1,720,968 research outputs found
Thermal and flow investigation of MHD natural convection in a nanofluid-saturated porous enclosure: an asymptotic analysis
No full text
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
Μελέτη της στατικής διαμόρφωσης ενός στοιχείου αντιμετώπισης του πλάσματος υπό την μορφή μίας τριχοειδούς πορώδους διάταξης (CPS)
No full textThe present PhD dissertation focuses on the modelling of alternative plasma facing components (PFCs) in the form of liquid metals in order to circumvent problems generated by plasma-wall interaction, namely handling the excessive heat and electric current loads generated in the bulk of the reactor and directed towards the divertor. The free surface PFCs constitute one of the most critical technological challenges of future fusion reactors. Out of the proposed liquid metal concepts, this PhD dissertation deals with the jet/drop curtain and, primarily, the Capillary Porous System (CPS) concepts.Regarding the jet/drop concept pertaining to the ISTTOK experiments, the simplified model developed in the context of the present study, provides a proof of principle explanation for the observed deflection from the original trajectory in a Tokamak environment. Furthermore, this PhD dissertation is an attempt, through first principles studies, to describe the major phases of the CPS operation. More specifically, it models-explains what happens during the preparation phase, that is to say before the machine is “turned on”. Subsequently, it delves into the replenishment process of liquid metal, following its depletion due to a large external heat load, identifying the interplay between the different forces that act towards pushing liquid lithium out of the porous matrix or resist its motion. Finally, the current PhD dissertation studies extensively the static arrangement of the liquid metal film that rests onto the CPS outer surface, as a function of the reservoir overpressure, the substrate nature and topography, external field forces and wetting properties of the working liquid metal on the substrate. It was thus seen for realistic reservoir overpressures, i.e. approaching vacuum conditions, that micron or even submicron coatings are established as a result of the balance between pressure and adhesive forces. In this regime, the pore size and mesh topography start playing an important role in the static arrangement. Furthermore, a threshold reservoir overpressure exists beyond which a static arrangement with the liquid metal coating the CPS is not possible. In the presence of a magnetic field and an incoming electric current the above static arrangement is modified within each pore due to the Maxwell stresses that develop, while the interface with plasma is pushed out of the pore as the magnetic pressure increases.Η παρούσα Διδακτορική Διατριβή επικεντρώνεται στην μοντελοποίηση εναλλακτικών στοιχείων αντιμετώπισης του πλάσματος υπό μορφή υγρών μετάλλων έτσι ώστε να προστατευτούν τα τοιχώματα του αντιδραστήρα από προβλήματα που σχετίζονται με την αλληλεπίδρασή τους με το πλάσμα, όπως τα πολύ υψηλά θερμικά φορτία και τα μεγάλα φορτία ηλεκτρικού ρεύματος που δημιουργούνται στο κέντρο του αντιδραστήρα και κατευθύνονται προς τον divertor. Τα στοιχεία αντιμετώπισης του πλάσματος υπό μορφή υγρών μετάλλων αποτελούν μία από τις πιο ζωτικής σημασίας τεχνολογικές προκλήσεις των μελλοντικών αντιδραστήρων σύντηξης. Η παρούσα Διδακτορική Διατριβή επικεντρώνεται στη συστοιχία από τζετ ή σταγόνες και κυρίως στην τριχοειδή πορώδη διάταξη (CPS).Όσο αναφορά την μελέτη σχετικά με την συστοιχία από τζετ ή σταγόνες, το απλοποιημένο αριθμητικό μοντέλο παρέχει μια πρώτη εξήγηση για την εκτροπή των παραπάνω από την αρχική τους πορεία σε ένα περιβάλλον TOKAMAK. Επιπλέον, η παρούσα Διδακτορική Διατριβή προσπαθεί μέσα από βασικές αρχές να περιγράψει τις κύριες φάσεις λειτουργίας του CPS. Συγκεκριμένα, μοντελοποιεί-εξηγεί τι συμβαίνει πριν η μηχανή "ανοίξει". Εν συνεχεία, μελετάει τη διεργασία ανατροφοδότησης του υγρού μετάλλου, που ακολουθάει την εξάντλησή του εξαιτίας ενός τεράστιου θερμικού φορτίου, έτσι ώστε να αναγνωριστούν οι κυρίαρχες δυνάμεις που λαμβάνουν χώρα και ενεργούν έτσι ώστε να σπρώχνουν το υγρό μέταλλο προς τα έξω ή ανθίστανται στην κίνησή του. Τέλος, η παρούσα Διδακτορική Διατριβή μελετάει εκτενώς την στατική διαμόρφωση του υγρού μετάλλου υπό μορφή υγρού υμένα που σχηματίζεται στην άνω επιφάνεια του CPS, ως συνάρτηση της επίδρασης της διαφοράς πίεσης, της τοπογραφίας του πορώδους υποστρώματος, εξωτερικών πεδιακών δυνάμεων και ιδιοτήτων διαβροχής του υγρού μετάλλου με το στερεό υπόστρωμα. Εν συντομία, διαπιστώθηκε ότι για ρεαλιστικές διαφορές πίεσης, δηλαδή κοντά σε καταστάσεις κενού, υγροί υμένες τάξεως μικρομέτρων και υπο-μικρομέτρων σχηματίζονται. Σε αυτή την περιοχή το μέγεθος του πόρου και η τοπογραφία του αρχίζουν να παίζουν πολύ σημαντικό ρόλο στην στατική διαμόρφωση. Επίσης, βρέθηκε μία κρίσιμη τιμή της διαφοράς πίεσης, πέραν της οποίας η στατική διαμόρφωση δεν μπορεί να επιτευχθεί. Στην παρουσία ενός μαγνητικού πεδίου και ενός προσπίπτοντος ηλεκτρικού ρεύματος η προαναφερθείσα στατική διαμόρφωση επηρεάζεται εξαιτίας των τάσεων Maxwell που αναπτύσσονται, ενώ η διεπιφάνεια με το πλάσμα σπρώχνεται έξω από τον πόρο όσο η μαγνητική πίεση αυξάνεται
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
- …
