International audienceLean burn natural gas fuelled spark-ignition engines are particularly attractive regarding environmental performance. Nevertheless, few data exist concerning lean combustion in gas engines in terms of ignition delay, combustion duration and combustion rate. Such data are necessary when using thermodynamic models to predict energy and environmental performance. The present study proposes a contribution to such combustion characterization as a function of spark timing, air excess and engine load. This work is based on experimental cylinder pressure measurements in an open chamber engine on the one hand, and on a one-zone thermodynamic model used as a heat release analysis tool on the other hand. Results obtained, such as mass fraction burned, ignition delay and combustion duration, allow identification of the parameters used in the Wiebe function, a semi-empirical law that is frequently used to describe the combustion in predictive models

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BackgroundThere is an increasing need to evaluate the production and impact of medical research produced by institutions. Many indicators exist, yet we do not have enough information about their relevance. The objective of this systematic review was (1) to identify all the indicators that could be used to measure the output and outcome of medical research carried out in institutions and (2) enlist their methodology, use, positive and negative points.MethodologyWe have searched 3 databases (Pubmed, Scopus, Web of Science) using the following keywords: [Research outcome* OR research output* OR bibliometric* OR scientometric* OR scientific production] AND [indicator* OR index* OR evaluation OR metrics]. We included articles presenting, discussing or evaluating indicators measuring the scientific production of an institution. The search was conducted by two independent authors using a standardised data extraction form. For each indicator we extracted its definition, calculation, its rationale and its positive and negative points. In order to reduce bias, data extraction and analysis was performed by two independent authors.FindingsWe included 76 articles. A total of 57 indicators were identified. We have classified those indicators into 6 categories: 9 indicators of research activity, 24 indicators of scientific production and impact, 5 indicators of collaboration, 7 indicators of industrial production, 4 indicators of dissemination, 8 indicators of health service impact. The most widely discussed and described is the h-index with 31 articles discussing it.DiscussionThe majority of indicators found are bibliometric indicators of scientific production and impact. Several indicators have been developed to improve the h-index. This indicator has also inspired the creation of two indicators to measure industrial production and collaboration. Several articles propose indicators measuring research impact without detailing a methodology for calculating them. Many bibliometric indicators identified have been created but have not been used or further discussed.

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