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Built Heritage Interface Models Multipurpose information access and data exchangeBarbini, Ambra 31 October 2024 (has links)
The research investigates models as interfaces to the built heritage, intended as representation forms and strategies for multipurpose information access and data exchange to enhance collaboration among practitioners and promote communication with stakeholders and generic audiences. After analyzing the research keywords through a theoretical framework, the study focuses on different methods and techniques for digital model development from data acquisition and processing, according to specific purposes and priorities. This focus relies on both literature review and real case studies, including integrated survey campaigns and paying particular attention to accessible and interoperable workflows also through the exploration of open solutions. Follows a section oriented to the potential uses of the developed models, offering some fruition options to allow specialized and generic users to access technical and cultural data. The point of view of different professional categories of the construction supply chain is further investigated through a questionnaire disseminated in the Province of Trento on data exchange and collaboration forms, digital tools adoption, and built heritage data collection and processing. Some of the solutions tested within the research are made available in tools such as self-orientation surveys and a check-list as user-friendly and easily accessible alternatives to traditional guidelines to promote knowledge transfer and benefit from further contamination between the academic state of art and professional praxis.
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SAR data processing for the detection and monitoring of braided gravelbed rivers morphodynamicsRossi, Daniele 23 April 2024 (has links)
Braided rivers represent one of the most complex forms of natural streams. Characterized by intense bed-load transport and highly dynamic channels, they carry significant naturalistic value and support a multiplicity of ecosystem services. Anthropogenic stressors and environmental changes put under stress hydro-morphological dynamics, biological processes, and ecosystem functioning and services of these fragile environments, necessitating integrated management and conservation strategies to preserve their biodiversity and ecological integrity. From a regulatory perspective, the two European Directives 2007/60/EC (the Floods Directive) and 2000/60/EC (the Water Framework Directive) identify and promote win--win measures that both reduce hydraulic risk and enhance the quality of water bodies. Some examples of win--win measures are river naturalization projects that not only restore river ecosystems to their natural state, enhancing biodiversity and ecosystem services but also provide flood protection, improve water quality, and offer recreational opportunities for local communities. This thesis contributes to the development of scientific knowledge in the previously mentioned areas, facilitating the know-how transfer of expertise from academia to the public institution. Building on these premises, this thesis aims to provide additional insights into the morphodynamics of braided rivers, offering new perspectives on the evolution of morphological indices during flood events and contributing valuable knowledge on how these complex systems respond to external stressors. The PhD thesis has been structured along three parts. The primary goal was to develop an innovative unsupervised algorithm for extracting the spatial and temporal evolution of braided river morphology. This computational framework is tailored for Sentinel--1 Synthetic Aperture Radar (SAR) data, overcoming the limitations imposed by weather conditions and day--night cicles. Moreover, it can be effortlessly adapted to additional SAR imagery databases. In cases where the water class covers only a minimal area of the entire scene, the histogram primarily represents the dry soil class. The framework faces this challenge employing a Self-Adaptive Thresholding Approach (SATA) to achieve a distinct bimodal distribution, enabling the accurate computation of threshold values for the 'dry soil' and 'water' classes. The tool, developed within the Python--API of Google Earth Engine (GEE), allowed us to assess the intra--event inundation dynamics, the estimation of the relationship between hydrometric level and wet area extension, and the assessment of bank erosion phenomena. The second chapter focuses on analyzing how morphological indices, such as the Total Braiding Intensity (TBI) index defined as the number of active channels, the Maximum Channel distance (MCD) defined as the distance between the most external channels, and the Cross-Sectional Cumulative Wetted Area (WA) defined as the sum of the wet area of all chanels in a cross section, correlate with discharge variations during flood events. To achieve this objective, the framework designed for Sentinel--1 images was adapted for use with high--definition imagery from the Italian COSMO--SkyMed satellite constellation. Leveraging the superior ground resolution of 3x3 meters provided by the Italian COSMO--SkyMed satellite constellation, we successfully segmented narrow secondary branches that remained undetected with Sentinel--1's 5x20 meter resolution. Thus obtained, the temporal evolution of the braiding