Hydrodynamic model, simulation and linear control for Cormoran-AUV

This work shows the mathematic calculation for obtention of a Cormoran-AUV hydrodynamic model, it also shows a linar control design for a path tracking. The model has been simplified to three degrees of freedom of movement and the whole system has been simulated using Matlab Simulink Software. The system has been linearizated for different velocities to design a linear control for each one of them. However, all resulting systems can be controlled by a unique linear control due characteristics of the vehicle. The designed control is a PD controller, which avoids the position error since the pole of the vehicle model is at the origin. Different paths have been simulated using this control and their results have been comparated in both rising time as establish time.Postprint (published version

Experimental study of influence of Liquefied Petroleum Gas addition in Hydrotreated Vegetable Oil fuel on ignition delay, flame lift off length and soot emission under diesel-like conditions

[EN] The fundamental behaviour on ignition and combustion characteristics of blends of Hydrotreated Vegetable Oil and Liquid Petroleum Gas was investigated in a constant high pressure, high temperature combustion chamber, using a prototype lab-scale injection system adapted from a conventional common-rail system to conduct the injection events, ensuring that fuel was liquid at any point of the injection system and avoiding the formation of fuel vapour bubbles that could alter the injected fuel behaviour. The ignition delay, flame lift-off length and the soot formation were studied by means of high-speed imaging techniques, for different operating conditions. The aim of the work is to characterize the effect of Hydrotreated Vegetable Oil-Liquid Petroleum Gas blend ratios on the previously mentioned parameters. Experimental results show that the behaviour of the fuel blends follow the expected trends of conventional diesel type fuels when varying ambient temperature, density and injection pressure. Hydrotreated Vegetable Oil, being the highest reactivity fraction, controls auto ignition of the blend. However, Liquid Petroleum Gas acts as combustion inhibitor increasing both ignition delay and lift-off length as its ratio in the blend increases. As a consequence, the differences observed in terms of flame radiation suggest that increasing Liquid Petroleum Gas fraction reduces soot formation as it promotes a higher air/mixture.The authors acknowledge that this research work has been partly funded by the Government of Spain and FEDER under TRANCO project (TRA2017-87694-R) and by Universitat Politècnica de València through the Programa de Ayudas de Investigación y Desarrollo (PAID01-18) program.Pastor, JV.; García Martínez, A.; Mico Reche, C.; Garcia-Carrero, AA. (2020). Experimental study of influence of Liquefied Petroleum Gas addition in Hydrotreated Vegetable Oil fuel on ignition delay, flame lift off length and soot emission under diesel-like conditions. Fuel. 260:1-11. https://doi.org/10.1016/j.fuel.2019.116377S111260Roadmap to a Single European Transport Area – Towards a competitive and resource efficient. Transport System, White Paper COM(2011):144–final.Sheehan J, Camobreco V, Duffield J, Graboski M, Shapouri H. An Overview of Biodiesel and Petroleum Diesel Life Cycles, NREL/TP-580-24772.Hasan, M. M., & Rahman, M. M. (2017). Performance and emission characteristics of biodiesel–diesel blend and environmental and economic impacts of biodiesel production: A review. Renewable and Sustainable Energy Reviews, 74, 938-948. doi:10.1016/j.rser.2017.03.045Bhardwaj, O. P., Kolbeck, A. F., Kkoerfer, T., & Honkanen, M. (2013). Potential of Hydrogenated Vegetable Oil (HVO) in Future High Efficiency Combustion System. SAE International Journal of Fuels and Lubricants, 6(1), 157-169. doi:10.4271/2013-01-1677Chakraborty, A., Roy, S., & Banerjee, R. (2016). An experimental based ANN approach in mapping performance-emission characteristics of a diesel engine operating in dual-fuel mode with LPG. Journal of Natural Gas Science and Engineering, 28, 15-30. doi:10.1016/j.jngse.2015.11.024Aatola, H., Larmi, M., Sarjovaara, T., & Mikkonen, S. (2008). Hydrotreated Vegetable Oil (HVO) as a Renewable Diesel Fuel: Trade-off between NOx, Particulate Emission, and Fuel Consumption of a Heavy Duty Engine. SAE International Journal of Engines, 1(1), 1251-1262. doi:10.4271/2008-01-2500Neste Oil, Hydrotreated vegetable oil, premium renewable biofuel for diesel engines, 2014.Singh, D., Subramanian, K. A., Bal, R., Singh, S. P., & Badola, R. (2018). Combustion and emission characteristics of a light duty diesel engine fueled with hydro-processed renewable diesel. Energy, 154, 498-507. doi:10.1016/j.energy.2018.04.139Zhong, W., Pachiannan, T., He, Z., Xuan, T., & Wang, Q. (2019). Experimental study of ignition, lift-off length and emission characteristics of diesel/hydrogenated catalytic biodiesel blends. Applied Energy, 235, 641-652. doi:10.1016/j.apenergy.2018.10.115Tira, H. S., Herreros, J. M., Tsolakis, A., & Wyszynski, M. L. (2014). Influence