1,720,955 research outputs found
Laminar burning velocity in hydrogen-oxygen-nitrogen mixtures
No full textAs today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from periodic table. As today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from the periodic table. Combustion of hydrogen has been observed as a renewable and efficient green method to replace the burning of hydrocarbon fuels with higher efficiency in the combustion systems. Even though hydrogen can be efficient in some ways, there are different factors that can be hazardous to the environment as well as to human beings. Due to the safety reasons for hydrogen utilization in the combustion systems, the required studies have been done to investigate the behaviors of hydrogen while mitigating the problems for safety purposes. In order to replace energy sources from fossil fuels, a required predictive and reliable modeling such as the laminar premixed burning velocity of the mixture is mainly used. In the method, the chemical reactions during the combustion process are based on and studied to proceed with the evaluation of the laminar burning velocity of the hydrogen-oxygen- nitrogen mixture. For numerical computations of chemical reactions and laminar burning flame speed, the chemical kinetics model and the tool Cantera are used. In the present study, the laminar burning velocity of the hydrogen-oxygen-nitrogen mixture is evaluated to find how hydrogen explosion in a confined space can be mitigated by varying the oxygen concentration. The concept that reducing oxygen concentration in the cloud can decrease the heat release and laminar burning velocity of the premixed gas is proposed. The study aims to find the burning velocity in hydrogen-oxygen-nitrogen mixtures by performing experiments in a 20-liter explosion vessel. The evaluation of laminar burning velocity is done on different concentrations of the mixture and different ignition energy. The literature study is first done, and the experiments are performed to investigate the laminar flame speed, Markstein length, stretch rate, and laminar burning velocity. Besides, the simulation tool Cantera is used to calculate the laminar burning velocity of the mixture and to validate the mechanisms and methods used in this study
Laminar burning velocity in hydrogen-oxygen-nitrogen mixtures
Get PDFAs today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from periodic table. As today’s world is demanding a greener environment where greenhouse gas emission and global warming are much reduced, hydrogen has become the most promising element among others from the periodic table. Combustion of hydrogen has been observed as a renewable and efficient green method to replace the burning of hydrocarbon fuels with higher efficiency in the combustion systems. Even though hydrogen can be efficient in some ways, there are different factors that can be hazardous to the environment as well as to human beings. Due to the safety reasons for hydrogen utilization in the combustion systems, the required studies have been done to investigate the behaviors of hydrogen while mitigating the problems for safety purposes. In order to replace energy sources from fossil fuels, a required predictive and reliable modeling such as the laminar premixed burning velocity of the mixture is mainly used. In the method, the chemical reactions during the combustion process are based on and studied to proceed with the evaluation of the laminar burning velocity of the hydrogen-oxygen- nitrogen mixture. For numerical computations of chemical reactions and laminar burning flame speed, the chemical kinetics model and the tool Cantera are used. In the present study, the laminar burning velocity of the hydrogen-oxygen-nitrogen mixture is evaluated to find how hydrogen explosion in a confined space can be mitigated by varying the oxygen concentration. The concept that reducing oxygen concentration in the cloud can decrease the heat release and laminar burning velocity of the premixed gas is proposed. The study aims to find the burning velocity in hydrogen-oxygen-nitrogen mixtures by performing experiments in a 20-liter explosion vessel. The evaluation of laminar burning velocity is done on different concentrations of the mixture and different ignition energy. The literature study is first done, and the experiments are performed to investigate the laminar flame speed, Markstein length, stretch rate, and laminar burning velocity. Besides, the simulation tool Cantera is used to calculate the laminar burning velocity of the mixture and to validate the mechanisms and methods used in this study
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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