Analisi CFD di un anfibio ultraleggero PrandtlPlane: validazione attraverso dati sperimentali di galleria del vento

This thesis, part of the IDINTOS project has the purpose to calibrate and validate the CFD methods, analyzing and trying to replicate the results previously obtained at the PoliMi wind tunnel. In the present work the STAR-CCM+ software, by Cd-Adapco, has been used to simulate a variety of cases. First the mesh has been validated, looking for a stability condition, changing the size of control volume and refining or making coarser both the wing meshes. Since the stability dimensions have been found, comparing the results given on some aerodynamic coefficients and choosing the dimensions which gave the stable results for all the coefficients, the chosen mesh has been used to simulate free air and wind tunnel conditions. The model has first been simulated in 1:1 scale, free air and cruise conditions, with a fully turbulent flow, then the geometry has progressively been translated to the wind tunnel conditions, scaling dimensions to 1:4, adding the pylon support and then the wind tunnel walls. To completely validate the data obtained at the wind tunnel facility, different kind of solvers have been used, switching from the k-ε full turbulence model, to the k-ω with fixed transition model. Once the physics have been set, several conditions of α and β wind incidence angles have been tested and recreated, managing to a redefinition of the aerodynamic surfaces that rule the lateral directional dynamics (posterior wing fences, tail fin).

Generalized spin-boson models with non-normalizable form factors

Generalized spin-boson (GSB) models describe the interaction between a quantum mechanical system and a structured boson environment, mediated by a family of coupling functions known as form factors. We propose an extension of the class of GSB models which can accommodate non-normalizable form factors, provided that they satisfy a weaker growth constraint, thus accounting for a rigorous description of a wider range of physical scenarios; we also show that such "singular" GSB models can be rigorously approximated by GSB models with normalizable form factors. Furthermore, we discuss in greater detail the structure of the spin-boson model with a rotating wave approximation (RWA): for this model, the result is improved via a nonperturbative approach which enables us to further extend the class of admissible form factors, as well as to compute its resolvent and characterize its self-adjointness domain.Comment: 40 pages; new section adde

What does the intention to be a volunteer for a student with autism predict? the role of cognitive brain types and emotion and behavior characteristics

The study was designed to verify which cognitive brain types and behaviors in classroom predicted the intention to volunteer to become a peer buddy for a student with Autism Spectrum Disorder (ASD). Five hundred and sixteen adolescents attending the first grade of public high schools were enrolled. Gender-related differences were discussed according to the empathizing-systemizing theory. As expected, empathy and prosocial behavior predicted volunteering in ASD intervention. We conclude that the selection of peers as intervention agents should require more informative sources. Clinical and research implications are discussedEste estudio se diseñó para verificar qué tipos de cerebro cognitivo y comportamientos en el aula predecían la intención de ofrecerse voluntario a acompañar a un alumno con trastorno del espectro autista (TEA). Se apuntaron 516 adolescentes de primer curso de enseñanza secundaria. Se abordaron las diferencias relativas al género de acuerdo a la teoría empatía-sistematización. Según lo esperado, la empatía y el comportamiento prosocial predecían la voluntariedad para intervenir en el TEA. Se concluye que la elección de compañeros como agentes de intervención necesitaría de más fuentes de información. Se comentan las implicaciones clínicas y de investigació

Self-adjointness of a class of multi-spin-boson models with ultraviolet divergences

We study a class of quantum Hamiltonian models describing a family of $N$ two-level systems (spins) coupled with a structured boson field, with a rotating-wave coupling mediated by form factors possibly exhibiting ultraviolet divergences (hence, non-normalizable). Spin-spin interactions which do not modify the total number of excitations are also included. Generalizing previous results in the single-spin case, we provide explicit expressions for the self-adjointness domain and the resolvent operator of such models, both of them carrying an intricate dependence on both the spin-field and spin-spin coupling via a family of concatenated propagators. This construction is also shown to be stable, in the norm resolvent sense, under approximations of the form factors via normalizable ones, for example an ultraviolet cutoff.Comment: 24 page

