Thèses : « GEO/08 »

1

Re, Viviana <1981&gt. « Groundwater in urban coastal areas : hydrogeochemical based approach for managing the transition areas : the example of the lagoon of Nador (Morocco) ». Doctoral thesis, Università Ca' Foscari Venezia, 2011. http://hdl.handle.net/10579/1059.

Texte intégral

Résumé :

Nell’ambito del progetto SAP MED, la laguna di Nador rappresenta il caso di studio Marocchino per la sottocomponente gestita da UNESCO-IHP. Lo studio dell’acquifero di Bou-Areg e della laguna di Nador ha due obiettivi principali: (i) dimostrare l’importanza degli studi idrogeochimici a supporto della gestione degli acquiferi costieri e (ii) definire la qualità delle acque sotterranee ed le loro interazioni con la laguna. Questo lavoro ha permesso di identificare le acque di ruscellamento e flussi di ritorno agricoli come le due principali fonti di ricarica dell’acquifero. In base all’analisi idrochimica e statistica, è possibile escludere la presenza di processi di intrusione salina, mentre, le attività agricole e domestiche sono considerate le principali cause dell’alterazione della normale salinità dell’acquifero. L’analisi isotopica ha infine permesso di individuare due principali fonti di azoto nelle acque sotterranee: (i) fertilizzanti sintetici e (ii) effluenti di fosse settiche.
The hydrogeochemical investigation on the Bou-Areg Plain and Lagoon of Nador (Morocco) is, framed within the UNESCO-IHP sub component of the MED MAP project, as the Moroccan pilot case study. Its main research goals were (i) to demonstrate the effectiveness of hydrogeochemical tools for coastal aquifers management, with focus on urban coastal areas in semi-arid climates and (ii) to unravel the role of groundwater in sustaining transition areas. The study allowed for the identification of surface runoff and agricultural return flows as the main sources of aquifer recharge. Moreover, the effects of agricultural practices are increasing the natural high salinization of the aquifer. The isotopic signal of dissolved nitrates allowed for the identification of two main nitrogen sources in the system: (i) fertilizers and (ii) manure and septic effluent. The PCA analysis supported the absence of saline water intrusion in the aquifer.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Di, Roberto Alessio <1978&gt. « Depositi torbiditici cogenetici a frane oloceniche del vulcano di Stromboli : implicazioni per la mitigazione del rischio derivante da tsunami ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/225/1/Tesi_dottorato.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

3

Di, Roberto Alessio <1978&gt. « Depositi torbiditici cogenetici a frane oloceniche del vulcano di Stromboli : implicazioni per la mitigazione del rischio derivante da tsunami ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/225/.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

4

Tesi, Tommaso <1978&gt. « Destino del carbonio organico di apporto fluviale sulle piattaforme continentali : Adriatico centro-settentrionale e Golfo del Leone ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/446/1/Tommaso_Tesi_XIX_ciclo_S._Ambientali.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

5

Tesi, Tommaso <1978&gt. « Destino del carbonio organico di apporto fluviale sulle piattaforme continentali : Adriatico centro-settentrionale e Golfo del Leone ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/446/.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

6

Chirico, Giuseppe Damiano <1973&gt. « Studio probabilistico della pericolosità da colate di lava al vulcano Nyiragongo (Repubblica Democratica del Congo) e possibili misure volte alla riduzione del rischio ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/537/1/chirico_tesi.pdf.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

7

Chirico, Giuseppe Damiano <1973&gt. « Studio probabilistico della pericolosità da colate di lava al vulcano Nyiragongo (Repubblica Democratica del Congo) e possibili misure volte alla riduzione del rischio ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2007. http://amsdottorato.unibo.it/537/.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Mori, Guido <1978&gt. « The use of Ground Penetrating Radar and alternative geophysical techniques for assessing embankments and dykes safety ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2138/1/Mori_Guido_Tesi.pdf.

