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Poesia e metrica di Niccolò Tommaseo
Get PDFNiccolò Tommaseo riconosce di avere conseguito i migliori risultati poetici della sua gioventù tra il 1833 e il 1838, pervenendo in questo periodo alla piena maturità non solo di poeta ma anche di uomo. Il presente lavoro si concentra su questo arco temporale, dall’ultimo anno del suo soggiorno a Firenze fino all’esilio in Francia, dapprima a Parigi dal febbraio 1834 al novembre del 1837, quindi a Nantes e infine in Corsica. In Francia nel giro di pochi anni, tra il 1836 e il 1838, Tommaseo allestisce ben due raccolte poetiche, costituite in gran parte dalle poesie scritte in esilio: le Confessioni, uscite anonime a Parigi nel gennaio 1836, e l’appendice di Poesie delle Memorie poetiche, stampate a Venezia nel 1838 ma composte in Corsica. Sempre a Parigi, nel marzo del 1837, egli pubblica un opuscolo destinato a una vendita di beneficenza, i Versi facili per la gente difficile, formato da sette poesie. Va ricordato, tuttavia, che molte delle poesie delle Confessioni e dei Versi facili vengono riproposte nell’appendice di Poesie delle Memorie poetiche.
Nella prima parte della tesi lo studio delle poesie è integrato con le notizie ricavate dai carteggi di Tommaseo, in particolare quelli con Gino Capponi, Giovan Pietro Vieusseux, Cesare Cantù, Alessandro Poerio e Giovita Scalvini, e con le annotazioni private dell’autore nel Diario intimo. Delle Confessioni, dei Versi facili e dell’appendice di Poesie delle Memorie poetiche si descrive inoltre l’organizzazione interna, prestando particolare attenzione al rapporto che i testi intrattengono con la macro-struttura. Vi si dimostra che nelle sezioni dedicate all’espressione privata di Tommaseo è presente uno svolgimento narrativo, che coincide con la sua “confessione”: dall’ammissione delle sue colpe fino al pentimento e alla volontà di espiare gli errori commessi. Infine si raccolgono i giudizi degli amici sulle poesie di Tommaseo, da lui richiesti con insistenza.
Nella seconda parte della tesi si offre un Repertorio metrico, fondato sull’edizione definitiva delle Poesie di Tommaseo (1872), ma valido anche per le raccolte poetiche precedenti, poiché nell’opera vengono riproposte quasi tutte le poesie già edite. Segue il Commento di tutti gli schemi impiegati nei 213 testi delle Poesie. Con questa scelta si è inteso mettere in rilievo la grandissima varietà dei metri adottati da Tommaseo, sperimentatore instancabile di forme. Nel Commento si segnalano, quando possibile, anche i possibili modelli degli schemi di Tommaseo, al fine di misurare il suo rapporto con la tradizione metrica italiana antica e recente.
Nell’appendice della tesi è collocata una Tavola sinottica, che consente di seguire più facilmente le poesie di Tommaseo nel transito di raccolta in raccolta, nelle quali in molti casi ricompaiono con titoli diversi
Modern in-situ XRD investigations on C3S-C3A-GY systems
Get PDFThe origin of cement, employed as a binding material, can be attributed to Romans who found that a mixture of lime and crushed volcanic ashes was able to set under water, the resistance being increased along the time, in a way completely different to any other material. Since that age, a huge amount of different kind of cements have been produced to satisfy the request of different mechanical behaviors. To deeply understand the mechanisms that lead to the development of mechanical strength, reaction kinetics that occur during the hydration process must be known. Nowadays we can affirm that cement research has set many important results but despite of this “long-time story”, a lot of improvements are required to better understand the mechanisms of kinetics.
Cements mixed with water are complex systems undergoing critical chemical and physical changes during the hydration process. A unique hydration model able to explain the controlling mechanisms is the main purpose of cement research, but the physical-chemical parameters involved are actually too many. To partly overcome the chemical complexity of common cement materials, simplified cement systems are often used for research purposes. A project has been set to investigate the fundamental reactions occurring during the hydration process and has been divided within 3 different partners: NIST (National Institute of Standards and Technology), W.R. GRACE and University of Padua. Our part of the project was to collect x-ray powder diffraction patterns on the hydrating suspensions, using Rietveld refinement for quantitative phase analysis.
Three simplified cement systems formed by the synthetic phases tricalcium silicate Ca3SiO5 (C3S), tricalcium aluminate Ca3Al2O6 (C3A) and a varying amount of gypsum CaSO4∙2H2O (CŠH2) were investigated by means of in-situ x-ray powder diffraction (XRPD) and isothermal calorimetry (IC) in order to evaluate dissolution-precipitation kinetics. The main hydration products detected by means of XRPD were ettringite, hemicarboaluminate, portlandite, Ca-Si hydrates (C-S-H): the same occurring in real cements.
