66 research outputs found

    FEW SHOT PHOTOGRAMETRY: A COMPARISON BETWEEN NERF AND MVS-SFM FOR THE DOCUMENTATION OF CULTURAL HERITAGE

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    3D documentation methods for Digital Cultural Heritage (DCH) domain is a field that becomes increasingly interdisciplinary, breaking down boundaries that have long separated experts from different domains. In the past, there has been an ambiguous claim for ownership of skills, methodologies, and expertise in the heritage sciences. This study aims to contribute to the dialogue between these different disciplines by presenting a novel approach for 3D documentation of an ancient statue. The method combines TLS acquisition and MVS pipeline using images from a DJI Mavic 2 drone. Additionally, the study compares the accuracy and final product of the Deep Points (DP) and Neural Radiance Fields (NeRF) methods, using the TLS acquisition as validation ground truth. Firstly, a TLS acquisition was performed on an ancient statue using a Faro Focus 2 scanner. Next, a multi-view stereo (MVS) pipeline was adopted using 2D images captured by a Mini-2 DJI Mavic 2 drone from a distance of approximately 1 meter around the statue. Finally, the same images were used to train and run the NeRF network after being reduced by 90%. The main contribution of this paper is to improve our understanding of this method and compare the accuracy and final product of two different approaches - direct projection (DP) and NeRF - by exploiting a TLS acquisition as the validation ground truth. Results show that the NeRF approach outperforms DP in terms of accuracy and produces a more realistic final product. This paper has important implications for the field of CH preservation, as it offers a new and effective method for generating 3D models of ancient statues. This technology can help to document and preserve important cultural artifacts for future generations, while also providing new insights into the history and culture of different civilizations. Overall, the results of this study demonstrate the potential of combining TLS and NeRF for generating accurate and realistic 3D models of ancient statues

    STUDI DI OTTIMIZZAZIONE DEI TRATTAMENTI TERMICI SU UNA LEGA AL-SI PER USO AUTOMOBILISTICO

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    Oggetto di questo lavoro è lo studio di trattamenti termici sulla lega 87S1 (nome commerciale), derivata dalla A357, appositamente modificata per migliorare la sua formabilità allo stato semi-solido. Tale lega è particolarmente idonea ad essere formata attraverso il processo Rheocast per la produzione di componenti soprattutto automobilistici. Per la lega presa in esame le caratteristiche meccaniche migliori sono state ad oggi ottenute con il trattamento brevettato dal produttore, un trattamento T6 con solubilizzazione multistadio seguito da un invecchiamento. La finalità del presente studio è quella di valutare la possibilità di effettuare un trattamento termico più economico di quello proposto senza gravose conseguenze per le proprietà meccaniche. La lega è stata sottoposta a trattamenti termici, prove meccaniche ed indagini microstrutturali di microscopia ottica ed elettronica in scansione. Sono stati studiati diversi trattamenti termici, T5 e T6 non multistadio di durate inferiore rispetto a quello brevettato, ottenendo, in alcuni casi, risultati promettenti in termini di proprietà di interesse ingegneristico. In particolare si è osservato come un semplice trattamento termico di solubilizzazione a 500°C per 4 ore fosse in grado di garantire un buon compromesso fra resistenza meccanica e duttilità a temperatura ambiente

    STUDIO COMPARATIVO DELL’AFFINAMENTO MICROSTRUTTURALE DURANTE TORSIONE-COMPRESSIONE E DOPO EQUAL-CHANNEL ANGULAR PRESSING

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    Tecniche di deformazione plastica severa, quali twist extrusion, deformazione ciclica, corrugate roll-bonding ed equal-channel angular pressing, applicate ai materiali metallici sono ormai giunte ad un livello di applicazione industriale. Si è ormai diffusa un’ampia letteratura che riguarda ogni aspetto di carattere microstrutturale e meccanico sulle differenti tecniche di deformazione plastica severa di interesse industriale applicate a materiali metallici ferrosi e non ferrosi (leghe di alluminio, titanio, magnesio). Questo studio ha l’obiettivo di esplorare le similitudini e le potenzialità di una tecnica di deformazione quale la torsionecompressione, la quale coinvolge costi ben più ridotti e probabilmente una più immediata fattibilità industriale, rispetto ad una delle tante altre tecniche già disponibili, nello specifico l’ECAP. Il confronto tra la torsione-compressione e l’ECAP è stato limitato ad una deformazione vera pari ad å=1 ed una deformazione uguale per la torsione-compressione, con =510-3s-1 in torsione, seguita dalla deformazione in compressione di =510-3s-1. Per tale studio è stata utilizzata una lega AA6103 Al-Mg-Si dopo ricottura. Le indagini microstrutturali sono state eseguite mediante microscopia elettronica in trasmissione e in luce polarizzata al microscopio ottico

    Constitutional trisomy 8 as first mutation in multistep carcinogenesis: clinical, cytogenetic, and molecular data on three cases.

