Dinamica di pneumatici aeronautici in frenata su macchina dinamometrica

Oggetto della presente tesi di laurea è lo studio della dinamica longitudinale di pneumatici radiali di impiego aeronautico in condizioni di frenata su macchina dinamometrica. Obiettivo principale è la revisione critica e l’affinamento di un modello elaborato in precedenti attività di ricerca. Tale modello, basandosi su un approccio energetico, consente di determinare gli effetti della coppia applicata alla ruota sulla forza di rotolamento e sul braccio di leva della reazione al carico verticale. La versione originale di questo modello, è stata sviluppata e tarata sfruttando dati raccolti nel corso di test sperimentali su un pneumatico di grandi dimensioni ed è stata poi validata confrontando i risultati dei test sperimentali con quelli ottenuti dalla simulazione degli stessi mediante la realizzazione di una macchina dinamometrica virtuale in ambiente Matlab-Simulink. Il programma per la simulazione numerica delle prove sperimentali viene qui rielaborato per includere l’azione aggiuntiva della coppia applicata al tamburo e per eliminare alcune anomalie riscontrate nel suo funzionamento. A partire dallo studio della condizione di frenata stazionaria, reso possibile dall’introduzione della coppia sul tamburo, si presenta una versione alternativa del modello nella quale viene linearizzata solo l’equazione della ruota, in modo da calcolare gli zeri, i poli ed i guadagni che descrivono la sua dinamica. Le risposte del modello linearizzato sono poi confrontate con quelle del modello non lineare. Infine si propone un programma per l’identificazione dei parametri delle funzioni di trasferimento della ruota sfruttando i dati sperimentali a disposizione, in modo da ottimizzare la risposta del modello linearizzato, nell’ottica di sintetizzare un modello semplificato ma che nel contempo dia dei risultati esaurienti

The building stones of the apsidal walls of the Pisa’s Cathedral

This paper reports the preliminary data about the stones used in the apsidal walls of the Cathedral of Pisa. The research was made during the study and restoration works of the monument, under the supervision of the Opera della Primaziale Pisana. The collected data shows the prevalence of stones commonly used in the historical buildings of the city. The main lithotypes are the marbles from the Monte Pisano and from the Apuan Alps. Moreover, there are numerous ashlars of Proconnesian marble and two capitals of Pentelic and one of Paros marbles, three lithotypes used during the Roman Age and coming from the Eastern Mediterranean. The wall of the loggia of the third storey is almost entirely made up of a calcarenite (Panchina) coming from the area South of Livorno. Black limestone from the Monti d’Oltre Serchio, and serpentinite and red marly limestone outcropping in different areas of Tuscany, were also identified

Chemical characterisation of historic mortars to evaluate decay and construction phases

The chemical characterization of ancient mortars allowed the researchers to answer relevant questions about production technologies, raw materials supply, construction phases and state of decay. In this work one hundred and sixteen samples were collected from different structures during two archaeological excavations carried out in Sagunto’s city centre (Valencia, Spain). The studied area has been interested by several continuous phases of occupation since the Iberian Epoch (5th century BC) to the present times [1,2]. The samples were analysed employing X-ray fluorescence and Inductively coupled plasma mass spectrometry to determine major and trace elements. The obtained data was statistically processed with Sagunto’s Castle mortar results [3], allowing us to identify the construction phases of most of the wall structures, confirming the particular effectiveness of Rare Earth Elements analysis to distinguish mortars from different periods. In conclusion, according to this data, the state of conservation of the different mortars has been evaluated. [1] Ripollés, Opulentissima Saguntum (2004) 165. [2] Monserrat, Arse 41 (2007) 231. [3] Gallello et al., Microchem. J. 132 (2017) 251

Chronological classification of ancient mortars employing spectroscopy and spectrometry techniques : Sagunto (Valencia, Spain) case

Forty-two mortar samples, from two archaeological excavations located in Sagunto (Valencian Community, Spain), were analysed by both portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to determine major and minor elements, and traces including rare earth elements (REE). Collected data were crossed with those previously obtained from Sagunto Castle mortars and principal component analysis (PCA) was applied to discriminate the construction phases of the unearthed buildings. REE permitted to ascribe most of the masonries to the Roman Imperial period. Moreover, a statistical model was built by employing partial least squares discriminant analysis (PLS-DA) in order to classify the mortars from Roman Imperial period and from Islamic period, due to the problematic overlapping between these two phases. Results confirmed the effectiveness of the developed indirect chronology method, based on REE data, to discriminate among historic mortars from different construction periods on a wide scale including different Sagunto archaeological sites

The source of the building stones from the Sagunto Castle archaeological area and its surroundings

