Wideband and UWB antennas for wireless applications. A comprehensive review

A comprehensive review concerning the geometry, the manufacturing technologies, the materials, and the numerical techniques, adopted for the analysis and design of wideband and ultrawideband (UWB) antennas for wireless applications, is presented. Planar, printed, dielectric, and wearable antennas, achievable on laminate (rigid and flexible), and textile dielectric substrates are taken into account. The performances of small, low-profile, and dielectric resonator antennas are illustrated paying particular attention to the application areas concerning portable devices (mobile phones, tablets, glasses, laptops, wearable computers, etc.) and radio base stations. This information provides a guidance to the selection of the different antenna geometries in terms of bandwidth, gain, field polarization, time-domain response, dimensions, and materials useful for their realization and integration in modern communication systems

IL DRAGAGGIO NEL DIVENIRE. LE MIGLIORI TECNICHE DISPONIBILI PER IL DRAGAGGIO IN SIN - SIR.

Il presente lavoro intende delineare un quadro generale delle problematiche legate alla progettazione ed esecuzione degli interventi di bonifica in ambito marino, alla luce delle vigenti disposizioni normative in ambito nazionale. Purtroppo l’attività di dragaggio attualmente è affetta da dubbi ed incertezze interpretative, disorganicità dell’attuale sistema normativo in materia ambientale, che non sono state superate neanche dopo l’emanazione del nuovo Testo Unico per l’Ambiente. Il problema ambientale, aggravatosi a causa della crescente evoluzione industriale, è ad oggi una complicata e pesante eredità da affrontare, in cui decenni di incuria e mancata vigilanza hanno consegnato alle nuove generazioni siti industriali dismessi, vecchi siti di centrali nucleari inattive, discariche abusive e rifiuti pericolosi mal gestiti, con conseguente alterazione delle caratteristiche qualitative dei terreni, delle acque superficiali e sotterranee. I siti inquinati possono essere un enorme risorsa se solo si riuscisse a promuovere la loro bonifica, assicurando la continuità delle attività produttive oppure per farne occasione di rilancio e riutilizzo del territorio. Affinché ciò possa accadere è necessario un grande sforzo pubblico e privato ed un cambiamento nell’approccio in tale disciplina. In particolare tale elaborato, vuole cercare di porre attenzione sull’azione di risanamento dei siti contaminati, che non deve limitarsi ad utilizzare esclusivamente tecnologie invadenti rapide ed onerose, ma deve perseguire come obiettivo principale l’impiego e la sperimentazione di nuove tecnologie che rispettino il naturale equilibrio dell’ambiente e la salute dell’uomo, e che conducano comunque a risultati efficienti e sostenibili. Tutto ciò dovrà passare attraverso un miglioramento dell’efficienza e della qualità dei processi produttivi, mediante il ricorso a nuove tecnologie, nuovi materiali e nuovi sistemi operativi, compatibili con la sicurezza e la salvaguardia dell’ambiente. L'Unione Europea ha emanato la Direttiva 96/61 CE con lo scopo di ottenere una prevenzione ed un controllo integrati dell'inquinamento proveniente dai diversi settori produttivi, attraverso interventi alla fonte delle attività inquinanti, con l'obiettivo di conseguire un elevato livello di protezione dell'ambiente nel suo complesso, attraverso l’utilizzo delle Migliori Tecnologie Disponibili (BAT, Best Available Techniques). Durante lo svolgimento della tesi verrà posto un confronto, su cui avanzeremo delle riflessioni, con l’attuale politica sui rifiuti. Nello specifico analizzeremo quanto affrontato dalla Commissione per le Migliori Tecnologie di gestione e smaltimento dei rifiuti, consapevole che le giuste modalità di intervento sono con tecnologie appropriate e con opportune iniziative di tipo gestionale in ogni sua fase. L’approccio con cui si attua una corretta politica di smaltimento dei rifiuti è basato sull’adozione di un preciso ordine gerarchico,che tenga conto dell’intera filiera partendo dalla loro produzione industriale, passando attraverso la raccolta, il recupero o riciclaggio, e terminando con lo smaltimento. A partire da ciò, cercheremo di comprendere perché quanto dettato dalla Direttiva Europea non venga recepito dalla normativa nazionale in campo di bonifica dei siti contaminati, analizzando in particolar modo casi pratici di bonifica di SIN presenti sul territorio italiano. Concluderemo l’elaborato con la presentazione di una valida alternativa, già esistente in campo industriale, che rappresenta come sia possibile operare con tecnologie e metodologie innovative tali da rispondere ai principi normativi da un lato e, dall’altro, conferire pregi operativi ed economici per i dragaggi in ambito portuale e per bonifiche in ambito SIN

