1,721,099 research outputs found
Estimation of the energy producibility of an offshore wave energy converter
No full textClimate change and environmental degradation are an existential threat to Europe and the world. Each year that passes the atmosphere warms up and the climate changes with possible catastrophic consequences for all living species. It is therefore necessary to implement a decisive change of course in terms of energy and environmental strategies at a global level, gradually abandoning the use of fossil sources in favor of renewable ones. A lot of country participates to European or global energy treaties or pacts to reduce step by step their fossil energy consumption and greenhouse gas. Among all renewable energies, the engineering department of the University of Palermo focuses the exploitation of sea energy. The study reported in this abstract involved the optimization of a WEC (wave energy converter) in term of geometry. The device focused is a point absorber with a PTO (power take off) composed by a linear generator. The software used to model the WEC is "Ansys Aqwa"
Fotografia, patrimonio, paesaggio. Tra inventario e raffronto
No full textLa prima immagine fotografica della storia è una fotografia di paesaggio. Si tratta di una ‘eliografia’ su lastra di peltro e bitume, ottenuta nel 1826 o 1827 da Joseph-Nicéphore Niépce, un gentiluomo francese di provincia con la passione per la tecnica e le invenzioni. Quasi tutti i manuali di storia della fotografia pubblicati dopo il 1952, anno del suo ritrovamento, si aprono con questa veduta dalla casa di famiglia a Saint-Loup-de Varennes, con il titolo Point de vue. La paternità di questa immagine è stata a lungo in discussione, perché i tentativi di riprodurla fallivano davanti all’impossibilità di trovare un punto di vista che le corrispondesse da una delle finestre della casa. Si scoprì poi che la finestra era stata spostata durante una ristrutturazione e l’immagine corrisponde effettivamente alla vista che si godeva dalla precedente apertura. Per questo, oggi è impossibile effettuare uno scatto di raffronto. Secondo Susan Sontag: “Le fotografie sono preziose perché danno informa-zioni. Dicono cosa c’è, fanno un inventario. Per le spie, i meteorologi, i conduttori di inchieste, gli archeologi e gli altri informatori professionisti, esse hanno un valore incalcolabile” (Sontag, 2004:20-21). Il loro valore do-cumentario si basa sul fatto che le immagini possano essere conservate e osservate in un momento diverso da quello in cui sono state scattate (Brunetta, Minici Zotti, 2014), confrontando lo stato in cui il soggetto si trovava quando fu immortalato, quello attuale, e uno o più stati futuri. A partire dal celebre prologo di Point de vue, le pagine seguenti propongono una riflessione sulla fotografia come strumento di documentazione, il suo rapporto con la memoria e la pratica del foto-raffronto
A review of the water desalination technologies
Full text linkDesalination is commonly adopted nowadays to overcome the freshwater scarcity in some areas of the world if brackish water or salt water is available. Different kinds of technologies have been proposed in the last century. In this paper, the state of the mainstream solutions is reported, showing the current commercial technologies like reverse osmosis (RO), Multi-Stages Flash desalination (MSF) and Multi-Effect Distillation (MED), and the new frontiers of the research with the aim of exploiting renewable sources such as wind, solar and biomass energy. In these cases, seawater treatment plants are the same as traditional ones, with the only difference being that they use a renewable energy source. Thus, classifications are firstly introduced, considering the working principles, the main energy input required for the treatment, and the potential for coupling with renewable energy sources. Each technology is described in detail, showing how the process works and reporting some data on the state of development. Finally, a statistical analysis is given concerning the spread of the various technologies across the world and which of them are most exploited. In this section, an important energy and exergy analysis is also addressed to quantify energy losses
An AI-Based Algorithm for Energy Management of Hybrid Renewable Energy System
Full text linkIn recent times energy demand has increased due to several factors, such as the growing world population, conventional ways of energy transmission & distribution, adopting less energy-efficient technologies, etc. These factors contribute towards more utilization of natural resources to meet the energy requirements, thus polluting the environment by producing harmful gases and increasing the energy cost. This paper addresses the aforementioned challenges, where it aims to look for more sustainable ways of energy production such as solar energy, wind energy, and biomass. This paper designed an off-grid system that aims to meet the University of Palermo's energy demand at a minimum annualized system cost. In this design, two ways are adopted for energy storage: 1) battery storage, and 2) hydrogen-based storage. The priority is to charge the batteries when excess energy is available. When the battery is fully charged and still some energy is available, this energy is used to operate the electrolyzer to produce hydrogen, which can also be used to produce again energy through fuel cells. This paper implemented an improved grey wolf optimization algorithm to find optimal power flow. The advantage of using it over other optimization algorithms is that it reduces premature convergence, and finds the global best solution. The result shows that, when the sources are not enough, the storage system can release enough energy for all time in the day
Sea wave energy. A review of the current technologies and perspectives
Full text linkThe proposal of new technologies capable of producing electrical energy from renewable sources has driven research into seas and oceans. Research finds this field very promising in the future of renewable energies, especially in areas where there are specific climatic and morphological characteristics to exploit large amounts of energy from the sea. In general, this kind of energy is referred to as six energy resources: waves, tidal range, tidal current, ocean current, ocean thermal energy conversion, and saline gradient. This review has the aim to list several wave-energy converter power plants and to analyze their years of operation. In this way, a focus is created to understand how many wave-energy converter plants work on average and whether it is indeed an established technology
BEST BEFORE? ADVANCED GEOMATICS FOR PRESERVATION AND PRESERVATION OF ADVANCED GEOMATICS
Full text linkThis discussion paper deals with the task of preserving past geometrical surveys and keeping them in use. The continuous advancement in technology caused a quick ageing of both survey techniques and their outcomes. This may result into a predetermined expiration date after which they risk losing their quality and usefulness (hence the title «Best Before»). Facing this risk, this paper focuses on the unceasing relevance of past surveys both as a legacy in the history of technique and as a fundamental source of information on heritage buildings, and thus a support to the preservation activity. The present paper offers an overview of the most recent attempts of preserving and keeping in use the paper surveys of the past
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
Il consumo di suolo nella montagna lombarda. Un confronto tra piano e progetto urbano nel Novecento
Full text linkIl testo confronta due forme di pianificazione che hanno governato lo sviluppo del
territorio e regolato il consumo del suolo montano nel corso del Novecento: il progetto
urbano degli anni Trenta-Quaranta e la pianificazione concordata degli anni Sessanta-
Duemila. L’analisi si concentra sul caso di Sondalo in Alta Valtellina, un centro abitato
d’impronta medievale dove, tra il 1932 e il 1940, fu costruito un Villaggio Sanatoriale di
oltre 600.000 mc. Questo grandioso esempio di urbanistica modernista fu progettato per
iniziativa statale nella forma di una megastruttura. Dopo la guerra, l’abitato di Sondalo è
cresciuto grazie allo sviluppo economico e demografico propiziato dal grande sanatorio,
secondo le indicazioni del Piano Regolatore e degli strumenti di pianificazione e
programmazione sovralocali (PTCP, PTA). Gli autori propongono un confronto sugli esiti
che queste due forme di urbanizzazione hanno prodotto sullo sviluppo territoriale e sul
consumo di suolo in questo tratto di montagna lombarda
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
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