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In this paper, the structural vibration control of short-period systems by a sliding model of a tuned liquid column damper (herein referred to as STLCD) is investigated from both theoretical and experimental points of view. The proposed STLCD is essentially composed of a U-tube container with liquid inside, which can slide on a linear guide rail and is connected to the structure by a spring-dashpot system. Unlike traditional fixed TLCDs, this type of arrangement allows the proposed STLCD to be tuned to short-period structural systems since the spring can be used for tuning while the dashpot provides additional damping. Details on the selection of the optimal design parameters of the STLCD are provided, and the validity of the introduced mathematical model is verified both in time and frequency domains through experimental tests conducted at the Laboratory of Experimental Dynamics at the University of Palermo, Italy. For the experimental tests, a scale model of an STLCD-controlled structure is considered, focusing on the reduction of the roof accelerations. Finally, for comparison purposes, the control performance of the proposed control strategy for the vibration suppression of stiff structures is evaluated by analyzing its structural responses in contrast with the corresponding uncontrolled structure under harmonic excitations. [ABSTRACT FROM AUTHOR]

Consumption of the avocado fruit and its availability in the retail market has increased in recent decades and with it the desire to learn more about the market and consumer choices. This research aims to explore the consumers' preference heterogeneity toward avocado fruit in Italy assessing their personal eating orientation and socio-demographic factors. To achieve this purpose, the answers of 817 Italian consumer of avocado were collected using a structured questionnaire shared online at national level. A survey based on the best–worst method was conducted to assess the declared preferences of individuals toward a set of intrinsic, extrinsic and credence attributes of avocado, as well as a latent class analysis of subject preferences indexes was applied to identify different clusters of individuals. The distribution of preferences indexes was investigated among latent classes, which were regressed on the socio-demographic variables covariates using multinomial logistic regression. The results suggest that the desirable attributes for choosing avocado were taste, consistency (ready to eat) and affordable price. In addition, five consumer profiles in the Italian context were defined (named Hedonistic, Avocado fruit lovers, Sustainability sensitive, Value for money and Health sensitive) and characterized in terms of preferences and socio-demographic features. The study addresses a topic that has already been explored, but with an unexploited approach (latent class analysis combined with best–worst choice modeling). Therefore, the results help fill the gap in the existing literature by enriching it with a study that characterizes avocado consumers' preferences considering their heterogeneity in terms of perception and socio-demographic characteristics. [ABSTRACT FROM AUTHOR]

This paper focuses on seismic fragility and damage scenario assessment of minor Italian historical centres through the development of urban fragility curves. With reference to the case study of Balvano, a small centre located in Basilicata Region of Italy, two hybrid models have been adopted. The first is a mechanic-based hybrid model developed by the authors to derive urban fragility curves specifically; the second is the macroseismic method, originally conceived to derive typological fragility curves for single building classes, expanded to derive urban fragility curve herein. Balvano was strongly struck by 1980 Irpinia-Basilicata earthquake (Ms = 6.90) and hence subjected to an intense reconstruction process during 1980s, where almost the 80% of the buildings were reconstructed with reinforced concrete structures in the place of unreinforced masonry ones. Seismic vulnerability and damage scenarios before and after 1980 have been assessed and compared with the purpose of validating the effectiveness of the urban scale fragility curves obtained through hybrid methodologies and quantifying the effect of the 'new' seismic hazard maps and first seismic codes and recommendations released by the Italian Government in the aftermath of 1980 for the construction of new buildings or for retrofitting the existing ones. A good matching between predicted and occurred damage scenario from the research outcomes emerged, confirming the effectiveness of the urban scale hybrid fragility curves to assess seismic vulnerability at urban scale. Moreover, the comparison of the damage scenarios pre and post-reconstruction highlighted the crucial role played by the code prescriptions adopted in that years for reducing the seismic vulnerability of the municipality and the importance of the 'new' seismic hazard maps introduced in 1980s. Finally, the differences between mechanical-based hybrid and macroseismic model have been discussed in the paper. [ABSTRACT FROM AUTHOR]

