1,721,096 research outputs found
Experimental assessment of a process including microbial fuel cell for nitrogen removal from digestate of anaerobic treatment of livestock manure and agricultural wastes
No full textThe main objective of the research was to verify the effectiveness of a MFC (Microbial Fuel Cell) based reactor for the removal of nitrogen from digested sludge (from anaerobic treatment of livestock manure and agricultural wastes). Preliminary tests were performed to study the development of biofilm at the electrodes, by running small Htype MFC under different conditions. Results of the preliminary lab scale tests showed an increase of more than 60 % of the potential (of both, EOCV and ECCV), in the case of biofilm enrichment. Moreover, scale-up tests were run in continuous, using a 17 L reactor designed and assembled to the scope, constituted by an anaerobic anodic chamber, followed by an aerobic cathodic stage and an anoxic stage. Results of five months operation showed that anodic potential quickly achieved a stable negative potential, in the typical range of the MFC, also leading to a volatile solids removal of about 60 %, thus confirming the good efficiency of the double anaerobic/aerobic system in carbon degradation. However, current generation and power produced was rather low, in comparison to previous results obtained in small batches. In the aerobic chamber, a good nitrogen removal was observed (up to 60 %), as a consequence of both, carbon degrading biomass uptake and nitrification. Mass balances performed, considering the nitrogen content in the waste sludge (about 3 % with respect to TS content), allowed to exclude a significant ammonia nitrogen volatilization. Copyright © 2015, AIDIC Servizi S.r.l
Programma per il rafforzamento del ruolo degli Energy Managers nella pubblica amministrazione e nel terziario, seguendo le indicazioni della legge italiana n. 10/91
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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
Sr-doped LaFeO3 thin coatings for protection of ferritic stainless steel interconnects in solid oxide cells: A study on Cr-barrier and electrical properties
No full textA high-temperature conversion process in molten carbonate baths was applied to produce thin Sr-doped LaFeO3 perovskite coatings on the surface of a K41 steel for interconnect applications in Solid Oxide Cells. Two conversion coatings with identical structure and phase composition, but slightly different thickness were produced in nitrate-accelerated baths containing the nitrate additive at two concentration levels. The as-prepared coatings consisted of a dual-layered perovskite-spinel structure with a top sub-micrometric Sr-doped LaFeO3 layer grown onto a micron-range thick inner Fe-Cr spinel oxide layer. Both coatings showed high protection against oxidation and chromia scale formation at 700°C. Further, excellent Area Specific Resistance (ASR) behavior was found for both coatings at 700°C, although an optimal balance of ASR and Cr-diffusion barrier properties was achieved with the coating produced in the lower nitrate content bath (N-02 coating). The causes for the enhanced barrier properties of the N-02 coating were ascribed not to a different coating thickness, but rather to the evolution of the pristine dual-layer into a more impervious three-layer structure during oxidation aging at 700°C. The evolved structure was formed by decomposition of the pristine sub-coating Fe-Cr spinel into two new spinel sublayers: an outer ferrite and an inner chromite layer, whereas the top thin-film perovskite layer remained essentially unaltered. Partial change in the Fe oxidation state and other possible causes involved in the observed decomposition of the pristine Fe-Cr spinel layer during the thermal aging are analyzed and discussed. Measurements of ASR activation energy indicated that the contact resistance behavior of the thin perovskite coatings was dominated by the internal spinel layer conductivity
Preparation and Electrical Properties of Sr-Doped LaFeO3 Thin-Film Conversion Coatings for Solid Oxide Cell Steel Interconnect Applications
Full text linkA study was conducted to explore the effects of Sr doping on the electrical properties of perovskite LaFeO3 thin-film protective conversion coatings grown onto a K41 ferritic stainless steel, a typical interconnect material for intermediate temperature solid oxide cell (SOC) applications. The Sr-doped coatings were prepared in La2 O3-and SrO-containing molten carbonate baths with minor added amounts of nitrate salt for accelerated coating formation. For comparison purposes, undoped coatings were obtained using the same carbonate bath, with the only difference being that SrO was replaced by inert MgO. SEM/EDX and XRD analyses were used for coating characterization and confirmed the effective incorporation of Sr but not of Mg into the LaFeO3 layer. Although both the Sr-doped and undoped coatings consisted of a LaFeO3 layer grown above an inner Fe-Cr spinel, the coating thickness of the Sr-doped coating was distinctly higher, approximately 2 μm, which is twice that of the undoped coating. Electrical measurements in terms of Area-Specific Resistance (ASR) were conducted at 700◦ C in air and showed that Sr-doping significantly improved the electrical conductivity of the coated K41 steel. Due to the Sr-doping, the ASR values of the coated steel dropped from 60 to 37 mΩ cm2 after 300 h of exposure, in spite of the higher Sr-doped coating thickness. The study concludes that Sr-doped thin-film perovskite coatings appear to be a promising solution for improved SOCs steel interconnect stability at intermediate temperatures
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
Innovative nanomaterials for fuel cells fed with biogas
No full textChallenges on sustainability promote research policy focused on renewable-energy technology development in order to enhance global energy security, local energy independence, environmental protection and economic growth. Biomass resources offer renewable energies that can play a key role in the current global strategies for reducing greenhouse gas emissions by partially replacing fossil fuels. The conversion of biomass chemical energy into electrical energy and cogenerated heat can be obtained by fuel cells. In particular, molten carbonate fuel cell (MCFC) is the most suitable device for bioenergy production because it can be fed directly with biogas, whose primary constituents all improve the performance of the cell. However hydrogen sulfide, which is the main biogas impurity, poisons the traditional nickel based anode, affecting the power and the endurance of the cell. In order to overcome this problem, an innovative anode material that resists against the sulfide corrosions has been developed. This material, made of a nanostructured and porous nickel support covered with a thin layer of ceria, exhibits high sulfur tolerance and recovering capability. © Società Italiana di Fisica
Effect of additive particle size on the CuO-accelerated formation of LaFeO3 perovskite conversion coatings in molten carbonate baths
No full textAn original iron conversion coating process has been recently developed to enhance the functional properties of ferritic stainless steels for use as Solid Oxide Fuel Cell interconnects. The conversion process produces a dense LaFeO3 perovskite layer grown above a spinel oxide underlayer by an immersion treatment in specially-formulated molten carbonate baths at around 600 °C. Galvanic coupling with a coarse CuO powder added to the bath has been earlier proved to be an effective approach to significantly reduce conversion times and coating thicknesses onto a 18Cr Type K41 ferritic stainless steel substrate. Further investigations on the CuO acceleration effects on the K41 steel are reported in the present work focusing on the effect of CuO particle size on the conversion times and coating structure. Studies carried out with different concentrations and particle sizes of the CuO additive have indicated that conversion coating kinetics is strongly affected by the CuO particle size highlighting thus the fact that CuO did not fully dissolve in the carbonate bath and that galvanic coupling effects took place prevalently with CuO particles dispersed in the molten bath. Dramatic reduction in conversion times could be obtained through CuO nanoparticle additions to the bath. The shortest conversion time of <3 h was achieved by adding 6 mol% nano CuO, at 610 °C. As consequence, perovskite coatings with thicknesses well below 10 μm could be produced due to minimal substrate corrosion and spinel underlayer growth during the short conversion processes in the nano CuO-containing salt baths. This structural refinement could play an important role for improving dimensional stability and functional properties of perovskite coatings in SOFC interconnect applications
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