1,721,118 research outputs found
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
Andrea Balbo (a cura di), I frammenti degli oratori romani dell’età augustea e tiberiana. Parte prima. Età augustea, 2004
No full textKnecht Daniel. Andrea Balbo (a cura di), I frammenti degli oratori romani dell’età augustea e tiberiana. Parte prima. Età augustea, 2004. In: L'antiquité classique, Tome 77, 2008. pp. 438-439
Influence of CeALO3 nanoparticles on the performances of silane coatings for AZ31 alloy
No full textThis research investigates the influence exerted by CeAlO3 nanoparticle additions on the protective performances of some silanes (3-mercapto-propyl-trimethoxy-silane, PSH; vinyltrimethoxy-silane, VS; 3-(trimethoxysilyl)propyl-methacrylate, PSMA; 1,2-bis(triethoxysilyl)-ethane, BTSE), used as conversion coatings for AZ31 Mg alloy. Among the tested silanes, PSH is the most efficient one, followed by the vinyl derivatives (VS and PSMA) and finally by BTSE. In fact, in comparison to the other silanes, PSH determines a more significant reduction in the cathodic and anodic polarization currents and maintains a higher degree of protection for at least 24 h. Afterwards, it gradually loses its protective effects. Conversely, VS, BTSE, PSMA conversion coatings allow the onset of significant corrosion rates within a few hours. In all silane coatings, the addition of CeAlO3 nanoparticles increases both the coating protectiveness and the persistence of the protective action. In particular, the higher the silane coating performance, the greater the enhancing effect of the nanoparticles. Thus, CeAlO3 nanoparticles particularly improve the protectiveness of PSH conversion coating, which displays an inhibiting efficiency of over 99%, after 168 h of immersion in 0.1 M NaCl solution. On this coating type containing nanoparticles, the electrochemical impedance spectra (EIS) and the scanning electron microscopy (SEM) observations evidence an increase in the layer thickness from 3.5±0.5 μm to 5.6±0.6 μm and a decrease in the layer porosity. Therefore, the nanoparticles induce slower diffusion processes, which particularly slow down the anodic reaction, so hindering the overall corrosion process
Studio di nuovi inibitori della corrosione per applicazione in calcestruzzo carbonatato inquinato da cloruri
No full textL’obiettivo di questa ricerca consiste nell’individuare nuove formulazioni di inibitori, utili a contrastare la corrosione delle armature nel calcestruzzo, in presenza sia di cloruri sia di carbonatazione e di studiarne il meccanismo di inibizione.
Prove precedenti a tempi brevi di esposizione hanno mostrato che una miscela di sostanze, in particolare il glicerofosfato di sodio (GPH) e il 2-amminobenzoato di sodio (2AMB), è in grado di rallentare in maniera significativa la corrosione dell’acciaio sia in soluzione carbonatata contenente cloruri, sia in calcestruzzo, mentre le sostanze da sole non risultavano efficaci. Perciò sono state condotte ulteriori prove in soluzione simulata in presenza di GPH, 2AMB, altri sali sodici di derivati amminici dell’acido benzoico (ovvero il 3-amminobenzoato (3AMB) e il 4-amminobenzoato di sodio (4AMB)) e loro miscele con GPH.
Il comportamento a corrosione dell’acciaio è stato investigato durante 3 giorni di immersione, tramite tecniche elettrochimiche (curve di polarizzazione e spettroscopia di impedenza elettrochimica, a tempi diversi di immersione). Si è potuto verificare che fra le sostanze studiate solo 3AMB usato da solo presenta un’ottima efficienza inibitrice, mentre il GPH offre inibizione sinergica della corrosione se aggiunto a 2AMB o 4AMB, ma non a 3AMB.
Al termine delle esposizioni all’ambiente aggressivo sono state applicate tecniche di indagine superficiali, quali la microscopia elettronica ad emissione di campo (FESEM), la spettroscopia infrarossa (FTIR) e la spettroscopia di fotoelettroni (XPS), per valutare il meccanismo di inibizione della miscela GPH / 2AMB
Resistance to localized corrosion of lean duplex stainless steels after brief thermal treatments
No full textLean duplex stainless steels are biphasic steels with a low nickel and/or molybdenum content, which represent an interesting and cost
effective alternative to the employment of the most common austenitic stainless steels (such as AISI 304 and 316) or traditional more
expensive duplex steels (such as DSS 2205). However, during production and welding operations, a relatively brief permanence (a few
minutes or tens of minutes) in the critical temperature range between 650 and 950 °C, induces the formation of undesirable secondary
phases (mainly chromium and molybdenum carbides and nitrides) which influence the alloy corrosion resistance. This paper compares
the pitting corrosion resistance of three lean duplex alloys, LDSS 2101, DSS 2304 and LDSS 2404, before and after heat treatments of
10 min at 650, 750 and 850 °C and analyses the correlated pitting propagation modes. With this aim, critical pitting temperature (CPT)
measurements were performed in 0.1 M NaCl solution. The results show that concerning the solubilized alloys their localized corrosion
resistance is in good agreement with PRENMn indications. Thermal treatments, and in particular that at 750 °C, reduce the pitting corrosion
resistance of the alloys, mainly in the case of LDSS 2404 and 2101, due to the impoverishment in passivating elements (especially
chromium and molybdenum) in regions close to precipitates. The heat treated DSS 2304 alloy shows a more limited reduction of its
performances in comparison to the solubilized material and its CPT does not vary significantly with the treatment temperature. This
phenomenon can be linked to the low nitrogen content of the alloy, which limits the volume of precipitates during heat treatments,
allowing to reduce the extent of impoverishment in passivating elements
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