Recurrence quantification analysis of spatio-temporal chaotic transient in a closed unstirred Belousov-Zhabotinsky reaction

We analyse the transient spatio-temporal chaos that we observe in the Belousov-Zhabotinsky reaction performed in a closed unstirred batch reactor by recurrence quantification analysis (RQA). We characterize the chaotic transient by measuring the Lyapunov exponent and the Kaplan-Yorke dimension. The latter shows the fractality of the attractor. The importance of the coupling between hydrodynamics and kinetics for the onset of chaos is also shown

Le comunità per minori: Una nuova prospettiva educativa

In this article we discuss the possibility to consider residential childcare context - just like other families characterized by the absence of biological generativity - as a family group, an educating family, when meaningful caregivers in a professional context guarantee parental functions to those children and adolescents who cannot have the opportunity to stay in their family of origin because of situations of deprivation, neglect or abuse. To define “residential childcare” as a “family” implies the assumption of an interpretative perspective whereby we consider all the family pluralities existing today, structured by the discontinuity between generativity, parenthood, conjugality and other variables, whose interconnection deconstructs the traditional idea of “natural” family (Fruggeri, 2007). In the light of these reflections, we can appreciate the complexity of the challenges which residential childcare is called upon to deal with, by configuring itself as one of the possible types of family.In questo articolo si discute la possibilità di considerare la comunità residenziale per l’accoglienza di bambini- al pari delle famiglie caratterizzate dall’assenza di generatività biologica- come un gruppo familiare, una famiglia educante, quando caregiver significativi, in un contesto professionale, garantiscono funzioni genitoriali a quei bambini e adolescenti che non hanno possibilità di rimanere nella famiglia di origine a causa di situazioni di deprivazione, abbandono o abuso. Definire la “comunità residenziale” come una “famiglia” implica l’assunzione di una prospettiva interpretative per la quale si considerano tutte le pluralità familiari oggi esistenti, caratterizzate dalla discontinuità tra generatività, genitorialità, coniugalità ed alter variabili, la cui interconnessione soppianta l’idea tradizionale di “naturale” (Fruggeri, 2007). Alla luce di queste riflessioni, possiamo apprezzare la complessità delle sfide che le comunità residenziali che accolgono i minori sono chiamate ad affrontare, configurandosi, di fatto, come una delle possibili tipologie di famiglia

Sustainability assessment of wheat production using Emergy

Sustainability of crop production has to be given high priority when global biomass resources are limited. Here emergy evaluation is applied in order to assess sustainability of crop production exemplified by winter wheat. Emergy evaluation takes into account all inputs involved in a production system (i.e. renewable and non-renewable, local and imported) and transforms them into a common measure of direct and indirect solar energy requirement. The evaluation of winter wheat production is conducted by comparing conventional and organic management on two soil types using Danish reference conditions. The resource use efficiency of wheat production per kg biomass is higher using conventional management practices. This is due to high yield based on large use of non-renewable resources. The environmental loading ratio from organic management practices is about a third of the conventional implying that the organic management can be considered more sustainable

Subexponential decay and regularity estimates for eigenfunctions of localization operators

We consider time-frequency localization operators Aaφ1,φ2 with symbols a in the wide weighted modulation space Mw∞(R2d), and windows φ1, φ2 in the Gelfand–Shilov space S(1)(Rd). If the weights under consideration are of ultra-rapid growth, we prove that the eigenfunctions of Aaφ1,φ2 have appropriate subexponential decay in phase space, i.e. that they belong to the Gelfand–Shilov space S(γ)(Rd) , where the parameter γ≥ 1 is related to the growth of the considered weight. An important role is played by τ-pseudodifferential operators Opτ(σ). In that direction we show convenient continuity properties of Opτ(σ) when acting on weighted modulation spaces. Furthermore, we prove subexponential decay and regularity properties of the eigenfunctions of Opτ(σ) when the symbol σ belongs to a modulation space with appropriately chosen weight functions. As an auxiliary result we also prove new convolution relations for (quasi-)Banach weighted modulation spaces

Subexponential decay and regularity estimates for eigenfunctions of localization operators

We consider time-frequency localization operators $A_a^{\varphi_1,\varphi_2}$ with symbols $a$ in the wide weighted modulation space $M^\infty_{w}(\mathbb{R}^{2d})$, and windows $\varphi_1, \varphi_2$ in the Gelfand-Shilov space $\mathcal{S}^{\left(1\right)}(\mathbb{R}^{d})$. If the weights under consideration are of ultra-rapid growth, we prove that the eigenfunctions of $A_a^{\varphi_1,\varphi_2}$ have appropriate subexponential decay in phase space, i.e. that they belong to the Gefand-Shilov space $\mathcal{S}^{(\gamma)} (\mathbb{R}^{d})$, where the parameter $\gamma \geq 1$ is related to the growth of the considered weight. An important role is played by $\tau$-pseudodifferential operators $\mathrm{Op}_\tau(\sigma)$. In that direction we show convenient continuity properties of $\mathrm{Op}_\tau(\sigma)$ when acting on weighted modulation spaces. Furthermore, we prove subexponential decay and regularity properties of the eigenfunctions of $\mathrm{Op}_\tau(\sigma)$ when the symbol $\sigma$ belongs to a modulation space with appropriately chosen weight functions. As a tool we also prove new convolution relations for (quasi-)Banach weighted modulation spaces.Comment: 29 page

