Monitoring and analysing oil condition to generate maintenance savings: a case study in a CNG engine powered urban transport fleet

The authors from Universitat Politecnica de Valencia wish to thank Spanish Grant TRA2008-06508 from Ministerio de Ciencia e Innovacion - Direccion General de Investigacion for supporting this work. Mr Gomez thanks the UPV for his grant 2011-S2-5003 in the frame of the PAID programme.Tormos Martínez, BV.; Olmeda González, PC.; Gomez Estrada, YA.; Galar, D. (2013). Monitoring and analysing oil condition to generate maintenance savings: a case study in a CNG engine powered urban transport fleet. Insight - Non-Destructive Testing & Condition Monitoring. 55(2):84-87. https://doi.org/10.1784/insi.2012.55.2.84S848755

Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations

The research leading to these results has received funding from the European Union's Horizon 2020 Programme under the ESTiMatE project, grant agreement No. 821418. The authors thankfully acknowledge the computer resources at MareNostrum and the technical support provided by Barcelona Supercomputing Center (IM-2020-3-0022, IM-2021-1-0016).García-Oliver, JM.; Pastor Enguídanos, JM.; Olmeda-Ramiro, I.; Both, A.; Mira, D. (2022). Combustion modeling in a pressurized gas turbine burner using Large-Eddy Simulations. 690-699. http://hdl.handle.net/10251/19067769069

Effect of in-cylinder swirl on engine efficiency and heat rejection in a light-duty diesel engine

[EN] During the last years, the growing awareness about the impacts of climate change lead to an increase in the importance of the efficiency over other criteria in the design of internal combustion engines. In this framework, the heat transfer to the combustion chamber walls can be considered as one of the main sources of indicated efficiency diminution. Hence, the main objective of this research is to thoroughly assess the effect of the swirl ratio on the heat rejection to the chamber walls, and thus on the efficiency, of a fully instrumented four-cylinder direct-injection diesel engine with variable swirl ratio (covering the range from 1.4 to 3). The analysis, based on the engine global energy balance, includes a combination of theoretical and experimental tools such as thermal flow measurement and dedicated thermocouples in the cylinder head and liner. Considering the results, it is shown that an increase in swirl ratio leads to a heat transfer enhancement, along with important changes on the combustion development. As a result of the combination of these two effects, it is shown that intermediate swirl ratios can slightly improve engine efficiency at low load, while increasing swirl worsens the combustion process and efficiency at high load. However, convective heat transfer increases about 3% of the fuel energy in the chamber when swirl ratio increases from 1.4 to 3. The heat rejection characterization is completed with the analysis of the wall temperatures. Despite the observed trends, heat transfer does not seem to be the only key issue for explaining the indicated and brake efficiencies, thus the pumping work plays an important role due to the effect of reducing the intake section to generate the swirl motion.This work was supported by GM Global R&D and the Spanish Ministry of Economy and Competitiveness (TRA2013-41348-R).Olmeda, 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. https://doi.org/10.1177/1468087417693078S8192181-

The diurnal cycle of shallow cumulus clouds over land: A single-column model intercomparison study

An intercomparison study for single-column models (SCMs) of the diurnal cycle of shallow cumulus convection is reported. The case, based on measurements at the Atmospheric Radiation Measurement program Southern Great Plains site on 21 June 1997, has been used in a large-eddy simulation intercomparison study before. Results of the SCMs reveal the following general deficiencies: too large values of cloud cover and Cloud liquid water, unrealistic thermodynamic profiles, and high amounts of numerical noise. Results are also strongly dependent on vertical resolution.These results are analysed in terms of the behaviour of the different parametrization schemes involved: the convection scheme, the turbulence scheme, and the cloud scheme. In general the behaviour of the SCMs can be grouped in two different classes: one class with too strong mixing by the turbulence scheme, the other class with too strong activity by the convection scheme. The coupling between (subcloud) turbulence and the convection scheme plays a crucial role. Finally, (in part) motivated by these results several models have been successfully updated with new parametrization schemes and/or their present schemes have been successfully modifie

Cognitive appraisal of environmental stimuli induces emotion-like states in fish

The occurrence of emotions in non-human animals has been the focus of debate over the years. Recently, an interest in expanding this debate to non-tetrapod vertebrates and to invertebrates has emerged. Within vertebrates, the study of emotion in teleosts is particularly interesting since they represent a divergent evolutionary radiation from that of tetrapods, and thus they provide an insight into the evolution of the biological mechanisms of emotion. We report that Sea Bream exposed to stimuli that vary according to valence (positive, negative) and salience (predictable, unpredictable) exhibit different behavioural, physiological and neuromolecular states. Since according to the dimensional theory of emotion valence and salience define a two-dimensional affective space, our data can be interpreted as evidence for the occurrence of distinctive affective states in fish corresponding to each the four quadrants of the core affective space. Moreover, the fact that the same stimuli presented in a predictable vs. unpredictable way elicited different behavioural, physiological and neuromolecular states, suggests that stimulus appraisal by the individual, rather than an intrinsic characteristic of the stimulus, has triggered the observed responses. Therefore, our data supports the occurrence of emotion-like states in fish that are regulated by the individual's perception of environmental stimuli.European Commission [265957 Copewell]; Fundacao para a Ciencia e Tecnologia [SFRH/BD/80029/2011, SFRH/BPD/72952/2010]info:eu-repo/semantics/publishedVersio

Thermo- and Fluid-Dynamic Processes in Direct Injection Engines. THIESEL2016 special issue

Payri, R.; Margot, X. (2017). Thermo- and Fluid-Dynamic Processes in Direct Injection Engines. THIESEL2016 special issue. International Journal of Engine Research. 18(1-2):3-5. doi:10.1177/1468087416680663S35181-

A Blind Circadian Clock in Cavefish Reveals that Opsins Mediate Peripheral Clock Photoreception

Evolution during millions of years in perpetual darkness leads to mutations in non-visual opsin genes (Melanopsin and TMT opsin) and an aberrant, blind circadian clock in cavefish

Retention and diffusion of radioactive and toxic species on cementitious systems: Main outcome of the CEBAMA project

Cement-based materials are key components in radioactive waste repository barrier systems. To improve the available knowledge base, the European CEBAMA (Cement-based materials) project aimed to provide insight on general processes and phenomena that can be easily transferred to different applications. A bottom up approach was used to study radionuclide retention by cementitious materials, encompassing both individual cement mineral phases and hardened cement pastes. Solubility experiments were conducted with Be, Mo and Se under high pH conditions to provide realistic solubility limits and radionuclide speciation schemes as a prerequisite for meaningful adsorption studies. A number of retention mechanisms were addressed including adsorption, solid solution formation and precipitation of radionuclides within new solid phases formed during cement hydration and evolution. Sorption/desorption experiments were carried out on several anionic radionuclides and/or toxic elements which have received less attention to date, namely: Be, Mo, Tc, I, Se, Cl, Ra and 14C. Solid solution formation between radionuclides in a range of oxidation states (Se, I and Mo) with the main aqueous components (OH−, SO4 −2, Cl−) of cementitious systems on AFm phases were also investigated