. M., Pla, B., & Soler, J. A. (2012). On the combination of high-pressure and low-pressure exhaust gas recirculation loops for improved fuel economy and reduced emissions in high-speed direct-injection engines. International Journal of Engine Research, 14(1), 3-11. doi:10.1177/1468087412437623Johnson, T. V. (2009). Review of diesel emissions and control. International Journal of Engine Research, 10(5), 275-285. doi:10.1243/14680874jer04009Tourlonias, P., & Koltsakis, G. (2011). Model-based comparative study of Euro 6 diesel aftertreatment concepts, focusing on fuel consumption. International Journal of Engine Research, 12(3), 238-251. doi:10.1177/1468087411405104Bermúdez, V., Serrano, J. R., Piqueras, P., & García-Afonso, O. (2011). Assessment by means of gas dynamic modelling of a pre-turbo diesel particulate filter configuration in a turbocharged HSDI diesel engine under full-load transient operation. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 225(9), 1134-1155. doi:10.1177/0954407011402278Payri, F., Serrano, J. R., Piqueras, P., & García-Afonso, O. (2011). Performance Analysis of a Turbocharged Heavy Duty Diesel Engine with a Pre-turbo Diesel Particulate Filter Configuration. SAE International Journal of Engines, 4(2), 2559-2575. doi:10.4271/2011-37-0004Galindo, J., Serrano, J. R., Arnau, F. J., & Piqueras, P. (2009). Description of a Semi-Independent Time Discretization Methodology for a One-Dimensional Gas Dynamics Model. Journal of Engineering for Gas Turbines and Power, 131(3). doi:10.1115/1.2983015Torregrosa, A. J., Serrano, J. R., Arnau, F. J., & Piqueras, P. (2011). A fluid dynamic model for unsteady compressible flow in wall-flow diesel particulate filters. Energy, 36(1), 671-684. doi:10.1016/j.energy.2010.09.047Desantes, J. M., Serrano, J. R., Arnau, F. J., & Piqueras, P. (2012). Derivation of the method of characteristics for the fluid dynamic solution of flow advection along porous wall channels. Applied Mathematical Modelling, 36(7), 3134-3152. doi:10.1016/j.apm.2011.09.090Galindo, J., Serrano, J. R., Piqueras, P., & García-Afonso, Ó. (2012). Heat transfer modelling in honeycomb wall-flow diesel particulate filters. Energy, 43(1), 201-213. doi:10.1016/j.energy.2012.04.04

Experimental and computational approach to the transient behaviour of wall-flow diesel particulate filters

[EN] The implementation of tight vehicle emission standards has forced manufactures to use aftertreatment systems extensively. In addition to pollutant emissions abatement, these devices have a noticeable impact on the wave pattern. This fact affects the muffler design criteria. All monolithic aftertreatment devices produces a damping effect because of the honeycomb structure and the narrow channels. However, this response is more marked in wall-flow diesel particulate filters (DPF) because of the alternatively plugged ends and the dissipative properties of the porous substrate. The main goal of this paper is to assess the transient fluid-dynamic behaviour of wall-flow DPFs using experimental and modelling techniques. The experimental data were gathered in clean and loaded conditions. The DPF was subjected to a variety of pressure excitations to characterise its transient behaviour in the time and frequency domains. Afterwards, the DPF response was evaluated under engine-like operating conditions in an unsteady flow gas stand. Once the main characteristics of the response were known, a non-linear gas-dynamics model was proposed for analysis and prediction. The model accounts for space and time gradients, combining the thermo-and fluid-dynamic solution with a model based on a packed bed of spherical particles that defines the meso-structure of the loaded substrate. (C) 2016 Elsevier Ltd. All rights reserved.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad through Grant No. TRA2013-40853-R.Torregrosa, AJ.; Serrano, J.; Piqueras, P.; García Afonso, Ó. (2017). Experimental and computational approach to the transient behaviour of wall-flow diesel particulate filters. Energy. 119:887-900. https://doi.org/10.1016/j.energy.2016.11.051S88790011

Assessment by means of gas dynamic modelling of a pre-turbo diesel particulate filter configuration in a turbocharged HSDI diesel engine under full-load transient operation