Arbuscular Mycorrhizal Symbiosis Limits Foliar Transcriptional Responses to Viral Infection and Favors Long-Term Virus Accumulation

Tomato (Solanum lycopersicum) can establish symbiotic interactions with arbuscular mycorrhizal (AM) fungi, and can be infected by several pathogenic viruses. Here, we investigated the impact of mycorrhization by the fungus Glomus mosseae on the Tomato spotted wilt virus (TSWV) infection of tomato plants by transcriptomic and hormones level analyses. In TSWV-infected mycorrhizal plants, the AM fungus root colonization limited virus-induced changes in gene expression in the aerial parts. The virus-responsive upregulated genes, no longer induced in infected mycorrhizal plants, were mainly involved in defense responses and hormone signaling, while the virus-responsive downregulated genes, no longer repressed in mycorrhizal plants, were involved in primary metabolism. The presence of the AM fungus limits, in a salicylic acid-independent manner, the accumulation of abscissic acid observed in response to viral infection. At the time of the molecular analysis, no differences in virus concentration or symptom severity were detected between mycorrhizal and nonmycorrhizal plants. However, in a longer period, increase in virus titer and delay in the appearance of recovery were observed in mycorrhizal plants, thus indicating that the plant's reaction to TSWV infection is attenuated by mycorrhization. </jats:p

Propagation of perturbations and meandering in a free surface shallow water jet

A shallow water free-surface turbulent jet is investigated at Froude numbers variable between about 0.15 and 0.6 and a Reynolds number equal to 5000, with a jet height-to-width aspect ratio variable from 0.5 to 1.1. In these experimental conditions, the flow is unstable and develops local transverse instabilities, which are amplified to a global meandering motion, forcing the jet to oscillate orthogonally to its axis. Instantaneous and averaged velocity fields are obtained by means of high-density, correlation-based time-resolved Particle Tracking Velocimetry. From the average point of view, the present jet configuration resembles a confined jet condition similar to that of wall jets, but with additional relevant three-dimensional effects, retaining self-similar properties, with a net co-flow and some ambient fluid entrainment. For increasing Froude numbers, such configuration is moved downstream and the jet spreading is delayed. The high resolution in space and time of present measurements allows to locally detect and following perturbed patterns and to derive amplitude and frequency of oscillation of the global meandering motion, the former increasing with axial distance and decreasing with Froude number, the latter doing just the opposite. The velocity of propagation of perturbed patterns is also investigated in comparison to the jet mean velocity, the local celerity of propagation of fluctuating velocity fields being derived. Results indicate that axial fluctuations propagate downstream similarly to transverse fluctuations along the orthogonal direction, thus showing a close coupling among the two motions and the onset of a self-sustained mechanism driven by the mean flow, responsible for the generation of the macroscopic meandering motion. This effect is in agreement with numerical predictions and is emphasised as the Froude number increases

The Extreme Energy Events HECR array: status and perspectives

The Extreme Energy Events Project is a synchronous sparse array of 52 tracking detectors for studying High Energy Cosmic Rays (HECR) and Cosmic Rays-related phenomena. The observatory is also meant to address Long Distance Correlation (LDC) phenomena: the network is deployed over a broad area covering 10 degrees in latitude and 11 in longitude. An overview of a set of preliminary results is given, extending from the study of local muon flux dependance on solar activity to the investigation of the upward-going component of muon flux traversing the EEE stations; from the search for anisotropies at the sub-TeV scale to the hints for observations of km-scale Extensive Air Shower (EAS).Comment: XXV ECRS 2016 Proceedings - eConf C16-09-04.