We consider approximately 23,000 microearthquakes that occurred between 2005 and 2016 in central Italy to investigate the crustal strength before and after the three largest earthquakes of the 2016 seismic sequence (i.e., the Mw 6.2, 24 August 2016 Amatrice, the Mw 6.1, 26 October 2016 Visso, and the Mw 6.5, 30 October 2016 Norcia earthquakes). We monitor the spatiotemporal deviations of observed radiated energy, ES, with respect to theoretical values, ESt, derived from a scaling model between ES and M0 calibrated for background seismicity in central Italy. These deviations, defined here as Energy Index (EI), allow us to identify in the years following the Mw 6.1, 2009 L'Aquila earthquake a progressive evolution of the dynamic properties of microearthquakes and the existence of high EI patches close to the Amatrice earthquake hypocenter. We show the existence of a crustal volume with high EI even before the Mw 6.5 Norcia earthquake. Our results agree with the previously suggested hypothesis that the Norcia earthquake nucleated at the boundary of a large patch, highly stressed by the two previous mainshocks of the sequence. We highlight the mainshocks interaction both in terms of EI and of the mean loading shear stress associated to microearthquakes occurring within the crustal volumes comprising the mainshock hypocenters. Our study shows that the dynamic characteristics of microearthquakes can be exploited as beacons of stress change in the crust and thus be exploited to monitor the seismic hazard of a region and help to intercept the preparation phase of large earthquakes. Plain Language Summary: Modern seismic networks provide large volumes of data, thereby allowing us to track the changing properties of the Earth's crust. Here, we analyze ∼23,000 microearthquakes related to the 2016 seismic sequence in central Italy. By comparing the seismic moment, which measures an earthquake's size, and the radiated energy, which measures the dynamic and frictional properties of the rupture, we can characterize the stress acting during the rupture process. We use a parameter that, for a given earthquake size, measures the difference between the theoretically expected radiated energy and the experimentally observed value. Hence, we study how such parameter changes over time and space. We identify areas characterized by high stress around which the Mw 6.2 Amatrice and Mw 6.5 Norcia earthquakes have nucleated. We also show that when one of these large earthquakes occurred, the crustal volume around the other was affected by a significant microseismic activity, suggesting that the two earthquakes interacted. Our study shows that by analyzing the characteristics and spatiotemporal variability of microearthquake source parameters, we can better understand how large earthquakes are generated and how they affect the host rock. Key Points: ∼23,000 microearthquakes of the 2016 central Italy seismic sequence are characterized in terms of their dynamic rupture propertiesDeviations of radiated energy versus seismic moment from a reference model highlight high stress areas close to future mainshock hypocentersMicroearthquakes provide clues for an interplay between the Mw 6.2 Amatrice and Mw 6.5 Norcia earthquakes [ABSTRACT FROM AUTHOR]

Indoor/outdoor air exchange on indoor radon concentration was investigated. We evaluated the effect of air extraction versus air introduction at different flow rates on equilibrium 222 Rn activity concentrations in a scale model room of 62 cm × 50 cm × 35 cm (inner length x width × height), made of a porous, radium and thorium-rich lithoid ignimbrite (Tufo di Gallese) from Vico volcano (Lazio, central Italy). Experiments were carried either with the inner walls of the chamber covered with a plasterboard shield or without any inner coating. Air introduction was always more effective than air extraction to reduce indoor 222 Rn and, in both cases, higher flow rates produced higher 222 Rn decreases. The presence of the plasterboard enhanced 222 Rn reduction when outdoor air was introduced in the chamber. Main results were that, with plasterboard, maximum reductions of 89.5 % and 25.0 % were obtained introducing and extracting air, respectively; without plasterboard, we found maximum radon decreases of 33.2 % and 26.6 %, namely with air introduction or extraction. The diffusion of 222 Rn through the walls of the scale model room was modelled with a modified version of Fick's second law, where a term considering air flow velocity was added. These findings suggested that the combined use of proper coatings on the inner walls of a house and outdoor air introduction at suitable rates are a good strategy to approach radon mitigation actions. [ABSTRACT FROM AUTHOR]