Diesel particulate filters (DPF) are becoming a standard technology in diesel engines because of the need for compliance with forthcoming regulations regarding soot emissions. When a great degree of maturity in management of filtration and regeneration has been attained, the influence of the DPF placement on the engine performance emerges as a key issue to be properly addressed. The novelty of this work leads to the study of an unusual location of an aftertreatment device in the architecture of the turbocharged diesel engine exhaust line. The problem of the pre-turbo DPF placement is tackled comparing the engine response under full-load transient operation as opposed to the traditional DPF location downstream of the turbine. The study has been performed on the basis of a gas dynamic simulation of the engine, which has been validated with experimental data obtained under steady-state and transient conditions. The DPF response has been simulated with a model able to deal with the characteristic highly pulsating flow upstream of the turbine. Several levels of DPF soot loading have been considered to represent fully the most exigent conditions in terms of performance requirements. As a result, the main physical phenomena controlling the engine and DPF response and interaction have been identified. Placing the DPF upstream of the turbine will lead to a number of important advantages, owing to the continuous regeneration mode at which the DPF will operate, the lower pressure drop in the DPF, and the thermal energy storage in the DPF, which is very useful to mitigate 'turbocharger lag' during engine transient operation. These three effects have been evidenced with calculations performed using the validated model and the results have been fully analysed and discussed.This work has been partially supported by the Spanish MCI grant DPI2010-20891-C02-02.Bermúdez, V.; Serrano Cruz, JR.; Piqueras, P.; García Afonso, Ó. (2011). Assessment by means of gas dynamic modelling of a pre-turbo diesel particulate filter configuration in a turbocharged HSDI diesel engine under full-load transient operation. PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AU. 225(9):1134-1155. https://doi.org/10.1177/0954407011402278S11341155225

Design and implementation of synchronization and AGC for OFDM-based WLAN receivers

An efficient implementation of several tasks at the receiver becomes crucial in OFDM-based high-speed WLAN systems, such as automatic gain control, time and frequency synchronization and offset tracking. This paper deals with fixed point constraints and accuracy requirements for implementation of those algorithms. Also, a complete set of thresholds for the practical implementation of time and frequency synchronization sub-blocks is obtained. Moreover, a technique to mitigate the remaining frequency offset after coarse acquisition is proposed, yielding a good trade-off between performance and complexity. Finally, we propose the implementation of a simple and effective automatic gain control procedure.This work has been partially funded by Spanish government with project TIC 2002-03498 (ORISE), Telefonica I+D by the contract nº 25756, and the Chamber of Madrid Community and European Social Fund by a grant to the first author

Experimental investigation on RCCI heat transfer in a light-duty diesel engine with different fuels: Comparison versus conventional diesel combustion

[EN] Reactivity controlled compression ignition (RCCI) combustion has demonstrated to be able to avoid the NOx-soot trade-off appearing during conventional diesel combustion (CDC), with similar or better thermal efficiency than CDC under a wide range of operating conditions. The high thermal efficiency of RCCI is explained by the combination of a short-duration and well-phased combustion process, which maximizes the fuel-to-work conversion efficiency, together with relatively low combustion temperatures, which increases the specific heat ratio during expansion and reduces thermal gradients for heat transfer losses. The objective of this work is to study the RCCI heat transfer characteristics and compare them to those of the CDC regime. To do this, a single-cylinder light-duty research engine instrumented with 25K-type thermocouples distributed among the cylinder head and cylinder liner is used. First, the influence of some engine settings on the RCCI heat transfer phenomenon is explored by means of parametric sweeps. Later, the RCCI heat transfer characteristics are compared for two different low reactivity fuels (LRF), gasoline and E85. Finally, the heat transfer characteristics of RCCI and CDC combustion regimes are compared at some representative operating points in matched load conditions. The results show that both LRF tested are suitable to be used in RCCI giving similar results in terms of energy usage. Moreover, the ability of RCCI combustion in exploiting the fuel energy to extract useful work is demonstrated, reducing by 13% the heat transfer versus CDC.The authors gratefully acknowledge General Motors Global Research & Development for providing the engine used in this investigation. The authors also acknowledge FEDER and Spanish Ministerio de Economia y Competitividad for partially supporting this research through TRANCO project (TRA2017-87694-R).Olmeda, P.; García Martínez, A.; Monsalve-Serrano, J.; Lago-Sari, R. (2018). Experimental investigation on RCCI heat transfer in a light-duty diesel engine with different fuels: Comparison versus conventional diesel combustion. Applied Thermal Engineering. 144:424-436. https://doi.org/10.1016/j.applthermaleng.2018.08.082S42443614