system, enables us to evaluate the temporal evolution and the relationship between the TBI, MCD, and WA indices with increasing discharge values. The last part of the PhD thesis, deals with the assessment of the river bed grain size. The initial concept behind this PhD work was to analyze the potential of Synthetic Aperture Radar (SAR) data in assessing not only river morphology but also the pattern of patches with different grain size. While the initial two parts of the work addressed this, the final section's analysis of SAR data, unfortunately, did not provide significant results. Nevertheless, the subjects of surface roughness and the creation of spatially distributed grain size maps continue to hold significant scientific value in the fields of hydraulic and eco--hydraulic modeling and a key information for river management and renaturation projects. The principal role of this factor led us to slightly shift the research focus towards a detailed investigation of these elements, utilizing orthophotos, digital imagery, and corresponding analytical methods to model patterns of river roughness and grain size. A map illustrating the spatial pattern of grain size at the river reach scale was produced through regression analysis. This analysis correlated the texture properties derived from orthophoto tiles with the d50, d84, d90, and d95 grain size characteristics obtained from digital images, thereby providing considerable support for the implementation of detailed hydraulic models.
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Protection infrastructures and methods for reducing the impacts downstream of hydropower plantsPisaturo, Giuseppe Roberto January 2017 (has links)
Hydropower plants, in particular High-head Hydropower Plants (HPPs), are an important source of energy also for their role in covering the daily peaks of energy demand. However, HPPs, especially storage power plants, have several negative effects on the ecosystems of downstream watercourses inducing unnatural changes in flow regime (hydropeaking).
One way to study ecological implications induced by hydropeaking is represented by the coupling of hydrodynamic models (CFD) with habitat suitability models, in which hydrodynamic parameters are typically used to describe the physical habitat of indicator species. The research activity wanted to investigate possible differences between the use of 2D and 3D CFD approaches to determine the watercourse hydraulic characteristics and their effects on habitat evaluations, performed with CASiMiR software, in complex morphology as usually presents in hydropeaked reaches.
In particular the habitat suitability for the two case studies (Valsura River and Rio Selva dei Molini), is analysed comparing different approaches for the reconstruction of the velocity field (depth-averaged velocities from 2D modelling, bottom velocity field reconstruction with log-law approach from 2D modelling and bottom velocity field from 3D modelling). The results show that the habitat suitability index (HSI) using 2D or 3D hydrodynamic models can be significantly different. Considering the entire flow range of hydropeaking events, the habitat simulations with bottom flow velocities from 3D modelling provide suitable habitats over the entire flow range representing the availability of stable suitable habitats. The results from the hydraulics and habitat analyses are used to investigate the effects of a hydropeaking mitigation project on the Valsura River (realization of a compensation bypass tunnel to decrease the peak flow rate and to remodel the up and down flow ramping rates) and on Rio Selva dei Molini (morphological measures to reduce the hydropeaking effects).
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Numerical Modelling of Braiding Processes in Gravel-Bed RiversBaral, Bishnu Raj January 2018 (has links)
Gravel-bed braided rivers are distinctive natural environments that provid a wide range of key environmental, economic and recreational services. There is, however,a growing concern that over the twentieth century, an increasing number of braided rivers have metamorphosed into wandering or single thread channels, representing a loss of key habitats, geodiversity and amenity. While in some situations, shifts in channel pattern may be unambiguously linked to abrupt changes in flow or sediment supply, the lack of a theoretical basis underpinning the development and maintenance of braiding makes identification of the cause and effect of channel metamorphosis hazardous. A growing body of research has suggested that the transition between channelpatterns may depend on the poorly understood interaction between the flow regime,sediment supply and vegetation colonisation. Such interactions are governed by critical thresholds, due to changes in flow resistance and bank strength associated with the distribution, form and intensity of vegetation colonisation. Subtle changes in flow or sediment supply that promote vegetation growth or indeed remove itthrough inundation or attrition. This can lead to complex non-linear shifts in the balance of forces that govern sediment transport and bedform morphodynamics, ultimately resulting in one-way changes in channel morphology. There is, therefore, a critical need to develop a quantitative understanding of these feedbacks in orderto design sustainable river management programmes that seek to optimize the ecological and socio-economic benefits these rivers offer.
