Research on the vocal culture of Orcinus orca in the Loro Parque, Tenerife: a pilot study

This research is focussed on the study of Orcinus orca's communication system. The analysis of vocalizations emitted by marine mammals has started in the '80s and most studies have been carried out in the wild. In this regard the most studied animal has been common dolphin (Tursiops truncatus) as the numerous presence of captive individuals worldwide made researches easier to be carried out. Studies about Orcinus orca's vocalizations have mainly been carried out in the wild (most in British Columbia) because its maintenance in a controlled environment results to be very difficult, only 17 among parks and oceanaria worldwide have some Orcinus orca (45 overall among which 64% born in captivity). These researches showed that Orcinus orca emit three main different types of sounds, classified as: whistles, clicks and calls. Besides, it was discovered that different groups (pods) produce sounds belonging only to the relevant pod (dialects). It is rare to find two pods sharing some calls. The two pods usually live in adjacent areas and can form a clan. This study was carried out in a controlled environment in the Orca ocean structure (Loro Parque, Tenerife, Spain) where, at the moment (March 2012) 6 individuals are hosted. Here it was developed an automatic sound recording system. Thanks to the use of suitable mathematical algorithms that allow to isolate only "interesting" sound events that differ from the "background noise", it was possible to create a database. The visualization of the sound events collected in the database is carried out with the use of a software. By looking at this output and at the observation register we could match the animal to the sound produced. Three situations were detected and studied: 1) Chosen alone: the animal chooses to go to the recording pool but it is free to move to another pool with other individuals. 2) Put alone: the animal is put alone in the recording pool. 3) With other orcas: more animals are together in the recording pool. The statistic analysis show that animals emit more vocalizations when they are in the situation "Chosen alone". The research will continue in order to observe eventual differences in the individual repertoire of each Orcinus orca.

Hybrid foundations for offshore wind turbines

Nowadays offshore wind turbines represents a valid answer for energy production but with an increasing in costs mainly due to foundation technology required. Hybrid foundations composed by suction caissons over which is welded a tower supporting the nacelle and the blades allows a strong costs reduction. Here a monopod configuration is studied in a sandy soil in a 10 m water depth. Bearing capacity, sliding resistance and pull-out resistance are evaluated. In a second part the installation process occurring in four steps is analysed. considering also the effect of stress enhancement due to frictional forces opposing to penetration growing at skirt sides both inside and outside. In a three dimensional finite element model using Straus7 the soil non-linearity is considered in an approximate way through an iterative procedure using the Yokota empirical decay curves.

Sviluppo dell'ingegneria di cantiere per la realizzazione del deck della piattaforma offshore Eni Fauzia

La tesi tratta di tutti gli studi, le verifiche e le procedure necessarie per realizzare il deck di una piattaforma offshore. Il progetto Eni Fauzia è stato seguito dalla Rosetti Marino Spa di Ravenna, presso il cantiere Piomboni.

Influence of advanced load simulation models on fatigue design of jackets for offshore wind turbines.

Constant developments in the field of offshore wind energy have increased the range of water depths at which wind farms are planned to be installed. Therefore, in addition to monopile support structures suitable in shallow waters (up to 30 m), different types of support structures, able to withstand severe sea conditions at the greater water depths, have been developed. For water depths above 30 m, the jacket is one of the preferred support types. Jacket represents a lightweight support structure, which, in combination with complex nature of environmental loads, is prone to highly dynamic behavior. As a consequence, high stresses with great variability in time can be observed in all structural members. The highest concentration of stresses occurs in joints due to their nature (structural discontinuities) and due to the existence of notches along the welds present in the joints. This makes them the weakest elements of the jacket in terms of fatigue. In the numerical modeling of jackets for offshore wind turbines, a reduction of local stresses at the chord-brace joints, and consequently an optimization of the model, can be achieved by implementing joint flexibility in the chord-brace joints. Therefore, in this work, the influence of joint flexibility on the fatigue damage in chord-brace joints of a numerical jacket model, subjected to advanced load simulations, is studied.

"Offshore tower or platform foundations: numerical analysis of a laterally loaded single pile or pile group in soft clay and analysis of actions on a jacket structure"

Laterally loaded piles are a typical situation for a large number of cases in which deep foundations are used. Dissertation herein reported, is a focus upon the numerical simulation of laterally loaded piles. In the first chapter the best model settings are largely discussed, so a clear idea about the effects of interface adoption, model dimension, refinement cluster and mesh coarseness is reached. At a second stage, there are three distinct parametric analyses, in which the model response sensibility is studied for variation of interface reduction factor, Eps50 and tensile cut-off. In addition, the adoption of an advanced soil model is analysed (NGI-ADP). This was done in order to use the complex behaviour (different undrained shear strengths are involved) that governs the resisting process of clay under short time static loads. Once set a definitive model, a series of analyses has been carried out with the objective of defining the resistance-deflection (P-y) curves for Plaxis3D (2013) data. Major results of a large number of comparisons made with curves from API (America Petroleum Institute) recommendation are that the empirical curves have almost the same ultimate resistance but a bigger initial stiffness. In the second part of the thesis a simplified structural preliminary design of a jacket structure has been carried out to evaluate the environmental forces that act on it and on its piles foundation. Finally, pile lateral response is studied using the empirical curves.

Immagine sismica del margine della piattaforma adriatica nell'offshore croato: implicazioni per la ricerca di idrocarburi

La zona della piattaforma Adriatica, visibile in sismica a sud della costa croato – montenegrina, è stata oggetto di ricerche petrolifere in passato. Nuovi dati sismici hanno permesso la visualizzazione di alcune caratteristiche che saranno esaminate ed interpretate nel presente lavoro. In particolare ci si concentrerà sulla caratterizzazione e sulla differenziazione dei margini incontrati durante il lavoro di interpretazione. In questa fase, sono emerse delle caratteristiche che hanno permesso una revisione del margine della piattaforma Adriatica e del bacino di Budva noti nella letteratura pregressa. Il problema della differenziazione dei margini della piattaforma è stato affrontato sia in chiave tettonica (influenza della subsidenza, inversione di margini ad opera di un Thrust, tettonica ialina, buckling) che in chiave paleoambientale (influenza di venti dominanti) ricoprendo un arco temporale che spazia tra il Triassico superiore ed il Miocene superiore. Grazie alle interpretazioni effettuate e al confronto con la letteratura, saranno proposte, in una seconda fase, alcune situazioni favorevoli all’accumulo di idrocarburi nella zona di studio. Verrà, infine, affrontato il confronto con casi di letteratura inerenti i margini della vicina piattaforma Apula, considerati come margini coniugati della piattaforma Adriatica.

Metodi di posizionamento di strutture offshore

Nel presente elaborato vengono approfonditi i principali metodi di posizionamento attualmente utilizzati, ossia il GPS e il GPS differenziale, con particolare riferimento a strutture posizionate in mare. Gli stessi sono utilizzati per il monitoraggio della subsidenza e dei movimenti tettonici cui le strutture offshore sono soggette, che, essendo movimenti dell’ordine di qualche millimetro all'anno, richiedono accuratezza nelle misure. Nell'ultima parte della tesi si è provveduto ad analizzare una serie di dati, derivanti da rilevamenti GPS, al fine di valutare gli effetti termici sulla struttura emersa di una piattaforma offshore.