Fracture mapping in challenging environment: a 3D virtual reality approach combining terrestrial LiDAR and high definition images

ArticleThis is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.The latest technological developments in computer vision allow the creation of georeferenced, non-immersive desktop virtual reality (VR) environments. VR uses a computer to produce a simulated three-dimensional world in which it is possible to interact with objects and derive metric and thematic data. In this context, modern geomatic tools enable the remote acquisition of information that can be used to produce georeferenced high-definition 3D models: these can be used to create a VR in support of rock mass data processing, analysis, and interpretation. Data from laser scanning and high quality images were combined to map deterministically and characterise discontinuities with the aim of creating accurate rock mass models. Discontinuities were compared with data from traditional engineering-geological surveys in order to check the level of accuracy in terms of the attitude of individual joints and sets. The quality of data collected through geomatic surveys and field measurements in two marble quarries of the Apuan Alps (Italy) was very satisfactory. Some fundamental geotechnical indices (e.g. joint roughness, alteration, opening, moisture, and infill) were also included in the VR models. Data were grouped, analysed, and shared in a single repository for VR visualization and stability analysis in order to study the interaction between geology and human activities.The authors gratefully acknowledge the assistance of the personal of the Romana Quarry and particularly Corniani M. This paper was possible because of support from the Tuscany Region Research Project known as “Health and safety in the quarries of ornamental stones—SECURECAVE”. The authors acknowledge Pellegri M and Gullì D (Local Sanitary Agency n.1, Mining Engineering Operative Unit—Department of Prevention) and Riccucci S (Centre of GeoTechnologies, University of Siena) for their support of this research

Modello coesivo per l’avanzamento di fratture mediante rilascio nodale di strutture discretizzate con elementi finiti

La simulazione numerica della propagazione di una frattura in MODO I, viaggiante ad elevatavelocità in un acciaio a comportamento duttile è realizzata attraverso un modello coesivo che governa ladistribuzione delle forze di rilascio nodale. Come noto, la ricerca di un valore di tensione all’apice non ha alcunsenso nel caso elastico; infatti, la tensione può essere valutata solo mediante fattori di campo. Nel caso elasto-plastico, incrudimento e softening di origine geometrica o legato al progressivo danneggiamento influisconodecisamente sull’andamento esponenziale del campo tensionale. È possibile comunque individuare un valore diriferimento, di entità finita, mediante estrapolazione delle tensioni elasto-plastiche nella zona di inizio softeningdella frattura. Tale grandezza può essere presa come fattore di riferimento per il calcolo delle forze di rilasciocoesive e quindi dell’energia dissipata. Nel lavoro viene discusso come determinare, dal campo di tensioneelasto-plastico locale, il valore che governa la zona coesiva al variare del T-stress

A geomatic approach for emergency mapping of shallow landslides

Nel presente contributo viene proposto un approccio geomatico per mappare e caratterizzare dal punto di vista geomorfologico i fenomeni franosi superficiali in situazioni di emergenza. Il metodo è stato applicato durante il rilevamento di una frana che il 27/10/2013 ha interessato la falesia costiera della località "Baia dei Porci", nel Comune di Monte di Procida, in provincia di Napoli. Durante il rilevamento, eseguito parzialmente da barca, sono state scattate 95 foto successivamente elaborate con il software Agisoft PhotoScanTM. Il prodotto ottenuto dall'elaborazione è stato un modello digitale 3D della frana (DEM), georeferenziato nel sistema UTM 33N-WGS84. Dall'elaborazione del DEM eseguita in ESRI ArcGisTM è stato possibile ottenere la carta topografica della frana in scala 1:500, la carta delle pendenze, l'area delle zone di distacco e di deposito ed il volume del materiale franato. Visti i risultati ottenuti si ritiene che l'approccio proposto sia idoneo per essere applicato in situazioni di emergenza provocate da frane superficiali, a supporto delle autorità di Protezione Civile

REDD+ and Climate Smart Agriculture in landscapes : from national design to local implementation

Global challenges posed by an increasing food demand and climate change call for innovative mechanisms that consider both agriculture and forests. Agriculture and forests are deeply interconnected in mosaic landscapes, just as multiple pieces of the same puzzle. These pieces are handled by numerous stakeholders with different and often contrasting goals. Hence landscape management is steered by power, access to scarce resources, but also vulnerability and hazards. In this thesis I analyze the roles each stakeholder plays on these dynamics, including policy makers, agribusiness actors and subsistence farmers. I explore landscapes as interconnected tiles of a game, in which players are real stakeholders and their goals determine land use dynamics on the game board just as in reality. Sometimes agreements made in the game translate to real-life actions influencing policy and management decisions. Other times the game is just fun and eventually contributes to social learning and trust. </p

