Heat transfer in turbocharger turbines under steady, pulsating and transient conditions

National audienc

Low Diversity of Alkhurma Hemorrhagic Fever Virus, Saudi Arabia, 1994–1999

Alkhurma hemorrhagic fever virus (genus Flavivirus, AHFV) was recently identified as the agent of a viral hemorrhagic fever in Saudi Arabia and characterized serologically and genetically as a variant genotype of Kyasanur Forest disease virus (KFDV). Since viral diagnosis and vaccine development may be hindered by genetic diversity, this study was intended to address AHFV genetic heterogeneity. Eleven strains isolated from hospitalized patients from 1994 to 1999 in Saudi Arabia were sequenced in the envelope, NS3, and NS5 genes. Homologous sequences were compared and used to look for patterns reflecting specific evolution associated with spatiality, temporality, infection pathway, and disease prognosis. Genetic analyses showed low diversity, which suggests a slow microevolution. Evaluation of divergence times showed that AHFV and KFDV ancestral lineage diverged 66–177 years ago, and the diversity observed within the studied AHFV strains reflected a 4- to 72-year period of evolution

Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes

The exhaust energy can represent up to 40% of the fuel chemical energy in turbocharged internal combustion engines. In order to calculate properly the available energy of the exhaust gases, a critical parameter is the temperature downstream the turbine. The prediction of this temperature will also benefit the two-stage turbochargers and after-treatment modelling that affects brake specific fuel consumption, exhaust gases emissions and the scavenging process. In this paper, turbocharger heat transfer losses have been modelled using a lumped capacitance model coupled with one-dimensional whole-engine simulation software. The data from the simulations of a turbocharged Diesel engine, with and without the turbocharger heat transfer model, have been compared with experimental measurements performed in an engine test bench. The analysis is focused on studying the influence in turbocharger outlet temperatures and predicting the engine performance. The main result of the study is the improvement in the prediction of both compressor and turbine outlet temperatures (up to an improvement of 70 K). The results from the model allow analysing how heat transfer losses are split in the turbocharger and quantifying the importance of heat transfer phenomena in turbocharger efficiency, at full load conditions and as a function of engine speed.This work has been financial supported by Jaguar Land Rover Ltd. It has been also partially supported by Ministerio de Economia y Competitividad, Secretaria de Estado de Investigacion, Subdireccion de proyectos de investigacion (TRA2013-40853-R).Serrano Cruz, JR.; Olmeda González, PC.; Arnau Martínez, FJ.; Dombrovsky, A.; Smith, L. (2015). Turbocharger heat transfer and mechanical losses influence in predicting engines performance by using one-dimensional simulation codes. Energy. 86:204-218. https://doi.org/10.1016/j.energy.2015.03.130S2042188

Detail from "Children at Play"

This fresco, located in Coit Tower, portrays children enjoying a pleasant day with their friends and parents.This fresco, located in Coit Tower, portrays children enjoying a pleasant day with their friends and parents

Hunting the watchmen: The Ulster Defence Regiment and IRA strategy

The Ulster Defence Regiment (UDR) were unique within the context of the Troubles-79% of their nearly 200 UDR casualties came while off-duty. This article frames these attacks, assesses their impact and concludes whether certain individuals (such as Catholics) were specifically targeted. I demonstrate that such tactics were ruthless pragmatism and were influenced by regionality. The IRA focused on eliminating security forces, although some pursued personal vendettas. I forward that overall, the IRA consistently demonstrated a concept of target legitimacy – ‘legitimacy frameworks’. I conclude that these practices are not only common, but should be anticipated in counterinsurgencies

Fluid dynamic modelling of junctions in internal combustion engine inlet and exhaust systems

National audienc

Analysis of unsteady flow through a throttle valve using CFD

National audienc

Impact de l'hygiène de vie et des polluants environnementaux sur la fertilité humaine

Depuis plusieurs dizaines d'années, on constate un déclin de la qualité spermatique et une augmentation du délai nécessaire à la conception. Il est donc légitime de s'interroger sur les facteurs pouvant être incriminés dans cette baisse de la fertilité et de déterminer de quelle manière il est possible d'optimiser ses chances de conception. La fertilité peut être influencée par la qualité de l'hygiène de vie notamment par la nutrition, qu'elle soit quantitative (surpoids, obésité) ou qualitative (nature des apports nutritionnels), la prise de substances toxiques (tabac, alcool, cannabis). La pollution environnementale, dont les perturbateurs endocriniens, sont également des facteurs pouvant jouer un rôle sur la capacité à concevoir.NANTES-BU Médecine pharmacie (441092101) / SudocSudocFranceF

An experimental evaluation of the thermal effects on engine valve model

International audienc