of the addition of LPG-reformate and H2 on an engine dually fuelled with LPG–diesel, –RME and –GTL Fuels. Fuel, 118, 73-82. doi:10.1016/j.fuel.2013.10.065Goto, S., Lee, D., Shakal, J., Harayama, N., Honjyo, F., & Ueno, H. (1999). Performance and Emissions of an LPG Lean-Burn Engine for Heavy Duty Vehicles. SAE Technical Paper Series. doi:10.4271/1999-01-1513Musthafa, M. M. (2019). A comparative study on coated and uncoated diesel engine performance and emissions running on dual fuel (LPG – biodiesel) with and without additive. Industrial Crops and Products, 128, 194-198. doi:10.1016/j.indcrop.2018.11.012Hashimoto, K., Ohta, H., Hirasawa, T., Arai, M., & Tamura, M. (2002). Evaluation of Ignition Quality of LPG with Cetane Number Improver. SAE Technical Paper Series. doi:10.4271/2002-01-0870Benajes, J., Molina, S., García, A., & Monsalve-Serrano, J. (2015). Effects of low reactivity fuel characteristics and blending ratio on low load RCCI (reactivity controlled compression ignition) performance and emissions in a heavy-duty diesel engine. Energy, 90, 1261-1271. doi:10.1016/j.energy.2015.06.088Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2016). Dual-Fuel Combustion for Future Clean and Efficient Compression Ignition Engines. Applied Sciences, 7(1), 36. doi:10.3390/app7010036Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). Achieving clean and efficient engine operation up to full load by combining optimized RCCI and dual-fuel diesel-gasoline combustion strategies. Energy Conversion and Management, 136, 142-151. doi:10.1016/j.enconman.2017.01.010Kokjohn, S. L., Hanson, R. M., Splitter, D. A., & Reitz, R. D. (2011). Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion. International Journal of Engine Research, 12(3), 209-226. doi:10.1177/1468087411401548Payri, R., Gimeno, J., Bardi, M., & Plazas, A. H. (2013). Study liquid length penetration results obtained with a direct acting piezo electric injector. Applied Energy, 106, 152-162. doi:10.1016/j.apenergy.2013.01.027Gimeno, J., Martí-Aldaraví, P., Carreres, M., & Peraza, J. E. (2018). Effect of the nozzle holder on injected fuel temperature for experimental test rigs and its influence on diesel sprays. International Journal of Engine Research, 19(3), 374-389. doi:10.1177/1468087417751531Pastor, J. V., García-Oliver, J. M., García, A., Micó, C., & Möller, S. (2016). Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions. Combustion and Flame, 164, 212-223. doi:10.1016/j.combustflame.2015.11.018Pastor, J., Garcia-Oliver, J. M., Garcia, A., & Nareddy, V. R. (2017). Characterization of Spray Evaporation and Mixing Using Blends of Commercial Gasoline and Diesel Fuels in Engine-Like Conditions. SAE Technical Paper Series. doi:10.4271/2017-01-0843Pastor, J. V., Payri, R., Garcia-Oliver, J. M., & Briceño, F. J. (2013). Schlieren Methodology for the Analysis of Transient Diesel Flame Evolution. SAE International Journal of Engines, 6(3), 1661-1676. doi:10.4271/2013-24-0041Siebers, D. L. (1998). Liquid-Phase Fuel Penetration in Diesel Sprays. SAE Technical Paper Series. doi:10.4271/980809ECN. Engine Combustion Network. https://ecn.sandia.gov/.Desantes, J. M., Pastor, J. V., García-Oliver, J. M., & Briceño, F. J. (2014). An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays. Combustion and Flame, 161(8), 2137-2150. doi:10.1016/j.combustflame.2014.01.022Payri, R., Viera, J. P., Pei, Y., & Som, S. (2015). Experimental and numerical study of lift-off length and ignition delay of a two-component diesel surrogate. Fuel, 158, 957-967. doi:10.1016/j.fuel.2014.11.072Reyes, M., Tinaut, F. V., Giménez, B., & Pastor, J. V. (2018). Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures. International Journal of Hydrogen Energy, 43(42), 19778-19791. doi:10.1016/j.ijhydene.2018.09.005Siebers, 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.2015.10.118Kook, S., & Pickett, L. M. (2012). Liquid length and vapor penetration of conventional, Fischer–Tropsch, coal-derived, and surrogate fuel sprays at high-temperature and high-pressure ambient conditions. Fuel, 93, 539-548. doi:10.1016/j.fuel.2011.10.004Payri, 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.2015.07.042Payri, R., Viera, J. P., Gopalakrishnan, V., & Szymkowicz, P. G. (2017). The effect of nozzle geometry over ignition delay and flame lift-off of reacting direct-injection sprays for three different fuels. Fuel, 199, 76-90. doi:10.1016/j.fuel.2017.02.075Pickett, L. M., Siebers, D. L., & Idicheria, C. A. (2005). Relationship Between Ignition Processes and the Lift-Off Length of Diesel Fuel Jets. SAE Technical Paper Series. doi:10.4271/2005-01-3843Xuan, T., Desantes, J. M., Pastor, J. V., & Garcia-Oliver, J. M. (2019). Soot temperature characterization of spray a flames by combined extinction and radiation methodology. Combustion and Flame, 204, 290-303. doi:10.1016/j.combustflame.2019.03.023Desantes, J. M., Pastor, J. V., García-Oliver, J. M., & Pastor, J. M. (2009). A 1D model for the description of mixing-controlled reacting diesel sprays. Combustion and Flame, 156(1), 234-249. doi:10.1016/j.combustflame.2008.10.00

