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Il diritto dell'uomo a manifestare liberamente il proprio pensiero e il diritto di informazione. Aspetti filosofici e prospettive giuridiche
No full textStudy of the gas migration mechanism in the natural laboratories for the characterisation and monitoring of CO2 geological storage sites
No full textThe greenhouse gas effect and the global warning phenomenon are largely discussed by scientific community and government and, in the next years, a number of actions focused on the reduction of the greenhouse gases emissions have to be finalised. The reduction of greenhouse gas emissions can be achieved in several ways but probably, at the short/mid-term, the only way with an acceptable cost/benefit ratio is to avoid the CO2 emission from the fossil fuel power plant and, in parallel, strongly develop the renewable energies.
A really interesting option for the reduction of CO2 emissions is CCS (CO2 capture and storage). This technique consists of capturing CO2 from power and industrial activities and storing it in deep geological reservoirs having different geological traps. The potential effectiveness of CCS is the reduction of 15% of the emission by 2050.
A critical component of long term geological sequestration of anthropogenic CO2 will be our ability to adequately monitor a chosen site to ensure public and environmental safety. Near surface monitoring is particularly important, as it is possible to conduct sensitive and direct measurements at the boundary between the subsurface and the biosphere (i.e. surface water or atmosphere).
In this work different aspects of direct gas measurements for the control and monitoring of CO2 storage sites were undertaken. In particular: i. the study of some fault systems at the Latera caldera allowed a better understanding of the gas migration mechanisms; ii. soil gas surveys carried out at “Concessione mineraria Monte Sinni” and at Kaniow allowed baseline characterization and the test of this approach for the discontinuous post injection monitoring; iii. the design and development of an innovative and low cost monitoring system that can make possible the use of direct geochemical methods of measurement where the currently required costs make them unsuitable.
The obtained results seem to confirm the potent of the geochemical approach, both in terms of sensitivity and cost/benefit ratio. In fact the discontinuous monitoring applied at Kaniow defined micro-leaks close to the injection site and the monitoring system tested at Panarea Island successfully worked highlighting a good sensitivity and repeatability of the measures.
Finally, in the framework of the CCS activities, it is important to consider the importance of the “public acceptance” of this process. In this regards, although a number of well-tested (i.e. in the oil exploration), indirect geophysical monitoring techniques can be used, the monitoring of the storage site by direct geochemical measurements in the near-surface environment can provide a clearer observation phenomenon and can be easier understood and accepted by local stakeholders
Campionamento del combustibile da rifiuto (CDR): rappresentatività del campione da laboratorio e affidabilità del dato finale
No full textIl combustibile da rifiuto (CDR) prodotto dagli impianti di deselezione e produzione si ottiene attraverso processi che eliminano i materiali non combustibili e la frazione umida;, imballaggi multimateriali gomme, resine e fibre sintetiche non contenenti cloro. Da diversi confronti interlaboratorio emergono chiare indicazioni sul contributo rilevante del campionamento all’incertezza finale del risultato analitico. La probabilità di analizzare campioni non rappresentativi non solo di CDR è molto concreta e altrettanto elevato è il rischio di non evidenziare situazioni di non conformità o al contrario creare allarmismi ingiustificati.
In questo studio si è esaminata la validità della procedura di campionamento del CDR secondo i diversi parametri indicati nella norma UNI 9903-1:2004 in termini di incertezza estesa di campionamento. Tale studio è stato applicato al campionamento di su un lotto di produzione definito dalla norma UNI 9903-3:2004.Scientific and Technological Park of Southern Lazi
ULTRASOUND-GUIDES ASPIRATION AND CORTICOSTEROID INJECTION COMPARED TO HORIZONTAL THERAPY FOR TREATMENT OF KNEE OSTEOARTHRITIS COMPLICATED WITH BAKER’S CYSTI: A RANDOMIZED, SINGLE BLIND, CONTROLLED TRIAL.
No full textA new approach for the evaluation of shaft friction of bored piles in sandy soils
No full textIn recent decades much research efforts have been dedicated to understand piles and piled foundations performance, but still a big amount of uncertainties remains on single pile behaviour. Although improvements have been made in identifying the processes that occur within the critical zone of soil immediately surrounding the pile, in literature are not available theories which allow to quantify the changes in state of soil during the load (stress, void index). This assessment is particularly true for piles embedded in sandy soils, on which the paper will focus on.
