1,720,961 research outputs found
Performance of clay based buffer material developed for use in a nuclear fuel waste disposal vault
No full textThis study is designed to evaluate water diffusion parameters of clay based buffer material (mixture of clay and sand) used in nuclear fuel waste disposal vault for the following three cases: (a) No volume change in the soil fabric with no air loss. (b) No volume change in the soil fabric with air loss. (c) A complete change in the soil fabric with air loss.One dimensional diffusion type unsaturated flow equation was solved by finite difference method. Powell's optimization technique was used to minimize the material parameters in the proposed diffusion function. The adopted technique makes the use of both theory and experimental data. In this concern several tests have been performed for the three aforementioned conditions to measure the volumetric water content and the soil water potential distributions as a function of time and space.The calculated diffusion parameters were used to predict the volumetric water content and the soil water potential as a function of space and time for longer period of time
Performance of unsaturated clay based barrier under opposing thermal and hydraulic gradients
No full textExperimental and numerical studies of coupled heat and moisture flow induced in an unsaturated soil by simultaneously imposed temperature and hydraulic gradients, in opposite directions, are presented. The experimental portion of the study was designed to provide information on the moisture and temperature distributions in relation to elapsed time and distance from the heat source. Tests were conducted on three different materials: (a) buffer (equal proportion of silica sand and sodium bentonite), (b) backfill (25 percent low swelling clay and 75 percent crushed granite rock), and (c) sand. Each material was compacted to its maximum dry density and optimum water content. The experiments were performed with the application of external hydraulic and temperature gradients in opposite directions. Swelling pressure tests were performed to quantify the local swelling pressure as well as the wall's effect on the resultant reaction pressure. The effect of swelling pressure on hydraulic pressure and local volume change has been studied using the experimental results.In the theoretical part of this research, a numerical solution of the governing coupled heat and mass flow equations was obtained via the implicit finite difference method. The solution was then used in conjunction with Powell's optimization technique to back-calculate the transport coefficients. A sensitivity analysis of the volumetric water content and temperature with respect to the transport coefficient was performed. Using the calculated transport parameters, the moisture content profile was predicted.The experimental results have shown that moisture flows from the hot and cold ends to the middle part of the soil column. The developed local swelling pressure appears to have significant effect on moisture movement and hydraulic pressure. The use of a sand layer between the buffer and waste container has been observed to be very useful in reducing the shrinkage of the buffer material.The numerical results strongly support the dependence of the transport coefficients, in the governing coupled heat and moisture flow equations, on temperature and volumetric water content
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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