In summary, this thesis aims to advance our understanding of the morphodynamics of braided rivers and the role numerical models may have in helping to interrogate their behavior and governing controls.
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Analysis of the impact of hydrological alterations and multiple stress factors on the ecological status of Alpine freshwater ecosystemsStella, Elisa January 2018 (has links)
Freshwater ecosystems are severely undergoing degradation due to the presence of multiple stressors that are undermining their biodiversity. In this sense, quantifying these effects on Alpine regions is challenging, due to the lack of tailored field measurements of hydrological, biological and chemical variables. This work aims to touch some of these aspects, with particular attention to hydrological dynamics and their effects on macroinvertebrates. Field activities have been conducted within the Adige catchment which has been selected as a case study in the FP7 project GLOBAQUA. Collected data have been analyzed by means of statistical tools and results showed a seasonal and spatial variability of biological communities related to hydrological and chemical variables. In particular, it has been observed that richness, diversity and relative composition of macroinvertebrates community are chiefly affected by hydrological alteration and urban pollution. Available literature confirmed that hydrological alteration is one of the most important factors affecting riverine ecosystems. In Alpine regions, most of the hydrological alterations observed are due to hydropower that represents the major source of energy in the Trentino-Alto Adige region. Since the introduction of the free energy market in Italy, hydropower production shows large fluctuations at the daily and larger temporal scales, as the managers aim at producing when the energy price is high. This increased the variability of streamflow downstream the restitution of the power plants. Changing climate is an additional stressor that can enhance the effects of these anthropogenic influences. Thereby, in this work hydrological alterations have been distinguished between those forced by climate change and those caused by the presence of hydropower plants and have been analysed in detail. The former have been analysed downstream of the Careser glacier, which has long-term observations of climatic variables, mass balances and streamflow. The main purpose of this study was finding a direct relationship linking biological indicators to streamflow variations related mainly to hydropower operations. Quantifying these effects is challenging due to the fact that the behaviour by which macroinvertebrates respond remains largely unexplained. However, analyses of similarities and independence, performed at the basin scale with data provided by the local Environmental Protection Agencies, showed evident differences in the biological communities between impacted and non-impacted sites. These results bring us to believe that a relationship between biological data and hydrological alteration is expected to exist, but that is not clearly explicated by simple correlations. Giving a quantitative interpretation of this correlation could help hydropower manager to improve and optimize the energy production with a more realistic scenario of the effects on the biological community, with also a perspective of the combined effects caused by the presence of multiple reservoirs within the basin.
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Development of a Damage Indicator Based on Detection of High-Frequency Transients Monitored in Bridge Piers During Earthquake Ground ShakingZhelyazkov, Aleksandar 05 August 2020 (has links)
Real-time structural health monitoring is a well established tool for post-earthquake damage estimation. A key component in the monitoring campaign is the approach used for processing the data from the structural health monitoring system. There is a large body of literature on signal processing approaches aimed at identifying ground-motion induced damage in civil engineering structures. This dissertation expands on a specific subgroup of processing approaches dealing with the identification of damage induced high-frequency transients in the monitoring data. The underlying intuition guiding the current research can be formulated in the following hypothesis - the time difference between the occurrence of a high-frequency transient and the closest deformation extremum forward in time is proportional to the degree of damage. A mathematical deduction is provided in support of the above hypothesis followed by a set of shaking table tests. For the purposes of this research two shaking table tests of reinforced concrete bridge piers were performed. Data from a shaking table test performed by another research group was also analyzed. The cases in which the proposed procedure could find a practical application are examined along with the present limitations.
