1,721,085 research outputs found
Electrification of Chemical Engineering: A New Way to Intensify Chemical Processes
No full textThe increasing use of fossil fuels as an energy source has resulted in a serious problem regarding two of their main drawbacks: (i) the exhaustion of these resources and (ii) the greenhouse gas (GHG) emissions associated with their use [...
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
Microwave-Assisted Steam Reforming in an Ultracompact Catalytic Reactor
No full textIn the last years the decarbonization of industrial chemical processes has become necessary and in this sense the use of H2 as an energy vector is strategic. Electrified hydrogen production may allow to avoid energy-related emissions. In this work, the use of microwaves as energy source for the methane steam reforming (MSR) process is proposed. Therefore, starting from commercial silicon carbide monoliths, two Ni/Ceria/Alumina structured catalysts able to absorb microwaves (with two different Ni loadings) were prepared, characterized, and tested at a gas hourly space velocity (GHSV) of 3300 h-1 by means of a specifically set-up laboratory plant. The results showed that the catalyst with the higher Ni loading (15wt% with respect to Ceria and alumina) approached the thermodynamic equilibrium values for both methane conversion and hydrogen yield at about 780°C. In terms of energy efficiency, both the systems showed an average value of 50%. These results evidenced that an effective and feasible process intensification is possible with this innovative system, mainly for a distributed hydrogen production
Microwave-susceptible structured catalysts for the highly selective dehydrogenation of propane to propylene
No full textAppropriate 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
Highly-efficient hydrogen production through the electrification of OB-SiC nickel structured catalyst: Methane steam reforming and ammonia cracking as case studies
No full textThe aim of this work is the preparation and the electrification of Ni_CeO2_Al2O3/OBSiC (Oxygen Bonded SIlicon Carbide) based foams used in two different endothermic reactions for H2 production: methane steam reforming and ammonia cracking. In particular, the heating of the catalytic foams occurs by the Joule effect, and to guarantee a uniform temperature profile in both the axial and radial direction, two different heating resistances were used. In addition, the high tortuosity together with the very high thermal conductivity of the OBSIC carrier, allow to overcome the heat and mass transfer limitations achieving a better control of the reaction behavior. Wet impregnation method was adopted for the Ni and Ce deposition, while the final catalysts was characterized through Hg penetration technique, Scanning Electron Microscope (SEM), N2 adsorption @77 K for the specific surface areas (SSA) determination and X-ray diffraction (XRD). The methane steam reforming and ammonia cracking tests were both carried out, in the same reactor, but at different space velocity values (WHSV). The results obtained are exciting, not only in terms of equilibrium approach and hydrogen production, but also in terms of energy consumption as kWh/Nm3 of H2 produced. In particular, in the case of methane steam reforming the results showed an energy consumption E [kWh/Nm3 H2] equal to 1.21 obtained at WHSV equal to 6.2 h−1, very close to the theoretical limit of 0.98 kW h/Nm3 H2. Also, for ammonia cracking, the energy consumption was very promising considering the scale of our reactor, with 1.5 kW h/Nm3 H2 obtained at a WHSV of 2.27 h−1, considering the theoretical limit equal to 0.71 kW h/Nm3 H2
Most recent advances in diesel engine catalytic soot abatement: Structured catalysts and alternative approaches
No full textDiesel engine emissions are typically composed of several hundred chemical compounds, partly present in the gas phase and partly in solid phase as particles, the so-called particulate matter or soot. The morphology of the catalyst is an important characteristic of soot particles’ abatement, since a good contact between catalyst and soot is mandatory. For practical purposes, the active species should be supported as a film on the structured carrier, in order to allow simultaneous soot filtration and combustion. This review focuses on the most recent advances in the development of structured catalysts for diesel engine catalytic soot combustion, characterized by different active species and supports, as well as by different geometric configurations (monoliths, foams, ceramic papers, or wire mesh); the most important peculiar properties are highlighted and summarized. Moreover, a critical review of the most recent advances in modeling studies is also presented in this paper. In addition, some highlights on some of the most recent alternative approaches proposed for limiting the soot emissions from diesel engines have been given, delineating feasible alternatives to the classical strategies nowadays used
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