Battles of Himera (480 and 409 b.c.): Analysis of Biological Finds and Historical Interpretation. Experiences of Restoration in the Ruins of Himera 2008-2010

Excavations conducted in the western necropolis of Himera by the Superintendence of Palermo, between 2008 and 2011, made it possible to investigate more than 9,500 graves of the 7th and 6th centuries B.C. It is a study of great importance as it gives a detailed historic and archaeological view of the funerary context of a Greek colony. Taphonomic studies of the tombs are of great interest to know the composition of the bodies in the graves and the rituals associated with the burial. Finally, the examination of hundreds of skeletons of children has provided data on child mortality. This report, briefly, also aims to present the restoration of the artifacts discovered. The article describes the organization of the restoration laboratory, built and equipped directly in situ at the excavation, the materials used during the restoration, the main problems presented during the various phases of restoration and several results.Gli scavi condotti nella necropoli occidentale di Himera dalla Soprintendenza di Palermo, tra il 2008 e il 2011, hanno consentito di indagare oltre 9500 sepolture, del VII e il VI sec. a.C. Si tratta di uno studio di eccezionale importanza che consente di avere un quadro storico e archeologico molto dettagliato della sfera funeraria di una colonia greca. Si accennerà anche allo studio dei reperti biologici attraverso uno scheletro di un individuo affetto da nanismo e prove di interventi chirurgici al cranio. La lettura tafonomica delle sepolture, è di grande interesse per conoscere la composizione dei cadaveri nelle tombe e dei rituali connessi alla sepoltura. Infine, l’esame di centinaia di scheletri di bambini, ha fornito dati sulla mortalità infantile. Viene inoltre illustrato sinteticamente il lavoro svolto in occasione del restauro dei manufatti rinvenuti. In particolare vengono descritte l’organizzazione del laboratorio di restauro, realizzato ed attrezzato nell’area di scavo; i materiali utilizzati durante gli interventi; le principali criticità presentate dai manufatti sottoposti alle diverse fasi di restauro e alcuni risultati raggiunti

Investigation of Ducted Fuel Injection Implementation in a Retrofitted Light-Duty Diesel Engine through Numerical Simulation

Ducted Fuel Injection (DFI) is a concept of growing interest to abate soot emissions in diesel combustion, based on a small duct within the combustion chamber in front of the injector nozzle. Despite the impressive potential of the DFI has been proven in literature, its application for series production and the complexity for the adaptation of existing compression-ignition (CI) engines need to be extensively investigated. In this context, the aim of this study is to numerically assess the potential of DFI implementation in a CI engine for light-duty applications, highlighting the factors which can limit or facilitate its integration in existing combustion chambers. The numerical model for combustion simulation was based on a 1D/3D-CFD coupled approach relying on a calibrated spray model, extensively validated against experimental data. Once assessed the coupling procedure by comparing the numerical results with experimental in-cylinder pressure and heat release rate data for both low and high load operating conditions, the duct impact was investigated introducing it in the computational domain. It was observed that DFI did not yield any significant advantage to engine-out soot emissions and fuel consumption with the existing combustion system. Although the soot formation was generally reduced, the soot oxidation process was partially inhibited by the duct adoption maintaining fixed the engine calibration, suggesting the need for complete optimization of the combustion system design. On the other hand, a preliminary variation of engine calibration highlighted several beneficial trends for DFI, whose operation improved with a simplified injection strategy. Present numerical results indicate that DFI retrofit solutions without specific optimization of the combustion system design do not guarantee soot reduction. Nevertheless, wide room for improvement remains in terms of DFI-targeted combustion chamber design and engine calibration towards the complete success of this technology for soot-free CI engines

Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application

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/10.1177/1468087418819250[EN] This article describes the main results of an investigation about counter-bore injector nozzle impact on the combustion process in a modern Euro 6 diesel engine. First, hydraulic and spray visualization tests have been performed, showing a potential advantage of such nozzle design in fuel-air mixing efficiency. Then, combustion performance has been assessed on a GM-designed 1.6-L four-cylinder engine. The engine has been installed on a dynamometric test bench and instrumented with an AVL cylinder pressure transducer for heat release rate analysis, as well as HORIBA MEXA gas analyzer for exhaust emissions and AVL 415 Smoke Meter. Engine efficiency and emissions have been analyzed on four different part-load steady-state points, representative of New European Driving Cycle and Worldwide harmonized Light duty Test Cycle certification cycles, and covering engine speeds from 1250 to 2000 r/min and brake mean effective pressure between 0.2 and 1.4 MPa. Results of indicated analysis show that counter-bore nozzles have significant differences in terms of pilot injection combustion at low load points, which in turn lead to a better ignition and shorter combustion of the main injection. In addition, an improvement of diffusive combustion is observed as load increases. Because of both, fuel consumption is reduced by approximately 1% with respect to a standard nozzle. Finally, an appreciable decrease in engine exhaust emissions has been recorded, especially in terms of particulate matter and hydrocarbon emissions. This reduction has been linked to the improvement of fuel-air mixing promoted by the counter-bore nozzle previously observed.The authors would like to thank General Motors Global Propulsion Systems-Torino S.r.l. for sponsoring the current work. Part of the equipment was purchased with the help of Generalitat Valenciana in project IDIFEDER2018 with title "Equipamiento de diagnostico optico de alta velocidad para estudiar procesos de inyeccion''.Payri, R.; De La Morena, J.; Monsalve-Serrano, J.; Pesce, FC.; Vassallo, A. (2019). Impact of counter-bore nozzle on the combustion process and exhaust emissions for light-duty diesel engine application. International Journal of Engine Research. 20(1):46-57. https://doi.org/10.1177/1468087418819250S4657201Kastengren, A. L., Tilocco, F. Z., Powell, C. F., Manin, J., Pickett, L. M., Payri, R., & Bazyn, T. (2012). ENGINE COMBUSTION NETWORK (ECN): MEASUREMENTS OF NOZZLE GEOMETRY AND HYDRAULIC BEHAVIOR. Atomization and Sprays, 22(12), 1011-1052. doi:10.1615/atomizspr.2013006309Payri, R., Viera, J. P., Gopalakrishnan, V., & Szymkowicz, P. G. (2016). The effect of nozzle geometry over internal flow and spray formation for three different fuels. Fuel, 183, 20-33. doi:10.1016/j.fuel.2016.06.041Postrioti, L., Malaguti, S., Bosi, M., Buitoni, G., Piccinini, S., & Bagli, G. (2014). Experimental and numerical characterization of a direct solenoid actuation injector for Diesel engine applications. Fuel, 118, 316-328. doi:10.1016/j.fuel.2013.11.001Payri, R., Gimeno, J., De la Morena, J., Battiston, P. A., Wadhwa, A., & Straub, R. (2016). Study of new prototype pintle injectors for diesel engine application. Energy Conversion and Management, 122, 419-427. doi:10.1016/j.enconman.2016.06.003Payri, R., Bracho, G., Marti-Aldaravi, P., & Viera, A. (2017). NEAR FIELD VISUALIZATION OF DIESEL SPRAY FOR DIFFERENT NOZZLE INCLINATION ANGLES IN NON-VAPORIZING CONDITIONS. Atomization and Sprays, 27(3), 251-267. doi:10.1615/atomizspr.2017017949Li, T., Moon, S., Sato, K., & Yokohata, H. (2017). A comprehensive study on the factors affecting near-nozzle spray dynamics of multi-hole GDI injectors. Fuel, 190, 292-302. doi:10.1016/j.fuel.2016.11.009Payri, 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.2017.02.075Yao, C., Geng, P., Yin, Z., Hu, J., Chen, D., & Ju, Y. (2016). Impacts of nozzle geometry on spray combustion of high pressure common rail injectors in a constant volume combustion chamber. Fuel, 179, 235-245. doi:10.1016/j.fuel.2016.03.097Hong, J. G., Ku, K. W., Kim, S. R., & Lee, C. W. (2010). EFFECT OF CAVITATION IN CIRCULAR NOZZLE AND ELLIPTICAL NOZZLES ON THE SPRAY CHARACTERISTIC. Atomization and Sprays, 20(10), 877-886. doi:10.1615/atomizspr.v20.i10.40Molina, S., Salvador, F. J., Carreres, M., & Jaramillo, D. (2014). A computational investigation on the influence of the use of elliptical orifices on the inner nozzle flow and cavitation development in diesel injector nozzles. Energy Conversion and Management, 79, 114-127. doi:10.1016/j.enconman.2013.12.015Taskiran, O. O., & Ergeneman, M. (2014). Effect of nozzle dimensions and fuel type on flame lift-off length. Fuel, 115, 833-840. doi:10.1016/j.fuel.2013.03.005He, Z., Guo, G., Tao, X., Zhong, W., Leng, X., & Wang, Q. (2016). Study of the effect of nozzle hole shape on internal flow and spray characteristics. International Communications in Heat and Mass Transfer, 71, 1-8. doi:10.1016/j.icheatmasstransfer.2015.12.002Salvador, F. J., de la Morena, J., Carreres, M., & Jaramillo, D. (2017). Numerical analysis of flow characteristics in diesel injector nozzles with convergent-divergent orifices. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 231(14), 1935-1944. doi:10.1177/0954407017692220Baldwin, E. T., Grover, R. O., Parrish, S. E., Duke, D. J., Matusik, K. E., Powell, C. F., … Schmidt, D. P. (2016). String flash-boiling in gasoline direct injection simulations with transient needle motion. International Journal of Multiphase Flow, 87, 90-101. doi:10.1016/j.ijmultiphaseflow.2016.09.004Payri, R., Salvador, F. J., Gimeno, J., & Bracho, G. (2008). A NEW METHODOLOGY FOR CORRECTING THE SIGNAL CUMULATIVE PHENOMENON ON INJECTION RATE MEASUREMENTS. Experimental Techniques, 32(1), 46-49. doi:10.1111/j.1747-1567.2007.00188.xDesantes, 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.2008.10.008PASTOR, J., JAVIERLOPEZ, J., GARCIA, J., & PASTOR, J. (2008). A 1D model for the description of mixing-controlled inert diesel sprays. Fuel, 87(13-14), 2871-2885. doi:10.1016/j.fuel.2008.04.017Payri, 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.2005.05.00