A multidisciplinary study was carried out on the building stones of the masonries belonging to the Castle of Sagunto (Valencia, Spain), an important historical and archeological complex, characterized by several construction phases from the Roman Period to the Modern Ages. For the first time, the stones of the Sagunto Castle have been analysed to determine their chemical, mineralogical and petrographic features, the main physical and mechanical properties, and to understand their decay, use and recycling dynamics in the different building during the entire occupational period. Geochemical and mineralogical analyses employing X-ray fluorescence (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray diffraction (XRD) were carried out together with optical and electronic microscope analysis to observe the stone macro- and micro-structures. The collected data were processed by Principal Component Analysis (PCA) to highlight differences among the studied structures. The results show that the stones employed to build Sagunto`s structures during the different historical periods are related to a specific quarried area located nearby Sagunto Castle hill and differences between the studied samples are mostly related to the conservation state of the buildings. Therefore, geochemical analyses confirm the origin of the raw materials, while petrographic and physical analyses have been useful to evaluate the conservation state of the studied Sagunto Castle structures

A Phylogenetic Analysis of Human Immunodeficiency Virus Type 1 Sequences in Kiev: Findings Among Key Populations

Background: The human immunodeficiency virus (HIV) epidemic in Ukraine has been driven by a rapid rise among people who inject drugs, but recent studies have shown an increase through sexual transmission. Methods: Protease and reverse transcriptase sequences from 876 new HIV diagnoses (April 2013–March 2015) in Kiev were linked to demographic data. We constructed phylogenetic trees for 794 subtype A1 and 64 subtype B sequences and identified factors associated with transmission clustering. Clusters were defined as ≥2 sequences, ≥80% local branch support, and maximum genetic distance of all sequence pairs in the cluster ≤2.5%. Recent infection was determined through the limiting antigen avidity enzyme immunoassay. Sequences were analyzed for transmitted drug resistance mutations. Results Thirty percent of subtype A1 and 66% of subtype B sequences clustered. Large clusters (maximum 11 sequences) contained mixed risk groups. In univariate analysis, clustering was significantly associated with subtype B compared to A1 (odds ratio [OR], 4.38 [95% confidence interval {CI}, 2.56–7.50]); risk group (OR, 5.65 [95% CI, 3.27–9.75]) for men who have sex with men compared to heterosexual males; recent, compared to long-standing, infection (OR, 2.72 [95% CI, 1.64–4.52]); reported sex work contact (OR, 1.93 [95% CI, 1.07–3.47]); and younger age groups compared with age ≥36 years (OR, 1.83 [95% CI, 1.10–3.05] for age ≤25 years). Females were associated with lower odds of clustering than heterosexual males (OR, 0.49 [95% CI, .31–.77]). In multivariate analysis, risk group, subtype, and age group were independently associated with clustering (P < .001, P = .007, and P = .033, respectively). Eighteen sequences (2.1%) indicated evidence of transmitted drug resistance. Conclusions Our findings suggest high levels of transmission and bridging between risk groups

Sviluppo di un display tattile a polimeri elettroattivi quale ausilio per non vedenti nell'utilizzo di smartphone

Realizzazione di un dispositivo in grado di aiutare la persona non vedente nell’utilizzo di un comune smartphone,in particolare si progetta un sistema che consenta di orientarsi su un’interfaccia touchscreen. Questo tipo d’interfaccia utente sta prendendo sempre più campo nei dispositivi di comunicazione, creando difficoltà alla persona non vedente, la quale non trova punti di riferimento percepibili con il tatto così come nelle tastiere a bottoni di un telefono tradizionale. Il dispositivo presentato in questa tesi è un primo studio sulla mappatura di un touchscreen utilizzata per un posizionamento veloce del non vedente sulle parti più importanti dell’interfaccia. Caratteristica importante del dispositivo, è la possibilità di collegarsi a uno smartphone senza modificarlo, come una sorta di accessorio per cellulare che introduce nuove funzionalità. Si realizza un frame equipaggiato con Attuatori ad elastomeri dielettrici con accoppiamento idrostatico (Hydrostatically Coupled Dielectric Elastomer Actuators – HC-DEAs) utilizzati come punti di riferimento per localizzare le aree d’interesse specifiche dello schermo touchscreen. L’utente abbina, in una certa applicazione, l’elemento X cercato, a un punto di riferimento Y relativo a un attuatore. Il dispositivo può essere considerato un vero e proprio ausilio per il non vedente. Più in generale questa divisione dello spazio dell’interfaccia, quindi una mappatura degli elementi nella matrice dello schermo, fa riferimento a un’interazione classica con il dispositivo elettronico, un’interazione cioè di tipo spaziale; teoricamente questa può essere integrata e talvolta sostituita da un’interfaccia a interazione vocale. Risulta però indispensabile riuscire a sostituire il senso della vista con il maggior numero d’informazioni possibili, quindi ogni informazione aggiuntiva, od ogni interfaccia aggiuntiva, atta a facilitare l’utente, è da considerarsi come importante supporto alla comprensione dell’informazione, alla comunicazione, all’autonomia del non vedente

La villa dell'Oratorio a Capraia e Limite. Primi dati sulla decorazione parietale.

.Abstract non disponibil

A novel shared control algorithm for industrial robots

Human management of robots in many specific industrial activities has long been imperative, due to the elevated levels of complexity involved, which can only be overcome through long and wasteful preprogrammed activities. The shared control approach is one of the most emergent procedures that can compensate and optimally couple human smartness with the high precision and productivity characteristic to mechatronic systems. To explore and to exploit this approach in the industrial field, an innovative shared control algorithm was elaborated, designed and validated in a specific case study