Two Neolithic structures at the archaeological site of Casa Garrido Nord II (Moixent, Valencia)

Es presenten les restes de cronologia neolítica documentades a les obres de canalització de gas a la vall de Montesa. Concretament, dues sitges del Neolític II de la seqüència regional, aparegudes al jaciment de Casa Garrido Nord, al terme municipal de Moixent. Encara que els materials són poc significatius, es tracta de les primeres estructures de cronologia neolítica, de les quals tenim constància, en què s’ha realitzat una excavació arqueològica sistemàtica a la comarca de la Costera. Paraules clau: Casa Garrido Nord II. Sitja. Neolític II. La Costera. Assentaments en pla.Es presenten les restes de cronologia neolítica documentades a les obres de canalització de gas a la vall de Montesa. Concretament, dues sitges del Neolític II de la seqüència regional, aparegudes al jaciment de Casa Garrido Nord, al terme municipal de Moixent. Encara que els materials són poc significatius, es tracta de les primeres estructures de cronologia neolítica, de les quals tenim constància, en què s’ha realitzat una excavació arqueològica sistemàtica a la comarca de la Costera. Paraules clau: Casa Garrido Nord II. Sitja. Neolític II. La Costera. Assentaments en pla.Herewith we submit the remains of Neolithic chronology found at the gas piping works performed at the Valley of Montesa (Valencia). They are specifically two Neolithic II underground storage places of a regional sequence, which appeared at the Casa Garrido Nord archaeological site, within the Moixent municipal borough (in the province of Valencia). Although the materials are not very meaningful, they represent the first structures of Neolithic chronology known to us, and therefore we have carried out a systematic archaeological excavation in the area of La Costera (Valencia). Key words: Casa Garrido Nord II. Silo. Neolithic II. La Costera. Settlements on flat lands

Development and validation of a radial variable geometry turbine model for transient pulsating flow applications

This paper presents the development and validation of a one-dimensional radial turbine model able to be used in automotive turbocharger simulations. The model has been validated using results from a numerical 3D CFD simulation of stationary and pulsating flow in a variable geometry radial turbine. As the CFD analysis showed, the main non-quasi-steady behavior of the turbine is due to the volute geometry, so special care was taken in order to properly model it while maintaining low computational costs. The flow in the volute has been decomposed in its radial and azimuthal direction. The azimuthal flow corresponds to the flow moving along the volute, while the radial flow is computed by coupling its flow with a stator model. Although the stator caused fewer accumulation effects than the volute, a small accumulation model has been used for it, which also allows to compute the evolution of the flow inside the turbine with lower costs. The flow in the moving rotor can be considered quasi-steady, so a zero-dimensional model for the rotor has been developed. Several losses models where implemented for both the stator and the rotor. The results show good agreement with the CFD computations. 2014 Elsevier Ltd. All rights reserved.The authors are indebted to the Spanish Ministerio de Economia y Competitividad through Project TRA 2010-16205.Galindo, J.; Tiseira Izaguirre, AO.; Fajardo, P.; García-Cuevas González, LM. (2014). Development and validation of a radial variable geometry turbine model for transient pulsating flow applications. Energy Conversion and Management. 85:190-203. https://doi.org/10.1016/j.enconman.2014.05.072S1902038

Compatison of S-SI, A-SI and CDTE technologies wording at the same conditions, after the first year of electricity production

Grid connected solar plants are a good opportunity for their use for research as a secondary objective. In countries were feed-in tariffs are still active, it is possible to include in the design of the solar plant elements for its use for research. In the case of the solar plant presented here both objectives are covered. The solar plant of this work is formed by PV modules of three different technologies: Multicrystalline, amorphous and CdTe. In one part of the solar plant, the three technologies are working at the same conditions, not only ambient conditions but also similar voltage and current input to the inverters. Both the commercial and the experimental parts of the solar plant have their own independent inverters with their meters but are finally connected to the same meter to inject. In this work we analyse the results for the first year of operation of the experimental solar plant. Productions of three different technologies in exactly the same conditions are compared and presented. According to the results, all the three technologies have conversion efficiencies dropping when the temperature increases. Amorphous module experiences the lesser reduction, whereas the multicrystalline module suffers the most