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Although the increased production of nanoparticles (NPs) has raised extensive concerns about the potential toxic effects on aquatic organisms, as well as the increasing evidences which documented the impact of ocean acidification (OA) on the physiology and fitness of marine invertebrates, limited number of studies reported their combined toxic effects. For these reasons, in the present study, we investigated the physiological and biochemical responses of one of the most economically important bivalve species in the World, the Manila clam Ruditapes philippinarum, after the exposure to an environmnetally relevant concentration of carboxylated carbon nanotubes and predicted OA conditions. The results showed that the organisms were not only susceptible to NPs but also to seawater acidification. Different responses between low pH and NPs for most tested biomarkers were observed, both in terms of physiological (respiration rate) and biochemical responses (metabolic capacity, oxitative status and neurotoxicity). Acidified pH significantly decreased the respiration rate and metabolism and increased the energy reserves consumption. Moreover, increase of the oxidative damage was also detected under this condition confirming that the mechanism of enhanced toxicity in the organisms should be attributed to lower aggregation state with more suspended NPs in acidified seawater, indicating that seawater acidification significantly influenced the impact of the used NPs in the exposed organisms.

Debris flows are among the most dangerous phenomena in mountain catchments and they are particularly destructive when they intersect transport routes or urban areas. Debris flows are expected to increase in the frequency and magnitude as a result of the current climate change. In order to test this hypothesis by analyzing the variations of debris-flow frequency and magnitude with time, it is of utmost importance the availability of a long time series of primary data on debris-flows occurrence and volume. Furthermore, to cope with these dangerous phenomena at the regional scale, the development of new tools for the assessment of areas affected by debris flows and their spatial characterization is needed. The aim of this work is twofold: to extend primary data collection on debris flows in northeastern Italy and to provide a simple GIS-based procedure that can be easily applied to identify debris-flow channels and alluvial fans in the same geographical context. The results of the analysis of date of occurrence and volume of the large collected dataset of debris-flows show the occurrence, in the last forty years, of some high-magnitude debris flows characterized by the largest unit volumes of the dataset. This seems to suggest a role played by climate changes on debris-flow magnitude that should be further investigated. In addition, a simple and fast semi-automated GIS based procedure is presented. It consists of a low data-demanding method for a preliminary mapping of potentially debris-flow affected areas to enable priority ranking of channels and alluvial fans at risk by debris flows. This approach has been validated by means of field checks and through its extensive application in the eastern Italian Alps.

Debris flows are a widespread natural hazard in mountain catchments causing major damage when they intersect transport vulnerable elements at risk, including transport routes and urban areas. Climate change is expected to lead to an increase in the frequency and magnitude of those phenomena. It is thus fundamental to extend the collection of primary data on debris-flows occurrence and volume in order to evaluate the variations of debris-flow frequency and magnitude with time and, at the same time, provide new tools for the assessment of areas affected by debris flows and their spatial characterization. This work presents the results of the analysis of date of occurrence and volume of a large dataset of debris-flows collected in the eastern Italian Alps. The occurrence, in the last forty years, of some high-magnitude debris flows characterized by the largest unit volumes of the dataset might be associated with current climate changes. In order to deal with the observed increase in this processes in mountain environments, a simple and fast semi-automated procedure is proposed for the regional-scale identification of debris-flow prone channels and alluvial fans. The main aim is to develop a low data-demanding method for a preliminary mapping of potentially debris-flow affected areas to enable priority ranking of channels and alluvial fans at risk by debris flows. This approach has been validated by means of field checks and through its extensive application in the eastern Italian Alps.

Ficopomatus enigmaticus is a serpulid polychaete, reef-forming, dioecious gamete spawner throughout different seasons and in different salinity conditions. Due to these characteristics, its candidacy as a model organism to monitor both marine and brackish matrices was assessed. Marine sediments collected in a polluted area near the port of Ancona (Italy) were used as case study. Besides the chemical characterization of sediments, the larval development of F. enigmaticus was adopted as an assay for ecotoxicological assessment of sediments in addition to a regulatory bioassay battery with different organisms and endpoints. The quality of sediments was classified according to the Italian Ministerial Decree for sediment management (Ministerial Decree 173, 2016) by using the SEDI-QUAL-SOFT® (ver. 109.0) software developed by the Italian Environmental Protection Agency (ISPRA). The F. enigmaticus larval development assay showed a quite similar sensitivity to C. gigas larval development assays, indicating its potential use in a regulatory battery of bioassays.

