25 research outputs found

    Application of a zero-dimensional model to assess the effect of swirl on indicated efficiency

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    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/10.1177/1468087418779726[EN] Increasing internal combustion engine efficiency continues being one of the main goals of engine research. To achieve this objective, different engine strategies are being developed continuously. However, the assessment of these techniques is not straightforward due to their influence on various intermediate phenomena inherent to the combustion process, which finally result in indicated efficiency trade-offs. During this work, a new methodology to assess these intermediate imperfections on gross indicated efficiency using a zero-dimensional model is developed. This methodology is applied to a swirl parametric study, where it has been concluded that the heat transfer and the rate of heat release are the single relevant changing phenomena. Results show that heat transfer always increases with swirl affecting negatively gross indicated efficiency (around -0.5%), while the impact of combustion velocity is not monotonous. It is enhanced up to a certain swirl ratio (it changes with engine speed) at low engine speed (resulting in an increment of +1.7% in gross indicated efficiency), but it is slowed down at high engine speed with the consequent worsening of gross indicated efficiency (-0.8%).The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was partially funded by GM Global R&D and the Government of Spain through Project TRA2013-41348-R. D. B.-C. was partially supported through contract FPI-S2-2016-1356 of the Programa de Apoyo para la Investigacion y Desarrollo (PAID) of Universitat Politecnica de Valencia.Broatch, A.; Martín, J.; García Martínez, A.; Blanco-Cavero, D.; Warey, A.; Domenech, V. (2019). Application of a zero-dimensional model to assess the effect of swirl on indicated efficiency. International Journal of Engine Research. 20(8-9):837-848. https://doi.org/10.1177/1468087418779726S837848208-9Mohan, B., Yang, W., & Chou, S. kiang. (2013). Fuel injection strategies for performance improvement and emissions reduction in compression ignition engines—A review. Renewable and Sustainable Energy Reviews, 28, 664-676. doi:10.1016/j.rser.2013.08.051Agarwal, A. K., Srivastava, D. K., Dhar, A., Maurya, R. K., Shukla, P. C., & Singh, A. P. (2013). Effect of fuel injection timing and pressure on combustion, emissions and performance characteristics of a single cylinder diesel engine. Fuel, 111, 374-383. doi:10.1016/j.fuel.2013.03.016Hiwase, S. D., Moorthy, S., Prasad, H., Dumpa, M., & Metkar, R. M. (2013). Multidimensional Modeling of Direct Injection Diesel Engine with Split Multiple Stage Fuel Injections. Procedia Engineering, 51, 670-675. doi:10.1016/j.proeng.2013.01.095Canakci, M. (2012). Combustion characteristics of a DI-HCCI gasoline engine running at different boost pressures. Fuel, 96, 546-555. doi:10.1016/j.fuel.2012.01.042Pan, M., Shu, G., Wei, H., Zhu, T., Liang, Y., & Liu, C. (2014). Effects of EGR, compression ratio and boost pressure on cyclic variation of PFI gasoline engine at WOT operation. Applied Thermal Engineering, 64(1-2), 491-498. doi:10.1016/j.applthermaleng.2013.11.013Fontana, G., & Galloni, E. (2010). Experimental analysis of a spark-ignition engine using exhaust gas recycle at WOT operation. Applied Energy, 87(7), 2187-2193. doi:10.1016/j.apenergy.2009.11.022Verhelst, S., Demuynck, J., Sierens, R., & Huyskens, P. (2010). Impact of variable valve timing on power, emissions and backfire of a bi-fuel hydrogen/gasoline engine. International Journal of Hydrogen Energy, 35(9), 4399-4408. doi:10.1016/j.ijhydene.2010.02.022Fontana, G., & Galloni, E. (2009). Variable valve timing for fuel economy improvement in a small spark-ignition engine. Applied Energy, 86(1), 96-105. doi:10.1016/j.apenergy.2008.04.009Perini, F., Miles, P. C., & Reitz, R. D. (2014). A comprehensive modeling study of in-cylinder fluid flows in a high-swirl, light-duty optical diesel engine. Computers & Fluids, 105, 113-124. doi:10.1016/j.compfluid.2014.09.011Wei, S., Wang, F., Leng, X., Liu, X., & Ji, K. (2013). Numerical analysis on the effect of swirl ratios on swirl chamber combustion system of DI diesel engines. Energy Conversion and Management, 75, 184-190. doi:10.1016/j.enconman.2013.05.044Olmeda, P., Martín, J., Blanco-Cavero, D., Warey, A., & Domenech, V. (2017). Effect of in-cylinder swirl on engine efficiency and heat rejection in a light-duty diesel engine. International Journal of Engine Research, 18(1-2), 81-92. doi:10.1177/1468087417693078Sandalcı, T., & Karagöz, Y. (2014). Experimental investigation of the combustion characteristics, emissions and performance of hydrogen port fuel injection in a diesel engine. International Journal of Hydrogen Energy, 39(32), 18480-18489. doi:10.1016/j.ijhydene.2014.09.044Sorate, K. A., & Bhale, P. V. (2015). Biodiesel properties and automotive system compatibility issues. Renewable and Sustainable Energy Reviews, 41, 777-798. doi:10.1016/j.rser.2014.08.079Ryan, T. W., & Callahan, T. J. (1996). Homogeneous Charge Compression Ignition of Diesel Fuel. SAE Technical Paper Series. doi:10.4271/961160Kiplimo, R., Tomita, E., Kawahara, N., & Yokobe, S. (2012). Effects of spray impingement, injection parameters, and EGR on the combustion and emission characteristics of a PCCI diesel engine. Applied Thermal Engineering, 37, 165-175. doi:10.1016/j.applthermaleng.2011.11.011Ramesh, A. K., Shaver, G. M., Allen, C. M., Nayyar, S., Gosala, D. B., Caicedo Parra, D., … Nielsen, D. (2017). Utilizing low airflow strategies, including cylinder deactivation, to improve fuel efficiency and aftertreatment thermal management. International Journal of Engine Research, 18(10), 1005-1016. doi:10.1177/1468087417695897Shelby, M. H., Leone, T. G., Byrd, K. D., & Wong, F. K. (2017). Fuel Economy Potential of Variable Compression Ratio for Light Duty Vehicles. SAE International Journal of Engines, 10(3), 817-831. doi:10.4271/2017-01-0639Yamasaki, Y., Ikemura, R., & Kaneko, S. (2017). Model-based control of diesel engines with multiple fuel injections. International Journal of Engine Research, 19(2), 257-265. doi:10.1177/1468087417747738Weberbauer, F., Rauscher, M., Kulzer, A., Knopf, M., & Bargende, M. (2005). Generally applicate split of losses for new combustion concepts. MTZ worldwide, 66(2), 17-19. doi:10.1007/bf03227736Payri, F., Olmeda, P., Guardiola, C., & Martín, J. (2011). Adaptive determination of cut-off frequencies for filtering the in-cylinder pressure in diesel engines combustion analysis. Applied Thermal Engineering, 31(14-15), 2869-2876. doi:10.1016/j.applthermaleng.2011.05.012Lapuerta, M., Armas, O., & Hernández, J. J. (1999). Diagnosis of DI Diesel combustion from in-cylinder pressure signal by estimation of mean thermodynamic properties of the gas. Applied Thermal Engineering, 19(5), 513-529. doi:10.1016/s1359-4311(98)00075-1Payri, F., Molina, S., Martín, J., & Armas, O. (2006). Influence of measurement errors and estimated parameters on combustion diagnosis. Applied Thermal Engineering, 26(2-3), 226-236. doi:10.1016/j.applthermaleng.2005.05.006Torregrosa, A. J., Olmeda, P., Martín, J., & Romero, C. (2011). A Tool for Predicting the Thermal Performance of a Diesel Engine. Heat Transfer Engineering, 32(10), 891-904. doi:10.1080/01457632.2011.54863