Granular soils at shallow depth from surface are subjected to low confining stresses, hence potentially dilating when sheared at failure. This is what systematically happens in the upper portion of axially loaded piles, as demonstrated by several experimental data collected by a number of researcher: it is well known from literature that measured unit shaft resistances are usually greater than theoretical values (e.g. O’Neill e Hassan, 1994; Chen e Kulhawy, 2002; Rollins et al., 2005).
In the thesis a conceptual framework for estimating pile shaft capacity has been presented, in which the dilatant behaviour of sand in the shear band, partially forbidden from the surrounding soil, is explicitly considered: shear band develops in a small portion of soil close to pile shaft and its thickness is controlled by grain size, since it is of the order of 5 to 20 times d50.
Theoretical model led numerical analyses (which have been performed with FLAC 2D, a two-dimensional explicit finite difference code), which focused on shaft friction evolution at pile-soil interface for “wished in place” axially loaded single piles, embedded in sandy soils. In detail, parametric analyses have been performed by changing relative density, stress history (OCR), friction angle and grain size distribution.
Numerical results highlighted those critical aspects which cannot be ignored if shaft friction evolution must be predict. Dilatancy of sand in shear bands at the pile-soil interface plays a major role in increasing normal stress (thus unit shaft friction) during loading, but its effect is strictly modulated by its initial thickness, or rather by grain size distribution. In others words, irrespective of its dilatants potentiality, fine sands does not allow for large values of qs as a consequence of plastic volumetric strains confined in a very thin shear band. Obviously all above strongly influences the pile load-settlement curve for a given soil condition, but with different grading.
From these results, a new designing approach is suggested in which shaft resistance prediction moves from a physical and mechanical behaviour description of soils surrounding pile shaft. The applicability of the proposed approach is showed for some real case study of vertical load tests on instrumented piles
Ballistic characterization of nanostructured composite materials for aerospace applications
No full textThe manuscript is arranged in three main parts.
In the first chapter the nanocomposite manufacturing is described. As far as the CNTfilled
polymeric composites are concerned, a carbon nanotube functionalization process
by thermal and chemical treatments has been performed, and Scanning Electron
Microscopy (SEM) analysis, as well as Raman and FT-IR spectroscopies were used to
verify the surface modifications of the CNTs by the added radical groups. Then, the
manufacturing of the CNT-reinforced epoxy composite has been carried out, and
Differential Scanning Calorimetry (DSC) was used to analyze the polymerization
process for the nano-reinforced thermosetting polymer systems. SEM investigations
were also performed to assess the nanocomposites quality in terms of nanoparticle
dispersion and material homogeneity. Regarding the STF-reinforced materials, STFs
have been synthesized in a single step reaction through high power ultrasound
technique, and characterized in terms of their rheological properties. The shear
thickening fluid is prepared by ultrasound irradiation of silica nanoparticles dispersed in
liquid polyethylene glycol polymer. Then, STF-reinforced fabrics have been realized by
soaking layers of several types of Kevlar in STF/ethanol solution; the morphology of
the as-realized fabrics, in particular for what concerns the STF/fibers interaction, has
been deeply investigated by SEM analysis.
In the second chapter the realization and the characterization of the in-house built Coil
Gun device for ballistic applications is presented. The realization of such experimental
apparatus, and mostly the optimization with a view to space debris testing plane, is quite
complex since the fundamental machine parameters have high non-linearity behavior.
With the aim to perform an as accurate as possible ballistic characterization, both
theoretical issues and experimental preliminary results of the prototypal device are
widely presented and discussed.
In the third chapter the results of the ballistic characterization of the realized
nanocomposite materials are reported. The response of the manufactured materials to
several levels of impact energy is widely investigated. Charpy impact and weight drop
tests were performed to obtain a preliminary ballistic characterization of the CNTVI
reinforced epoxy composites in the low energy impact range. In order to assess the
influence of the nanoparticles content as well as the effectiveness of the nano-filler itself
and after chemical treatments, samples with different percentages of functionalized
CNTs embedded in two different epoxy resins were tested and compared with samples
reinforced by pristine CNTs and micrometric graphite powder. Finally, the response of
CNT-reinforced epoxy materials and STF-reinforced Kevlar fabrics was experimentally
investigated by Coil Gun ballistic tests at different impact energy: the effects of the
nanoparticles on the penetration failure and the impact absorbing mechanism is
analyzed and discussed
Alcune considerazioni sull'economia del petrolio
No full textIl petrolio sembra spingere i Paesi dominanti, che rifiutano di cambiare il loro stile di vita, a condurre guerre di conquista, con il solo obiettivo di assicurarsi la disponibilità di questa risorsa a prezzi accettabili e la guerra in Iraq ne è un esempio. Infatti, è proprio in Iraq che oggi sono localizzate la maggiori risorse mondiali di petrolio; qui il greggio è facilmente accessibile e di ottima qualità.
