1,721,122 research outputs found
Circular Tutelage: a Sustainable Approach Toward Remediation and Enhancement of Endangered Areas
No full textNowadays, one of the most important topics in the public dialogue concerns the concept of sustainability and its application in everyday life, given the urgence to reduce or counteract the negative effects partly caused by human activities. Fighting poverty, eradicating hunger and malnutrition, increasing the quality of life, protecting and restoring biodiversity, ensuring access to energy sources are just some of the goals for sustainable development included in the United Nations Organization's 2030 Agenda. Every country is called to make its contribution to jointly face these great challenges, rising from the awareness that the planet's resources are limited, unequally distributed and their exploitation often involves the alteration of delicate environmental balances.
In the present work, a very productive transitional area prone to suffer from pollution and dangerous algal blooms, has been studied in order to propose methodologies and solutions which, if adopted, can contribute not only to mitigate environmental damages but also to provide new tools that can contribute to the development of local populations in a circular economy perspective. In particular, research has been carried out aimed at the development of solutions for the environmental restoration of ecosystems threatened by human pressure, proposing highly circular and sustainable processes based on the use of biomass from wastes or by-products. The proposed production processes are aimed at exploiting and valorizing these wastes, avoiding the compromission of the hygiene and quality of the ecosystem. In addition to the environmental sustainability also the economic and social one are considered in the proposed solutions.
The area is characterized by a semi-enclosed lagoon structure, depths of up to two meters, over 25 km2. This area alone is responsible for the production of 55% of all clams produced in Italy, with over fifty million euros in turnover; essentially a collective heritage for the cities and economies that depend precisely on mussel farming and supporting activities. In order to mitigate the effects related to the excessive presence of algal biomass in the area, a cost / benefit analysis was carried out to determine the possibility of exploit this biomass as a secondary raw material for the production of market goods such as biofuels, drugs, supplements, and much more. The possibilities for economic exploitations of the biomass would in fact make the collection of this component from the environment advantageous and would avoid negative phenomena in the aquatic environment. The feasibility of the proposed solutions was also accompanied by a foresight analysis in which possible social dynamics were considered which have led, in the past, to the failure of a project whose mission was to safeguard and improve the conditions of the lagoon.
In order to carry out the feasibility study, in addition to the composition of the constituent elements of algae determination, their possible contamination by various classes of pollutants, whose presence could constitute an obstacle to their exploitation, was also studied.
The thesis also considers another voluminous waste biomass present in the lagoon, namely byproduct seashells which constitute a process waste from the bivalves that are produced in the lagoon and which, unfortunately, are often illegally discharged into the canals or deployed in landfill and classified as special waste. Landfilling not only has an economic impact on small fishing businesses but also reduces the sustainability of aquaculture activities, which according to many, will be a key sector for development in the coming years. Hence, the shell of the clam essentially consists of calcium carbonate and can be used as a constituent of soil conditioners and fertilizers for agricultural purposes or as an adsorbent material in biofilters and in environmental bioremediation methodologies.Oggigiorno, una delle tematiche di maggior rilievo nel dialogo comune riguarda il concetto di sostenibilità e della sua applicazione nel quotidiano per rispondere all’esigenza di ridurre o contrastare vari effetti negativi in parte causati dalle attività umane. Contrastare la povertà, eradicare la fame e la malnutrizione, tutelare e ripristinare la biodiversità, sicurezza energetica, sono solo alcuni degli obiettivi per lo sviluppo sostenibile presenti nell’Agenda 2030 dell’Organizzazione delle Nazioni Unite. Ogni Paese è chiamato a fornire il suo contributo per affrontare in comune queste grandi sfide, nate dalla consapevolezza che le risorse del pianeta sono limitate, distribuite iniquamente e il loro sfruttamento spesso comporta l’alterazione di delicati equilibri ambientali.
Nel presente lavoro di tesi si è studiato un ecosistema di transizione molto produttivo, ma fragile, per proporre metodologie e soluzioni che se adottate possano contribuire non solo a mitigare i danni ambientali, ma anche a fornire nuovi strumenti che possano contribuire allo sviluppo delle popolazioni locali in un’ottica di economia circolare.