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Improving some non-structural risk mitigation strategies in mountain regions: debris-flow rainfall thresholds, multi-hazard flooding scenarios and public awarenessMartinengo, Marta 29 September 2022 (has links)
Hydrogeological hazards are quite diffuse rainfall-induced phenomena that affect mountain regions and can severely impact these territories, producing damages and sometimes casualties. For this reason, hydrogeological risk reduction is crucial. Mitigation strategies aim to reduce hydrogeological risk to an acceptable level and can be classified into structural and non-structural measures. This work focuses on enhancing some non-structural risk mitigation measures for mountain areas: debris-flow rainfall thresholds, as a part of an Early Warning System (EWS), multivariate rainfall scenarios with multi-hazard mapping purpose and public awareness. Regarding debris-flow rainfall thresholds, an innovative calibration method, a suitable uncertainty analysis and a proper validation process are developed. The Backward Dynamical Approach (BDA), a physical-based calibration method, is introduced and a threshold is obtained for a study area. The BDA robustness is then tested by assessing the uncertainty in the threshold estimate. Finally, the calibrated threshold's reliability and its possible forecast use are assessed using a proper validation process. The findings set the stage for using the BDA approach to calibrate debris-flow rainfall thresholds usable in operational EWS. Regarding hazard mapping, a multivariate statistical model is developed to construct multivariate rainfall scenarios with a multi-hazards mapping purpose. A confluence between a debris-flow-prone creek and a flood-prone river is considered. The multivariate statistical model is built by combining the Simplified Metastatistical Extreme Value approach and a copula approach. The obtained rainfall scenarios are promising to be used to build multi-hazard maps. Finally, the public awareness within the LIFE FRANCA (Flood Risk ANticipation and Communication in the Alps) European project is briefly considered. The project action considered in this work focuses on training and communication activities aimed at providing a multidisciplinary view of hydrogeological risk through the holding of courses and seminars.
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Neglected aspects in the alteration of river flow and riverine organic matter dynamics: a global perspectiveShumilova, Oleksandra January 2018 (has links)
In the current era of the Anthropocene, human activities are powerful forces that affect the geosphere, atmosphere, and biosphere – globally, fundamentally, and in most cases irreversibly. In freshwaters, land use change, chemical pollution, decline in biodiversity, spread of invasive
species, climate change, and shifts in the hydrological regime are among the key drivers of changes. In the 21st century, major water engineering projects such as large dams and water diversion schemes will fundamentally alter the natural hydrological regime of entire landscapes and even continents. At the same time, the hydrological regime is the governing variable for biodiversity, ecosystem functions and services in river networks. Indeed, there will be an increasing conflict between managing water as a resource for human use and waters as highly valuable ecosystems. Therefore, research needs to unravel the challenges that the freshwaters are facing, understand their potential drivers and impacts, and develop sustainable management practices – for the benefit of humans and ecosystems alike.
The present thesis focuses on three currently understudied alterations in flow and material dynamics within river networks, namely (i) on the dynamics of floating organic matter (FOM) and its modification in dammed rivers, (ii) on river intermittency and its effects on nutrient and organic matter (OM) dynamics, and (iii) on major future water transfer schemes. Massive construction and operation of dams cause modification of water flow and material fluxes in rivers, such as of FOM. FOM serves as an essential component of river integrity, but a comprehensive understanding of its dynamics is still lacking. River damming, climate change and water extraction for human needs lead to a rapid expansion in number and extent of intermittent rivers worldwide, with major biogeochemical consequences on both regional and global scales. Increased intermittency of river networks also forces people to implement engineering solutions, such as water transfer schemes, which help to supply water to places of demand. Water transfer projects introduce artificial links among freshwater bodies modifying the hydrological balance. Impacts of abovementioned activities on freshwaters have been assessed in single case studies.