Open-addressing hashing with unequal-probability keys

This paper describes the use of a drone in collecting data for mapping discontinuities within a marble quarry. A topographic survey was carried out in order to guarantee high spatial accuracy in the exterior orientation of images. Photos were taken close to the slopes and at different angles, depending on the orientation of the quarry walls. This approach was used to overcome the problem of shadow areas and to obtain detailed information on any feature desired. Dense three-dimensional (3D) point clouds obtained through image processing were used to rebuild the quarry geometry. Discontinuities were then mapped deterministically in detail. Joint attitude interpretation was not always possible due to the regular shape of the cut walls; for every discontinuity set we therefore also mapped the uncertainty. This, together with additional fracture characteristics, was used to build 3D discrete fracture network models. Preliminary results reveal the advantage of modern photogrammetric systems in producing detailed orthophotos; the latter allow accurate mapping in areas difficult to access (one of the main limitations of traditional techniques). The results highlight the benefits of integrating photogrammetric data with those collected through classical methods: the resulting knowledge of the site is crucially important in instability analyses involving numerical modelling.Part of the present study was undertaken within the framework of the Italian National Research Project PRIN2009, funded by the Ministry of Education, Universities and Research, which involves the collaboration between the University of Siena, ‘La Sapienza’ University of Rome, and USL1 of Massa and Carrara (Mining Engineering Operative Unit – Department of Prevention). The authors acknowledge M. Pellegri and D. Gullì (USL1, Mining Engineering Operative Unit – Department of Prevention), M. Ferrari, M. Profeti and V. Carnicelli (Cooperativa Cavatori Lorano), X. Chaoshui and P.A. Dowd (School of Civil, Environmental and Mining Engineering, University of Adelaide, South Australia) and M. Bocci (Geographike) for their support of this research

Geological 3D modeling for excavation activity in an underground marble quarry in the Apuan Alps (Italy)

The three-dimensional laser scanning technique has recently become common in diverse working environments. Even in geology, where further development is needed, this technique is increasingly useful in tackling various problems such as stability investigations or geological and geotechnical monitoring. Three-dimensional laser scanning supplies detailed and complete geometrical information in short working times, as a result of the acquisition of a large number of data-points that accurately model the detected surfaces. Moreover, it is possible to combine these data with high quality photographic images so as to provide important information for geological applications, as follows. A working approach, that combines terrestrial laser scanning and traditional geological surveys, is presented. A three-dimensional model, that includes information about the geological structure in an underground quarry in the Apuan Alps, is realized. This procedure is adaptable to other geological contexts, and because of its operating speed and accuracy it is invaluable for optimal excavation, in which a proper planning of quarrying activity is vital for safety and commercial reasons. © 2014 Elsevier Ltd.The authors gratefully acknowledge the assistance of the personnel of the Romana Quarry and particularly Geol. Massimo Corniani. This paper was possible because of support from the Tuscany Region Research Project known as “Health and safety in the quarries of ornamental stones – SECURCAVE”

Active Surface Structure of SnO2 Catalysts for CO2 Reduction Revealed by Ab Initio Simulations

Tin oxide (SnO2) is an efficient catalyst for the CO2 reduction reaction (CO2RR) to formic acid; however, the understanding of the SnO2 surface structure under working electrocatalytic conditions and the nature of catalytically active sites is a current matter of debate. Here, we employ ab initio density functional theory calculations to investigate how the selectivity and reactivity of SnO2 surfaces toward the CO2RR change at varying surface stoichiometry (i.e., reduction degree). Our results show that SnO2(110) surfaces are not catalytically active for the CO2RR or hydrogen evolution reaction, but rather they reduce under an applied external bias, originating surface structures exposing few metal tin layers, which are responsible for formic acid selectivity

Real time imaging by antenna and hybrid device

We propose, for localisation of acoustical sources and imaging, an hybrid proceeding working in real time . From array antenna signais we make a spatial transversal filter with analog and digital electronic devices : speed is assumed by the analog part and accuracy of angular pointing or focalisation by the digital part .On propose de localiser des sources acoustiques et d'en former une image par une méthode de traitement hybride opérant en temps rée