1,720,961 research outputs found
Numerical investigation of a porous media combustor in a small-scale diesel engine
No full textThe application of porous media in compression ignition engines has significant effects on its combustion behavior. In this work, a Computational Fluid Dynamics (CFD) analysis of combustion in diesel engine is performed for 100% load, and the effects of porous media addition in the combustion chamber are quantified. With a porosity of 66.7%, silicon carbide is applied as porous media of cylindrical shape in the modified piston bowl in the conventional engine. The combustion analysis outputs include average cylinder-pressure, temperature; Nitrogen Oxides (NOx), mean mixture fraction, turbulent kinetic energy, total energy and modified Peclet number. The results of the CFD study for the cases of non-porous media are validated against the performed baseline experimental analysis, whereas porous media predictions are compared to the state-of-the-art studies available in the literature. In presence of porous media, the average peak pressure and temperature are found to drop by similar to 26 bar and similar to 550 K, respectively, as compared to that of non-porous media. Furthermore, NOx emissions are significantly reduced up to 97%. The generation of turbulent kinetic energy is enhanced by 86% for PM leading to an increment of similar to 36% in the thermal energy conversion than without a porous media. (C) 2019 Elsevier Ltd. All rights reserved
Effects of different biofuels blends on performance and emissions of an automotive diesel engine
No full textThe impact of blending Ultra Low Sulfur Diesel (ULSD) with different biofuels, obtained from Rapeseed Methyl Ester (RME) and Hydrotreated Vegetable Oil (HVO) respectively, on the performance and emissions of a European passenger car diesel engine was assessed in this paper. First, the hydraulic behavior of the common rail fuel injection system was analyzed in terms of injected volume, injection rate, spray global shape, single jet tip penetration and cone angle with both RME and HVO blends in comparison with neat ULSD. Afterwards, the impact of biofuel blends on engine full load performance was analyzed, both for the standard calibration and for a calibration which was specifically adapted to biofuels characteristics. The effects of biofuel blends on brake specific fuel consumption and on regulated exhaust emissions were then evaluated at different part load operating conditions, representative of the New European Driving Cycle. Finally, the sensitivity of the different fuels to different calibration settings, such as Exhaust Gas Recirculation (EGR) and injection timing, was studied in order to investigate which further emission benefits could be achieved by means of a more extensive engine re-calibration
Influence on the performance and emissions of an automotive Euro 5 diesel engine fueled with F30 from Farnesane
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