The presence of unreinforced masonry buildings with timber floors in seismic areas has promoted the development of various retrofitting techniques. Among them, the increase of the in-plane stiffness of the floors is normally assumed as an improvement of the seismic behaviour of the building. However, the effectiveness of this retrofitting strategy is not easily predictable due to the difficulties in evaluating the modification of the seismic response of the building. In this work, a masonry case-study building with stiffened timber floors is analysed, simulating the actual non-linear behaviour of masonry piers and the hysteretic response of stiffened and unstiffened timber floors, calibrated according to tests available in literature. The 3D numerical model of the case-study building was implemented in the finite element software OpenSees. The model is able to simulate the in-plane hysteretic response of the floors and different types of failure of masonry walls. Results from non-linear dynamic analyses show that, in contrast to common expectations, traditional masonry buildings with timber floors may decrease their seismic performance if a retrofitting method leading to excessive in-plane floor stiffening is adopted.

A oltre sessant’anni dalla costruzione, molti quartieri Ina-Casa mostrano la necessità di essere estesamente rammendati. Attuarne la riqualificazione considerando la molteplicità di attori ed esigenze in gioco, il valore testimonial del patrimonio e la frammentazione proprietaria, richiede l’adozione di specifiche metodiche di intervento. L’analisi delle inadeguatezze e la valutazione delle priorità che gli abitanti vi attribuiscono sono state basilari per definire una strategia di riqualificazione partecipata, sperimentata nel comparto “La Fiorita” di Cesena. La ricerca ha sviluppato un repertorio di soluzioni componibili in pacchetti, concepito come manuale d’intervento, congegnato per favorire la combinazione di azioni individuali e collettive, e associato a un sistema di incentivi. Over sixty years after their construction, many Ina-Casa neighbourhoods demonstrate the need for extensive “mending”. Specific intervention methodologies are required to redevelop them considering the many players and needs involved, the testimonial value of the patrimony, and the fragmented ownership structure. An analysis of the inadequacies and an assessment of the priorities that inhabitants attribute to them were fundamental in defining a participatory redevelopment strategy, which has been tested on “La Fiorita” in Cesena. The research developed a catalogue of solutions that can be incorporated into packages and is conceived as an intervention manual. It has been devised to foster a combination of individual and collective actions and is associated with an incentive system.

The assessment and mitigation of floods in mountain streams, when large wood (LW) is transported, pose several challenges. The process chain consisting of flood propagation, LW recruitment, entrainment, transport, and entrapment triggers, at critical sections such as bridges, unexpected and exacerbated impacts to the exposed built environment. We provide a review on the recent advances in modelling LW dynamics during extreme river floods through computational approaches. Moreover, we describe how scaled flume experiments can enhance process understanding at critical flow sections such as bridges to address risk mitigation problems. Additionally, we present a framework based on Formative Scenario Analysis (FSA) to allow for expert knowledge integration and to subsequently derive consistent hazard process scenarios in steep mountain streams where the application of computational approaches is less reliable. Finally, we discuss how the application of the presented set of assessment methods can support integral flood risk management by explicitly considering LW dynamics since the effectiveness of mitigation critically depends on the acquired process understanding.

The assessment of flow velocity has a central role in quantitative analysis of debris flows, both for the characterization of the phenomenology of these processes and for the assessment of related hazards. Large-scale particle image velocimetry (LSPIV) can contribute to the assessment of surface velocity of debris flows, provided that the specific features of these processes (e.g. fast stage variations and particles up to boulder size on the flow surface) are taken into account. Three debris-flow events, each of them consisting of several surges featuring different sediment concentrations, flow stages, and velocities, have been analysed at the inlet of a sediment trap in a stream in the eastern Italian Alps (Gadria Creek). Free software has been employed for preliminary treatment (orthorectification and format conversion) of video-recorded images as well as for LSPIV application. Results show that LSPIV velocities are consistent with manual measurements of the orthorectified imagery and with front velocity measured from the hydrographs in a channel recorded approximately 70m upstream of the sediment trap. Horizontal turbulence, computed as the standard deviation of the flow directions at a given cross section for a given surge, proved to be correlated with surface velocity and with visually estimated sediment concentration. The study demonstrates the effectiveness of LSPIV in the assessment of surface velocity of debris flows and permit the most crucial aspects to be identified in order to improve the accuracy of debris-flow velocity measurements.

