1,720,966 research outputs found
Performance of shallow borehole of spiral-tube ground heat exchanger / Jalaluddin, Rustan Tarakka and Akio Miyara
Full text linkThe use of geothermal energy has been recognized as a possible solution for reducing emissions. This energy source is a renewable and green energy sources with wide applications such as for space air conditioning and hot water supply. A ground heat exchanger (GHE) can be applied in the space air conditioning system for exchanging heat with the ground. This study present an investigation of thermal performance of shallow spiral-tube GHE buried in the 5 m depth. The performance of this GHE is investigated by numerical method using CFD code. The performance of the spiral-tube GHE is 46.9 Watt per meter borehole depth in laminar flow and 64.6 Watt per meter borehole depth in turbulent flow. Comparison between the spiral-tube and the conventional U-tube GHEs shows the possibility to reduce borehole depth and installation cost. Using the spiral-tube GHE can reduce the borehole about a half compared with using the conventional U-tube GHE. Shallow spiral-tube GHEs can be arranged in series and parallel configurations to meet the needs in the application
Flow Separation Characteristics of Tandem Minibus Model Configuration
Full text linkThis study aims to determine the characteristics of the pressure coefficient and fluid flow separation in a tandem minibus model using the Fluent 6.3.26 computational method and experimental testing in a wind tunnel. Pressure measurements are taken by installing 14 pressure taps connected to a manometer on a 1:40-scale minibus model. Tests were conducted at five different distances between minibuses in a series configuration at seven-speed levels. The results showed that at the highest speed tested, minimal flow separation occurred at a distance ratio of L/D = 0.455, with values of CP = -0.083 in the first minibus and CP = -0.250 in the second minibus. This configuration is identified as the optimal spacing to reduce aerodynamic disturbance in the tandem minibus system
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
Effect of Weir Height on Undershot Water Wheel Turbine Performance
Full text linkUndershot water wheel turbines are suitable for operation in low-elevation regions and locations with very low water head. Turbines with curved blade configurations are commonly implemented to optimize efficiency. This research examines how variations in weir height influence the performance of undershot turbines when operating under limited water flow conditions. A turbine with six blades is tested experimentally and numerically using seven weir heights ranging from 0.02 m to 0.14 m. The study used both experimental and computational fluid dynamics approaches, employing the dynamic mesh model. The results indicate that applying a curved weir as a passive flow-control device can significantly enhance turbine efficiency. At a weir height of 0.10 m, the maximum efficiency reached 80.83% based on the experimental approach and 84.69% based on the computational approach. These findings demonstrate the potential of weir-assisted undershot turbines for energy harvesting in shallow rivers under low-flow conditions
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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