In particolare, si sono effettuate ricerche orientate allo sviluppo di soluzioni per il ripristino ambientale di ecosistemi minacciati dalla pressione antropica, proponendo processi altamente circolari e sostenibili basati sull’utilizzo di biomasse provenienti da scarti o sottoprodotti. I processi produttivi proposti sono orientati a sfruttare e valorizzare questi scarti evitando che compromettano l’igiene e la qualità degli ecosistemi in cui essi sono presenti o in cui vengono riversati. In questo ambito si sono approfonditi argomenti propri della sfera sociale ed economica, per garantire oltre alla sostenibilità ambientale anche quella economica e sociale delle soluzioni proposte.
La zona è caratterizzata da una struttura lagunare semichiusa, fondali profondi massimo due metri e complessivamente è uno specchio d’acqua di 25 km2. Quest’area sola è responsabile per la produzione del 55% di tutte le vongole prodotte in Italia, con oltre cinquanta milioni di euro di volume d’affari; sostanzialmente un patrimonio collettivo per le città e le economie che dipendono appunto dalle attività di mitilicoltura e dalle attività consortili e coadiuvanti. Allo scopo di mitigare gli effetti legati alla presenza eccessiva di biomassa algale nella zona, si è svolta una analisi costi / benefici per determinare la possibilità di sfruttare al meglio tale biomassa come materia prima seconda per la produzione di oggetti e beni di consumo, come biocombustibili, farmaci, integratori e tanto altro. La possibilità di sfruttare economicamente la biomassa renderebbe infatti vantaggiosa la raccolta di questa componente dall’ambiente.
La realizzabilità delle soluzioni proposte è stata inoltre corredata da un’analisi in previsione in cui si sono considerate possibili dinamiche sociali che hanno portato, in passato, al fallimento di un progetto che aveva la missione di salvaguardare e migliorare le condizioni della laguna. inoltre, è stata studiata la composizione degli elementi costitutivi di alghe e anche la loro possibile contaminazione da parte di varie classi di inquinanti la cui presenza potrebbe costituire un ostacolo per il loro sfruttamento.
Nella tesi viene inoltre considerata anche un’altra voluminosa biomassa di scarto presente nella laguna, “il capulerio” che costituisce uno scarto di lavorazione dei bivalvi prodotti. Lo smaltimento in discarica non solo incide economicamente sulle piccole imprese di pescatori, ma riduce la sostenibilità delle attività di acquacultura. In un’ottica di sostenibilità e circolarità, il guscio delle conchiglie è costituito da carbonato di calcio e può trovare impiego come costituente di ammendanti e fertilizzanti per scopi agricoli o come materiale adsorbente in biofiltri e in altre metodologie di bioremediazione ambientale
Tailoring core size, shell thickness, and aluminium doping of Au@ZnO core@shell nanoparticles
Get PDFPlasmonic materials, such as gold nanoparticles (AuNPs), exhibit significant extinction and near-field enhancement across the visible and near-infrared spectrum, attributable to localized surface plasmon resonances (LSPRs). Epsilon-near-zero (ENZ) materials, such as aluminium doped zinc oxide (AZO) are known in non-linear optics for their ability to generate and manipulate light-matter interactions through processes like higher harmonic generation. Combining doped ZnO with plasmonic materials therefore holds promise for enhancing non-linear efficiencies and tuning their operational wavelengths. To date, however, only top-down structures based on plasmonically decorated thin ENZ films have been realized, and no colloidal and scalable route to obtain these hybrid materials has been reported yet. Here, we introduce a novel colloidal synthesis approach for fabricating Au@AZO core@shell nanoparticles with tunable core size, shell thickness, and dopant concentration, allowing for the spectral alignment of the LSPRs of the AuNPs with the non-linear optical properties of the AZO shells. Our method involves the colloidal synthesis of gold cores followed by an ascorbic acid-assisted process to deposit polycristalline ZnO and AZO shells, resulting in core diameters ranging from 25 to 69 nm, shell thicknesses from 16 to 47 nm, and aluminium doping levels between 0 and 4 at%. Our procedure widens the range of hybrid plasmonic nanostructures that can be colloidally synthesised, opening new possibilities for the large scale fabrication of high-performance nanomaterials for integration in photonic, photocatalytic, and sensing applications.</p
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
A Bi-Phasic Approach to Model Progressive Matrix Damage in Composites: Development and Application
No full textVariations 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
Study of Interlaminar Fracture Propagation in Composite Laminates using Fiber Bragg Grating Sensors
No full textAnalyses of Delamination in Composite Laminates in Standard Tests and Low Energy Impacts
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