1,721,027 research outputs found
Thermo-oxidative resistance of crosslinked polyethylene (XLPE) coated by hybrid coatings containing graphene oxide
No full textCrosslinked polyethylene (XLPE) has been coated with hybrid organic-inorganic thin films obtained via sol-gel reactions and containing small amounts (from 02 to 0.8 wt%) of graphene oxide (GO), with the aim to improve durability of electrical insulators and devices. Accelerated aging in an air-circulating oven at 120 degrees C, slightly above the typical on-service temperature of insulators for high-voltage electrical cables, has been carried out over times up to 2000 h. The thermo-oxidation of XLPE substrate has been assessed by isothermal differential scanning calorimetry (DSC) and infrared analysis (FTIR) to determine the oxidative induction time (DSC-OIT) and the oxidation index, respectively. Indirect evidence of the damages induced by thermo-oxidation has been achieved by tensile tests on aged samples. Data collected by DSC, FTIR and tensile tests outline a remarkable contribution of GO to the improvement of the thermo-oxidative resistance of the coated XLPE. The effect of GO is attributable to an improved barrier against oxygen diffusion, which in turn results in a lower damage of XLPE with significant improvement of mechanical properties (durability) over long aging times.
Additional measurements of the surface resistivity have been also carried out before and after the chemical reduction of GO in the coatings, by exposition to hydrazine hydrate vapours. A strong decrease of surface resistivity has been observed after GO reduction with hydrazine, leading, for the sample containing 0.8 wt% of GO in the coating, to an almost antistatic behaviour of the resulting coated XLPE
Techno-economic and environmental multi-objective design of photovoltaic systems with battery energy storage
No full textThe technological development and the increasing market competitiveness of the renewables creates favourable conditions to partially switch the electricity generation from large centralised facilities to small decentralised plants. Photovoltaic (PV) systems find effective applications if the energy production is dedicated to local self-consumption, while the grid parity concept is extended to a comparison of PV energy generation costs toward the grid electricity tariff. However, the intermittent nature of the solar source suggests the adoption of storage systems to meet the energy demand during the solar absence.
The design of PV plants integrating Battery Energy Storage (BES) includes multiple aspects. Therefore, a techno-economic and environmental multi-objective design approach is proposed in this chapter to determine the PV-BES system configuration able to optimise both the economic and environmental criteria. The model, based on the hourly energy demand, the irradiation and the temperature profiles, is described and the analysis outcomes are widely discussed
A review of technologies and applications for water purification in the food & beverage industry
No full textFood & Beverage (F&B) industry is known as a water intensive sector. Thousands of litres per hour of pure water are necessary to produce the final drinks, for the line and backup process requirements of medium size production plants. Due to health restrictions and the F&B standard, the physical, chemical and biological quality of process water has to fit with high level of purity. To this purpose, all F&B plants require a dedicate water purification unit making raw water (both primary and recovered) ready-for-use. Such units are process plants based on mechanical and chemical purification technologies, mainly. This paper aims at revising the state-of-art of research and practice in this field. Starting from the process description and the expected water quality level, a matrix analysis, according to a panel of classification drivers, allows outlining the current research streams and the most popular technologies. The industrial sector, the fluid features and the adopted technology are among the investigated drivers. Results highlight a wide range of solutions, often combined in series to increase the final effect. Lacks are in applications dedicated to the wastewater purification, implementing local close-loops to decrease the overall F&B water intensity
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
SYNTHESIS OF PHOTOLUMINESCENT CORE-SHELL SILICA PARTICLES BY SACRIFICIAL POLYMER SHELL METHOD
No full textA novel approach has been developed for the synthesis of SiO 2@Y 2O 3:Eu 3+ particles with core-shell structure. In this method the polymer shell is obtained by copolymerization of methacryl oxyethyl isocyanate onto silica particles which are chemically modified by 3-(trimethoxysilyl) propyl methacrylate. The grafted polymer acts as template to prepare the luminescent shell on silica particles. Then, the obtained silica-polymer core-shell particles are dispersed in a solution of Yttrium and Europium nitrates to allow a physical adsorption of the ions by the polymer shell. The sacrificial polymer shell will be removed by thermal treatment to obtain photoluminescent SiO 2@Y 2O 3:Eu 3+ core-shell particles. Results reveal that the intensity of photoluminescence of these core-shell particles is much higher than intensity of particles prepared without sacrificial polymer shel
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
- …
