1,720,966 research outputs found
Thermoacoustic cooler to meet medical storage needs of rural communities in developing countries – High pressure system
No full textDevelopment of a thermoacoustic cooler driven by a thermoacoustic engine is presented. The engine is of standing wave type and is coupled to a coaxial travelling wave cooler. This is to test the principles of building a linear thermoacoustic engine-cooler coupling that would be easy to make and thus lend itself to the deployment in rural communities of developing countries. These often lack electrical grid connection but require refrigeration capabilities for storing vital medical supplies. Such function could be provided by using waste heat from everyday cooking (biomass combustion) to drive the proposed device. In the presented laboratory demonstrator, the heat input is mimicked by resistive heating (varied from 1.75 to 2.5 kW), the acoustic resonator is made from 6-in. diameter stainless steel pipe with the total device length of about 3.7 m, and the working gas is air at the mean pressure of 10 bar. The system is modelled using DeltaEC and its performance verified experimentally. The lowest temperature, obtained at zero cooling load, is −19.7 °C, while the cooling load of 120 W can be applied at the cooling temperature of +8 °C, which is one of the criteria for storing medical supplies. The maximum COPR is 5.94%.</p
Numerical studies of co-axial travelling-wave thermoacoustic cooler powered by standing-wave thermoacoustic engine
No full textDesign and optimisation of a co-axial travelling-wave thermoacoustic cooler (TWTC) powered by a standing-wave thermoacoustic engine (SWTE) is conducted based on the linear thermoacoustic theory. The target application is storage of medical supplies in rural communities of developing countries with no access to electricity grid, where waste heat from cooking can be used as energy input. The design is guided by construction simplicity and low cost. Thus the SWTE/TWTC coupling is enclosed in a constant-diameter resonator which accommodates a compact co-axial configuration of the TWTC. Following earlier experiments, working fluid is air at 10 bar, and operating frequency is 50 Hz. Parameters such as the ratio of the cross-sectional area of the cooler to feedback inertance and stack and regenerator geometries, have been optimised for maximum system efficiency. Here, at the target input power of 600 W a drive ratio of 7.75% can be obtained, leading to the cooling load of 133 W at 250 K. This corresponds to the SWTE thermal-to-acoustic efficiency of 17% and TWTC COP of 1.9, and the combined efficiency of 22.2%. The simulations are to inform the build of an enhanced prototype of the proposed device. A detailed discussion and guidelines for practical builds are provided.</p
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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