Experimental Study of the Influence of Gasoline-Diesel Blends on the Combustion Process and Soot Formation under Diesel Engine-Like Conditions

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy & Fuels, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.energyfuels.0c00091.[EN] Recent research has demonstrated that a reduction in pollutant emissions of diesel engines can be achieved by using high octane fuels such as gasoline, methane, or liquefied petroleum gas. Therefore, in this study, the focus was to investigate the influence of blends of diesel and gasoline on combustion characteristics such as ignition delay, rate of heat release, and lift-off length as well as the influence on soot formation. The experiments were carried out in a test rig with optical access which mimics a single-cylinder diesel engine. Four blends were tested: one blend with 100% diesel and then three diesel-gasoline blends with 30%, 50%, and70% gasoline. The blends were made in volumetric proportions and injected using a common rail injection system without any kind of modification. The ignition delay and the apparent heat release were obtained by means of the in-cylinder pressure signal. Furthermore, the combustion development and soot formation were studied using three optical techniques: OH* chemiluminescence, natural luminosity, and diffused back-illumination extinction imaging (DBI). Different engine operating conditions were analyzed. Results showed that ID increases with the gasoline content in the blend. Similarly, as the reacting time increased, the lift-off length was longer. On the other hand, the apparent rate of heat release decreased due to a reduction of the fuel injection rate, which depends on the density of the blend. In addition, differences in the flame radiation were also observed. Gasoline-diesel blends had less luminosity, which is related to less soot formation. To confirm this, the KL factor obtained from the DBI technique was determined, and it was concluded that increasing the gasoline fraction in the blend reduces soot formation.This research work has been partly funded by the Government of Spain and FEDER under TRANCO project (TRA2017-87694-R) and by Universitat Politecnica de Valencia through the Programa de Ayudas de Investigacion y Desarrollo (PAID-01-18 and PAID-06-18) program.Pastor, JV.; García Martínez, A.; Mico Reche, C.; Garcia-Carrero, AA. (2020). Experimental Study of the Influence of Gasoline-Diesel Blends on the Combustion Process and Soot Formation under Diesel Engine-Like Conditions. Energy & Fuels. 34(5):5589-5598. https://doi.org/10.1021/acs.energyfuels.0c00091S55895598345Murugesa Pandian, M., & Anand, K. (2018). Comparison of different low temperature combustion strategies in a light duty air cooled diesel engine. Applied Thermal Engineering, 142, 380-390. doi:10.1016/j.applthermaleng.2018.07.047Kokjohn, S. L., Hanson, R. M., Splitter, D. A., & Reitz, R. D. (2011). Fuel reactivity controlled compression ignition (RCCI): a pathway to controlled high-efficiency clean combustion. International Journal of Engine Research, 12(3), 209-226. doi:10.1177/1468087411401548Kokjohn, S. L., Hanson, R. M., Splitter, D. A., & Reitz, R. D. (2009). Experiments and Modeling of Dual-Fuel HCCI and PCCI Combustion Using In-Cylinder Fuel Blending. SAE International Journal of Engines, 2(2), 24-39. doi:10.4271/2009-01-2647Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2016). Dual-Fuel Combustion for Future Clean and Efficient Compression Ignition Engines. Applied Sciences, 7(1), 36. doi:10.3390/app7010036Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). Achieving clean and efficient engine operation up to full load by combining optimized RCCI and dual-fuel diesel-gasoline combustion strategies. Energy Conversion and Management, 136, 142-151. doi:10.1016/j.enconman.2017.01.010Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). An investigation on the particulate number and size distributions over the whole engine map from an optimized combustion strategy combining RCCI and dual-fuel diesel-gasoline. Energy Conversion and Management, 140, 98-108. doi:10.1016/j.enconman.2017.02.073Benajes, J., García, A., Monsalve-Serrano, J., & Boronat, V. (2017). Gaseous emissions and particle size distribution of dual-mode dual-fuel diesel-gasoline concept from low to full load. Applied Thermal Engineering, 120, 138-149. doi:10.1016/j.applthermaleng.2017.04.005Dempsey, A. B., Curran, S., & Reitz, R. D. (2015). Characterization