1,721,026 research outputs found
Smart Solar Panels for Space Applications
No full textThe Photovoltaic (PV) Solar Panels are the key technology for the generation of electric energy in space environment. In order to maximize the efficiency of the PV solar panels, two aspects of this technology can be improved: keeping the solar panels surface orthogonal to the direction of the Sun light and cleaned from the deposition of dusts and other contaminants that can absorb a quota of the incoming solar irradiance. The present paper reports the preliminary design of a system of Smart Solar Panels (SSPs) that represents an improvement of PV solar panels aimed to be implemented specifically in space environment. To maximize the produced energy of a solar panel, it has to be kept oriented toward the Sun and with its sensitive surface very clean, without the presence of contaminants. In order to obtain this goal in an autonomous way, the solar panels shall be provided with robotic functionalities to move the panels according to the relative movement of the Sun and to remove the contaminants deposited on the surface as well. Combination of these two functionalities and the adopted solutions, aimed expressly for space application, are the novelty of this work. The SSPs find their application in fixed solar power plant or mobile installation (e.g. lander and rovers) for the exploration of Solar System bodies, primarily the Moon and Mars, but have also a positive impact for terrestrial sites located in desert or mountain areas, where maintenance operations are difficult. The concept has been submitted to the 'call for ideas' for the ESA European Large Logistics Lander (EL3)
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
Design of a flowrate measurement system for low-pressure gases
No full textDesign of a flow meter to be used in a low-pressure environment is hereafter presented. The need of this activity comes from the lack of commercial flow meters operating at low pressures due to the unusual working environment, where outgassing and sublimation phenomena becomes relevant for many materials and rarefied atmosphere changes dramatically the heat and mass exchange phenomena. In our case, the need of a low pressure compatible measurement system comes from the need of measuring the flow rate of a rotary vane pump working under an environmental pressure between 10 and 6 mbar, simulating the condition of the Martian atmosphere at the surface. The pump will be the key component of a particle analyzer that should be part of the ExoMars 2020 ESA-Roscosmos mission. The designed measurement system is based on the deformation of a control volume, a stainless-steel bellow, which has been designed on the basis of the expected flow rate. The measurement system has been calibrated at ambient condition and testing in low-pressure has been performed in order to validate the measurement method and derive the flow rate performances within the expected working conditions
Smart Solar Panels project, the design outline
No full textThe Photovoltaic (PV) Solar Panels are one of the key technologies for the generation of electric energy in space environment. This paper focuses on the improvement of standard PV Solar Panels that can be achieved by maximizing their efficiency. The Smart Solar Panels (SSPs) improve two aspects of the baseline technology: the capability to keep the solar panels surface orthogonal to the direction of the sunlight and, also, cleaned from the deposition of dust and other contaminants that can absorb a quota of the incoming solar irradiance. The present paper reports the preliminary design of the configuration of SSPs aimed to be implemented specifically, but not exclusively, for space applications. The SSPs shall be provided with robotic functionalities to move the panels according to the relative movement of the Sun and to remove the contaminants deposited on the surface. The SSPs are particularly suitable to support Solar System exploration, in fact, they can implement fixed or mobile installations of power plants in an efficient way. Furthermore, this new concept is advantageous also due to the cost-saving derived from the reduction of the overall mass to be launched in space and it can be transferred, as technology, from space to terrestrial applications. In fact, terrestrial sites with dry and dusty climate conditions, often located in desert or mountain areas, can benefit from this technology. The concept of the SSPs was submitted to the call for ideas for the ESA European Large Logistics Lander (EL3) in 2020
Preliminary design of the inlet duct of a dust analyzer for Mars
No full textAirborne dust characterization is very important in planetary climatology, especially on Mars, where dust is always present and its concentration varies with seasons. This work deals with the design of the inlet duct of an instrument named MicroMED, devoted to characterize Martian dust but suitable to be mounted on different planetary landers or rovers. An inertial classifier has been developed to cut particles with diameter larger than 20 μm in order to avoid obstruction of the pumping system of the instrument. CFD simulations based on the Eulerian-Lagrangian approach were performed to characterize the separation performance of the classifier. Finally, the inlet duct has been mechanically designed by FE approach to assure resistance and proper mechanical behavior within expected mechanical environment
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