    Acid Catalysis with Alkane/Water Microdroplets in Ionic Liquids

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    Ionic liquids are composed of an organic cation and a highly delocalized perfluorinated anion, which remain tight to each other and neutral across the extended liquid framework. Here we show that n-alkanes in millimolar amounts enable a sufficient ion charge separation to release the innate acidity of the ionic liquid and catalyze the industrially relevant alkylation of phenol, after generating homogeneous, self-stabilized, and surfactant-free microdroplets (1–5 μm). This extremely mild and simple protocol circumvents any external additive or potential ionic liquid degradation and can be extended to water, which spontaneously generates microdroplets (ca. 3 μm) and catalyzes Brönsted rather than Lewis acid reactions. These results open new avenues not only in the use of ionic liquids as acid catalysts/solvents but also in the preparation of surfactant-free, well-defined ionic liquid microemulsions.PNICTOCHEM 804110 (G.A.)PID2019-111742-GA-I00CIDEGENT/2018/00

    Aspectos didácticos en la formación de traductores para el ámbito económico e institucional

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    Este trabajo tiene que ver con uno de los objetivos perseguidos, en el marco del Proyecto Redes de Investigación en Docencia Universitaria del Instituto de Ciencias de la Educación de la Universidad de Alicante, por la red 2986 "Planificación docente y uso de COMENEGO (Corpus Multilingüe de Economía y Negocios) en la enseñanza de la traducción económica e institucional", relacionado, en concreto, con las metodologías docentes en traducción económica. Se presenta una síntesis de una serie de comunicaciones que se pronunciaron en el Congreso Internacional de Traducción Económica, Comercial, Financiera e Institucional, celebrado en la Facultad de Filosofía y Letras de la Universidad de Alicante a finales de mayo de 2014