Debris flows are widespread phenomena in mountain catchments that often cause damage to urbanized areas and transport routes. The spatial characterization of the affected areas is a major issue in the framework of watershed management. We developed a simple and fast semi-automated and low data-demanding procedure for regional-scale identification of debris-flow prone channels and alluvial fans. A GIS-based approach enables a preliminary mapping of potentially debris-flow affected areas and provides information for the priority ranking of channels and alluvial fans exposed to debris flows. The methodology exploits Digital Elevation Models (DEMs) to derive geomorphometric parameters analyzed for the identification of debris-flow triggering areas and their propagation along the channel. Potential initiation sites of debris flows are identified as those exceeding a threshold of local slope versus contributing area, while channel reaches corresponding to debris flows propagation, deceleration and halting conditions are derived from thresholds of local slope. An analysis of longitudinal channel profiles, which considers the traveled distance and the local slope, is used for the computation of the debris-flow runout. The procedure takes into account the presence of hydraulic control works (i.e. check dams) along with information on erosion-resistant bedrock channels and sediment availability. This approach has been validated by means of field checks and through its extensive application in the eastern Italian Alps. The developed methodology has been implemented in a set of freely-available software tools (https://github.com/HydrogeomorphologyTools) in order to facilitate its application and further validation in different environments.

Debris flows are widespread phenomena in mountain catchments causing major damage when they intersect transport routes or urban areas. The assessment of areas affected by debris flows and their spatial characterization is thus a major issue in the framework of watershed management. This work presents a simple and fast semi-automated procedure developed for a regional-scale identification of debris-flow prone channels and related downstream alluvial fans. The main aim is to develop a low data-demanding method for a preliminary mapping of potentially debris-flow affected areas at the regional scale to enable priority ranking of channels and alluvial fans at risk by debris flows. The methodology is based on a geomorphometric approach that involves the analysis of morphometric parameters derived from Digital Elevation Models (DEMs) for the identification of debris-flow triggering areas and their kinematic along the channel. Potential initiation sites of debris flows are identified as those exceeding a threshold identified on a plot of local slope versus contributing area whereas channel reaches corresponding to debris flows deposition, deceleration and halting conditions are derived from thresholds of local slope. An empirical method, which considers the traveled distance and the local slope along the channel profile, is used for the computation of the debris-flow runout. The presence of hydraulic control works (i.e. check dams) along with information on erosion-resistant bedrock channels and sediment availability are taken into account within the procedure. This approach has been validated by means of field checks and through its extensive application in the eastern Italian Alps. The developed methodology has been implemented in a set of freely-available software tools (https://github.com/HydrogeomorphologyTools) in order to facilitate its application and further validation in different environments. Potential and limitations of the method will be also presented.

In this work, a sensor formed by clustering three ad-hoc shaped piezoelectric patches is proposed for guided waves direction of arrival (DoA) estimation in laminate composite and metallic structures. The irregular shaping of the transducer electrodes allows to simplify the signal processing procedures which are necessary to detect the wave DoA. The cluster is conceived so that there is a linear dependence between the difference in time of arrival (DToA) of the wavefront at two of the sensor patches and the DoA of the wavefront itself. The third piezoelectric patch is shaped so that the estimation of the DoA from the DToA can be performed without knowing the actual wave velocity. The transducer performance in terms of DoA estimation accuracy are evaluated through numerical simulations, in which the plate response to a point source is evaluated in the frequency domain using the Green's function approach. Results show that the standard deviation of the error in the estimation of the DoA is less than 2°. This device is meant as a basic building block for the development of passive sensor networks in smart structure applications.