Enhanced temperature-index distributed models for snowpack simulation, incorporating air temperature and a term for clear sky potential solar radiation, are increasingly used to simulate the spatial variability of the snow water equivalent. This paper presents a new snowpack model (termed TOPMELT) which integrates an enhanced temperature-index model into the ICHYMOD semi-distributed basin-scale hydrological model by exploiting a statistical representation of the distribution of clear sky potential solar radiation. This is obtained by discretizing the full spatial distribution of clear sky potential solar radiation into a number of radiation classes. The computation required to generate a spatially distributed water equivalent reduces to a single calculation for each radiation class. This turns into a potentially significant advantage when parameter sensitivity and uncertainty estimation procedures are carried out. The radiation index may be also averaged in time over given time periods. Thus, the model resembles a classical temperature-index model when only one radiation class for each elevation band and a temporal aggregation of 1 year is used, whereas it approximates a fully distributed model by increasing the number of the radiation classes and decreasing the temporal aggregation. TOPMELT is integrated within the semi-distributed ICHYMOD model and is applied at an hourly time step over the Aurino Basin (also known as the Ahr River) at San Giorgio (San Giorgio Aurino), a 614 km 2 catchment in the Upper Adige River basin (eastern Alps, Italy) to examine the sensitivity of the snowpack and runoff model results to the spatial and temporal aggregation of the radiation fluxes. It is shown that the spatial simulation of the snow water equivalent is strongly affected by the aggregation scales. However, limited degradation of the snow simulations is achieved when using 10 radiation classes and 4 weeks as spatial and temporal aggregation scales respectively. Results highlight that the effects of space–time aggregation of the solar radiation patterns on the runoff response are scale dependent. They are minimal at the scale of the whole Aurino Basin, while considerable impact is seen at a basin scale of 5 km 2. [ABSTRACT FROM AUTHOR]

This paper identifies the application domain, context of use, processes and goals of low-cost street-level photogrammetry after urban disasters. The proposal seeks a synergy between top-down and bottom-up initiatives carried out by different actors during the humanitarian response phase in data scarce contexts. By focusing on the self-organisation capacities of local people, this paper suggests using collaborative photogrammetry to empower communities hit by disasters and foster their active participation in recovery and reconstruction planning. It shows that this task may prove technically challenging depending on the specifics of the collected imagery and develops a grounded framework to produce user-centred image acquisition guidelines and fit-for-purpose photogrammetric reconstruction workflows, useful in future post-disaster scenarios. To this end, it presents an in-depth analysis of a collaborative photographic mapping initiative undergone by a group of citizen-scientists after the 2016 Central Italy earthquake, followed by the explorative processing of some sample datasets. Specifically, the paper firstly presents a visual ethnographic study of the photographic material uploaded by participants from September 2016 to November 2018 in the two Italian municipalities of Arquata del Tronto and Norcia. Secondly, it illustrates from a technical point of view issues concerning the processing of crowdsourced data (e.g. image filtering, selection, quality, semantic content and 3D model scaling) and discusses the viability of using it to enrich the pool of geo-information available to stakeholders and decision-makers. Final considerations are discussed as part of a grounded framework for future guidelines tailored to multiple goals and data processing scenarios. [ABSTRACT FROM AUTHOR]

