1,721,067 research outputs found
Final height in chidlren with hormone growth deficiency treated with ricombinant growth hormone
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Water: Social Responsibility and the Concept of Common Good in the Ancient City of Pompeii
Get PDFPompeii was connected to the great Serino aqueduct under the principate of Augustus. From that moment on, water became not only a precious resource for the inhabitants but also their true social indicator. It is no coincidence, in fact, that the concentration of sumptuous dwellings is in Regio VI, the district closest to the aqueduct reservoir (castellum aquae in Latin) and the one most equipped with piezometric towers, the first of the network, the ones that would never leave the decorative fountains of the peristyles dry. From this observation follows the original possibility of considering the water network a factor that contributed to designating the morphology of urban neighbourhoods and blocks
La Tomba di Giulio II a Roma: dal rilievo fotogrammetrico alla stampa 3D per non vedenti
Get PDFLa stampa 3D di manufatti e monumenti consente alle persone non vedenti e ipovedenti di scoprire, comprendere e godere della bellezza del patrimonio culturale. La riproduzione dei manufatti inizia solitamente con il rilievo 3D con tecniche basate sulla realtà al fi ne di ottenere la loro copia digitale metrica e accurata. Con una corretta post-elaborazione, il modello digitale viene quindi predisposto per la stampa. Il risultato è un modello fi sico che può essere toccato e ispezionato, rendendo l’arte visibile a tutti.Questo articolo presenta la pipeline seguita per la riproduzione 3D della famosa Tomba di Giulio II di Michelangelo, visibile nella chiesa di San Pietro in Vincoli a Roma. Il rilievo fotogrammetrico viene descritto e valutato, e tutto il processo seguito per post-elaborare il modello 3D al fi ne di renderlo computabile per la stampa 3D. Particolare attenzione è stata data ai problemi verifi catisi durante il rilievo (mancanza di spazio, luci) e quindi la post-elaborazione relativa alla creazione di diversi modelli fi sici stampati. I modelli fi nali sono stati stampati in accordo con le richieste del cliente, in modo da renderli adatti ai non vedenti
A New Methodology for the Structural Analysis of 3D Digitized Cultural Heritage through FEA
No full textFinite Elements Analysis (FEA) is widely used for modelling stress behaviour in any mechanical system. The processing workflow starts from CAD 3D models representing the ideal shape of the object to be simulated. Such models are typically made of mathematical elements defining its geometrical components. Those are pre-processed before the simulation for creating a volumetric mesh out of the CAD model. Recently the use of FEA has also been extended to the simulation of ancient structures and artefacts, revealing significant potentialities for the conservation of Cultural Heritage. Unlike modern mechanical systems, heritage objects are usually altered by the time passed since their original creation, and the representation with a schematic CAD model may introduce an excessive level of approximation leading to wrong simulation results. In the last two decades, 3D documentation of CH has been developed through reality-based approaches. However, the related mesh models of the exterior surfaces are not proper for direct use in FEA. Such high-resolution surface meshes has to be converted to volumetric meshes made of tetrahedral or hexahedral elementary volumes and a limited number of external and internal nodes. The focus of this paper is on a new method aiming at generating the best possible 3D solid representation of a real artefact from its accurate reality-based surface model by reducing its number of nodes of several orders of magnitude while maintaining a geometrical coherence in the order of the measurement uncertainty of the 3D capturing technique used. The approach proposed is based on wise use of retopology procedures and a transformation of this retopologized model to a mathematical one made by NURBS surfaces, suitable for being processed by a volumetric mesh generator typically embedded in any standard FEM package. The resulting volumetric mesh allows obtaining FEA of ancient structures, providing a far better accurate simulation than those attainable by a rough CAD redrawing of the heritage asset of interest
A GEOMETRIC PROCESSING WORKFLOW FOR TRANSFORMING REALITY-BASED 3D MODELS IN VOLUMETRIC MESHES SUITABLE FOR FEA
No full textConservation of Cultural Heritage is a key issue and structural changes and damages can influence the mechanical behaviour of
artefacts and buildings. The use of Finite Elements Methods (FEM) for mechanical analysis is largely used in modelling stress
behaviour. The typical workflow involves the use of CAD 3D models made by Non-Uniform Rational B-splines (NURBS) surfaces,
representing the ideal shape of the object to be simulated. Nowadays, 3D documentation of CH has been widely developed through
reality-based approaches, but the models are not suitable for a direct use in FEA: the mesh has in fact to be converted to volumetric,
and the density has to be reduced since the computational complexity of a FEA grows exponentially with the number of nodes.
The focus of this paper is to present a new method aiming at generate the most accurate 3D representation of a real artefact from highly
accurate 3D digital models derived from reality-based techniques, maintaining the accuracy of the high-resolution polygonal models
in the solid ones. The approach proposed is based on a wise use of retopology procedures and a transformation of this model to a
mathematical one made by NURBS surfaces suitable for being processed by volumetric meshers typically embedded in standard FEM
packages. The strong simplification with little loss of consistency possible with the retopology step is used for maintaining as much
coherence as possible between the original acquired mesh and the simplified model, creating in the meantime a topology that is more
favourable for the automatic NURBS conversion
Management of puberty in growth hormone deficient children
No full textThe pubertal growth spurt accounts for approximately one-eighth of adult height and is regulated by complex hormonal interactions involving the somatotropic and gonadal axes. The observation that children with growth hormone deficiency (GHD) may fail to achieve an appropriate pubertal growth spurt led to the development of strategies to optimize GH therapy during puberty. In one strategy the dosage of GH is increased during puberty to support pubertal growth and in keeping with the physiological increase in serum levels of the hormone seen at that age. A different approach is to combine a GnRH analog (GnRHa) to GH to stop pubertal development, delaying epiphyseal fusion and prolonging peripubertal growth. Both strategies require caution. As regards the first strategy, too high doses of GH may shorten the pubertal time for growth; we found a small, nonsignificant, improvement in final height by increasing the dose by less than half. Preliminary results on the second strategy are more encouraging. However, manipulation of puberty should be limited to selected patients who show a statural height SDS for bone age unfavorable in terms of height prognosis
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