    An investigation of partially premixed compression ignition combustion using gasoline and spark assistance

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    Nowadays the automotive scientific community and companies are focusing part of their efforts on the investigation of new combustion modes in Compression Ignition (Cl) engines, mainly based on the use of locally lean air fuel mixtures. This characteristic, combined with exhaust gas recirculation, provides low combustion temperatures that reduce pollutant formation. However these combustion concepts have some shortcomings, related to combustion phasing control and combustion stability under the light load engine operating range which must be overcome. The aim of this work is focused on the study of the integration of phasing and cycle-to-cycle repeatability control by means of an ignition spark plug system in a CI engine working under partially premixed charge (PPC) in order to overcome the lack of combustion stability in light load conditions when very low fuel reactivity is used. To achieve this objective, experimental tests have been carried out in a single cylinder optical engine combining broadband luminosity images with cylinder pressure derived heat release rate analysis. Research results reveals the spark assistance as a proper methodology to provide temporal and spatial control over the combustion process solving the lack of cycle to cycle control on the highly premixed compression ignition modes overall in light loads with high octane number (ON) fuels. Additionally, different stages have been identified in the combustion mode. The process starts with the spark discharge, which produces a flame kernel around the spark plug that later evolves to a premixed flame front. This premixed flame front heats unburned mixture and progresses into an auto-ignition combustion that burns out the rest of the charge with higher light intensity and finally an extinction of combustion process. Finally, the effect of injected fuel mass on the combustion mode has been also tested. An increase in the injected fuel mass has a positive effect on the assistance of the spark in the combustion process for both, combustion stability and cycle to cycle control. (C) 2013 Elsevier Ltd. All rights reserved.The authors would like to thank General Motors for supporting this research.Benajes Calvo, JV.; García Martínez, A.; Doménech Llopis, V.; Durret, R. (2013). An investigation of partially premixed compression ignition combustion using gasoline and spark assistance. Applied Thermal Engineering. 52(2):468-477. doi:10.1016/j.applthermaleng.2012.12.025S46847752

    Towards User-Centric Operation in 5G Networks

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    © 2016 Monserrat et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.There are three pillars that characterize the new 5G revolution, namely, the use of heterogeneous wireless access technologies conforming an ultra-dense network, the software-driven flexibility of this network, and the simplified and user-centric operation and management of the system. This next-generation network operation and management shall be based on the usage of Big Data Analytics techniques to monitor the end-user quality of experience through direct measures of the network. This paper describes the Astellia approach towards this network revolution and presents some results on the performance of quality estimation techniques in current cellular networks. Thanks to the use of this approach, operators may fill the gap of knowledge between network key performance indicators and user experience. This way, they can operate in a proactive manner and have actual measurements of the users' experience, which leads to a fairer judgement of the users' complaints.The authors would like to thank the funding received from the Ministerio de Industria, Energia y Turismo TSI-100102-2013-106 funds.Monserrat Del Río, JF.; Alepuz Benaches, I.; Cabrejas Peñuelas, J.; Osa Ginés, V.; López Bayo, J.; García-Zarza, R.; Domenech-Benlloch, MJ.... (2016). Towards User-Centric Operation in 5G Networks. EURASIP Journal on Wireless Communications and Networking. 2016(6):1-7. https://doi.org/10.1186/s13638-015-0506-zS1720166J Monserrat et al., Rethinking the mobile and wireless network architecture: the METIS research into 5G, in European Conference on Networks and Communications (EuCNC), 2014, pp. 1–55G-PPP, The 5G Infrastructure Public Private Partnership: the next generation of communication networks and services, 2015. Available at http://5g-ppp.eu/wp-content/uploads/2015/02/5G-Vision-Brochure-v1.pdfJF Monserrat, M Fallgren (eds.), Report on simulation results and evaluations, 2015. ICT-317669 METIS Deliverable 6.5Z Yingxiao, Z Ying Jun, User-centric virtual cell design for Cloud Radio Access Networks, in IEEE Signal Processing Advances in Wireless Communications (SPAWC), 2014, pp. 249–253JF Monserrat, G Mange, V Braun, H Tullberg, G Zimmermann, Ö Bulakci, METIS research advances towards the 5G mobile and wireless system definition. EURASIP. J. Wirel. Commun. Netw. 2015, 53 (2015)F Boccardi, RW Heath, A Lozano, TL Marzetta, P Popovski, Five disruptive technology directions for 5G. IEEE. Commun. Mag. 52(2), 74–80 (2014)P Agyapong, M Iwamura, D Staehle, W Kiess, A Benjebbour, Design considerations for a 5G network architecture. IEEE. Commun. Mag. 52(11), 65–75 (2014)Nokia Siemens Networks, Acquisition and retention white paper, 2013. http://networks.nokia.com/sites/default/files/document/acquisition___retention_white_paper.pdfDZ Yazti, S Krishnaswamy, Mobile big data analytics: research, practice, and opportunities, in IEEE 15th International Conference on Mobile Data Management (MDM), 2014R Kreher, UMTS performance measurement: a practical guide to KPIs for the UTRAN environment (Wiley, Chichester, 2006)S Mehrotra, On the implementation of a primal-dual interior point method. SIAM. J. Optim. 2, 575–601 (1992)V Osa, J Matamales, J Monserrat, J Lopez, Localization in wireless networks: the potential of triangulation techniques. Wirel. Pers. Commun. 68(4), 1525–1538 (2013

