1,722,381 research outputs found
Lacalamita, M., Mesto, E., Mongelli, G., Mameli, P., Cerri, G., Pinto, D., Buccione, R., Schingaro, E. 2023. Characterization of Red Muds as valuable resource for sustainability. Convegno Nazionale Italiano sui Geopolimeri. Bari February, 16-17 2023.
No full textOrder-disorder, Polytypes and Twinning in the Crystal Structure of vurroite
No full textVurroite, ideally Pb20Sn2(Bi,As)22S54Cl6, is a complex mineral type, where the two minor chemical components, Sn and Cl, act as essential constituents together with Pb, Bi, As and S 1, 2. X-ray single crystal data on vurroite strongly indicate an orthorhombic Fcentred symmetry 1, 3. In this study the crystal structure of vurroite is interpreted as an OD structure belonging to the category III of OD structures composed of equivalent layers 4. The application of the OD procedures allowed the derivation of the OD-groupoid family (λ and σ operations), as well as the MDO (Maximum Degree of Order) structures. The layer symmetry (λ) is A(2)mm, the interlayer symmetry (σ) consists of a glide plane n1/2,1/2 and two-fold screw axes parallel to 010 and 001 with the translation components 1⁄4 b and 1⁄4 c, respectively. For this OD family two MDO polytypes exists. The former has monoclinic symmetry, C12/c1, whereas the latter is monoclinic, P12/c1. The OD treatment of the crystal structure of vurroite allowed to prove that the true symmetry of this mineral is monoclinic and that the apparent orthorhombic symmetry observed for the X-ray pattern of the measured crystal is due to a twinning phenomenon. Prof. S. Merlino is gratefully acknowledged for his contribution on the OD interpretation of the structure of vurroite. 1 Pinto D., PhD thesis, University of Bari, 2004, 165. 2 Garavelli A.,Mozgova N.N., Orlandi P., Bonaccorsi E., Pinto D., Borodaev Y., Canadian Mineralogist, 2005, in press. 3 Pinto D., Balić-Žunić T., Bonaccorsi E., Makovicky E., 26th Nordic Geological Winter Meeting, Uppsala, Sweden,2004, 106-107, abstract. 4 Dornberger-Schiff K., Abh. Dtsch. Akad. Wiss. Berlin. Kl. Chem. Geol. Biol., 1964, 3, 1-107
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
Pulsed reactivity on LaCoO3-based perovskites: A comprehensive approach to elucidate the CO oxidation mechanism and the effect of dopants
No full textIn this contribution we focus on three lanthanum cobaltate perovskites: undoped, Sr-doped, and Cudoped to investigate the effect of doping on reactivity. The catalysts are prepared by a citric acid route and characterized by X-ray diffraction, temperature programmed desorption, energy dispersive X-ray analysis, and BET specific surface area measurement. A pulsed reactivity experiment has been set up in order to investigate the catalytic oxidation reaction of carbon monoxide (CO). Within a single experiment, this analysis allowed evaluation of the oxygen storage capacity (OSC) and derivation of kinetic parameters to compare the behavior of the different catalysts. Compared to the traditional steady-state experiments, a clear insight into the reaction mechanism is obtained, providing a deeper mechanistic view on the role of the perovskite oxide. An active role of the oxygen species of the catalysts has been demonstrated, with the temperature of 350 degrees C representing a threshold for the activation of bulk oxygen mobility. The effect of doping has been discussed in terms of enhancement of the reducibility of the perovskite oxides, resulting in lower activation energies for the catalytic oxidation of CO
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