Quasi-Banach modulation spaces and localization operators on locally compact abelian groups

We introduce new quasi-Banach modulation spaces on locally compact abelian (LCA) groups which coincide with the classical ones in the Banach setting and prove their main properties. Then we study Gabor frames on quasi-lattices, significantly extending the original theory introduced by Gr\"{o}chenig and Strohmer. These issues are the key tools in showing boundedness results for Kohn-Nirenberg and localization operators on modulation spaces and studying their eigenfunctions' properties. In particular, the results in the Euclidean space are recaptured

SUSTAINABILITY OF POULTRY PRODUCTION USING THE EMERGY APPROACH: COMPARISON OF CONVENTIONAL AND ORGANIC REARING SYSTEMS

The organic production system is an important strategy, compatible with sustainable agriculture, avoiding the use of chemical compounds,limiting the intensity of production and providing controls along the entire chain of production. The aim of this study is to compare conventional and organic poultry production in terms of emergy analysis. The main differences in the two systems were the emergy cost for poultry feed and for cleaning/sanitization of the buildings between successive productive cycles. In both production systems the poultry feed represented more than 50% of the emergy flow. Regarding the agronomic phase, it was shown that almost all the organic crops, avoiding chemical fertilizers and pesticides, saved around 60% emergy. The emergetic costs for housing of the birds were very similar in both systems. Relating the emergy results with productive performance it is possible to show that, although the annual productive performance was much lower in organic than in conventional (206%), transformity of organic poultry was around 10% lower. Comparison of the organic poultry system with a conventional one from the viewpoint of sustainability showed that all the emergy-based indicators are in favour of the organic farming system with a higher efficiency in transforming the available inputs in the final product, a higher level of renewable inputs, a higher level of local inputs and a lower density of energy and matter flows

Decay and Smoothness for Eigenfunctions of Localization Operators

We study decay and smoothness properties for eigenfunctions of compact localization operators. Operators with symbols a in the wide modulation space M^{p,\infty} (containing the Lebesgue space L^p), p<\infty, and windows \f_1,\f_2 in the Schwartz class are known to be compact. We show that their L^2-eigenfuctions with non-zero eigenvalues are indeed highly compressed onto a few Gabor atoms. Similarly, for symbols a in the weighted modulation spaces M^{\infty}_{v_s\otimes 1} (\rdd), s>0 (subspaces of M^{p,\infty}(\rdd), p>2d/s) the L^2-eigenfunctions of the localization operator are actually Schwartz functions. An important role is played by quasi-Banach Wiener amalgam and modulation spaces. As a tool, new convolution relations for modulation spaces and multiplication relations for Wiener amalgam spaces in the quasi-Banach setting are exhibited.Comment: To appear on J. Math. Anal. App

