Dipartimento di Fisica - Tesi di Dottorato

Permanent URI for this collectionhttp://localhost:4000/handle/10955/35

Questa collezione raccoglie le Tesi di Dottorato afferenti al Dipartimento di Fisica dell'Università della Calabria.

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Subject: search.filters.subject.Processi

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    Turbulence and Stochastic Processes in Nematic Liquid Crystals
    (2010-10-22) Carbone, Francesco; Strangi, Giuseppe; Versace, Carlo
    In this work we studied the electrohydrodynamics instabilities (EHD) from a different point of view. We used the traditional tools, belonging to the traditional fluid turbulence framework, to the world of liquid crystals. This tools in addition, for the first time, a 3D scanning of the NLC sample driven in these turbulent regimes, give us some interesting results. As an example a fragmentation of the large scale structures (Williams Domains) whit characteristics similar to the Richardson cascade. We also studied, for the first time, the intensity fluctuation at different depth z inside the sample, and we found a strong non gaussianity in the probability density function of this fluctuation. Further information has been obtained by by studying the decorrelation processes in EHD. We found a local transition between two different regimes: the classical Kolomokorov K41 law in the y direction, and a random sweeping decorrelation in the opposite x direction. Finally we study the weak localization of light obtained during the EHD. We found a drastic reduction in the scattering mean free path `? and a strong enhancement of the backscattering cone.
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    Remediaciòn de unsitio contaminado (Pertusola):modelaciòn del transporte subterraneo Y anàlisis de riesgo sanitario
    (2009) Rivera Velasquez, Maria Fernanda; Troisi, Salvatore; Guerra, Ignazio
    This work applies deterministic and probabilistic methodology to the analysis of health risk of a contaminated site. The risks we have calculated are both cancerogenous and no-cancerogenous. The area we studied was formerly used for chemical industry, and is called “Pertusola South Crotone”. Due to its high concentrations of heavy metals it has been declared “area of national interest”. The receptors we have considered are adults, children and workers. As point where the target is exposed to the contamination we have taken the coast line. The contaminants that were considered are As, Cd y Zn. A mathematical model is utilized for the simulation of destination and transportation of contaminants from the point of origin of the contamination to that of exposition. The methodology of risk analysis is applied in direct and inverse way. The direct calculation allows the estimate of health risk to which the target is exposed in presence of a strong contamination. The inverse calculation makes possible to determine the maximum acceptable contamination of the target, compatible with an acceptable level of risk. The deterministic methodology has been used to calculate the RME and MLE values. The probabilistic one (based on Monte Carlo method) has been used to calculate the estimated average value, UCL 95%, UCL 99%. If the exposition rate RME is considered and deterministic and probabilistic results are compared, one obtains an overestimate of the risk in the case of the deterministic values. The probabilistic calculation allows to fulfil less conservative remediation objectives. This leads to a lower cost of the remediation work. From the uncertainty and sensitivity analysis one finds that toxicological factors contribute to the risk equation more than hydrogeological factors.
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