Con il pretesto della questione nucleare o del finanziamento del terrorismo, altri Paesi, come l’Iran e L’Arabia Saudita, potrebbero subire la stessa sorte dell’Iraq.
Con questo lavoro ho voluto fare un percorso storico/politico/economico su un argomento complesso come il petrolio. Tante previsioni e teorie in merito, nonostante la certezza che il greggio sia destinato all’esaurimento, non risolvono il problema contingente.
L’Italia non è un produttore di petrolio, soltanto in Lucania se ne produce un po’, tuttavia il nostro Paese riesce, con le sue capacità professionali, ad essere leader nel mondo in un settore con una concorrenza elevatissima e questo grazie all’Eni, che è il nostro fiore all’occhiello in questo campo
Il gotico a distanza: nuove prospettive per lo studio dell'evoluzione dei generi letterari
No full textRisultati a medio termine dopo correzione endovascolare di aneurismi dell'aorta addominale negli ultraottantenni
No full textIntroduzione:
L'aumento dell'età media della popolazione e la maggiore diffusione dei programmi di screening hanno comportato un notevole incremento del numero di aneurismi dell'aorta addominale sottorenale diagnosticati, specie in pazienti ultraottantenni.
Vi sono pareri discordanti se questa categoria di pazienti benefici di un trattamento chirurigico endovascolare dell'aorta addominale (EVAR).
Scopo del lavoro è valutare la mortalità e la morbilità precoce e tardiva dopo EVAR in pazienti con età maggiore o uguale ad 80 anni operati presso due unità operative complesse di chirurgia vascolare della Regione Lazio.
Materiali e metodi:
Sono stati revisionati i dati raccolti prospetticamente dal 2003 all’aprile 2012 di 184 pazienti trattati con EVAR con età maggiore o uguale a ottanta anni e confrontati con quelli di 407 pazienti con età inferiore operati nello stesso periodo.
Il follow up medio è stato di 30.5 mesi. E' stata eseguita un'analisi statistica ad identificare differenze tra i due gruppi in termini di risultati a breve e a medio temine.
Risultati:
Gli ottantenni sono risultati essere maggiormente ipertesi e diabetici mentre l'incidenza di bronchite cronica ostruttiva non differiva sostanzialmente tra i due gruppi (<80 aa 22% vs 17% >80 aa; P: N.S.). La mortalità perioperatoria non è risultata statisticamente diversa fra i due gruppi (<80 aa 0.5% vs 2.2% >80 aa; P: N.S.). Gli ottantenni hanno presentato più frequentemente complicanze ischemiche degli arti, a fine procedura, che hanno richiesto procedure aggiuntive e complicanze respiratorie nel postoperatorio. A distanza nel gruppo degli ultraottantenni si è assistito ad una più frequente insorgenza di endoleak di primo tipo (<80 aa 0.4 vs 2.7% >80 aa; P: 0.02).
Inoltre nel gruppo degli ultraottantenni la mortalità a distanza correlata all'aneurisma è stata significativamente più alta (<80 aa 0.2% vs 2.2% >80 aa; P: 0.02).
Conclusioni:
Il contenuto rischio di mortalità intraoperatoria e a distanza per aneurisma giustifica un trattamento endovascolare nell'ultraottantenne. Purtroppo in questo gruppo di pazienti i reinterventi chirurgici o endovascolari sono gravati più spesso da insuccesso terapeutico e più alto rischio di mortalità perioperatoria
Artopia: utopia e distopia nell'arte contemporanea. Dal 1989 ad oggi
No full textLa tesi esplora i temi dell'utopia e della distopia nella produzione artistica contemporanea, concentrandosi sul periodo storico che va dal 1989 ad oggi