The Amatrice–Norcia–Visso sequence is characterized by complex behaviour that is somewhat atypical of main-shock–aftershock sequences, as there were multiple large main shocks that continued for months. In this study we focus on the Amatrice sequence (main shock 2016 August 24, M w = 5.97) to evaluate the apparent stress values and magnitude-dependent scaling in order to improve our knowledge of processes that control small and large earthquakes within this active region of Italy. Apparent stress is proportional to the ratio of radiated seismic energy and seismic moment, and as such, these stress parameters play an important role in hazard prediction as they have a strong effect on the observed and predicted ground shaking. We analyse 83 events of the sequence from 2016 August 24 to October 16, within a radius of 20 km from the main shock and with an M w ranging between 5.97 and 2.72. Taking advantage of the averaging nature of coda waves, we analyse coda-envelope-based spectral ratios between neighbouring event pairs. We use equations proposed by Walter et al. to consider stable, low-frequency and high-frequency spectral ratio levels which provide measures of the corner frequency and apparent stress ratios of the events within the sequence. The results demonstrate non-self-similar behaviour within the sequence, suggesting a change in dynamics between the largest events and the smaller aftershocks. The apparent stress and corner frequency estimates are compared to those obtained by Malagnini and Munafò who utilized hundreds of direct S -wave spectral ratio measurements to obtain their results. Although our analysis is based only on 83 events, our results are in very good agreement, demonstrating once more that the use of coda waves is very stable and provides lower variance measures than those using direct waves. A comparison with recent Central Apennines source scaling models derived from various seismic sequences (1997–1998 Colfiorito, 2002 San Giuliano di Puglia, 2009 L'Aquila) shows that the Amatrice sequence source scaling in this study is well represented by the models proposed by Pacor et al. and Malagnini and Mayeda. [ABSTRACT FROM AUTHOR]

When applying hydrological models at basin scale, it is essential to take into account the contribution of groundwater and its behaviour, together with the hydrological state before and after storm events. The main objectives of the present study were the evaluation and discussion of factors contributing to the formation of river discharge, how and to what extent these factors affect the risk of flood and, finally, how they are related to the type, duration and intensity of rainfall events, especially associated with flash floods. This was achieved by applying HEC-HMS models to a small watershed in central Italy, characterised by high hydrogeological risk. The watershed is equipped for total rainfall, river discharge and groundwater level measurement. In addition, double ring infiltrometric tests were performed during different hydrological periods. The results highlighted a direct correlation between flood risk and the hydrological period; the insertion of groundwater data in the model allowed for a sensitivity analysis of the relationship between the level of risk and the hydrogeological settings and properties of the area. Moreover, the analysis of some “extreme” events occurring in the summer period highlighted river behaviour in very different hydrological states. [ABSTRACT FROM AUTHOR]

Most crop models are designed for point-based modeling and to simulate agronomic variables on their native spatial footprint, i.e. typically as a uniform field-scale value. Precision agriculture needs crop model simulations at sub-field scales to support differential management application. Spatialization processes are used to change the simulation scale of crop models. The objective of this study is to investigate the spatialization of a complex crop model by using a spatial calibration approach to modify its native spatial footprint and to evaluate if it is relevant to use this kind of crop model at the within-field scale. APSIM was spatialized to simulate durum wheat yield at different spatial scales (field, within-field and site-scale) on an experimental field under Mediterranean conditions in southern Italy. Ancillary soil data were used to derive potential management (modeling) zones at different scales, which were then used to spatially calibrate soil and biomass parameters in APSIM to spatially predict yield in two different production years (one year was used for calibration and the other for evaluation). Spatialized crop model performances were evaluated using the spatial balanced accuracy (SBA) score, a metric to evaluate the global preservation of patterns between maps. The spatial structure of the yield data influenced the effectiveness of the spatial calibration process. When the agronomic variable (durum wheat yield) was spatially structured, a spatialized APSIM approached performed best (5-zone modeling scale, SBA = 0.17) and outperformed the field-scale (native footprint) model (SBA = 0.19). In contrast, when the target agronomic variable was more random (less spatially structured), the uniform field-scale modeling performed best and spatial calibration had no benefit. The spatialized APSIM performances were mainly based on the reliability of the delineated zones that undeniably affected the quality of the spatialized model outputs. Thus, more research is needed on how best to model scale-dependent processes to have more reliable modeling at the within-field scale. Based on the example of a complex crop model like APSIM, this study showed that spatial calibration can be effective and has a role to play in the spatialization of complex crop models. [Display omitted] • Spatialization is of great interest to use crop models in precision agriculture. • Spatial calibration efficiently downscaled APSIM at the within-field scale. • Spatial calibration performed best when modeling spatially structured variables. • Ancillary data used in downscaling need to be correlated with the target variable. • Better formalism of spatial processes improves spatialized crop model performance. [ABSTRACT FROM AUTHOR]

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