However, the current knowledge does not allow a generalization of their globally applicable meaning for ecosystems. Furthermore, mostly neglected aspects of these alterations, such as the potential consequences of FOM extraction from rivers, the biogeochemical role of intermittent rivers upon rewetting, and the current scale of water transfers require better understanding before
bold conclusions could be made. By combining research methods such as extensive literature reviews, laboratory experiments and quantitative analyses including spatial analyses with Geographic Information Systems, I investigated (1) the natural cycle, functions, and amounts of FOM in rivers fragmented by dams, (2) effects of rewetting events on the pulsed release of nutrients and OM in intermittent
rivers and ephemeral streams (IRES), and (3) the potential extent of water transfer megaprojects (WTMP) that are currently under construction or in the planning phase and their role in modifying the global freshwater landscape. In all three cases, I provide a global perspective.
The role of FOM in rivers as a geomorphological agent, a resource, a dispersal vector and a biogeochemical component was investigated based on an extensive literature review. Collected information allowed for conceptualizing its natural cycle and dynamics, applicable to a wide range of rivers. Data on FOM accumulations at 31 dams located within catchments of 13 rivers showed that damming leads to FOM entrapment (partly or completely) and modifies its natural cycling. The results of a spatial analysis considering environmental properties revealed that catchment
characteristics can explain around 57% in the variation of amounts of trapped FOM. Effects of rewetting events on the release of nutrients and OM from bed sediments and course particulate organic materials (CPOM) accumulated in IRES was studied in laboratory experiments. Using a large set of samples collected from 205 rivers, located in 27 countries and distributed across five major climate zones, I determined the concentrations and qualitative characteristics of nutrients and OM released from sediments and CPOM. I also assessed how these characteristics can be predicted based on environmental variables within sampled IRES. In addition, I calculated area-specific fluxes of nutrients and OM from dry river beds. I found that the characteristics of released substances are climate specific. In the Continental zone I found the highest concentrations of released nutrients, but the lowest quality of OM in terms of its potential bioavailability. In contrast, in the Arid zone the concentrations of released nutrients were the lowest, but the quality of OM the highest. The effect of environmental variables on the concentrations of nutrients and the quality of OM was better predicted for sediments than for other substrates with the highest share of explained variance in the Continental and Tropical zones. On the global scale, dissolved organic carbon, phenolics, and nitrate dominate fluxes released during rewetting events. Overall, this study emphasized that on the global scale rewetting events in IRES represent biogeochemical “hot moments†, but characteristics of released nutrients and OM differ greatly among climate zones. The present thesis fills also a major knowledge gap on the global distribution of large water transfer schemes (referred to as “megaprojects†) that are actually planned or under construction. To provide an inventory of WTMP, I collected data from various literature sources, ranging from published academic studies, the official web-sites of water transfer projects, environmental impact assessments, reports of non-governmental organizations, and information available in on-line newspapers. In total, 60 WTMP were identified. Information on spatial location, distances and volumes of water transfer, costs, and purposes of WTMP was collected and compared with those of existing schemes. The results showed that North America, Asia and Africa will be the most affected by future WTMP having the highest densities of projects and the largest water transfer distances and volumes. If all projects were completed by 2050, the total water transfer distances would reach 77,063 km transferring more than 1,249 km3 per year, which corresponds to about 20 times the annual flow of the river Rhine. The outcomes of the thesis provide major implications for environmental management. Natural FOM is an important component for sustaining the ecological and geomorphic integrity of rivers and, therefore, should be managed appropriately. Intermittent rivers must be considered in models quantifying nutrient and OM fluxes in river networks. First flush events in particular release huge amounts of nutrients and OM, which may cause dramatic metabolic effects on downstream receiving waters. Finally, the future WTMP alter the hydrological balance of entire river basins and continents. They require multiple assessments before construction and careful management practices for sustainable operation in order to consider both freshwater as a resource as well as freshwaters as pivotal ecosystems.
