1,721,209 research outputs found
Implementazione e utilizzo di un modello costitutivo avanzato per argille nella risoluzione di problemi al finito: studio del comportamento di gallerie realizzate mediante scavo meccanizzato
Full text linkLa realizzazione in sotterraneo di opere civili rappresenta una soluzione valida e sostenibile sia dal punto di vista ingegneristico che da quello ambientale, sia in area urbana che extra-urbana. Lo studio delle gallerie ha tradizionalmente richiesto l’adozione di importanti ipotesi semplificative, che sono state parzialmente e gradualmente rimosse grazie ai rilevanti progressi della ricerca in questo campo ed alla diffusione dell’analisi numerica. Tuttavia, la complessità del problema è tale che la progettazione di questa tipologia di opere risente ancora di un marcato empirismo.
Il lavoro sviluppato nella tesi si inquadra all’interno di un filone di ricerca che ha come obiettivo di lungo termine la messa a punto di procedure di calcolo robuste che permettano di valutare accuratamente le caratteristiche di sollecitazione sui rivestimenti, necessarie per una corretta progettazione. La tesi affronta lo studio dell’interazione terreno-rivestimento nel caso di gallerie realizzate mediante scavo meccanizzato in terreni a grana fine. Si tratta di fenomeni complessi nei quali il comportamento meccanico delle argille svolge un ruolo di grande rilevanza; le non linearità e la significativa dipendenza dal percorso di carico, nonché l’interazione acqua-scheletro solido, essenziale per una accurata valutazione delle sovrappressioni interstiziali in condizioni non drenate, richiedono infatti l’impiego di legami costitutivi avanzati, in grado di simulare fedelmente tali aspetti della risposta tensio-deformativa. Per tale ragione nella tesi è stato implementato un modello costitutivo a incrudimento cinematico per argille naturali, ritenuto idoneo allo studio dello specifico problema applicativo. Il modello è stato impiegato nell’analisi del problema al finito con riferimento ad un caso di studio, adoperando una metodologia innovativa che prevede l’utilizzo accoppiato di analisi piane ed analisi assialsimmetriche. I risultati delle analisi numeriche sono stati confrontati con i dati di monitoraggio relativi ad un caso di studio e con i risultati di analisi condotte impiegando un legame costitutivo semplice
The oxydation process of Antarctic fish hemoglobins.
No full textAnalysis of the molecular properties of proteins extracted from organisms living under extreme conditions often highlights peculiar features. We investigated by UV-visible spectroscopy and X-ray crystallography the oxidation process, promoted by air or ferricyanide, of five hemoglobins extracted from Antarctic fishes (Notothenioidei). Spectroscopic analysis revealed that these hemoglobins share a common oxidation pathway, which shows striking differences from the oxidation processes of hemoglobins from other vertebrates. Indeed, simple exposure of these hemoglobins to air leads to the formation of a significant amount of the low-spin hexacoordinated form, denoted hemichrome. This hemichrome form, which is detected under a variety of experimental conditions, can be reversibly transformed to either carbomonoxy or deoxygenated forms with reducing agents. Interestingly, the spectra of the fully oxidized species, obtained by treating the protein with ferricyanide, show the simultaneous presence of peaks corresponding to different hexacoordinated states, the aquomet and the hemichrome. In order to assign the heme region state of the alpha and beta chains, the air-oxidized and ferricyanide-oxidized forms of Trematomus bernacchii hemoglobin were crystallized. Crystallographic analysis revealed that these forms correspond to an alpha(aquomet)-beta(bishistidyl-hemichrome) state. This demonstrates that the alpha and beta chains of Antarctic fish hemoglobins follow very different oxidation pathways. As found for Trematomus newnesi hemoglobin in a partial hemichrome state [Riccio, A., Vitagliano, L., di Prisco, G., Zagari, A. & Mazzarella, L. (2002) Proc. Natl Acad. Sci. USA99, 9801-9806], the quaternary structures of these alpha(aquomet)-beta(bishistidyl-hemichrome) forms are intermediate between the physiological R and T hemoglobin states. Together, these structures provide information on the general features of this intermediate state
Expression, isolation and characterisation of tetrameric haemoglobin as a model to study the Root effect
No full textThe Elliott's Wave Theory: Is It True During the Financial Crisis?
No full textIn this study we apply the Elliott’s Wave theory to the index S&P 500 for a period of three years, starting from the October 2008 and until December 31, 2011. An analytical forecast for the first half of 2012 has been carried out. Our principle empirical findings un-derline that the evolution of the first five months of 2012 will be even more turbulent, even if with a slightly bullish phase until May; then we will see a collapse of the financial markets (also in the light of the probable Greek bankruptcy), with a more pronounced Bear Market. If our estimates of the downturn of the financial markets were to prove correct, the immediate implications of this analysis would lead to an accommodating monetary policy, made up of further cuts to the official interest rate
A multi-array tomographic approach for Through-Wall maging
No full textA through-wall imaging problem for a 2-D scalar geometry is addressed. It is cast as an inverse scattering problem and tackled under the linear Born model by means of the truncated singular value decomposition inversion scheme. A multiarray-based inversion strategy is considered. In particular, first the data collected by each single array are processed to obtain different tomographic images of the same scene under test. Then, the different images are suitably combined to obtain the overall image. The inversion scheme is tested for the challenging case of objects located within a complex environment resembling a room in a building
Fishes of the Antarctic Ocean.
No full textESF Completed network-Evaluation Completion Report, ESF Documents, 15 pp
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
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