of Reactivity Controlled Compression Ignition (RCCI) Using Premixed Gasoline and Direct-Injected Gasoline with a Cetane Improver on a Multi-Cylinder Engine. SAE International Journal of Engines, 8(2), 859-877. doi:10.4271/2015-01-0855Bendu, H., & Murugan, S. (2014). Homogeneous charge compression ignition (HCCI) combustion: Mixture preparation and control strategies in diesel engines. Renewable and Sustainable Energy Reviews, 38, 732-746. doi:10.1016/j.rser.2014.07.019Bermúdez, V., García, J. M., Juliá, E., & Martínez, S. (2003). Engine with Optically Accessible Cylinder Head: A Research Tool for Injection and Combustion Processes. SAE Technical Paper Series. doi:10.4271/2003-01-1110Pastor, J. V., García-Oliver, J. M., García, A., Micó, C., & Möller, S. (2016). Application of optical diagnostics to the quantification of soot in n-alkane flames under diesel conditions. Combustion and Flame, 164, 212-223. doi:10.1016/j.combustflame.2015.11.018Pastor, J., Garcia-Oliver, J. M., Garcia, A., & Nareddy, V. R. (2017). Characterization of Spray Evaporation and Mixing Using Blends of Commercial Gasoline and Diesel Fuels in Engine-Like Conditions. SAE Technical Paper Series. doi:10.4271/2017-01-0843Pastor, J. V., García-Oliver, J. M., García, A., & Pinotti, M. (2017). Effect of laser induced plasma ignition timing and location on Diesel spray combustion. Energy Conversion and Management, 133, 41-55. doi:10.1016/j.enconman.2016.11.054Pastor, J. V., García-Oliver, J. M., García, A., & Pinotti, M. (2016). Laser induced plasma methodology for ignition control in direct injection sprays. Energy Conversion and Management, 120, 144-156. doi:10.1016/j.enconman.2016.04.086Pastor, J. V., Payri, R., Gimeno, J., & Nerva, J. G. (2009). Experimental Study on RME Blends: Liquid-Phase Fuel Penetration, Chemiluminescence, and Soot Luminosity in Diesel-Like Conditions. Energy & Fuels, 23(12), 5899-5915. doi:10.1021/ef9007328Pastor, J. V., García-Oliver, J. M., Nerva, J.-G., & Giménez, B. (2011). Fuel effect on the liquid-phase penetration of an evaporating spray under transient diesel-like conditions. Fuel, 90(11), 3369-3381. doi:10.1016/j.fuel.2011.05.006Reyes, M., Tinaut, F. V., Giménez, B., & Pastor, J. V. (2018). Effect of hydrogen addition on the OH* and CH* chemiluminescence emissions of premixed combustion of methane-air mixtures. International Journal of Hydrogen Energy, 43(42), 19778-19791. doi:10.1016/j.ijhydene.2018.09.005Siebers, D. L., & Higgins, B. (2001). Flame Lift-Off on Direct-Injection Diesel Sprays Under Quiescent Conditions. SAE Technical Paper Series. doi:10.4271/2001-01-0530Pastor, J. V., Garcia-Oliver, J. M., Garcia, A., & Pinotti, M. (2017). Soot Characterization of Diesel/Gasoline Blends Injected through a Single Injection System in CI engines. SAE Technical Paper Series. doi:10.4271/2017-24-0048Pastor, J. V., García, J. M., Pastor, J. M., & Buitrago, J. E. (2005). Analysis Methodology of Diesel Combustion by Using Flame Luminosity, Two-Colour Method and Laser-Induced Incandescence. SAE Technical Paper Series. doi:10.4271/2005-24-012Xuan, T., Pastor, J. V., García-Oliver, J. M., García, A., He, Z., Wang, Q., & Reyes, M. (2019). In-flame soot quantification of diesel sprays under sooting/non-sooting critical conditions in an optical engine. Applied Thermal Engineering, 149, 1-10. doi:10.1016/j.applthermaleng.2018.11.112Xuan, T., Desantes, J. M., Pastor, J. V., & Garcia-Oliver, J. M. (2019). Soot temperature characterization of spray a flames by combined extinction and radiation methodology. Combustion and Flame, 204, 290-303. doi:10.1016/j.combustflame.2019.03.023Wang, J., Yang, F., & Ouyang, M. (2015). Dieseline fueled flexible fuel compression ignition engine control based on in-cylinder pressure sensor. Applied Energy, 159, 87-96. doi:10.1016/j.apenergy.2015.08.101Han, M. (2013). The effects of synthetically designed diesel fuel properties – cetane number, aromatic content, distillation temperature, on low-temperature diesel combustion. Fuel, 109, 512-519. doi:10.1016/j.fuel.2013.03.039Benajes, 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.2013.04.044Pickett, L. M., Siebers, D. L., & Idicheria, C. A. (2005). Relationship Between Ignition Processes and the Lift-Off Length of Diesel Fuel Jets. SAE Technical Paper Series. doi:10.4271/2005-01-3843Payri, 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.2015.10.11

Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions

[EN] Featured Application This work contributes to the understanding of the macroscopic characteristics of the spray as well as to the evolution of the combustion process for alternative fuels. All these fuels have been studied under the same operating conditions than diesel therefore the comparison can be made directly, leaving in evidence that some fuels can achieve a similar behavior to diesel in terms of auto ignition but avoiding one of the biggest disadvantages of diesel such as the soot formation. Moreover, the quantification of characteristic parameters such as ignition delay, liquid length, vapor penetration and flame lift-off length represent the most important data to adjust and subsequently validate the computational models that simulate the spray evolution and combustion development of these alternative fuels inside the combustion chamber. The stringent emission regulations have motivated the development of cleaner fuels as diesel surrogates. However, their different physical-chemical properties make the study of their behavior in compression ignition engines essential. In this sense, optical techniques are a very effective tool for determining the spray evolution and combustion characteristics occurring in the combustion chamber. In this work, quantitative parameters describing the evolution of diesel-like sprays such as liquid length, spray penetration, ignition delay, lift-off length and flame penetration as well as the soot formation were tested in a constant high pressure and high temperature installation using schlieren, OH* chemiluminescence and diffused back-illumination extinction imaging techniques. Boundary conditions such as rail pressure, chamber density and temperature were defined using guidelines from the Engine Combustion Network (ECN). Two paraffinic fuels (dodecane and a renewable hydrotreated vegetable oil (HVO)) and two oxygenated fuels (methylal identified as OME(1)and a blend of oxymethylene ethers, identified as OMEx) were tested and compared to a conventional diesel fuel used as reference. Results showed that paraffinic fuels and OME(x)sprays have similar behavior in terms of global combustion metrics. In the case of OME1, a shorter liquid length, but longer ignition delay time and flame lift-off length were observed. However, in terms of soot formation, a big difference between paraffinic and oxygenated fuels could be appreciated. While paraffinic fuels did not show any significant decrease of soot formation when compared to diesel fuel, soot formed by OME(1)and OME(x)was below the detection threshold in all tested conditions.This research has been partly funded by the European Union's Horizon 2020 Programme through the ENERXICO project, grant agreement no 828947, and from the Mexican Department of Energy, CONACYT-SENER Hidrocarburos grant agreement no B-S-69926 and by Universitat Politecnica de Valencia through the Programa de Ayudas de Investigacion y Desarrollo (PAID-01-18).Pastor, JV.; García-Oliver, JM.; Mico Reche, C.; Garcia-Carrero, AA.; Gómez, A. (2020). Experimental Study of the Effect of Hydrotreated Vegetable Oil and Oxymethylene Ethers on Main Spray and Combustion Characteristics under Engine Combustion Network Spray A Conditions. Applied Sciences. 10(16):1-20. https://doi.org/10.3390/app10165460S1201016Reşitoğlu, İ. A., Altinişik, K., & Keskin, A. (2014). The pollutant emissions from diesel-engine vehicles and exhaust aftertreatment systems. Clean Technologies and Environmental Policy, 17(1), 15-27. doi:10.1007/s10098-014-0793-9Mohan, 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.2013.08.051Leach, F., Kalghatgi, G., Stone, R., & Miles, P. (2020). The scope for improving the efficiency and environmental impact of internal combustion engines. Transportation Engineering, 1, 100005. doi:10.1016/j.treng.2020.100005Kim, H., Ge, J., & Choi, N. (2018). Application of Palm Oil Biodiesel Blends under Idle Operating Conditions in a Common-Rail Direct-Injection Diesel Engine. Applied Sciences, 8(12), 2665. doi:10.3390/app8122665Tziourtzioumis, D., & Stamatelos, A. (2017). Experimental Investigation of the Effect of Biodiesel Blends on a DI Diesel Engine’s Injection and Combustion. Energies, 10(7), 970. doi:10.3390/en10070970Merola, S. S., Tornatore, C., Iannuzzi, S. E., Marchitto, L., & Valentino, G. (2014). Combustion process investigation in a high speed diesel engine fuelled with n-butanol diesel blend by conventional methods and optical diagnostics. Renewable Energy, 64, 225-237. doi:10.1016/j.renene.2013.11.017Choi, K., Park, S., Roh, H. G., & Lee, C. S. (2019). Combustion and Emission Reduction Characteristics of GTL-Biodiesel Fuel in a Single-Cylinder Diesel Engine. Energies, 12(11), 2201. doi:10.3390/en12112201Dimitriadis, A., Seljak, T., Vihar, R., Žvar Baškovič, U., Dimaratos, A., Bezergianni, S., … Katrašnik, T. (2020). Improving PM-NOx trade-off with paraffinic fuels: A study towards diesel engine optimization with HVO. Fuel, 265, 116921. doi:10.1016/j.fuel.2019.116921Pastor, J. V., García, A., Micó, C., & Lewiski, F. (2020). An optical investigation of Fischer-Tropsch diesel and Oxymethylene dimethyl ether impact on combustion process for CI engines. Applied Energy, 260, 114238. doi:10.1016/j.apenergy.2019.114238Bergthorson, J. M., & Thomson, M. J. (2015). A review of the combustion and emissions properties of advanced transportation biofuels and their impact on existing and future engines. Renewable and Sustainable Energy Reviews, 42, 1393-1417. doi:10.1016/j.rser.2014.10.034Yehliu, K., Boehman, A. L., & Armas, O. (2010). Emissions from different alternative diesel fuels operating with single and split fuel injection. Fuel, 89(2), 423-437. doi:10.1016/j.fuel.2009.08.025Gómez, A., Soriano, J. A., & Armas, O. (2016). Evaluation of sooting tendency of different oxygenated and paraffinic fuels blended with diesel fuel. Fuel, 184, 536-543. doi:10.1016/j.fuel.2016.07.049Benajes, J., García, A., Monsalve-Serrano, J., & Martínez-Boggio, S. (2020). Potential of using OMEx as substitute of diesel in the dual-fuel combustion mode to reduce the global CO2 emissions. Transportation Engineering, 1, 100001. doi:10.1016/j.treng.2020.01.001Burger, J., Siegert, M., Ströfer, E., & Hasse, H. (2010). Poly(oxymethylene) dimethyl ethers as components of tailored diesel fuel: Properties, synthesis and purification concepts. Fuel, 89(11), 3315-3319. doi:10.1016/j.fuel.2010.05.014Iannuzzi, S. E., Barro, C., Boulouchos, K., & Burger, J. (2017). POMDME-diesel blends: Evaluation of performance and exhaust emissions in a single cylinder heavy-duty diesel engine. Fuel, 203, 57-67. doi:10.1016/j.fuel.2017.04.089Omari, A., Heuser, B., & Pischinger, S. (2017). Potential of oxymethylenether-diesel blends for ultra-low emission engines. Fuel, 209, 232-237. doi:10.1016/j.fuel.2017.07.107Bjørgen, K. O. P., Emberson, D. R., & Løvås, T. (2020). Combustion and soot characteristics of hydrotreated vegetable oil compression-ignited spray flames. 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In-flame soot quantification of diesel sprays under sooting/non-sooting critical conditions in an optical engine. Applied Thermal Engineering, 149, 1-10. doi:10.1016/j.applthermaleng.2018.11.112Choi, M. Y., Mulholland, G. W., Hamins, A., & Kashiwagi, T. (1995). Comparisons of the soot volume fraction using gravimetric and light extinction techniques. Combustion and Flame, 102(1-2), 161-169. doi:10.1016/0010-2180(94)00282-wLi, D., He, Z., Xuan, T., Zhong, W., Cao, J., Wang, Q., & Wang, P. (2017). Simultaneous capture of liquid length of spray and flame lift-off length for second-generation biodiesel/diesel blended fuel in a constant volume combustion chamber. Fuel, 189, 260-269. doi:10.1016/j.fuel.2016.10.058Lequien, G., Berrocal, E., Gallo, Y., Themudo e Mello, A., Andersson, O., & Johansson, B. (2013). Effect of Jet-Jet Interactions on the Liquid Fuel Penetration in an Optical Heavy-Duty DI Diesel Engine. SAE Technical Paper Series. doi:10.4271/2013-01-1615Kook, S., & Pickett, L. M. 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Necrotizing Fasciitis in a Patient with Type II Diabetes Mellitus - A Case Report

