POINT CLOUD EXPLOITATION FOR STRUCTURAL MODELING AND ANALYSIS: A RELIABLE WORKFLOW

none4noThe digitization and geometric knowledge of the historical built heritage is currently based on point cloud, that rarely or only partially is used as digital twin for structural analysis. The present work deals with historical artefacts survey, with particular reference to masonry structures, aimed to their structural analysis and assessment. In detail, the study proposes a methodology capable of employing semi-directly the original data obtained from the 3D digital survey for the generation of a Finite Element Model (FEM), used for structural analysis of masonry buildings. The methodology described presents a reliable workflow with twofold purpose: the improvement of the transformation process of the point cloud in solid and subsequently obtain a high-quality and detailed model for structural analyses. Through the application of the methodology to a case study, the method consistency was assessed, regarding the smoothness of the whole procedure and the dynamic characterization of the Finite Element Model. The main improvement in respect with similar or our previous workflows is obtained by the introduction of the retopology in data processing, allowing the transformation of the raw data into a solid model with optimal balancing between Level of Detail (LOD) and computational weight. Another significant aspect of the optimized process is undoubtedly the possibility of faithfully respecting the semantics of the structure, leading to the discretization of the model into different parts depending on the materials. This work may represent an excellent reference for the study of masonry artefacts belonging to the existing historical heritage, starting from surveys and with the purpose to structural and seismic evaluations, in the general framework of knowledge-based preservation of heritage.openLucidi, A.; Giordano, E.; Clementi, F.; Quattrini, R.Lucidi, A.; Giordano, E.; Clementi, F.; Quattrini, R

Infrared Behaviour of Massless Integrable Flows entering the Minimal Models from phi_31

It is known that any minimal model M_p receives along its phi_31 irrelevant direction *two* massless integrable flows: one from M_{p+1} perturbed by phi_{13}, the other from Z_{p-1} parafermionic model perturbed by its generating parafermion field. By comparing Thermodynamic Bethe Ansatz data and ``predictions'' of infrared Conformal Perturbation Theory we show that these two flows are received by M_p with opposite coupling constants of the phi_31 irrelevant perturbation. Some comments on the massless S matrices of these two flows are added.Comment: 12 pages, Latex - One misprinted (uninfluent) coefficient corrected in Tab.

Excited State Destri - De Vega Equation for Sine-Gordon and Restricted Sine-Gordon Models

We derive a generalization of the Destri - De Vega equation governing the scaling functions of some excited states in the Sine-Gordon theory. In particular configurations with an even number of holes and no strings are analyzed and their UV limits found to match some of the conformal dimensions of the corresponding compactified massless free boson. Quantum group reduction allows to interpret some of our results as scaling functions of excited states of Restricted Sine-Gordon theory, i.e. minimal models perturbed by phi_13 in their massive regime. In particular we are able to reconstruct the scaling functions of the off-critical deformations of all the scalar primary states on the diagonal of the Kac-table.Comment: Latex, 12 page

Nonlinear integral equations for finite volume excited state energies of the O(3) and O(4) nonlinear sigma-models

We propose nonlinear integral equations for the finite volume one-particle energies in the O(3) and O(4) nonlinear sigma-models. The equations are written in terms of a finite number of components and are therefore easier to solve numerically than the infinite component excited state TBA equations proposed earlier. Results of numerical calculations based on the nonlinear integral equations and the excited state TBA equations agree within numerical precision.Comment: numerical results adde

EXTENDING A MOBILE DEVICE WITH LOW-COST 3D MODELING AND BUILDING-SCALE MAPPING CAPABILITIES, FOR APPLICATION IN ARCHITECTURE AND ARCHAEOLOGY

One of the most challenging problem in architecture is the automated construction of 3D (and 4D) digital models of cultural objects with the aim of implementing open data repositories, scientifically authenticated and responding to well accepted standards of validation, evaluation, preservation, publication, updating and dissemination. The realization of such an ambitious objective requires the adoption of special technological instruments. In this paper we plan to use portable devices (i.e. smartphones, tablets or PDAs eventually extended to wearable ones), extended with a small plug-in, for automatically extracting 3D models of single objects and building-scale mapping of the surrounding environment. At the same time, the device will provide the capability of inserting notes and observations. Where the instrument cannot be directly applied, for example for exploring the top of a complex building, we consider mounting our device, or using equivalent existing equipment, on a drone, in a modular approach for obtaining data de-facto interchangeable. The approach based on the expansion packs has the advantage of anticipating (or even promoting) future extensions of new mobile devices, when the spectrum of possible applications justify the corresponding increased costs. In order to experiment and verify this approach we plan to test it in two specific scenarios of the cultural heritage domain in which such devices seem particularly promising: Strada Nuova in Genoa and Palazzo Ducale in Urbino, both located in Italy

Irradiation detection of herbal ingredients used in plant food supplements by Electron Spin Resonance on samples pre-treated with alcoholic extraction

This study aimed to verify the applicability of the EN 1787 method for the detection of irradiation in herbal ingredients used in Plant Food Supplements (PFSs). In matrices such as herbs and spices the main limit of the method is the presence of intrinsic radicals responsible for spurious signals leading to complex ESR spectra. To overcome this limit, before ESR measurement a treatment with alcohol has been proposed (Delincée and Soika, 2002; Ahn et al., 2012, 2014). As reported in the literature, this treatment is expected to reduce/eliminate the confounding signals so that the samples may be correctly classified. In this study the efficacy of the pre-treatment was tested on raw herbal ingredients largely used for PFSs, namely Camellia sinensis, Cinnamomum verum, Curcuma longa, Ginkgo biloba, Silybum marianum, Vaccinium myrtillus and Zingiber officinale. Non-irradiated and irradiated (5, 10 kGy) samples were analysed before and after pre-treatment. The results showed a general decrement of signal intensity. In some cases, this was associated with the elimination of some spurious signals, which, however, did not always ensue in an easier interpretation of the ESR spectra. Only for two matrices (Camellia sinensis and Vaccinium myrtillus) was alcoholic extraction crucial for the correct classification of the samples