1,721,034 research outputs found
A short overview of ITER-like pulsed MCF reactors application as hybrid nuclear systems for actinides transmutation
No full textThe fusion-fission hybrid reactor is a promising technology that is likely to assume more and more importance in the
global energy scenario in the coming years. Although this kind of nuclear system dates back to the earliest times of the
fusion projects (when it was recognized that using fusion neutrons to “support” nuclear fission fuel cycle could widely
increase the exploitation of the fusion plants), it appears to receive relatively limited attention since the mid-1980s.
Notwithstanding, hybrid fusion fission systems have been already studied for some decades, in the most prominent
laboratories and a relatively large bibliography was produced. Obviously much more papers on this topic have been
published in more recent years.
The fusion-fission hybrid concept can use both the nuclear fusion and fission processes: in a typical application, neutrons
from fusion reactions can be used to sustain the fission chain of a sub-critical system. This is the basis of the hybrid
reactor concept: neutron generation is not produced just in neutron-induced fissions, but also as a “by-product” of the
fusion reactions inside the nuclear fusion reactor “core” (i.e., respectively, the void chamber for MCF or the fuel particles
for ICF). This method allows to have an intrinsically safe facility (with a higher efficiency than a fusion reactor itself and
a harder neutron energy spectrum than a fission reactor) which could be suitable for nuclear waste transmutation, too.
In the last years, many initiatives on nuclear waste transmutation were proposed in order to reduce the long-term
radiotoxicity of the wastes by eliminating a high fraction of the TRU from the SNF before their final disposal. In this
frame, as already anticipated, hybrid fusion-fission systems could have an additional degree of freedom because of the
independent source: this means that the neutron spectrum can be (reasonably) tailored for the transmutation purposes.
In the present study a special focus has been devoted to the transmutation of SNF from fission reactors loaded in a
fusion system, operated under the hypothesis to take into account the behaviour of a planned “real” (i.e. pulsed) MCF
(ITER-like) plant
A Preliminary Assessment of the Transmutation Potentialities for an ITER-like FW Sector Loaded with MA
Full text linkThe fusion-fission hybrid reactor is a promising technology that is likely to assume an increasingly important role in the global energy scene in the coming years. This kind of reactor can use both the nuclear fusion and fission processes to produce energy: neutrons from fusion reactions are used to sustain the fission of a sub-critical system. This method allows to have an intrinsically safe facility, with higher efficiency than a fusion reactor itself and with a harder neutron energy spectrum than a fission reactor, which could be suitable for nuclear waste transmutation. This paper, in particular, analyzes a type of hybrid reactor for the transmutation of Minor Actinides (MA). Nuclear waste, in the oxide form, is inserted as an element of the First Wall (FW) of an ITER-like fusion reactor. The aim is to demonstrate the feasibility of the transmutation of the MA characterized by higher long term radiotoxicity into shorter lived nuclides. The neutron transport in a detailed 3D geometrical model of the ITER reactor (B-lite) was performed by MCNP6 code, while the transmutation of the MA loaded in a single element of the FW was performed by SERPENT2 code. A pulsed ITER-like irradiation scenario was used. The analysis, which must be considered as a preliminary feasibility study, lead to very promising results, which could be further improved with a longer DEMO-like irradiation scenario and a larger number of MA loaded (“fission waste”) elements loaded in the FW
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
- …
