1,720,975 research outputs found
Phase separation of VO2 and SiO2 on SiO2-Coated float glass yields robust thermochromic coating with unrivalled optical properties
No full textVanadium dioxide displays thermochromic properties based on its structural phase transition from monoclinic VO2 (M) to rutile VO2 (R) and vice versa, and the accompanying reversible metal-insulator transition. We developed a single layer coating comprising VO2 (M) and SiO2. We applied the coating from an alcoholic solution comprising vanadium(IV) oxalate complex and pre-oligomerized tetra ethoxy silane to SiO2-coated float glass using dip coating, and thermally annealed the dried xerocoat in a two-step process. The addition of SiO2 as coating matrix resulted in non-scattering coatings with low surface roughness and random distribution of VO2 nanodomains (≤200 nm). Furthermore, the formation of the coating, comprising a phase separation yielding SiO2 and VO2 nanodomains during the thermal anneal, was studied in detail. The coating displays unrivalled optical properties, combining high visible light transmission Tvis > 60% and large solar modulation ΔTsol ≥ 10%. When applied in insulating glass units, the coating has a positive impact on energy savings for heating and cooling of buildings in intermediate climates, which we demonstrated through building energy simulations. For a typical house in the Netherlands, energy savings up to 24% were obtained. In addition, we demonstrate a coating stability comparable to current energy-efficient window coatings during processing into and in insulating glass units through (accelerated) life time tests
The influence of siloxane side-chains on the photovoltaic performance of a conjugated polymer
Full text link\u3cp\u3eThe effect of gradually replacing the branched alkyl side chains of a diketopyrrolopyrrole (DPP) conjugated polymer by linear side chains containing branched siloxane end groups on the photovoltaic performance of blends of these polymers with a common fullerene acceptor is investigated. With an increasing proportion of siloxane side chains, the molecular weight and solubility of the polymers decreases. While the siloxane containing polymers exhibit a higher hole mobility in field-effect transistors, their performance in solar cells is less than the polymer with only alkyl sides chains. Using grazing-incidence wide-angle X-ray scattering, transmission electron microscopy, and fluorescence spectroscopy we identify two main reasons for the reduced performance of siloxane containing polymers in solar cells. The first one is a somewhat coarser phase-separated morphology with slightly wider polymer fibers. This is unexpected as often the fiber width is inversely correlated with polymer solubility. The second one is stronger non-radiative decay of the pristine polymers containing siloxane side chains.\u3c/p\u3
Design Guidelines for Building and Infrastructure Integrated Photovoltaics
No full textThe demand for renewable energy is increasing as efforts to decarbonize energy sources continue. Photovoltaic (PV) generation systems are the main contributor to the growth of renewable energy, but limited land availability in countries such as Belgium and Netherlands poses a challenge to their deployment. Integrated PV (IPV) can be a promising solution, but requires special consideration regarding electrical and fire safety, efficiency, durability, cost, and environmental impact in the design process. This study aims to assist in designing PV Semi-Fabricates (SF) by offering choices of materials, technologies and structures. The general design guidelines are validated based on the Building Integrated PV (BIPV) and Infrastructure Integrated PV (IIPV) demonstrators being developed in the Solar Energy Made Regional (SolarEMR) project.The SolarEMR project, is being carried out within the context of Interreg V-A Euregio MeuseRhine, with support from the European Regional Development Fund. Additionally, we would like to thank Marta Casasola Paesa, Jonathan Govaerts, Aldo Kingma, Marc Meuris, Dorrit Roosen-Melsen and Arvid Van der Heide for their help
Design Guidelines for Building and Infrastructure Integrated Photovoltaics
No full textThe demand for renewable energy is increasing as efforts to decarbonize energy sources continue. Photovoltaic (PV) generation systems are the main contributor to the growth of renewable energy, but limited land availability in countries such as Belgium and Netherlands poses a challenge to their deployment. Integrated PV (IPV) can be a promising solution, but requires special consideration regarding electrical and fire safety, efficiency, durability, cost, and environmental impact in the design process. This study aims to assist in designing PV Semi-Fabricates (SF) by offering choices of materials, technologies and structures. The general design guidelines are validated based on the Building Integrated PV (BIPV) and Infrastructure Integrated PV (IIPV) demonstrators being developed in the Solar Energy Made Regional (SolarEMR) project.The SolarEMR project, is being carried out within the context of Interreg V-A Euregio MeuseRhine, with support from the European Regional Development Fund. Additionally, we would like to thank Marta Casasola Paesa, Jonathan Govaerts, Aldo Kingma, Marc Meuris, Dorrit Roosen-Melsen and Arvid Van der Heide for their help
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
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