395 research outputs found

    U.ph.o and mago: Two useful instruments in support of photogrammetric uav survey

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    In emergency and critical scenarios, the UAV could play a key role in accessing unreachable sites in a safe and rapid way, guaranteeing at the same time the necessary accuracy and precision of the survey. In this context, UAV survey campaigns have been performed by the authors in Norcia (Italy), hit by tragic seismic events in August and October 2016. The surveys were motivated by the artistic and historical value of monuments, the need to plan and design the restoring and retrofitting of buildings, and also to quantify and manage the ruins. Goal of such surveys was the description of the structures geometry with a centimetric precision and a high level of reliability. Recently, the authors have conceived two tools, U.Ph.O (Unmanned Photogrammetric Office) and MAGO (Adaptive Mesh for Orthophoto Generation), dedicated to the planning and restitution phases of the survey, respectively. U.Ph.O. and MAGO are here applied to two different buildings in Norcia, i.e. the Civic Tower of Norcia and San Salvatore Church of Campi di Norcia. The former is a standing-out structure, surrounded by the complex of the historical centre, while the latter is located in an isolated site in the countryside. These features make the survey planning and the orthophoto reconstruction completely different, mainly due to the different optimal shooting geometry and the presence or absence of obstructions

    Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy

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    A simple, reliable method for preparation of bulk Cr tips for Scanning Tunneling Microscopy (STM) is proposed and its potentialities in performing high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to what happens with conventional W tips, rest atoms of the Si(111)-7x7 reconstruction can be routinely observed, probably due to a different electronic structure of the tip apex. SP-STM measurements of the Cr(001) surface showing magnetic contrast are reported. Our results reveal that the peculiar properties of these tips can be suited in a number of STM experimental situations

    Laser cleaning of diagnostic mirrors from tokamak-like carbon contaminants

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    This paper presents a laboratory-scale experimental investigation of laser cleaning of diagnostic First Mirrors (FMs). Redeposition of contaminants sputtered from tokamak first wall onto FMs surface could dramatically decrease their reflectivity in an unacceptable way for the functioning of the plasma diagnostic systems. Laser cleaning is a promising solution to tackle this issue. In this work, pulsed laser deposition was exploited to produce rhodium films functional as FMs and to deposit onto them carbon contaminants with tailored features, resembling those found in tokamaks. The same laser system was also used to perform laser cleaning experiments by means of a sample handling procedure that allows to clean some cm(2) in few minutes. The cleaning effectiveness was evaluated in terms of specular reflectivity recovery and mirror surface integrity. The effect of different laser wavelengths (lambda = 1064, 266 nm) on the cleaning process is also addressed

    Utilizzo di immagini acquisite da UAV per la documentazione e una miglior fruizione di beni culturali e paesaggistici

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    L'uso di immagini aeree acquisite con velivoli senza pilota, i cosiddetti UAVs (Unmanned Aerial Vehicles), si sta sempre più diffondendo per scopi sia descrittivi sia geometrici. Ne è previsto, ad esempio, l'impiego all'interno del progetto FoGLIE (Fruition of Goods Landscape in Interactive Environment) recentemente finanziato dalla Regione Lombardia. Esso nasce dalla necessità di valorizzare il patrimonio culturale e paesaggistico presente sul territorio lombardo, allo scopo di proporne una maggiore fruibilità, tramite sistemi audio-visuali con i quali rappresentare i beni nel loro contesto cartografico di riferimento. Le finalità principali del progetto sono: - la creazione di un sistema di guida multimediale innovativo per la fruizione di beni culturali e paesaggistici anche di zone ad oggi inaccessibili; - il superamento di strutture ingombranti ed invasive quali totem o postazioni di interfaccia, di grande impatto sull’ambiente architettonico e naturale, sostituite da sistemi mobili; - l'integrazione di fruibilità e monitoraggio attivo del bene e del territorio, grazie a segnalazioni “garantite” che gli utenti potranno inviare dal dispositivo. FoGLIE, che ha avuto inizio nell'Ottobre del 2010 e sarà concluso a fine 2012, vede coinvolte alcune realtà imprenditoriali lombarde e il DIIAR del Politecnico di Milano, in qualità di componente scientifica e di consulenza tecnica in ambito cartografico e fotogrammetrico. Durante lo svolgimento del progetto si è presa in analisi una area test, individuata nel Parco Adda Nord, che racchiude al suo interno diverse categorie di beni paesaggistici e culturali (di valore architettonico e tecnologico) e paesaggistici. L’intento è di mettere a punto una metodologia per il rilievo, la documentazione e la divulgazione dei risultati che possa essere esportata ad altri casi simili. Nel presente lavoro si dà spazio all’organizzazione della ricerca, ai risultati ottenuti e alle raccomandazioni alle quali si è giunti al fine di utilizzare le nuove tecnologie nell’ambito della fruizione dei beni culturali e paesaggistici, con particolare attenzione alle riprese con UAV, alla realizzazione di modelli virtuali delle emergenze culturali del Parco, opportunamente georeferenziati e inseriti in ortofotocarta