Renormalization of spin\unicode{x2013}boson interactions mediated by singular form factors

We study and discuss the extension of the rotating-wave spin\unicode{x2013}boson model, together with more general models describing a system\unicode{x2013}field coupling with a similar rotating-wave structure, to interactions mediated by possibly singular (non-normalizable) form factors satisfying a weaker growth constraint. To this purpose, a construction of annihilation and creation operators as continuous maps on a scale of Fock spaces, together with a rigorous renormalization procedure, is employed.Comment: 19 page

Municipal Treated Wastewater Irrigation: Microbiological Risk Evaluation

Municipal wastewater for irrigation, though treated, can contain substances and pathogens toxic for humans and animals. Pathogens, although not harmful from an agronomical aspect, undoubtedly represent a major concern with regards to sanitary and hygienic profile. In fact, vegetable crops irrigated with treated wastewater exalt the risk of infection since these products can also be eaten raw, as well as transformed or cooked. Practically, the evaluation of the microbiological risk is important to verify if the microbial limits imposed by law for treated municipal wastewater for irrigation, are valid, thus justifying the treatments costs, or if they are too low and, therefore, they don' t justify them. Different probabilistic models have been studied to assess the microbiological risk; among these, the Beta-Poisson model resulted the most reliable. Thus, the Dipartimento di Scienze delle Produzioni Vegetali of the University of Bari, which has been carrying out researches on irrigation with municipal filtered wastewater for several years, considered interesting to verify if the microbial limits imposed by the italian law n.185/03 are too severe, estimating the biological risk by the probabilistic Beta-Poisson model. Results of field trials on vegetable crops irrigated by municipal filtered wastewater, processed by the Beta-Poisson model, show that the probability to get infection and/or illness is extremely low, and that the actual italian microbial limits are excessively restrictive

Hemodynamic profiles of functional and dysfunctional forms of repetitive thinking

Background: The ability of the human brain to escape the here and now (mind wandering) can take functional (problem solving) and dysfunctional (perseverative cognition) routes. Although it has been proposed that only the latter may act as a mediator of the relationship between stress and cardiovascular disease, both functional and dysfunctional forms of repetitive thinking have been associated with blood pressure (BP) reactivity of the same magnitude. However, a similar BP reactivity may be caused by different physiological determinants, which may differ in their risk for cardiovascular pathology. Purpose: To examine the way (hemodynamic profile) and the extent (compensation deficit) to which total peripheral resistance and cardiac output compensate for each other in determining BP reactivity during functional and dysfunctional types of repetitive thinking. Methods: Fifty-six healthy participants randomly underwent a perseverative cognition, a mind wandering, and a problem solving induction, each followed by a 5-min recovery period while their cardiovascular parameters were continuously monitored. Results: Perseverative cognition and problem solving (but not mind wandering) elicited BP increases of similar magnitude. However, perseverative cognition was characterized by a more vascular (versus myocardial) profile compared to mind wandering and problem solving. As a consequence, BP recovery was impaired after perseverative cognition compared to the other two conditions. Conclusions: Given that high vascular resistance and delayed recovery are the hallmarks of hypertension the results suggest a potential mechanism through which perseverative cognition may act as a mediator in the relationship between stress and risk for developing precursors to cardiovascular disease

Variabilita’ climatica e ricorrenza delle calamita’ idrogeologiche in Puglia

Il contributo si basa sull’analisi di diversi tipi di dati, elaborati fino a costituire serie storiche mensili inerenti il clima (pioggia, temperatura, giorni piovosi e intensità di pioggia) dal 1877 al 2008. Nonostante la tendenza al calo della piovosità e dell’intensità di pioggia e all’incremento della temperatura e dei giorni piovosi, si osserva la crescente ricorrenza di piene e frane, a conferma della crescente antropizzazione di aree a pericolosità idrogeologica. La discussione delle relazioni clima-frane ha evidenziato delle limitazioni ragionevolmente dovute al concentrarsi delle frane in parte del territorio e alla minore qualità del dato storico