1,721,101 research outputs found
Deceleration of the Cold Flow in the Vortex Tube
Get PDFEnhancement of the cold flow deceleration unit is considered in the paper to improve the energetic efficiency of the vortex tube. It was shown that the gradual expansion of the cross-section in the cold flow diffuser is inefficient for reducing the gas flow velocity in presence of its significant rotation. Installation of a blade grid at the entrance to the cold flow diffuser was suggested for interruption of the flow swirling. A notable reduction of the energy losses has been demonstrated improving the efficiency of the vortex tube. © Published under licence by IOP Publishing Ltd
Novel transonic nozzle for Ranque-Hilsch vortex tube
No full textThe process of the vortex flow formation in the Ranque-Hilsch vortex tube is studied. Starting from deficiencies of the existing vortex tubes, a novel type for the transonic nozzle is suggested and designed. The proposed nozzle is different from the existing classical ones by the presence of additional supersonic section placed after the blades. This section creates controlled conditions for acceleration of the vortex flow to supersonic speed. Analysis of the gas flow in the transonic nozzle using 3D RANS simulations showed that slightly improper selection of nozzle dimensions may lead to destabilization of the vortex flow and deterioration of the vortex tube performance. Simplified semi-one-dimensional model of swirling gas flow was derived and utilized for correction of the nozzle dimensions in order to stabilize the flow. Detailed validation of this model against full 3D RANS simulations demonstrated its applicability for preliminary engineering computations. It was demonstrated that application of the novel transonic nozzle extends the region in the energy separation chamber occupied by the supersonic vortex. This results in increase of both temperature separation effect and vortex tube energy efficiency. Main advantages and disadvantages of the novel transonic nozzle are summarized in the concluding section
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
Breakthrough directions in chemical reaction engineering at the intersection of fundamental research and engineering science approaches
No full textChemical reaction engineering has gradually evolved into a scientific discipline that studies the interaction of chemical reactions with numerous physical factors, such as heat and mass exchange, phase transfer, fluid dynamics etc., in chemical reactors of various scale and type. The methodology of this discipline is based on physical chemistry, catalysis, physics, mathematics, advanced computing and data processing technologies and other advanced areas of science and technology. Chemical reaction engineering is a general methodology for efficient tool for development, scale-up and optimization of chemical reactors and chemical processes. CRE covers a wide range of existing and future technologies for the petroleum and natural gas processing, metallurgy, chemical industry, energy manufacturing and storage, manufacturing of renewable feedstocks, environment protection and utilization of wastes, biotech and pharmaceutical industries. The purpose of this VSI is to publish selected novel contributions across the entire innovative research range - from the fundamental foundations of the reaction engineering to applied developments for emerging applications. These contributions were selected from the proceedings of the XIV International Conference on Chemical Reactors ChemReactor-24, which was organized by Boreskov Institute of Catalysis of the Siberian Branch of the Academy of Sciences, Novosibirsk, Russia together with Politecnico di Milano, Italy. The conference was traditionally held under the auspices of the European Federation of the Chemical Engineering. The conference took place during 12–17 September 2021. Though, all previous conferences were held in a usual format, the pandemia limitations forced us to make it the online event. Despite complicated conditions, the conference brought together 251 researchers and engineers from 38 countries all over the world. The conference was traditionally devoted to the fundamental aspects and practical application of the catalytic processes and chemical reactors, as well as to the development of the novel technologies
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
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