Synergetic Application of Zero-, One-, and Three-Dimensional Computational Fluid Dynamics Approaches for Hydrogen-Fuelled Spark Ignition Engine Simulation

Nowadays hydrogen, especially if derived from biomass or produced by renewable power, is rising as a key energy solution to shift the mobility of the future toward a low-emission scenario. It is well known that hydrogen can be used with both internal combustion engines (ICEs) and fuel cells (FCs); however, hydrogen-fuelled ICE represents a robust and cost-efficient option to be quickly implemented under the current production infrastructure. In this framework, this article focuses on the conversion of a state-of-the-art 3.0L diesel engine in a hydrogen-fuelled Spark Ignition (SI) one. To preliminarily evaluate the potential of the converted ICE, a proper simulation methodology was defined combining zero-, one-, and three-dimensional (0D/1D/3D) Computational Fluid Dynamics (CFD) approaches. First of all, a detailed kinetic scheme was selected for both hydrogen combustion and Nitrogen Oxides (NOx) emission predictions in a 3D-CFD environment. Afterward, to bring the analysis to a system-level approach, a 1D-CFD predictive combustion model was firstly optimized by implementing a specific laminar flame speed correlation and, secondly, calibrated against the 3D-CFD combustion results. The combustion model was then integrated into a complete engine model to assess the potential benefit derived from the wide range of flammability and the high flame speed of hydrogen on a complete engine map, considering NOx formation and knock avoidance as priority parameters to control. Without a specific modification of turbocharger and combustion systems, a power density of 34 kW/L and a maximum brake thermal efficiency (BTE) of about 42% were achieved, thus paving the way for further hardware optimization (e.g., compression ratio reduction, turbocharger optimization, direct injection [DI]) to fully exploit the advantages enabled by hydrogen combustion

Thermolytic reverse electrodialysis heat engine: model development, integration and performance analysis

