1,720,962 research outputs found
Multi-scale and multi-physics models for photochemical fuel generation
No full textL'abstract è presente nell'allegato / the abstract is in the attachmen
An overview on modelling approaches for photochemical and photoelectrochemical solar fuels processes and technologies
Get PDFPhoto-electrochemical and photocatalytic technologies are promising solutions for solar fuel production and involve a number of physical and chemical phenomena. We provide an overview of numerical and analytical tools to describe such phenomena occurring at disparate time and space scales within devices such as photo-electrochemical cells and photo-chemical reactors. On one hand, chemical phenomena include photo-induced electron transfer, charge separation, recombination, equilibrium reactions between species in solutions and adsorption reactions. On the other hand, examples of physical phenomena are the transport of chemical species or self-assembling of molecular structures. In this respect, we critically review macroscale continuum models for transport phenomena combined with kinetic descriptions including their possible coupling with models at even lower scales. We specifically focus on atomistic and coarse-grained models able to represent the local environment of the reactive interfaces such as photoelectrodes or supra-molecular assemblies. The critical role of the latter structures on photochemical conversion is highlighted: Therefore, morphological structure of self-assemblies, such as micelles and monolayers, in solution and at the solid–liquid or gas–liquid interfaces are also discussed. Finally, important scientific gaps are identified and possible perspectives for future research outlooked
Atomistic modelling of water transport and adsorption mechanisms in silicoaluminophosphate for thermal energy storage
Get PDFSAPO-34 – a silicoaluminophosphate microporous material – has recently attracted a great attention in the field of sorption thermal storage, since it is characterized by good water adsorption behavior (i.e. type V adsorption isotherms) and low regeneration temperature (i.e. 80 °C, for instance available by standard solar thermal energy collectors). However, the nanoscale mechanisms of water transport and adsorption in the microporous framework of SAPO-34 cannot be fully unveiled by experiments alone. In this work, water adsorption onto SAPO-34 is for the first time studied by means of an atomistic model built upon experimental evidence. First, Monte Carlo simulations are employed to set up a convenient atomistic model of water/SAPO-34 interactions, and numerical adsorption isotherms are validated against experimental measures. Second, the validated model is used to study the water diffusion through SAPO-34 by molecular dynamics simulations, and to visualize preferential adsorption sites with atomistic detail. Such atomistic model validated against experiments may ease the investigation and in silico discovery of silicoaluminophosphates for thermal storage applications with tailored adsorption characteristics
A multi-scale perspective of gas transport through soap-film membranes
Get PDFSoap films represent unique aqueous systems, whose physical properties can be tuned by acting on their nanoscale structure. Here, we specifically focus on transport properties through membranes realized in the form of soap films. While diffusion phenomena in the water core and surfactant monolayers are described using a continuum model, molecular dynamics is used to compute the static and dynamical properties of water, gases and the surfactant in the monolayers which is hexaethylene glycol monododecyl ether (C12E6). The obtained atomistic details are then incorporated into a drift-diffusion model for consistently extracting a boundary condition for the above continuum model describing transport phenomena at a larger scale. Numerical predictions are validated against experimental data from both properly designed experiments and the literature. Finally, the developed model is used to estimate the characteristic time for disparate gas mixing when initially separated by soap film membranes
A novel concept of photosynthetic soft membranes: a numerical study.
Get PDFWe focus on a novel concept of photosynthetic soft membranes, possibly able to allow the conversion of solar energy and carbon dioxide (CO[Formula: see text]) into green fuels. The considered membranes rely on self-assembled functional molecules in the form of soap films. We elaborate a multi-scale and multi-physics model to describe the relevant phenomena, investigating the expected performance of a single soft photosynthetic membrane. First, we present a macroscale continuum model, which accounts for the transport of gaseous and ionic species within the soap film, the chemical equilibria and the two involved photocatalytic half reactions of the CO[Formula: see text] reduction and water oxidation at the two gas-surfactant-water interfaces of the soap film. Second, we introduce a mesoscale discrete Monte Carlo model, to deepen the investigation of the structure of the functional monolayers. Finally, the morphological information obtained at the mesoscale is integrated into the continuum model in a multi-scale framework. The developed tools are then used to perform sensitivity studies in a wide range of possible experimental conditions, to provide scenarios on fuel production by such a novel approach
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Design and testing of a device for the characterization of gas transfer through soap films and measurement protocol based on color matching
Get PDFMetals in Catalysis, Biomimetics & Inorganic Material
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
- …