Background: Necrotizing fasciitis (NF) is a rare necrotizing soft tissue infection (NSTI) of high mortality; clinically characterized by fulminant tissue destruction and systemic signs of toxicity. Clinical manifestations include erythema (72%), extended edema (75%), severe pain (72%), fever (60%), crepitus (50%), skin bullae, necrosis, or ecchymosis (38%). Worldwide, 1:3 of patients with NF die from this rapidly progressive infection. Case presentation: A 44-year-old female patient with a past medical history of DM type II attended ER with pain in the right inguinal area. Vital signs on admission were heart rate 113bpm, blood pressure 124/82mmHg, and temperature 38.1℃. A physical exam revealed redness, swelling, and black eschar. There was crepitus and severe pain on palpation in the right inguinal area. The lab reported leukocytosis with WBC 14,800, and uncontrolled DM with a glucose level of 350 mg/dL and HbA1c \u3e14: otherwise unremarkable. Abdomen/pelvis CT scan report indicated extensive pockets of air plus soft tissue fat stranding seen in the right infra pubic region extending along the right perineum and into the medial aspect of the proximal thigh featuring necrotizing fasciitis. The patient was admitted, and sepsis protocol was initiated. Surgery was consulted, and the patient was taken immediately for surgical debridement, resulting in an open wound (27x12cm). Post-op the patient was transferred to ICU for close follow-up and later transferred to the surgical ward. During the hospital stay, wound cultures were positive for the Streptococcus viridians group in addition to a few Staphylococci coagulase-negative, most likely flora contaminants. No growth on blood cultures. Post-open wound was managed by wound care consultants. Broad-spectrum IV antibiotics were continued during hospitalization, and the patient was later discharged with oral antibiotics. Conclusion: Inadequate management of undiagnosed skin ulcers can rapidly progress in diabetic patients to Necrotizing Fasciitis due to immunosuppressed status and uncontrolled Diabetes Mellitus. Necrotizing Fasciitis has a high mortality rate and complications can range from amputation to chronic complex wounds. Adequate diagnosis and immediate medical and surgical treatment remain vital for decreased mortality and a higher rate of recovery

Influence of Three Dental Implant Surfaces on Cell Viability and Bone Behavior. An In Vitro and a Histometric Study in a Rabbit Model

