Emergent matter from 3d generalised group field theories

We identify classical solutions of a generalised group field theory model in 3 dimensions, and study the corresponding perturbations, deriving their effective dynamics. We discuss their interpretation as emergent matter fields. This allows us, on the one hand to test the proposed mechanism for emergence of matter as a phase of group field theory, and on the other hand to expose some limitations of the generalised group field theory formalism.Comment: 14 pages, 1 figure, RevTex4, v

Characterisation of cyclic variability in an optically accessible IC Engine by means of phase-independent POD

Investigation of cyclic variability in engine operation has recently received new impulse with the widespread application of advanced numerical and experimental techniques. The present work attempts to shed some light on the existence and nature of correlations between coherent structures dynamics and cyclic variability in IC engines by means of phase-independent Proper Orthogonal Decomposition applied to highly-resolved PIV measurements obtained in an optically accessible, motored engine. Analysis of the conditional means and variances of the reconstruction coefficients reveal interesting patterns in the break-up of coherent structures which are also confirmed by experimental observation and leave room for speculation on the true nature of the flow field at different crank angles. A first attempt has also been carried out to reconstruct missing information from available measurements, with encouraging results: the development of such interpolation/reconstruction technique could obviously have a great impact on the reduction of the cost normally involved in experimental and computational campaigns

Effect of pressure on the flow behavior of polybutene

The rheology of submicron thick polymer melt is examined under high normal pressure conditions by a recently developed photobleached‐fluorescence imaging velocimetry technique. In particular, the validity and limitation of Reynold equation solution, which suggests a linear through‐thickness velocity profile, is investigated. Polybutene (PB) is sheared between two surfaces in a point contact. The results presented in this work suggest the existence of a critical pressure below which the through‐thickness velocity profile is close to linear. At higher pressures however, the profile assumes a sigmoidal shape resembling partial plug flow. The departure of the sigmoidal profile from the linear profile increases with pressure, which is indicative of a second‐order phase/glass transition. The nature of the transition is confirmed independently by examining the pressure‐dependent dynamics of PB squeeze films. The critical pressure for flow profile transition varies with molecular weight, which is consistent with the pressure‐induced glass transition of polymer melt

Sustainability and multifunctionality for next-generation construction materials

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Progettazione di un'applicazione web di telemonitoraggio usabile e sicura

La presente tesi riguarda la progettazione di un sistema di telemonitoraggio sanitario; lo scopo è quello di fornire ai medici un potente strumento di monitoraggio dei propri pazienti via web. Il lavoro inizia con un’analisi delle soluzioni attualmente disponibili, al fine di individuarne pregi e difetti; in questa fase vengono anche considerate attentamente le esigenze di medici e pazienti, fruitori del sistema. Viene poi progettata e in parte realizzata un’interfaccia web che permetta al medico di visualizzare, tramite grafici, le misure inviate al sistema dai pazienti. Per i pazienti, invece, viene ideata la struttura di un’interfaccia TV su digitale terrestre che permetta loro di interagire col sistema utilizzando il classico telecomando del televisore. L’ultima parte riguarda la necessità, da parte dei medici, di apporre una firma digitale ai documenti prodotti. Viene, quindi, progettato e realizzato un sistema di firma digitale basato su smart card

Reynolds stresses and turbulent heat fluxes in fan-shaped and cylindrical film cooling holes

Large eddy simulation (LES) is carried out to predict the thermal performance, unsteady flow patterns, and turbulence characteristics of the fan-shaped hole and the cylindrical hole cooling films. Velocity fields, Reynolds stresses, and turbulent heat flux distributions are the factors that ultimately determine the film cooling effectiveness by deciding the concentration of coolant and heat near the surface. Accurate prediction of these processes can provide a reliable data set for the design of film cooling systems. It can also help solve difficulties of improving RANS-based simulations in terms of their inaccuracies in matching measured flow rates for a given pressure drop across the film and the mixing process once the coolant is ejected from the film. Credible estimates and modest costs of the current LES originate from the multiblock hexahedra meshing, the turbulence inflow generator, and the numerical schemes implemented. Multiblock hexahedra meshes are adopted and generated by a quasi-automatic mesh generation algorithm utilizing template-based multi-block construction followed by elliptic smoothing. Computational resources are utilized in a way that mesh refinement exists only near cooling decorations of small size and wall boundaries, without the need for associated clustering in the far field which is commonly used in commercial packages. The high orthogonality and continuous smoothness throughout the computational domain are maintained to facilitate turbulence capturing. The synthetic inflow generator produces a random field matching a realistic set of two-point statistics based on eigen-reconstruction in a computationally inexpensive processing step. To prove that the current LES simulations of modest cost can reproduce with high accuracy, the discharge characteristics, velocity, and turbulence intensity profiles of cylindrical and fan-shaped cooling films are compared with published measured data on the same flow configurations. Results reveal that the set of modeling methodologies is valid for calculating film-cooling performance within an acceptable range of accuracy. The energy-carrying turbulence structures in and near the cooling holes are shown and their behaviors are linked to turbulent Reynolds stresses. Reynolds stresses and turbulent heat fluxes are compared for different blowing ratios and two types of cooling holes in the parametric study. Similarity patterns of velocity profiles, non-dimensional temperature profiles, Reynolds stress and turbulent heat flux profiles are discussed