Questo lavoro descrive l'analisi strutturale di un nuovo telaio in legno modulare accoppiato con un pannello OSB e una lastra di gesso tamponata con tecnoprene, che conferiscono, nel piano, resistenza al taglio al telaio e permettono la realizzazione di pareti di taglio efficienti e dissipative. Il comportamento sismico previsto del sistema è stato confermato da prove sperimentali. Per definire le principali caratteristiche meccaniche del sistema sono stati condotti test di carico ciclico (quasi statico) secondo il protocollo della norma EN 12512. Infine, sulla base dei risultati di prova, è stato calibrato un modello numerico, al fine di caratterizzare il comportamento dinamico non lineare di un edificio preso come caso in studio e di stimare l'opportuno valore di fattore di struttura per questo sistema. This work discusses the structural analysis of a novel modular timber frame coupled with an OSB panel and a tecnoprene plaster-infilled slab, which confer in-plane shear resistance to the frame and allow the realization of efficient and dissipative shear walls. The expected seismic behaviour of the system was confirmed by experimental tests. Quasi-static cyclic-loading tests were conduced according to EN 12512 protocol to define the main mechanical properties of the system. Finally, a numerical model was calibrated on the basis of test results, in order to characterize the dynamic non-linear behaviour of a case-study building and to estimate the suitable behaviour factor value for this system.

L’integrazione di dati topografici ad alta risoluzione, derivanti da diverse tecnologie quali LiDAR sia aereo (ALS) sia terrestre (TLS) e strumentazione GPS, ha permesso di generare, mediante una procedura di “data fusion”, una serie di Modelli Digitali del Terreno (DTM) multitemporali con 1 m di risoluzione. I DTM realizzati sono stati utilizzati per stimare gli effetti della costruzione di una nuova briglia sulla dinamica del sedimento in un piccolo bacino interessato da colate detritiche. Il calcolo di un indice di connettività del sedimento, prima e dopo i lavori di sistemazione idraulico-forestale, ha consentito di valutare l’efficacia degli interventi eseguiti e la potenziale variazione del flusso di materiale trasportato.

Il presente studio nasce dall'esigenza degli uffici della Regione Veneto di predisporre una procedura finalizzata alla valutazione della pericolosità sui conoidi alluvionali classificati come zone d'attenzione nei PAI Piave, Brenta-Bacchiglione e Livenza. Al fine di individuare un percorso oggettivo per la valutazione della pericolosità sono state identificate e proposte metodologie di raccolta dati e di analisi atte ad individuare la tipologia del processo da investigare distinguendo, in particolare, tra colate detritiche e piene con trasporto solido, essendo questa distinzione di fondamentale importanza al fine di orientare le successive analisi. Nell'ambito dello studio sono stati sviluppati due strumenti per condurre e facilitare la raccolta dati del sistema bacino-conoide: i) una scheda, in formato digitale editabile, strutturata in diverse sezioni per la raccolta di una serie di informazioni che concorrono a caratterizzare oggettivamente la morfologia, la genesi, i processi attualmente attivi e lo stato di funzionamento del sistema bacino-conoide; ii) un database geografico delle aree di conoide che integra le informazioni riportate nelle schede e la documentazione su eventi storici reperita da diverse fonti documentarie. Nell'ambito della procedura per la valutazione della pericolosità sono stati sviluppati diversi software liberamente disponibili per l'identificazione lungo il reticolo idrografico delle aree di potenziale innesco, rallentamento e deposito di colate detritiche e per il calcolo della distanza di arresto delle colate detritiche finalizzato all'assegnazione di una priorità d'indagine dei conoidi. Questi applicativi costituiscono un prezioso ausilio per condurre le analisi previste dalla procedura sviluppata. Il presente contributo presenta inoltre i risultati delle analisi in tre aree test situate nelle province di Vicenza, Treviso e Belluno.

Il contributo presenta le caratteristiche essenziali dei sistemi di allarme per le colate detritiche e ne descrive limiti e potenzialità, con particolare riguardo all'impiego nella gestione del rischio a scala locale.