The chemical composition and the surface characteristics of dental implants are factors that have a decisive effect on the osseointegration process. The surface characterization at the compositional and topographic level of three dental implants available in the market was performed with different surface treatments: (1) sandblasted and acid etched surface (SLA), (2) hydroxyapatite (HA) and tricalcium phosphate (TCP) blasted surface (HA/TCP), and (3) HA-blasted and non-etching acid washed surface (HA + AW). In addition, an in vitro viability study of MG-63 osteoblast cells was performed with a JC-1 test. To complete the study, an in vivo study was conducted in New Zealand rabbits. The study analyzed the histometric characteristics of the bone formed around the implants at the level of area, volume, bone density, accumulated bone density, and bone–implant contact (BIC). The rabbits were sacrificed at 6 weeks after implants were placed in the tibial metaphysis. No statistically significant differences were observed at the level of cell viability or histometric parameters between the different study groups (p > 0.05). SLA and HA/TCP surfaces were the ones that obtained a higher BIC value. Taking into account the limitations of this study, it can be concluded that the different implant surfaces analyzed favor a good bone response

Estudio de la situación financiera y económica de la empresa Nutresa S.A 2019-2021

Con este trabajo de investigación se busca alcanzar como objetivo principal mostrar a tutores, docentes, a estudiantes y todo el cuerpo de activos académicos, como a través del análisis se puede llegar al conocimiento de la situación actual económica y financiera del Grupo Nutresa S.A, aun mas cuando se lleva a cabo la aplicación de la disciplina de la contaduría y las finanzas, por medio de las cuales se llaga a poder determinar a través de las herramientas financieras, como se encuentra la compañía desde un momento de histórico hasta la actualidad en la parte financiera, económica y competitiva, como también se puede determinar sus estado de rentabilidad haciendo un análisis de sus últimos años de actividad, donde se observa su situación financiera y su estado de resultados, de sus inversiones, teniendo en cuenta que estos análisis a través de ratios e indicadores financieros, mostraran los resultados indicando de qué manera se puede llevar a cabo las conclusiones sobre el estado real financiero y económico del Grupo Nutresa S.A, los que demuestra la importancia del entendimiento sobre los aspectos financieros y económicos que son importantes en el marco empresarial al momento de realizar una inversión real, donde se identifican que tan positiva o negativa puede ser esta en un momento determinado.The main objective of this research work is to show tutors, teachers, students and the whole body of academic assets how, through the analysis, it is possible to obtain an understanding of the current economic and financial situation of the Nutresa Group S. A even more so when it is carried out the application of the discipline of accounting and finance, by means of which it is possible to determine by means of the results obtained. financial tools, such as the company’s financial, economic and competitive position from a historical moment to the present, as well as its profitability status can be determined by analyzing its last years of activity, where its financial situation and its statement of results, of its investments can be observed, taking into account that these analyses by means of financial ratios and indicators, will show the results indicating how to carry out the conclusions on the actual financial and economic status of the Nutresa Group S. A. , which demonstrates the importance of understanding the financial and economic aspects that are important in the business context at the time of making a real investment, identifying how positive or negative this may be at a given time

La imagen y la narrativa como herramientas para el abordaje psicosocial en escenarios de violencia en los municipios Aguachica, San Martin Cesar y Barrancabermeja Santander.

El conflicto armado ha dejado un gran número de víctimas en Colombia, personas que han perdido territorios, familiares, empleos y demás, pero ante todo han perdido la seguridad y la tranquilidad. Algunas veces estos fenómenos dejan como consecuencia lesiones físicas y psicológicas que han frustrado su proyecto de vida, reconociendo la historia de nuestro país, este tipo de vivencias se han generado por muchos años en varias regiones, no todas las víctimas de las Acciones bélicas, puedan recibir el acompañamiento psicosocial por parte del estado por diferentes motivos. En el siguiente trabajo presentaremos un análisis de las dificultades o impactos psicosociales que han experimentado las personas víctimas del conflicto armado y como éstas llevan en su memoria los recuerdos que les crean resentimientos, frustración, culpa, duelo y emociones que nos les permiten gozar de calidad de vida, se puede visualizar en los relatos presentados, teniendo en cuenta que su mundo giraba en torno a su territorio, una actividad económica especifica o a un ser querido que está ausente, por lo que requirieron algún tipo de atención psicosocial, para de esta manera mitigar los efectos de los hechos violentos. La actividad nos brinda herramientas a los psicólogos en formación, basadas en el estudio y análisis de casos, nos orienta para la creación de preguntas estratégicas, circulares y reflexivas, para implementarlas en el caso elegido a las personas que han vivenciado algún tipo de violencia, elegir estrategias para abordar psicosocialmente a las comunidades, como el caso de Cacarica donde se reflejan los emergentes psicosociales, los impactos que generaron al ser estigmatizados, determinar acciones a implementar para mitigar los impactos negativos en las victimas, en este mismo sentido se deben aplicar las estrategias psicosociales, para darles orientación y el Acompañamiento a las víctimas ante cualquier situación que genere algún tipo de crisis o alteración psíquica generando confianza en las personas para que reconozcan las posibles debilidades y afectaciones que no les permiten tener una estabilidad emocional y al mismo tiempo reconocer y explorar habilidades que desconocían en sí mismos, para resarcir los impactos negativos de las situaciones traumáticas del conflicto armado en Colombia.The armed conflict has left a large number of victims in Colombia, people who have lost territories, family members, jobs and others, but above all they have lost security and tranquility. Sometimes these phenomena leave as a consequence physical and psychological injuries that have frustrated their life project, recognizing the history of our country, this type of experiences has been generated for many years in various regions, not all victims of warlike actions, may receive psychosocial support from the state for different reasons. In the following work we will present an analysis of the difficulties or psychosocial impacts experienced by people who are victims of the armed conflict and how they carry in their memories the memories that create resentment, frustration, guilt, grief and emotions that allow them to enjoy quality life, can be seen in the stories presented, taking into account that their world revolved around their territory, a specific economic activity or a loved one who is absent, so they required some type of psychosocial care, in order to mitigate the effects of violent acts. The activity provides tools to psychologists in training, based on the study and analysis of cases, guides us to create strategic, circular and reflective questions, to implement them in the chosen case for people who have experienced some type of violence, choose strategies to psychosocially approach communities, such as the case of Cacarica where psychosocial emergencies are reflected, the impacts generated by being stigmatized, determine actions to implement to mitigate negative impacts on victims, in this same sense, the psychosocial strategies, to give guidance and accompaniment to victims in any situation that generates some type of crisis or psychic alteration, generating confidence in people so that they recognize possible weaknesses and affections that do not allow them to have emotional stability and at the same time recognize and explore unknown skills They were in themselves, to compensate the negative impacts of the traumatic situations of the armed conflict in Colombia

