1,721,007 research outputs found
Cuma, Foro. Le terrecotte architettoniche arcaiche e classiche dai riempimenti del podio del Capitolium (Rescigno pp. 280-282, 290-293)
No full textSUPPORTED CuO/Ce1-xZrxO2 CATALYSTS FOR THE PREFERENTIAL OXIDATION OF CO IN H2-RICH GASES
No full textThe catalytic properties of CuO supported on ceria or ceria-zirconia mixed oxides have been investigated in the preferential oxidation of CO in H 2-rich gases. CuO/CeO2 shows very high activity towards the oxidation of CO with a light-off temperature of about 70°C. This catalyst is very selective for the oxidation of CO rather than of H2 in the low temperature region (70-120°C), while at higher temperatures, the oxidation of hydrogen begins, causing of a maximum of CO conversion to arise with increasing temperatur
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
Supported CuO/Ce1-xZrxO2 catalysts for the preferential oxidation of CO in H2-rich gases
No full textVariations 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
ON THE ROLE OF REDOX PROPERTIES OF CuO/CeO2 CATALYSTS IN THE PREFERENTIAL OXIDATION OF CO in H2-RICH GASES
No full textCuO/CeO2 catalysts with CuO content ranging from 0.5 wt.% to 8 wt.%, prepared by wet impregnation of commercial ceria, have been tested for the preferential oxidation of CO (CO-PROX) under H2-rich conditions at 70-210°C. Catalytic activity increases up to 4 wt.% CuO content, with less concentrated catalysts showing higher intrinsic activity. Catalysts have been characterized by means of XRD, BET analysis and UV spectroscopy. Formation of segregated CuO clusters has been detected for Cu richest CuO/CeO2 sample. Redox properties have been deeply investigated using TP analysis (H2 TPR, CO TPR, TPO) of fresh or pre-treated samples. Participation of surface ceria, induced by the strong interaction with copper, to reduction/oxidation reactions in the temperature range explored (up to 430*C) has been demonstrated. Different copper species and their reactivity towardsH2 and CO have been individuated by comparing TPR of fully oxidized catalysts with those of partially oxidized catalysts. Active species have been identified as copper-ceria sites able to oxidize CO even at room temperature and to be re-oxidized by O2 at the same temperature. Transient experiments have been carried out at different temperature using a diluted mixture starting from oxidized or reduced catalysts and followed by a H2 TPR of the used samples. The results of these tests have showed that active centres for CO oxidation contain copper in the +2 oxidation state. At T > 100°C some reduced copper sites are stabilized which promote H2 oxidation thus lowering the selectivity of the CO-PROX proces
KINETICS OF THE PREFERENTIAL OXIDATION OF CO OVER CuO/CeO2 CATALYSTS IN H2-RICH GASES
No full textThe influence of reaction parameters such as temperature, contact time, and O2, CO, H2, CO2, and H2O partial pressures on the catalytic performances of 4 wt % CuO/CeO2 in the CO-PROX process (the preferential oxidation of CO) has been investigated in a fixed-bed reactor. Catalyst appears very active (light-off at 70 C) and selective; reaction kinetics is weakly depressed by CO2 and H2O and not significantly increased with increasing O2 concentration, while the reaction order in CO is variable with temperature ranging from values <1 up to 110 C and >1 at higher temperatures. A power-law rate equation fitted the experimental data under typical CO-PROX conditions in order to evidence the lower activation energy of the catalytic oxidation of CO with respect to H2. A Langmuir-Hinshelwood type reaction rate is able to describe the catalytic behavior in the whole field of experimental conditions explore
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
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