Salinity gradient heat engines represent an innovative and promising way to convert low-grade heat into electricity by employing salinity gradient technology in a closed-loop configuration. Among the aqueous solutions which can be used as working fluid, ammonium bicarbonate-water solutions appear very promising due to their capability to decompose at low temperature. In this work, an experimentally validated model for a reverse electrodialysis heat engine fed with ammonium bicarbonate-water solutions was developed. The model consists of two validated sub-models purposely integrated, one for the reverse electrodialysis unit and the other for the stripping/absorption regeneration unit. The impact of using current commercial membranes and future enhanced membranes on the efficiency of the system was evaluated, along with the effect of operating and design parameters through sensitivity analyses. Results indicated that exergy efficiency up to 8.5% may be obtained by considering enhanced future membranes and multi-column regeneration units

A fundamental study of injection and combustion characteristics of neat Hydrotreated Vegetable Oil (HVO) as a fuel for light-duty diesel engines

Renewable fuels are essential for decarbonization because they can significantly reduce greenhouse gas emissions compared to fossil fuels. Among the renewable fuels capable to be mass produced, Hydrotreated Vegetable Oil (HVO) is attracting major attention thanks to its noticeable physical and chemical properties, which make it a viable and effective diesel substitute. In this work, the fundamental injection and combustion characteristics of neat Hydrotreated Vegetable Oil (HVO) as an alternative fuel for light-duty diesel engines have been analysed by means of an extensive experimental campaign based on a single injection strategy in both spray and engine laboratory tests. A Euro 6 light-duty diesel engine was selected as a case study for the research activity, comparing the neat HVO injection, combustion, and emission characteristics with those of a B5 diesel fuel. Differences were firstly scrutinized in terms of injection rate and main spray characteristics, these latter by means of both spray imaging and Phase Doppler Anemometry (PDA) techniques. Then, engine tests were performed for three different operating conditions (at low, medium, and medium–high load, respectively) to investigate the combustion properties and emissions. Furthermore, the sensitivity of neat HVO and B5 diesel to different Exhaust Gas Recirculation (EGR), Start of Injection (SOI), and injection pressure levels was also explored. In conclusion, HVO showed an excellent adaptability to nowadays automotive diesel engines also as a neat fuel without the necessity of a specific engine recalibration, allowing to achieve an impressive 85% reduction in terms of CO emissions on a WTW basis, with a limited increase (lower than 4%) in volumetric fuel consumption and with impressive reductions in terms of CO and HC emissions (more than 40 and 50 %, respectively)

Bismuth-based quadruple therapy following H. Pylori eradication failures: A multicenter study in clinical practice

Background & Aims: Helicobacter pylori (H. pylori) eradication in patients who failed one or more therapeutic attempts remains challenging. This study aimed to assess the efficacy of three-in-one capsules bismuth-based quadruple therapy (Pylera®) in these patients managed in clinical practice. Methods: This was a prospective, open-label, multicenter study enrolling consecutive, adult patients with persistent H. pylori infection following at least one standard therapy. All patients received a rescue quadruple therapy with Pylera (3 capsules four times daily) and esomeprazole 20 mg (1 tablet twice daily) for 10 days. H. pylori eradication was assessed by using Urea Breath Test 4-6 weeks following therapy ending. H. pylori eradication rates, compliance, and side-effects were calculated. Results: A total of 208 patients in the 9 participating centres were enrolled. Overall, 180 patients were successfully cured from the infection, accounting for 86.5% (95% CI 81.9-91.2) and 92.3% (95% CI 88.6-96.1) eradication rates at intention-to-treat analysis and at per protocol analysis, respectively. Cure rates were similar across patients who failed one to three previous therapy attempts, but the success rate fell to 67% after 4 or more therapy failures. Compliance to therapy was good in 198 (95.2%) patients, whilst in 7 (5.3%) cases the therapy was interrupted within 5 days due to side effects. A total of 97 (46.6%) patients complained of at least one side effect; nausea, diarrhea and vomiting were the most frequently reported. Conclusions: Our study found that this bismuth-based quadruple therapy is highly effective as second-line and rescue therapy for H. pylori eradication in clinical practic