The magazine´s journalistic construction Caras y Caretas in the repression of the "Semana Trágica" ("Tragic Week") in 1919

La revista Caras y Caretas, como publicación semanal de actualidad, estructuró un discurso acerca de los conflictos obreros durante la época radical (1916-1930), con las cuales ofreció su postura frente a las tensiones sociales y políticas de la época. En ese sentido, se indaga la construcción periodística de la publicación ante el reclamo de los sectores obreros en los hechos de la denominada Semana Trágica de 1919. La investigación toma para el análisis los aportes teórico-metodológicos de Roger Chartier, Miguel Rodrigo Alsina, Roberto Marafioti, Héctor Borrat, entre otros. Entre las conclusiones obtenidas, se demostró la posición del semanario como actor político de cara a los conflictos obreros y en el marco de las relaciones de dominio instituidas. Construyó un discurso que presentó realidades dicotómicas o pares antagónicos entre un “ellos” y un “nosotros”, los cuales además se diferenciaban por principios de superioridad e inferioridad y de la necesidad de asimilar o proscribir a quienes no encajaban en el orden establecido. A través de diversas estrategias discursivas, la revista legitimó prácticas represivas por parte de la policía, el Ejército y del sector parapolicial Liga Patriótica Argentina.The magazine Caras y Caretas, as a current weekly, lead a speech about the workers conflicts during the radical period (1916-1930), through which it offered it position against the social and political tensions of the epoch. In that sense, the publication ́s journalistic construction is inquired due to the workers sectors claims in what is known as “Semana Trágica” (“Tragic week”) in 1919. The research takes into account the theorical-methodological approaches for the analysis, as well as Roger Chartier, Miguel Rodrigo Alsina, Roberto Marafioti, Hector Borrat, among others. It was determined that journal position as a political actor face to the worker issues and with the power relations installed. It structured a speech that showed the dichotomous facts or antagonic pairs between “them” and “us”, who were also distinguised by superiority and inferiority principles and the need of setting aside to the ones that did not fit in the status quo. Through the different discursive strategies, the magazine legitimized repressive practices of the police, the Army and the parapolicial sector Liga Patriótica Argentina (Argentine Patriotic League)

Mirabilia Coralii. Capolavori barocchi in corallo tra maestranze ebraiche e trapanesi

La pregevole lavorazione del corallo trapanese ricostruita attraverso la puntuale analisi delle fonti documentarie, manoscritte e bibliografiche. L’organizzazione della maestranza e il ruolo che la committenza,sia laica che ecclesiastica, ha esercitato nella realizzazione di capolavori oggi presenti in rinomate collezioni pubbliche e private e nei principali musei nazionali ed internazionali. Una rassegna di importanti manufatti, un tempo mirabili opere da Wunderkammer, criticamente commentata, che bene evidenzia l’aulica produzione siciliana ricercata da Sovrani, Viceré ed alti prelati. Un’originale ed inedita trattazione che per la prima volta rende noti nomi e biografie di gran parte degli artisti specializzati, tra XVI e XIX secolo, nella trasformazione del prezioso materiale marin

Angular response of hot-wire probes

A new equation for the convective heat loss from the sensor of a hot-wire probe is derived which accounts for both the potential and the viscous parts of the ow past the prongs. The convective heat loss from the sensor is related to the far- eld velocity by an expression containing a term representing the potential ow around the prongs, and a term representing their viscous e ect. This latter term is absent in the response equations available in the literature but is essential in representing some features of the observed response of miniature hot-wire probes. The response equation contains only four parameters but it can reproduce, with great accuracy, the behaviour of commonly used single-wire probes. The response equation simpli es the calibration the angular response of rotated slanted hot-wire probes: only standard King's law parameters and a Reynolds-dependent drag coefficient need to be determined

Opinion formation models based on game theory

A way to simulate the basic interactions between two individuals with different opinions, in the context of strategic game theory, is proposed. Various games are considered, which produce different kinds of opinion formation dynamics. First, by assuming that all individuals (players) are equals, we obtain the bounded confidence model of continuous opinion dynamics proposed by Deffuant et al. In such a model a tolerance threshold is defined, such that individuals with difference in opinion larger than the threshold can not interact. Then, we consider that the individuals have different inclinations to change opinion and different abilities in convincing the others. In this way, we obtain the so-called ``Stubborn individuals and Orators'' (SO) model, a generalization of the Deffuant et al. model, in which the threshold tolerance is different for every couple of individuals. We explore, by numerical simulations, the dynamics of the SO model, and we propose further generalizations that can be implemented.Comment: 18 pages, 4 figure