1,721,003 research outputs found
Mauro, E.; Levi, L.; Fabbrini, S. & Pasquino, G. (2023). La Formazione del Sistema Partitico Europeo – The Formation of the European Party System
Full text linkBOOK REVIEW OF:
Mauro, E.; Levi, L.; Fabbrini, S. & Pasquino, G.
La Formazione del Sistema Partitico Europeo – The Formation of the European Party System
Latina, Atlantide Editore, 2023, 120 p.
ISBN: 978-88-99580-88-
La2O3 as primer for supporting La0.9Ce0.1CoO3 +/-delta on cordieritic honeycombs
No full textTo understand better the effect of La2O3 as primer for the preparation of honeycomb supported La0.9Ce0.1CoO3 +/- delta catalyst, some samples were prepared starting from different La-precursors. Physical and morphological properties of both the primer-coated honeycomb and its precursors (as-prepared and after thermal treatment at different temperature) have been investigated by TGA, TPD-MS. XRD and SEM. Calcination at high temperature brought about a rearrangement of both primer and active phase morphology. When La acetate was used as precursor, such a transformation seemed not to alter substantially the morphology of the primer layer, leading to a poorer anchoring to the support, with deep cracking and exfoliation of the La oxide platelets so formed. By contrast, when the primer precursor was La nitrate, the higher reactivity of the hydroxynitrates, forming during calcination, with respect to both the active phase and the honeycomb, led to a more uniform and compact La2O3 layer, anchoring much better the perovskite to the monolith support
Perovskite catalysts for the catalytic flameless combustion of methane : preparation by flame-hydrolysis and characterisation by TPD-TPR-MS and EPR
Full text linkA new method was employed for the preparation of a set of lanthanum cobaltites of general formula La1-(x)M(x)CoO3+(δ) with M=Ce, Eu and x=0, 0.05, 0.1, 0.2. All the samples thus prepared were nanostructured, thermally very stable and characterised by highly crystalline perovskite-like structure and high surface area. Their activity as catalysts for the catalytic tameless combustion (CFC) of methane was by ca. one order of magnitude higher than that of their analogues, prepared through the usual calcination-milling (CM) procedure. Adsorption of oxygen was accompanied by formation of paramagnetic species. Desorption of preadsorbed oxygen was dependent on the nature of the doping element and on the value of the stoichiometric coefficient x of their formula. A correlation between the temperature of the maximal rate of oxygen release and catalytic activity was found. The following scale of activity for the title reaction versus x values could be set up: 0.1Ce>0.05Ce>0>0.05Eu>0.1 Eu≃0.2Ce. The higher activity of Ce-doped catalysts as compared to those doped with Eu was found to be related to the strength of the bond between oxygen and Co ions
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
Effect of preparation parameters on SrTiO(3+d) catalyst for the flameless combustion of methane
No full textEFFECT OF PREPARATION PARAMETERS ON SrTiO3 CATALYST FOR THE FLAMELESS COMBUSTION OF METHANE
C. Oliva(a), S. Cappelli(a), L. Fabbrini(a), V. Alberti(a), A. Kryukov(b) and Lucio Forni(a)
(a) Dip.CFE, Università di Milano (Italy) (b) D.I.Mendeleev University, Moscow (Russia)
Two nano-size-particle samples (T1 and T2) of SrTiO3 have been prepared by a recently proposed innovative method, based on flame-hydrolysis(FH) of aqueous solutions. Besides identical amounts of the other precursors’ salts, either 3 mol excess of tartaric acid (sample T1) or 1.5 mol excess of citric acid (sample T2) as complexing agent were added to the precursors’ solution. The catalysts were characterised by BET, XRD, SEM, EPR. Both of them consisted of SrTiO3 perovskite with some SrCO3 as impurity, T1 being more crystalline than T2. T1 showed the most active as catalyst for the flameless combustion of methane. Both Ti4+/O2- systems and isolated T3+ ions contributed to the EPR spectrum of T1, whilst only the former was present in T2, but with O2- in different position. From the gzz value of the Ti4+/O2- systems, the energy gap (E) for the electron transfer between Ti3+ and O2 to form O2- was calculated, leading to E(T1) = 144; E(T2) = 334 kJ mol-1. This difference, likely connected to the different temperature attained during the FH process with the two different complexing agents, can explain the higher activity of the T1 sample, occurring through the reaction O2- + Ti4+ Ti3+ + O2
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