1,721,008 research outputs found
Analysis of the Impact of the WLTP Procedure on CO2 Emissions of Passenger Cars
No full textUntil 2017 in Europe the Type Approval (TA) procedure for light duty vehicles for the determination of pollutant emissions and fuel consumption was based on the New European Driving Cycle (NEDC), a test cycle performed on a chassis dynamometer. However several studies highlighted significant discrepancies in terms of CO2 emissions between the TA test and the real world, due to the limited representativeness of the test procedure. Therefore, the European authorities decided to introduce a new, up-to date, test procedure capable to closer represent real world driving conditions, called Worldwide Harmonized Light Vehicles Test Procedure (WLTP). This work aims to analyze the effects of the new WLTP on vehicle CO2 emissions through both experimental and simulation investigations on two different Euro 5 vehicles, a petrol and a diesel car, representatives of average European passenger cars. The study also considers the effect of the engine warm-up and the impact of the start-stop technology in this new TA scenario. Since the WLTP imposes higher test mass and Road Loads (RLs), as well as higher driving cycle dynamics, a 44% cycle energy demand increase for the petrol car and a 23% increase for the diesel car were found. However, CO2 emissions increased in the same proportion only for the diesel car, while they increased only by 10% for the petrol car, thanks to the improvement of the average internal combustion engine efficiency along the WLTC cycle. Finally, the effectiveness of the start-stop in terms of fuel (or CO2) savings, was found to be almost halved for both vehicles when passing from the NEDC to the WLTP
The development of the World-wide Harmonized Test Procedure for Light Duty Vehicles (WLTP) and the pathway for its implementation into the EU legislation
No full textIn order to assess vehicle performances in terms of criteria compounds, CO2 emissions and fuel/energy consumption, laboratory tests are mainly carried out. During these tests a vehicle is driven on a chassis dynamometer (which simulates the resistances the vehicle encounters during its motion) to follow a predefined test-cycle. In addition, all the conditions to run a test must strictly adhere to a predefined test-procedure. This is necessary to ensure that all the tests are carried out in a comparable way, following the requirement set by the relevant legislation. Test results are indeed used to assess the vehicle compliance with respect to, e.g., emission limits or to evaluate the fuel consumption that will be communicated to the customers.
Any region in the world follows its own approach to carry out these types of tests. This has a series of drawbacks for both vehicle manufacturers and regulating authorities, leading in any case to a plethora of different conditions and results. In order to make a step towards the harmonization of the different test-procedures, the United Nations Economic Commission for Europe (UNECE) in 2009 launched a project for the development of a World-wide harmonized Light duty Test Procedure (WLTP), including also a new test cycle. Objective of the present paper is to provide a brief description of the WLTP and to outline the possible pathway for its introduction in the European Legislation
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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