Geographic patterns of tree dispersal modes in Amazonia and their ecological correlates

Aim: To investigate the geographic patterns and ecological correlates in the geographic distribution of the most common tree dispersal modes in Amazonia (endozoochory, synzoochory, anemochory and hydrochory). We examined if the proportional abundance of these dispersal modes could be explained by the availability of dispersal agents (disperser-availability hypothesis) and/or the availability of resources for constructing zoochorous fruits (resource-availability hypothesis). Time period: Tree-inventory plots established between 1934 and 2019. Major taxa studied: Trees with a diameter at breast height (DBH) ≥ 9.55 cm. Location: Amazonia, here defined as the lowland rain forests of the Amazon River basin and the Guiana Shield. Methods: We assigned dispersal modes to a total of 5433 species and morphospecies within 1877 tree-inventory plots across terra-firme, seasonally flooded, and permanently flooded forests. We investigated geographic patterns in the proportional abundance of dispersal modes. We performed an abundance-weighted mean pairwise distance (MPD) test and fit generalized linear models (GLMs) to explain the geographic distribution of dispersal modes. Results: Anemochory was significantly, positively associated with mean annual wind speed, and hydrochory was significantly higher in flooded forests. Dispersal modes did not consistently show significant associations with the availability of resources for constructing zoochorous fruits. A lower dissimilarity in dispersal modes, resulting from a higher dominance of endozoochory, occurred in terra-firme forests (excluding podzols) compared to flooded forests. Main conclusions: The disperser-availability hypothesis was well supported for abiotic dispersal modes (anemochory and hydrochory). The availability of resources for constructing zoochorous fruits seems an unlikely explanation for the distribution of dispersal modes in Amazonia. The association between frugivores and the proportional abundance of zoochory requires further research, as tree recruitment not only depends on dispersal vectors but also on conditions that favour or limit seedling recruitment across forest types

Geography and ecology shape the phylogenetic composition of Amazonian tree communities

AimAmazonia hosts more tree species from numerous evolutionary lineages, both young and ancient, than any other biogeographic region. Previous studies have shown that tree lineages colonized multiple edaphic environments and dispersed widely across Amazonia, leading to a hypothesis, which we test, that lineages should not be strongly associated with either geographic regions or edaphic forest types.LocationAmazonia.TaxonAngiosperms (Magnoliids; Monocots; Eudicots).MethodsData for the abundance of 5082 tree species in 1989 plots were combined with a mega-phylogeny. We applied evolutionary ordination to assess how phylogenetic composition varies across Amazonia. We used variation partitioning and Moran's eigenvector maps (MEM) to test and quantify the separate and joint contributions of spatial and environmental variables to explain the phylogenetic composition of plots. We tested the indicator value of lineages for geographic regions and edaphic forest types and mapped associations onto the phylogeny.ResultsIn the terra firme and várzea forest types, the phylogenetic composition varies by geographic region, but the igapó and white-sand forest types retain a unique evolutionary signature regardless of region. Overall, we find that soil chemistry, climate and topography explain 24% of the variation in phylogenetic composition, with 79% of that variation being spatially structured (R2 = 19% overall for combined spatial/environmental effects). The phylogenetic composition also shows substantial spatial patterns not related to the environmental variables we quantified (R2 = 28%). A greater number of lineages were significant indicators of geographic regions than forest types.Main ConclusionNumerous tree lineages, including some ancient ones (>66 Ma), show strong associations with geographic regions and edaphic forest types of Amazonia. This shows that specialization in specific edaphic environments has played a long-standing role in the evolutionary assembly of Amazonian forests. Furthermore, many lineages, even those that have dispersed across Amazonia, dominate within a specific region, likely because of phylogenetically conserved niches for environmental conditions that are prevalent within regions