The Avrami nucleation and growth model successfully fits the degree of hydration data, confirming that C-S-H should have a layered structure as well as the phases resulting from the decomposition of ettringite. The mass balance method was used to calculate the exact amount of C-S-H formed during hydration, which is not directly accessible from Rietveld refinement. The comparison between the degree of hydration calculated from isothermal calorimetry data and the degrees of hydration calculated from x-ray diffraction has revealed how much the reactant phases are responsible for heat release. In particular, it was seen that the study of C3S-C3A-Gy systems is not a simple sum of the investigations of C3S-Gy and C3A-Gy systems, which are two further simplified model cements. The synthetic materials suffered a loss on reactivity despite of the under-vacuum sealing, leading to a continuous and unpredictable change of the materials features (particle size, degree of reactivity) during time.
The obtained experimental data should be necessary to proof the effectiveness of software modelling (HydratiCA). The software has been tested and returned satisfactory results for further simplified systems, such C3S-Gy. Nevertheless, the software is still under a development stage and improvements has to be planned for C3A-Gy systems before testing more complex blend
In-situ XRPD of hydrating cement with lab instrument: reflection vs. transmission measurements
No full textThe complex system of reactions taking place during cement hydration can be investigated by means of in-situ XRPD. Time-resolved synchrotron XRPD is the optimal source although it is hardly accessible for routine measurements. The present work was aimed to test the feasibility of in situ measurements of hydrating cement pastes using a labo-ratory diffractometer (PANalytical X’Pert PRO) in reflecting and focusing transmission geometries. Ordinary CEM-I 52.5 R paste (w/c = 0.5) was measured using three different instrumental settings: reflection Bragg-Brentano geometry, focusing transmission capillary geometry and focusing transmission flat sample geometry. Semi-quantitative phase analysis were performed using a Rietveld full profile fitting approach. Advantages and disadvantages of the three different experimental configurations are critically discussed
Extreme diagenesis in the Late Pleistocene stratigraphic sequence of Grotta Guattari (central Italy) and its impact on the archaeological record
No full textGrotta Guattari is a key cave site for Mediterranean prehistory. It is where a perfectly preserved paleosurface,
littered with bones and containing a Neandertal cranium, was exposed in 1939. Recent
research, moreover, has yielded even more Neandertal remains in a side chamber that had remained
unexplored. This paper gives an account of the stratigraphic sequence of the atrial portion of Grotta
Guattari described in 1989 along the walls of the 1939 to 1950 excavation trenches. This key sequence,
capable of elucidating the sequence of events recorded in Grotta Guattari, remained until now unstudied.
The stratigraphy represents the interval between ca 125 ky BP (Marine Isotope Stage e hereafter, MIS e
5.5 or Tyrrhenian transgressive cycle) and ca 50 ky BP (MIS 3). Grain size, chemical, and heavy mineral
analyses were coupled with the micromorphological study of thin sections, corroborated by SEM/EDS
chemical determinations and XRD analyses. The presence of secondary CaeAl and CaeFe phosphates,
formed in response to the weathering of guano, indicates that part of the archaeological record (bones and ash) has weathered away. Weathering was so intense that also the more unstable mineral species, especially augite, disappeared from the heavy mineral assemblage. The differential preservation of the archaeological record shall therefore be taken in consideration when interpreting in behavioural terms old and new excavation data
Challenges in seabird by-catch mitigation
Get PDFRead the Feature Paper: Significant reductions in mortality of threatened seabirds in a South African trawl fishery; other Commentaries on this paper: Minimizing seabird by-catch in industrial fisheries and the Response from the authors: Problems and solutions for seabird bycatch in trawl fisheriesFil: Favero, Marco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Seco Pon, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin
Antarctic Tourism. An Essay on Contrasts Between Environmental Impact, Current Regulations and Opportunities to Generate Environmental Awareness
No full textAlthough Antarctica is commonly considered a pristine environment it is a part of the world that has been visited for more than 200 years for exploration, exploitation of renewable resources, militarization,science and more recently tourism. The flow of tourists has increased significantly since its inception,reaching current values that exceed 45,000 tourists annually, featuring a marked seasonality and a high spatial density. This spatial-temporal concentration has required, from IAATO and in line with current regulations within the Antarctic Treaty System, a proactive agenda with the progressive development of operational regulations. A factor that cannot be ignored is that tourism, associated with current climate processes and their effect on the biodiversity and their habitats, can exacerbate the impact of tourism activity. Other aspect, although not necessarily circumscribed to it, is the potential for introducing non native species into the environment, incorporated into the agenda of the Antarctic Treaty System and taken proactively by industry through the design of protocols that require the implementation of strict biosecurity measures. In contrast to the potential or actual negative effects on the Antarctic environment, it is worthhighlighting the value of the educational programs implemented on board as a tool to transfer conservation values over Antarctica. The challenge for multilateral organizations is to achieve a broad understanding of the tourism activity, and to develop and refine regulations that prevent impacts that exceed the resilience capacity of the environment and its fauna. For IAATO the challenge will be to ensure that its members continue developing activities within a framework of growing and more sophisticated regulations aimed at further improving the performance of operations on land and at-sea, to minimize the impact of tourism over the Antarctic environment.Fil: Favero, Marco. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin
Laboratory in situ X-ray diffraction and isothermal calorimetry: a useful tool to evaluate cement kinetics
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
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