Il design nel tappeto. Il tappeto nel design. Relazione tra progetto e prodotto

LAUREA SPECIALISTIC

Image analysis techniques for the study of turbulent flows

In this paper, a brief review of Digital Image Analysis techniques employed in Fluid Mechanics for the study of turbulent flows is given. Particularly the focus is on the techniques developed by the research teams the Author worked in, that can be considered relatively "low cost" techniques. Digital Image Analysis techniques have the advantage, when compared to the traditional techniques employing physical point probes, to be non-intrusive and quasi-continuous in space, as every pixel on the camera sensor works as a single probe: consequently, they allow to obtain two-dimensional or three-dimensional fields of the measured quantity in less time. Traditionally, the disadvantages are related to the frequency of acquisition, but modern high-speed cameras are typically able to acquire at frequencies from the order of 1 KHz to the order of 1 MHz. Digital Image Analysis techniques can be employed to measure concentration, temperature, position, displacement, velocity, acceleration and pressure fields with similar equipment and setups, and can be consequently considered as a flexible and powerful tool for measurements on turbulent flows

New Eco-gas mixtures for the Extreme Energy Events MRPCs: results and plans

The Extreme Energy Events observatory is an extended muon telescope array, covering more than 10 degrees both in latitude and longitude. Its 59 muon telescopes are equipped with tracking detectors based on Multigap Resistive Plate Chamber technology with time resolution of the order of a few hundred picoseconds. The recent restrictions on greenhouse gases demand studies for new gas mixtures in compliance with the relative requirements. Tetrafluoropropene is one of the candidates for tetrafluoroethane substitution, since it is characterized by a Global Warming Power around 300 times lower than the gas mixtures used up to now. Several mixtures have been tested, measuring efficiency curves, charge distributions, streamer fractions and time resolutions. Results are presented for the whole set of mixtures and operating conditions, %. A set of tests on a real EEE telescope, with cosmic muons, are being performed at the CERN-01 EEE telescope. The tests are focusing on identifying a mixture with good performance at the low rates typical of an EEE telescope.Comment: 8 pages, 6 figures, proceedings for the "XIV Workshop on Resistive Plate Chambers and Related Detectors" (19-23 February 2018), Puerto Vallarta, Jalisco State, Mexic

No Evidence for Seed Transmission of Tomato Yellow Leaf Curl Sardinia Virus in Tomato

Seed transmission is an important factor in the epidemiology of plant pathogens. Geminiviruses are serious pests spread in tropical and subtropical regions. They are transmitted by hemipteran insects, but a few cases of transmission through seeds were recently reported. Here, we investigated the tomato seed transmissibility of the begomovirus tomato yellow leaf curl Sardinia virus (TYLCSV), one of the agents inducing the tomato yellow leaf curl disease, heavily affecting tomato crops in the Mediterranean area. None of the 180 seedlings originating from TYLCSV-infected plants showed any phenotypic alteration typical of virus infection. Moreover, whole viral genomic molecules could not be detected in their cotyledons and true leaves, neither by membrane hybridization nor by rolling-circle amplification followed by PCR, indicating that TYLCSV is not a seed-transmissible pathogen for tomato. Examining the localization of TYLCSV DNA in progenitor plants, we detected the virus genome by PCR in all vegetative and reproductive tissues, but viral genomic and replicative forms were found only in leaves, flowers and fruit flesh, not in seeds and embryos. Closer investigations allowed us to discover for the first time that these embryos were superficially contaminated by TYLCSV DNA but whole genomic molecules were not detectable. Therefore, the inability of TYLCSV genomic molecules to colonize tomato embryos during infection justifies the lack of seed transmissibility observed in this host