1,720,959 research outputs found
Studying Remediation Processes Using a Dimensionless Classification of Potential Storage Sites
No full textInternational audienceThe current CO 2 storage operation requires a thorough integrated qualification process consisting in storage evaluation, leakage risk analysis and remediation planning in case of leaking. One of the current methods considered as a remediation method is the reproduction of the CO 2. This paper presents results of a " generic " qualification of storage remediation capacity, based on a methodology using a dimensionless analysis of the potential aquifer sites supposed to qualify for storage. The methodology consists in building a database of dimensionless numbers governing the storage, leading to an experimental design based on the minimum/maximum values found within the database. Further reduction of the cases under study was achieved through a fractional experimental method, consisting in balancing the experiments, therefore achieving a workable statistical representative number of cases. Parameters difficult to obtain from the field were generated from literature and reproduction of CO 2 simulations were performed on all cases, representing the full variability of dimensionless numbers encountered in the field. The reproduction was initiated after an injection period. Results were analyzed in terms of the net ratio of CO 2 produced/CO 2 injected leading to the concept of " remediation " efficiency, attached to any site to which the similar dimensionless numbers are associated. In that sense the approach is considered as being generic. The qualitative behavior of the CO 2 plume and the over-pressure criteria governing the safety of the storage are also discussed
Study of N 2 as a Mean to Improve CO 2 Storage Safety
No full textInternational audienceCurrent CO 2 storage operations in aquifer reservoirs are naturally limited, among other parameters, by entry pressures encountered in cap-rocks, thus limiting over-pressures allowed during the storage process. The injection of nitrogen in a zone just below the cap-rock, prior CO 2 injection, could be a viable protective measure to increase the storage safety by lowering the leakage risk and increasing the maximum allowable reservoir pressure. The physical background of the beneficial impact of Nitrogen on the caprock entry pressure is based on the higher N 2 –brine interfacial tension (IFT) compared to CO 2 –brine. As a maximum possible effect (for pure N 2-brine systems), IFT could increase by a factor of two, yielding correspondingly to the same increase of allowable pressure. However, the N 2 injection decreases the storage volume and the trade-off must be studied carefully. The IFT spread decreases rapidly with the mixing ratio of CO 2 in the N 2. Mixing can occur due to advective processed induced by differential absolute pressure due to CO 2 injection and also due to vertical mixing due to different partial pressure. Injection placement is carefully studied carefully, especially the vertical conformance as well as saturation rarefaction. In order to study the feasibility of such approach for different storage conditions, a series of CO 2 injection simulations were performed within a generic characterization framework based on dimensionless numbers. A database of dimensionless numbers governing the storage was build, using literature information. The application of an experimental design based on the minimum/maximum values found within the database identified a series of cases to be simulated, further reduced by a fractional approach of such design. The scenarios simulated consisted in a CO 2 injection within a reservoir storage zone found at some distance from the N 2 zone, just below the cap-rock, followed by a resting period during which the CO 2 saturation is monitored. The N 2 zone is refined, rendering possible the study of the the potential mixing and contamination with CO 2. For all case members of the data base, the CO 2 conformance was studied in terms of possible mixing and override of the CO 2 plume. Discussion of the potential benefits and possible difficulties are addressed. Conclusions were drawn considering the possible field application of such a technique, identifying a-priori sites more suitable for such a technique, based on the dimensionless numbers characterizing them
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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