    Impact of interstitial lung disease on the survival of systemic sclerosis with pulmonary arterial hypertension

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    To assess severity markers and outcomes of patients with systemic sclerosis (SSc) with or without pulmonary arterial hypertension (PAH-SSc/non-PAH-SSc), and the impact of interstitial lung disease (ILD) on PAH-SSc. Non-PAH-SSc patients from the Spanish SSc registry and PAH-SSc patients from the Spanish PAH registry were included. A total of 364 PAH-SSc and 1589 non-PAH-SSc patients were included. PAH-SSc patients had worse NYHA-functional class (NYHA-FC), worse forced vital capacity (FVC) (81.2 ± 20.6% vs 93.6 ± 20.6%, P < 0.001), worse tricuspid annular plane systolic excursion (TAPSE) (17.4 ± 5.2 mm vs 19.9 ± 6.7 mm, P < 0.001), higher incidence of pericardial effusion (30% vs 5.2%, P < 0.001) and similar prevalence of ILD (41.8% vs. 44.9%). In individuals with PAH-SSc, ILD was associated with worse hemodynamics and pulmonary function tests (PFT). Up-front combination therapy was used in 59.8% and 61.7% of patients with and without ILD, respectively. Five-year transplant-free survival rate was 41.1% in PAH-SSc patients and 93.9% in non-PAH-SSc patients (P < 0.001). Global survival of PAH-SSc patients was not affected by ILD regardless its severity. The multivariate survival analysis in PAH-SSc patients confirmed age at diagnosis, worse NYHA-FC, increased PVR, reduced DLCO, and lower management with up-front combination therapy as major risk factors. In conclusion, in PAH-SSc cohort risk of death was greatly increased by clinical, PFT, and hemodynamic factors, whereas it was decreased by up-front combination therapy. Concomitant ILD worsened hemodynamics and PFT in PAH-SSc but not survival regardless of FVC impairment

    Impact of interstitial lung disease on the survival of systemic sclerosis with pulmonary arterial hypertension

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    To assess severity markers and outcomes of patients with systemic sclerosis (SSc) with or without pulmonary arterial hypertension (PAH-SSc/non-PAH-SSc), and the impact of interstitial lung disease (ILD) on PAH-SSc. Non-PAH-SSc patients from the Spanish SSc registry and PAH-SSc patients from the Spanish PAH registry were included. A total of 364 PAH-SSc and 1589 non-PAH-SSc patients were included. PAH-SSc patients had worse NYHA-functional class (NYHA-FC), worse forced vital capacity (FVC) (81.2 +/- 20.6% vs 93.6 +/- 20.6%, P < 0.001), worse tricuspid annular plane systolic excursion (TAPSE) (17.4 +/- 5.2 mm vs 19.9 +/- 6.7 mm, P < 0.001), higher incidence of pericardial effusion (30% vs 5.2%, P < 0.001) and similar prevalence of ILD (41.8% vs. 44.9%). In individuals with PAH-SSc, ILD was associated with worse hemodynamics and pulmonary function tests (PFT). Up-front combination therapy was used in 59.8% and 61.7% of patients with and without ILD, respectively. Five-year transplant-free survival rate was 41.1% in PAH-SSc patients and 93.9% in non-PAH-SSc patients (P < 0.001). Global survival of PAH-SSc patients was not affected by ILD regardless its severity. The multivariate survival analysis in PAH-SSc patients confirmed age at diagnosis, worse NYHA-FC, increased PVR, reduced DLCO, and lower management with up-front combination therapy as major risk factors. In conclusion, in PAH-SSc cohort risk of death was greatly increased by clinical, PFT, and hemodynamic factors, whereas it was decreased by up-front combination therapy. Concomitant ILD worsened hemodynamics and PFT in PAH-SSc but not survival regardless of FVC impairment

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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