Studio di materiali nanostrutturati per applicazioni nel campo biomedico

Abstract Lo studio dei materiali riveste un ruolo di primaria importanza nella società moderna per il suo grande impatto in tutte le attività umane. In particolare i materiali nanostrutturati suscitano al giorno d’oggi un grande interesse sia dal punto di vista della ricerca di base che in ambito applicativo. Scopo di questa tesi di Dottorato è stato lo studio di leghe metalliche per applicazioni nel campo biomedico, in particolare leghe di Co–Cr–Mo–W e Ti-6Al-4V, usate per costruire provini tramite la tecnica Additive Manufacturing (AM) di tipo DMLS (Sinterizzazione Diretta di Metalli mediante Laser), che consiste nella produzione di oggetti a partire da polveri di particolari leghe metalliche tramite fusione operata da un raggio laser ad alta potenza che, strato dopo strato, costruisce l’oggetto le cui forme geometriche sono descritte in un file CAD. I provini ottenuti sono stati studiati sia nelle loro proprietà meccaniche sia nelle loro proprietà nanostrutturali e queste proprietà sono state studiate sia sui campioni semplicemente sinterizzati sia dopo trattamento termico seguito alla sinterizzazione. Sono state eseguite misure di rugosità e durezza ed anche test di trazione e flessione per testare le proprietà meccaniche, mentre la diffrazione di raggi X, la microscopia elettronica (SEM, TEM, STEM, HRTEM) e la microanalisi (EDX) sono state usate per investigare la nanostruttura. La caratterizzazione ha mostrato che per la lega Co–Cr–Mo–W si ha una trasformazione, indotta dal processo di produzione DMLS, che porta la polvere iniziale, essenzialmente costituita da fase γ-Co (cubica a facce centrate), al campione sinterizzato in cui vi è la presenza anche di fase ε-Co (esagonale) in forma di lamelle inserite nella matrice γ-Co. Tale configurazione è responsabile dell’alta resistenza a trazione (UTS) e durezza dei campioni sinterizzati. Dopo il trattamento termico si è riscontrato un aumento della frazione volumica della fase ε-Co, che modifica leggermente la dimensione media delle formazioni lamellari, inoltre dopo il trattamento termico si ha un sensibile aumento di UTS e durezza ed una forte riduzione della duttilità. Quest’ultima è attribuita ad una massiccia precipitazione di un probabile composto Co3(Mo,W)2Si con fase esagonale e alla contemporanea formazione di inclusioni ricche in Si. Per i campioni in lega di Ti-6Al-4V, costruiti in diverse orientazioni, è stata riscontrata una bassa porosità ed alte proprietà meccaniche indipendentemente dalle orientazioni. La caratterizzazione ha mostrato una fase martensitica α’-Ti (esagonale) dopo il primo trattamento di rilassamento degli sforzi, mentre il ciclo termico induce una fase stabile (α+β)-Ti, con la fase β-Ti (cubica) che cresce al bordo-grano della α-Ti, ma le proprietà meccaniche restano comunque molto buone. L’analisi quantitativa sulla frazione volumetrica α/β, ottenuta dagli strumenti di caratterizzazione, è stata inoltre confrontata con i risultati ottenuti per via grafica con l’applicazione software ImageJ, ottenendo un buon accordo. Il confronto tra i test meccanici e la caratterizzazione nanostrutturale suggerisce possibili applicazioni innovative della tecnologia DMLS per la produzione di parti meccaniche in campo medico/odontoiatrico.Abstract The study of materials plays an important role in modern society for its great impact in all human activities. In particular, the nanostructured materials arouse nowadays a great interest both from the point of view of basic research and of applicative field. The aim of this PhD thesis was the study of metal alloys for applications in the biomedical field. In particular alloys of Co-Cr-Mo-W and Ti-6Al-4V, were used to make samples through technical Additive Manufacturing (AM) of type DMLS (Direct Metal Laser Sintering). This technique consists in the production of objects starting from powders of special metal alloys by fusion effected by a high-power laser beam that, layer after layer, constructs the object whose geometric shapes are described in a CAD file. The specimens obtained were studied both in their mechanical properties and in their nanostructural properties. These properties have been studied both on simply sintered samples and after heat treatment following the sintering. Roughness and hardness measurements were performed together with tensile and bending tests to evaluate the mechanical properties. X-ray diffraction, electron microscopy (SEM, TEM, STEM, HRTEM) and microanalysis (EDX) techniques were used for investigate the nanostructure. The analysis showed that for the alloy Co-Cr-Mo-W there is a transformation, induced by the production process DMLS, that brings the initial powder, essentially consisting of γ-Co phase (face-centered cubic), at the sintered sample in which there is also the presence of ε-Co phase (hexagonal) in the form of lamellae inserted in the γ-Co matrix. This configuration is responsible for the high tensile strength (UTS) and hardness of the sintered samples. After heat treatment, it was found an increase of the volumetric fraction of the ε-Co phase, which slightly modifies the average size of the lamellae. Also after heat treatment a significant increase in UTS and hardness, and a strong reduction of the ductility was found. The ductility reduction is attributed to a massive precipitation of a probable compound Co3(Mo,W)2Si with hexagonal phase and the simultaneous formation of inclusions rich in Si. For Ti-6Al-4V samples, built in different orientations, a low porosity and high mechanical properties regardless of orientation were found. The analysis showed a martensitic Ti α'-phase (hexagonal) after the first relaxation treatment of efforts, while the thermal cycle induces a stable phase (α + β)-Ti, with the β-Ti (cubic phase) growing at the α-Ti edge-grain. The mechanical properties remain very good. The quantitative analysis on the volume fraction α/β was obtained by different characterization tools. The comparison between the mechanical properties and nanostructural details suggests possible innovative applications of the DMLS technology for the production of mechanical parts in the medical and dental fields

Funzioni di cura e genitorialità

Il presente lavoro è focalizzato sulla discussione inerente la stretta contiguità tra i costrutti di cura e di genitorialità intesi come due ambiti di discorso strettamente interconnessi e interdipendenti, che non possono prescindere l’uno dall’altro, e la cui stretta interconnessione consente di dare un apporto scientifico al dibattito attuale sull’adeguatezza genitoriale delle nuove costellazioni di famiglie ancora profondamente intriso di pregiudizi e stereotipi discriminanti e portatori di logiche escludenti e stigmatizzanti. A partire dalla genesi della genitorialità, dalla sua definizione e dalla descrizione delle sue caratteristiche di funzionamento, verrà argomentato come la genitorialità vada considerata una funzione autonoma e processuale dell’essere umano, preesistente all’atto di concepire, che ne è soltanto una, seppur fondamentale, ma non necessaria espressione da ricondurre all’esperienza di figlio che accomuna ogni essere umano aldilà della sua possibile esperienza generativa e risultante di processi interattivi, simbolici, interpersonali e sociali