    Psychometric properties of the Italian Tinnitus Functional Index (TFI)

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    Diversi questionari sono utilizzati per valutare l\u2019impatto dell\u2019acufene sulla qualit\ue0 della vita. Il Tinnitus Functional Index (TFI) proposto da Meikle et al, nel 2012, ha dimostrato propriet\ue0 eccellenti per misurare la gravit\ue0 e le modificazioni indotte dal trattamento degli acufeni, sia in ambito clinico che di ricerca. Lo scopo di questo studio \ue8 stato valutare le propriet\ue0 psicometriche della versione italiana del TFI, in particolare, l\u2019analisi fattoriale, la consistenza interna, l\u2019affidabilit\ue0 e la validit\ue0. La versione originale inglese del TFI \ue8 stata tradotta in italiano secondo la procedura translation - back translation; 137 partecipanti con acufeni da almeno 3 mesi (39,4% femmine, et\ue0: 18-80 anni, et\ue0 media: 48,26, SD: 14,08), reclutati presso la Tinnitus Clinic di Milano, hanno completato la versione italiana del TFI, il Tinnitus Handicap Inventory, la Beck Depression Inventory - Versione Primary Care e la scala di valutazione numerica per il fastidio. Una parte del campione, 57 pazienti, ha completato la versione italiana del TFI in una seconda visita, dopo 7-14 giorni, prima di ricevere qualsiasi tipo di trattamen- to, per ricavare i dati per la valutazione della riproducibilit\ue0. Le propriet\ue0 psicometriche sono state studiate attraverso un\u2019analisi fattoriale esplorativa ed il calcolo di misure di consistenza interna e affidabilit\ue0 test-retest. La validit\ue0 convergente \ue8 stata valutata mediante i coefficienti di correlazione con le restanti misure. La versione italiana del TFI ha mostrato una struttura a quattro fattori, parzialmente diversa dalla struttura originale a otto fattori. L\u2019adattamento italiano del TFI ha rivelato buoni livelli di consistenza interna (0,92 64 \u3b1 64 0,96) e affidabilit\ue0 test-retest (0,79 64 \u3b1 64 0,85). In termini di validit\ue0 convergente, ha mostrato buone correlazioni con i punteggi del THI (r = 0,77) e della scala del fastidio (r = 0,70) e correlazioni medie con i punteggi del BDI (r = 0,46). Le difficolt\ue0 nel riprodurre la struttura originale a otto fattori sono coerenti con altri studi di validazione del TFI nelle lingue europee. Nonostante tali discrepanze, la versione italiana del TFI ha mostrato una struttura fattoriale caratterizzata da alti livelli di affidabilit\ue0 e validit\ue0. Nel complesso, l\u2019adattamento italiano di TFI si \ue8 rivelato idoneo a misurare l\u2019impatto degli acufeni sulla vita quotidiana degli individui.Various questionnaires are used to assess the impact of tinnitus on the quality of life. The Tinnitus Functional Index (TFI) has excellent properties for scaling the severity of tinnitus and treatment-related changes in both clinical and research settings. The aim of this study was to evaluate the psychometric properties of the Italian version of the TFI with particular emphasis on factor analysis, internal consistency, reliability and validity. The original English version of the TFI was translated into Italian using the translation/back - translation process; 137 participants who were re- cruited at the Tinnitus Clinic in Milan and had suffered from tinnitus for at least three months (39.4% females, age: 18-80 years, mean age: 48.26, SD: 14.08) completed the Italian version of the TFI, the Tinnitus Handicap Inventory (THI), the Beck Depression Inventory - Primary Care Version (BDI-PC) and the Numeric Rating Scale of annoyance (NRS-A). Of these patients, 57 completed the TFI again at a second visit 7-14 days later, before undergoing any intervention, in order to provide data for reproducibility assessment. The psychometric properties were investigated using exploratory factor analysis and internal consistency and test-retest reliability instruments. The convergent validity of the TFI was evalu- ated using correlation coefficients obtained from the remaining measurements. The Italian TFI has a four-factor structure that was somewhat different from the original. The internal consistency proved to be good (0.92 64 \u3b1 64 0.96) as did the test-retest reliability (0.79 64 \u3b1 64 0.85). In terms of convergent validity, the TFI showed high correlations with the THI (r = 0.77) and the NRS-A (r = 0.70) scores, and moderate correlations with the BDI-PC scores (r = 0.46). The difficulties encountered when attempting to reproduce the original eight-factor structure were consistent with other studies in which the TFI was translated into European languages. In spite of this, the factorial structure of the Italian version of the TFI was characterised by high levels of reliability and validity. Overall, the Italian adaptation of the TFI was shown to be suitable to measure the impact of tinnitus on the daily lives of individuals