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Integrated solar thermal facade component for building energy retrofitGiovanardi, Alessia January 2012 (has links)
In the perspective of the "Net Zero Energy Buildings" as specified in the EPBP 2010/31/EU, herein a modular unglazed solar thermal facade component for facilitating the installation of active solar thermal facades has been conceived and designed to answer three considerations: (1) easily installable elements, offering high modularity to be sized for the specific needs of the buildings considered, (2) low-price unglazed technology, given by the industrial process already developed for the fridge evaporators, and (3) versatile modules to be used for both new buildings and for existing buildings for energy retrofitting. The existing buildings stock offers a high-potential opportunity to improve the energy efficiency when using such a system. Indeed, the building envelope elements have a significant impact on energy consumptions and performances of the building, and this is a key aspect to consider during renovation. Considering buildings integrating solar thermal (BIST) by the means of facade retrofitting of solar thermal collectors (STC) opens up new challenges for engineers. Facade usage, compared to the traditional roof installations, offers two interesting potentialities: (1) increased available surfaces, and (2) minimization of the unwanted overheating problem, that appears in summer, thanks to the vertical tilt (as the energy production is almost constant over the year). This allows sizing the STC according to the actual heat needs and avoids as much as possible energy fluxes mismatch. The design methodology of such a modular component is the main contribution of the PhD work. The challenges are tackled via a parametric approach. Dynamic simulation tools support the design choices for the energy systems of BIST and to optimize the interactions between the envelope and the STC with the criteria of reducing the overall energy consumption. This methodology is described and applied to the design of a modular prototype of an innovative facade component integrating unglazed STC. We first analyze a variety of typologies of buildings as potential commercial targets of the facade component of unglazed STC integrated facade element. Both residential and non residential buildings are considered. The purpose of this analysis is to match the heat loads for properly sizing the facade elements for each typology. Benchmark models of buildings from the Department of Energy are used such as multifamily houses, hospitals, big and small hotels, schools, offices. These are simulated through EnergyPlus in three European locations (Stockholm, Zurich and Rome) in order to define the yearly heat loads for domestic hot water (DHW) and space heating (SH) needs. Finally, the prototype is conceived and designed as a low-cost product to implement into facades with the criteria of optimizing the energy production. The unglazed STC is combined with a simple configuration of combisystem in order to define some rule of thumbs through Trnsys. By the fact that the energy is produced at lower temperatures, if compared with glazed flat plate collectors, this technology is potential applicable to those buildings having the proper heat loads and the suitable system layout.
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Building skin as energy supply: Prototype development of a wooden prefabricated BiPV wallMaturi, Laura January 2013 (has links)
In the perspective of “nearly zero energy buildings” as foreseen in the EPBD 2010/31/EU, herein a prototype of a wooden prefabricated BiPV wall is conceived, designed, built and tested. The prototype key concepts, identified according to the recommendations of the IEA Task 41 research project, are: multi-functionality, prefabrication, sustainability and integration. The prototype design is the result of a theoretical study which takes into account both architectural integration aspects and energy performance issues. The latter in particular, is based on the evaluation and improvement of both PV and building-related aspects, through the investigation and implementation of low-cost passive strategies to improve the overall BiPV performance. A modular specimen of the prototype was built thanks to an industrial collaboration and tested through an experimental approach, based on the combination of several phases performed in two test facilities (i.e. INTENT lab and SoLaRE-PV lab) by means of original experimental set-up. The effectiveness of the proposed BiPV prototype configuration is proven by comparing the results of the experiments with monitored data of two BiPV systems (a roof and a façade system) located in South Tyrol (North of Italy). The experimental results are then generalized, providing significant data and experimental expressions for a deeper understanding of BiPV systems energy performance.
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