1,720,968 research outputs found
Mechanical Robustness Investigation of Organic Photovoltaics for Membrane Integrated Flexible Solar Cells
No full textFlexible Photovoltaics (PV) are promising alternatives to established crystalline silicon technologies for their possible integration onto flexible and translucent architectural membrane materials like Ethylene tetrafluoroethylene (ETFE) and Polytetrafluoroethylene (PTFE). This research proposes an experimental methodology based on coupled electrical characterization and uniaxial tensile tests to examine the mechanical robustness and the failure mechanism of a commercial organic photovoltaic module sample upon tensile loads
Photochromic Electret: A New Tool for Light Energy Harvesting
No full textIn this paper, a photochromic electret for light energy harvesting is proposed and discussed. Such electret directly converts the photon energy into electric energy thanks to a polarization modulation caused by the photochromic reaction, which leads to a change in dipole moment. Theoretical concepts on which the photochromic electret is based are considered with an estimation of the effectiveness as a function of material properties. Finally, an electret based on a photochromic diarylethene is shown with the photoelectric characterization as a proof of concept device
Experimental investigation of the mechanical robustness of a commercial module and membrane-printed functional layers for flexible organic solar cells
Full text linkA coupled mechanical and electrical characterization method to monitor the correlation of organic photovoltaic (OPV) electrode resistance and cell performance upon tensile strain and to verify the cause of deterioration and the effect of OPV performance under tensile stress has been developed. Both a commercial OPV module and ethylene tetrafluoroethylene (ETFE) membrane-printed OPV electrode layers have been tested by applying the method. The encapsulation layer strength has been found to be the mechanical bottleneck of the tested commercial OPV module. The decrease in the transparent electrode conductance has been found to be responsible for cell degradation upon tensile strain, with the threshold tensile strain at approximately 2%. A test results comparison between ETFE- and polyethylene terephthalate (PET)-printed OPV layers demonstrated that ETFE-printed electrodes are less brittle and sensitive to tensile strain owing to the network pattern response of ETFE-printed electrodes. In addition, the adoption of Ag/poly(3,4-ethylenedioxythiophene) (PEDOT) layering can improve the tensile strain threshold to almost double to maintaining 80% of the initial normalized layer conductance through the advantage of its “bridging effect”. Collectively, our results provide valuable information and illustrate a promising future for architectural membrane printed OPV
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
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