The Moscardo Torrent (eastern Italian Alps) is a small rugged catchment (drainage area 4.1 km2, range in elevation between 890 and 2043 m) frequently affected by debris flows that deliver large amounts of sediment to the receiving stream, and cause concerns for infrastructures located on the alluvial fan and near the confluence. Over the last decades, hydraulic control works were implemented in the main channel to limit bed erosion and to stabilize channel banks. Although the objectives of training works have been only partly achieved, check dams and hillslope stabilization works have affected the sediment transfer from hillslopes to the channels and along the main channel. The effects of hydraulic control works were investigated by means of multi-temporal Structure from Motion (SfM) surveys based on images taken from the ground and UAV. The ground and air based surveys were carried out over a channel reach in which two check dams have recently been built. SfM surveys were taken before and after three debris-flow events (occurred between June and July 2016), allowing the generation of four high-resolution Digital Elevation Models (DEMs). Geomorphic changes caused by the debris-flow events have been assessed in order to produce the DEM of Differences (DoDs with a 0.2 m spatial resolution) that allowed estimating erosion and deposition volumes in the study area. Furthermore a debris-flow monitoring system has been in operation in the Moscardo Torrent; the analysis of the videos and of the hydrographs recorded by ultrasonic sensors permitted to assess the debris-flow volumes. These estimates were used to characterize the magnitude of events in support of the topographic analysis. By examining the changing pattern of erosion and deposition over time it was possible to understand the check dams' effects on sediment dynamics. The results show that the new check dams effectively stored sediment transported by the three debris flows. However, once the check dams have been completely filled, they lost their functionality, letting sediment flow downstream along paths drawn accidentally by the torrent control works and by the morphology of debris-flow deposits. Moreover, debris-flow lobes deposited upstream of the check dams could act as sediment sources further increasing downstream debris-flow magnitude.

In this study, we investigate the surface flow time of rise in response to rainfall and snowmelt events at different spatial scales and the main sources originating channel runoff and spring water in a steep nested headwater catchment (Rio Vauz, Italian Dolomites), characterized by a marked elevation gradient. We monitored precipitation at different elevations and measured water stage/streamflow at the outlet of two rocky subcatchments of the same size, representative of the upper part of the catchment dominated by outcropping bedrock, at the outlet of a soil-mantled and vegetated subcatchment of similar size but different morphology, and at the outlet of the main catchment. Hydrometric data are coupled with stable isotopes and electrical conductivity sampled from different water sources during five years, and used as tracers in end-member mixing analysis, application of two component mixing models and analysis of the slope of the dual-isotope regression line. Results reveal that times of rise are slightly shorter for the two rocky subcatchments, particularly for snowmelt and mixed rainfall/snowmelt events, compared to the soil-mantled catchment and the entire Rio Vauz Catchment. The highly-variable tracer signature of the different water sources reflects the geomorphological and geological complexity of the study area. The principal end-members for channel runoff and spring water are identified in rainfall and snowmelt, which are the dominant water sources in the rocky upper part of the study catchment, and soil water and shallow groundwater, which play a relevant role in originating baseflow and spring water in the soil-mantled and vegetated lower part of the catchment. Particularly, snowmelt contributes up to 64 ± 8% to spring water in the concave upper parts of the catchment and up to 62 ± 11% to channel runoff in the lower part of the catchment. These results offer new experimental evidences on how Dolomitic catchments capture and store rain water and meltwater, releasing it through a complex network of surface and subsurface flow pathways, and allow for the construction of a preliminary conceptual model on water transmission in snowmelt-dominated catchments featuring marked elevation gradients.