    Identifying key denning habitat to conserve brown bear (Ursus arctos) in Croatia

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    CONTEXT: The preservation of denning habitat is paramount to the recovery of threatened bear populations because of the effect that den site disturbance can have on cub mortality. Understanding habitat suitability for denning can allow management efforts to be directed towards the regions where conservation interventions would be most effective. AIM: We sought to identify the environmental and anthropogenic habitat variables associated with the presence of Eurasian brown bear (Ursus arctos) den sites in Croatia. Based on these associations, in order to inform future conservation decisions, we also sought to identify regions of high suitability for denning across Croatia. METHODS: Using the locations of 91 dens inhabited by bears between 1982 and 2011, we opted for the presence-only modelling option in software Maxent to determine the most important predictors of den presence, and thus predict the distribution of high-value denning habitat across Croatia. KEY RESULTS: We found that structural elements were the most important predictors, with ruggedness and elevation both relating positively to den presence. However, distance to nearest settlement was also positively associated with den presence. CONCLUSION: We determine that there is considerable denning habitat value in areas with high and rugged terrain as well as areas with limited human activity. We suspect that high and rugged terrain contains a greater concentration of the karstic formations used for denning than lower-lying regions. IMPLICATIONS: Our study presents the first habitat suitability model for brown bears in Croatia, and identifies core areas suitable for denning both within and outside the species’ current range. As such, it provides useful evidence for conservation decision making and the development of scientifically-based management plans. Our results also support the need for finer spatial scale studies that can reveal specific denning preferences of subpopulations

    Two-dimensional TiOx nanostructures on Au(111): a Scanning Tunneling Microscopy and Spectroscopy investigation

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    We investigated the growth of titanium oxide two-dimensional (2D) nanostructures on Au(111), produced by Ti evaporation and post-deposition oxidation. Scanning tunneling microscopy and spectroscopy (STM and STS) and low-energy electron diffraction (LEED) measurements characterized the morphological, structural and electronic properties of the observed structures. Five distinct TiOx phases were identified: the honeycomb and pinwheel phases appear as monolayer films wetting the gold surface, while nanocrystallites of the triangular, row and needle phases grow mainly over the honeycomb or pinwheel layers. Density Functional Theory (DFT) investigation of the honeycomb structure supports a (2 x 2) structural model based on a Ti-O bilayer having Ti2O3 stoichiometry. The pinwheel phase was observed to evolve, for increasing coverage, from single triangular crystallites to a well-ordered film forming a (4*sqrt(7) x 4*sqrt(7))R19.1° superstructure, which can be interpreted within a moire-like model. Structural characteristics of the other three phases were disclosed from the analysis of high-resolution STM measurements. STS measurements revealed a partial metallization of honeycomb and pinwheel and a semiconducting character of row and triangular phases

    Extrusion of aluminium hollow pipes:seam weld quality assessment via numerical simulation

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    The continuous extrusion of an aluminium alloy for hollow tubes production was investigated by numerical simulations. A variety of model runs were carried out exploring different combinations of die geometries and extrusion speeds. The primary objective of this work was to compare different criteria for evaluating the quality of longitudinal seam welds. The results of the numerical experiments show that the currently used quality indices, based on the integration of some characteristic variables across the welding surface are significantly affected by the extension of the dead flow zones. As a result, they do not behave coherently with respect to changes in shapes of the mandrel legs. The use of a novel Lagrangian approach in the estimation of the quality indices - based on the integration of the variables along the actual welding paths - leads to a more consistent behavior of the parameters with respect to both the extrusion velocity and the front leg shape. In this study we also show that the Lagrangian parameters can be applied to get a deeper insight into the quality of the extruded products, like the seam weld quality along the tube thickness. Further research is needed to investigate the relation between the Lagrangian quality indices and the microstructure of the material
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