1,720,989 research outputs found
The Italian hydrogen mobility scenario implementing the European directive on alternative fuels infrastructure (DAFI 2014/94/EU)
No full textThe European commitment to promote a sustainable (green and clean) mobility has been strengthening in recent years. An important milestone is the DAFI Directive 2014/94/EU, targeting the deployment of an alternative fuels infrastructure in the European Union, to be implemented through national policy frameworks. The DAFI Directive has been implemented in Italy through the Legislative Decree n. 257 (December 2016), including hydrogen in the list of alternative fuels. Concerning the hydrogen mobility, this paper describes the methodology and the main results of the Scenario MobilitaH2IT. On behalf of the Italian Ministry of Economic Development, it summarized the common vision of several stakeholders joined in the initiative “Mobilita Idrogeno Italia” (MH2IT), established in June 2015. Moreover, these results are reproduced in the Annex III of the Legislative Decree n. 257, thus representing an official reference. With a 2050 time horizon, the applied methodology considers: (1) Sizing of the FCEV fleet and hydrogen demand at the refueling stations; (2) Hydrogen production for the transport sector and integration of renewable electricity with hydrogen storage; (3) Sizing of the hydrogen refueling stations; (4) The consumer perspective; (5) Reduction of CO2 emissions and other harmful pollutants; (6) Measures to support the national policy framework. This methodology can be replicated in other national studies and the Italian results can be checked as a comparison term
Integration of a solid oxide electrolysis system with solar thermal and electrical energy: A testing campaign for operation and control strategy definition
Full text linkThe EU project PROMETEO has the scope of testing a 25 kW solid oxide electrolysis system integrated with a concentrated solar power plant via thermal energy storage in a relevant environment. Given the plant layout and the hydrogen demand characteristics, this work aims to identify how to operate the system effectively when renewable electricity is unavailable and how to modulate the load during hydrogen generation, thus defining the system’s operation modes and control strategy. A 5 kWe stack has been tested at the FBK facility. The hot standby tests show that feeding a reducing gas at the negative electrode and air at the positive electrode, without polarizing the stack, effectively keeps the stack hot at 750◦C and prevents degradation. Conversely, the electric protection approach leads to significant stack degradation (15% voltage drop in 200 h for one cluster). Regarding modulation of hydrogen generation, with low steam flowrates, the stack current and the flow rate of produced hydrogen mainly depend on the steam flow rate, while it is not affected by the stack temperature; conversely, with high steam flowrates, the current depends only on the stack temperature (from 25 A at 670◦C to 65 A at 760◦C). Based on the results, two hot standby modes and two load control strategies to be implemented and tested in the PROMETEO prototype are proposed
MLOps: A Taxonomy and a Methodology
No full textOver the past few decades, the substantial growth in enterprise-data availability and the advancements in Artificial Intelligence (AI) have allowed companies to solve real-world problems using Machine Learning (ML). ML Operations (MLOps) represents an effective strategy for bringing ML models from academic resources to useful tools for solving problems in the corporate world. The current literature on MLOps is still mostly disconnected and sporadic. In this work, we review the existing scientific literature and we propose a taxonomy for clustering research papers on MLOps. In addition, we present methodologies and operations aimed at defining an ML pipeline to simplify the release of ML applications in the industry. The pipeline is based on ten steps: business problem understanding, data acquisition, ML methodology, ML training & testing, continuous integration, continuous delivery, continuous training, continuous monitoring, explainability, and sustainability. The scientific and business interest and the impact of MLOps have grown significantly over the past years: the definition of a clear and standardized methodology for conducting MLOps projects is the main contribution of this paper
Dynamic modelling of an Ammonia to Power application at high efficiency using a solid oxide fuel cell system
Full text linkAmmonia is a promising zero carbon and sustainable hydrogencarrier that can be used as a fuel in solid oxide fuelcells (SOFC) by offering advantages related to the ease ofstorage and the possibility of being used directly withoutan external reformer. In this study, a Modelica-baseddynamic model of an 'Ammonia to Power' (A2P) system wasdeveloped by integrating ammonia decomposition kinetics,electrochemical reactions, all the system-level componentsand the main control loops. A novel Balance of Plant (BoP)configuration is proposed, featuring a five-way heatexchanger that recovers waste heat primarily using the fuelstream as the thermal energy vector instead of air. Themodel evaluates transient responses to operationalperturbations, the behavior of the different control loops,and recirculation percentage rates to optimize systemperformance. Efficiency is calculated as the ratio of thepower output from the SOFC to the power derived from thefresh ammonia line
Direct Ammonia Solid Oxide Fuel Cell Stack: Modelling and Experimental Validation
Full text linkInterest in ammonia as an energy carrier is growing due toits superior storage and transport properties compared tohydrogen. The objective of this work is to construct auseful tool for predicting the behavior of a solid oxidefuel cell (SOFC) stack fed directly with ammonia. Thisconfiguration is particularly interesting because theinternal cracking of ammonia eliminates the need for anexternal cracker, thus reducing the overall cost of thesystem. The ammonia decomposition reaction was implementedin the anode channel of the stack and calibrated againstliterature results. The model was then validated in theohmic region only by calculating the area specificresistance (ASR) and comparing the results withexperimental data collected at the Bruno Kessler Foundation(FBK) laboratory. This SOFC model can therefore be used asa starting point for the analysis of a scale-up application
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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