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    Three patients, with constitutional trisomy 8 mosaicism (CT8M), who developed a malignancy are reported. The diagnoses were refractory anaemia, acute lymphoblastic leukaemia, and idiopathic myelofibrosis. In the child with acute leukaemia, the CT8M was diagnosed at birth due to severe dysmorphisms and malformations; the other two patients showed a milder phenotype, and the CT8M was diagnosed only after the finding of trisomy 8 in neoplastic cells. The review of eight similar, previously reported cases and the clinical, cytogenetic, and molecular studies performed in our patients led us to make the following observations: (1) CT8M predisposes to neoplasms, preferentially to myelo- or lymphoproliferative diseases; (2) a gene dosage effect for glutathione reductase in red blood cells was seen in two of our patients; (3) the wide phenotypic variation of CT8M was confirmed: trisomy 8 in neoplastic cells of phenotypically near-normal cases may be misinterpreted as acquired; and (4) molecular studies suggested a postzygotic origin of the trisomy in our three cases, with the supernumerary chromosome being of paternal origin in one case and of maternal origin in the other two. We postulate that the trisomy 8 in neoplasms may often occur by mitotic nondisjunction in an early embryonic multipotent cell and that what is usually interpreted as an acquired trisomy 8 may in fact be CT8M. The constitutional trisomy 8 would act as a pathogenetically important first mutation in multistep carcinogenesis. Whenever trisomy 8 is found in malignancies, the patient should be reevaluated clinically to exclude CT8M, and CT8M patients should be monitored for the possible development of malignancies

    Issues and challenges in the application of Husserlian phenomenology to the Lived Experience of Hate Crime and Its Legal Aftermath

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    The field of hate crime research addresses the presence, sources and impact of particular types of expressions of prejudice, often perceived as particularly damaging and hurtful forms of interpersonal abuse and violence. Little, if any, credible academic research seeks to vindicate the specific racist, gendered and other vicious prejudices articulated by many perpetrators of hate crime. In turn, this raises the reflexive question of the possibilities of researchers themselves ever being able to adopt a truly "unprejudiced" approach to the presence of such damaging prejudices. Can this goal be realised without a researcher necessarily losing an experientially-grounded understanding of what these meanings, values and purposes have come to mean, and how they are themselves interpretatively re-constituted anew, including within the lived experience of victims, witnesses, police, prosecutors, judges and victim support workers? A possible philosophically-informed approach to the dilemmas posed by this topic is offered by Husserl's phenomenology. Husserl's perpetually unfinished philosophical methodology strives, with concerted if sometimes tragic reflective rigor, to "suspend," "bracket out" and "neutralise" those core presuppositions constitutive of the research field that typically pre-judge precisely whatever demands to be questioned and explored in a radically non-prejudicial manner. This study critically explores the possibilities, reflective stages and theoretical limitations of a sympathetically reconstructed Husserlian approach to hate crime, itself understood as a would-be qualitative "science of consciousness." It argues that despite its manifest tensions, gaps, ambiguities and internal contradictions, aspects of the Husserlian philosophical approach directed towards the different levels of experienced hate crime still retain the potential to both challenge and advance our understanding of this topic. It is the "instructive" part of "instructive failure" that this article highlights

    Comparative Study Of High Temperature Workability OF ZM21 And AZ31 Magnesium Alloys

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    High temperature regime, 300-450?C for Mg-Al-Zn alloys, is currently used in primary processing, such as rolling and extrusion, as well as for secondary operation like forging. The knowledge of temperature and strain rate proper combination (processing window) as well as the microstructure evolution occurring during hot deformation clarifies the relationships between forming variables and final properties of components. Numerous data on AZ31 and few other Mg-Al alloys, produced by laboratory testing, are available in the scientific and technical literature. The ZM21, Mg-2Zn-1Mn, by contrast, is characterized by absolute lack of scientific data. In the alloy the addition of manganese, by suppressing the formation of beta phase, increases the solidus temperature that results in the larger processing window than in AZ31. The benefit requires extensive analysis aimed at optimizing the deformation variables that affect the microstructure refinement under dynamic and static recrystallization. The high-temperature plastic deformation and the microstructure evolution of the ZM21 were thus investigated in the temperature range between 200 and 500?C and results were analysed and compared with those of a conventional heat-treated AZ31

    Bancos clonais de Eucalyptus dunnii MAIDEN.

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    bitstream/item/101091/1/PA-1983-Higa-BancosClonais.pdf.pd

    Thin Polymer Brush Decouples Biomaterial's Micro-/Nano-Topology and Stem Cell Adhesion

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    Surface morphology and chemistry of polymers used as biomaterials, such as tissue engineering scaffolds, have a strong influence on the adhesion and behavior of human mesenchymal stem cells. Here we studied semicrystalline poly(ε-caprolactone) (PCL) substrate scaffolds, which exhibited a variation of surface morphologies and roughness originating from different spherulitic superstructures. Different substrates were obtained by varying the parameters of the thermal processing, i.e. crystallization conditions. The cells attached to these polymer substrates adopted different morphologies responding to variations in spherulite density and size. In order to decouple substrate topology effects on the cells, sub-100 nm bio-adhesive polymer brush coatings of oligo(ethylene glycol) methacrylates were grafted from PCL and functionalized with fibronectin. On surfaces featuring different surface textures, dense and sub-100 nm thick brush coatings determined the response of cells, irrespective to the underlying topology. Thus, polymer brushes decouple substrate micro-/nano-topology and the adhesion of stem cells
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