The increasing availability of high-resolution Digital Terrain Models (DTMs) in recent years represents a great opportunity for Geosciences being this input information a fundamental prerequisite for an accurate representation of the surface and of the processes acting on it. Nowadays, a number of techniques in order to produce high-resolution DTMs are available. Depending on the scale of analysis, the most used survey techniques are: i) Radar, ii) LiDAR and iii) Photogrammetry. The raw survey-derived products are often in need of a careful post-processing in order to filter out unwanted features. This, for example, could be the case of vegetation removal for surface processes modeling. After the filtering procedures, usually either the point density under filtered areas drops down or missing data areas are created. Resulting interpolated surfaces, in particular over these areas, could vary significantly, mainly depending on the selected interpolation algorithm, sometimes leading to the creation of artifacts that are not able to mimic the original surface trend and texture. In this work, we devised an experiment in order to compare the results of an image inpainting technique over missing data holes against commonly used interpolators (IDW, Spline, Kriging, Natural Neighbor) quantifying the accuracy of the approaches. The image inpainting technique has demonstrated in all the cases a significantly better performance in reconstructing the original surface. An assessment of the extent up to which such an approach could be regarded as robust has also been carried out. Selected applications of surface propagation models to the reconstructed surfaces have been reported so as to highlight how surface variability and uncertainty in surface reconstruction can influence (positively/negatively) model results. Applications of such an approach could pave the way for accurate surface interpolation and/or surface reconstruction in case of the need to remove selected features to characterize several modeling scenarios or to fill the gaps to reproduce the original surface in a consistent way.

Debris-flow catchments are characterised by remarkable geomorphic changes that can occur with high frequency. Accordingly, monitoring topographic changes induced by these processes requires high-resolution surveys acquired with high frequency. Recent photogrammetric techniques, such as Structure from Motion (SfM) and Multi-View Stereo (MVS), represent a low-cost opportunity for acquiring multi-temporal high-resolution topography. However, these techniques need important steps of data processing and uncertainty analysis to identify and filter erroneous or unwanted data, that may have a significant effect on the estimates of topographic changes. Within this context, in this paper we present a methodological and standardized workflow for: i) data-acquisition and post-processing to obtain usable and accurate Digital Terrain Models (DTMs) and ii) error analysis to assess uncertainty in the study of topographic changes through DEM-differencing analysis (DEMs of Difference or DoD). This workflow is based in the application of SfM and MVS techniques and was developed and tested in a small area of the Moscardo catchment (eastern Italian Alps). Multi-temporal SfM-MVS photogrammetry based on images taken from the ground and by means of UAV were carried out before and after three debris-flows occurred between June and July 2016. The developed workflow involves the following steps: (a) point cloud generation through the application of SfM-MVS; (b) analysis of the precision and accuracy of the Ground Control Points (GCPs) and the resultant point clouds by means of Check Points (CPs); (c) data filtering, cleaning and decimation through geostatistical tools; (d) evaluation of the need to carry out the alignment of multi-temporal point clouds; (e) DTMs generation; (f) assessment of a minimum Level of Detection (minLoD) based on data precision; (g) DoDs preparation and thresholding based on the minLoD; (h) assessment of topographic changes.

The paper describes the design process and experimental testing of an innovative dissipative connection suitable for XLam buildings in seismic areas. As XLam technology provides the use of massive timber shear walls characterized by low dissipative capabilities, an efficient connection system with ductile behaviour is essential in order to avoid brittle failure and to increase energy dissipation capability under seismic action. Hold-down and angle-bracket connections were originally developed for platform-frame constructions, and then adopted also in XLam structures. When such elements are subjected to cyclic and/or combined forces, they show reduced strength and unfavourable brittle behaviour. Therefore, a new generation of dissipative connections for specific usage in XLam structures is required. The proposed connection element was designed to allow large and very ductile hysteretic behaviour even under combined loading. A suitable over-strength is assured on the wood side in fulfilment of capacity design criteria. The characterization of the proposed connector was first conduced via numerical FE modelling and then supported by cyclic-loading tests according to EN 12512 protocol. Experimental results allowed to verify the actual mechanical parameters (i.e., strength, stiffness and ductility) and to obtain a comparison with a traditional connection system.

Debris flows are one of the most relevant natural hazards in mountain regions. A combination of structural (e.g. check-dams) and non structural (e.g. warning systems) measures is needed in most cases to reduce debris flow risks, and both benefit from experimental data on debris-flow characteristics. A new experimental site is being equipped in the Autonomous Province of Bolzano (Italy) for both monitoring purposes and testing warning systems. The study site (Gadria basin) is a small channel subjected to frequent debris flows. The overall system includes the following components: 4 rain gauges located at different elevations, 5 radar sensors and 5 geophones, and 3 video cameras and flash lights to record the propagation and the deposition of the debris flow. Transmission of data and alerts from the instruments will use radio technology because GSM coverage is not available in the basin.