Texte intégral

Résumé :

The research is part of a survey for the detection of the hydraulic and geotechnical conditions of river embankments funded by the Reno River Basin Regional Technical Service of the Region Emilia-Romagna. The hydraulic safety of the Reno River, one of the main rivers in North-Eastern Italy, is indeed of primary importance to the Emilia-Romagna regional administration. The large longitudinal extent of the banks (several hundreds of kilometres) has placed great interest in non-destructive geophysical methods, which, compared to other methods such as drilling, allow for the faster and often less expensive acquisition of high-resolution data. The present work aims to experience the Ground Penetrating Radar (GPR) for the detection of local non-homogeneities (mainly stratigraphic contacts, cavities and conduits) inside the Reno River and its tributaries embankments, taking into account supplementary data collected with traditional destructive tests (boreholes, cone penetration tests etc.). A comparison with non-destructive methodologies likewise electric resistivity tomography (ERT), Multi-channels Analysis of Surface Waves (MASW), FDEM induction, was also carried out in order to verify the usability of GPR and to provide integration of various geophysical methods in the process of regular maintenance and check of the embankments condition. The first part of this thesis is dedicated to the explanation of the state of art concerning the geographic, geomorphologic and geotechnical characteristics of Reno River and its tributaries embankments, as well as the description of some geophysical applications provided on embankments belonging to European and North-American Rivers, which were used as bibliographic basis for this thesis realisation. The second part is an overview of the geophysical methods that were employed for this research, (with a particular attention to the GPR), reporting also their theoretical basis and a deepening of some techniques of the geophysical data analysis and representation, when applied to river embankments. The successive chapters, following the main scope of this research that is to highlight advantages and drawbacks in the use of Ground Penetrating Radar applied to Reno River and its tributaries embankments, show the results obtained analyzing different cases that could yield the formation of weakness zones, which successively lead to the embankment failure. As advantages, a considerable velocity of acquisition and a spatial resolution of the obtained data, incomparable with respect to other methodologies, were recorded. With regard to the drawbacks, some factors, related to the attenuation losses of wave propagation, due to different content in clay, silt, and sand, as well as surface effects have significantly limited the correlation between GPR profiles and geotechnical information and therefore compromised the embankment safety assessment. Recapitulating, the Ground Penetrating Radar could represent a suitable tool for checking up river dike conditions, but its use has significantly limited by geometric and geotechnical characteristics of the Reno River and its tributaries levees. As a matter of facts, only the shallower part of the embankment was investigate, achieving also information just related to changes in electrical properties, without any numerical measurement. Furthermore, GPR application is ineffective for a preliminary assessment of embankment safety conditions, while for detailed campaigns at shallow depth, which aims to achieve immediate results with optimal precision, its usage is totally recommended. The cases where multidisciplinary approach was tested, reveal an optimal interconnection of the various geophysical methodologies employed, producing qualitative results concerning the preliminary phase (FDEM), assuring quantitative and high confidential description of the subsoil (ERT) and finally, providing fast and highly detailed analysis (GPR). Trying to furnish some recommendations for future researches, the simultaneous exploitation of many geophysical devices to assess safety conditions of river embankments is absolutely suggested, especially to face reliable flood event, when the entire extension of the embankments themselves must be investigated.

Styles APA, Harvard, Vancouver, ISO, etc.

9

Mori, Guido <1978&gt. « The use of Ground Penetrating Radar and alternative geophysical techniques for assessing embankments and dykes safety ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2138/.

Texte intégral

Résumé :

The research is part of a survey for the detection of the hydraulic and geotechnical conditions of river embankments funded by the Reno River Basin Regional Technical Service of the Region Emilia-Romagna. The hydraulic safety of the Reno River, one of the main rivers in North-Eastern Italy, is indeed of primary importance to the Emilia-Romagna regional administration. The large longitudinal extent of the banks (several hundreds of kilometres) has placed great interest in non-destructive geophysical methods, which, compared to other methods such as drilling, allow for the faster and often less expensive acquisition of high-resolution data. The present work aims to experience the Ground Penetrating Radar (GPR) for the detection of local non-homogeneities (mainly stratigraphic contacts, cavities and conduits) inside the Reno River and its tributaries embankments, taking into account supplementary data collected with traditional destructive tests (boreholes, cone penetration tests etc.). A comparison with non-destructive methodologies likewise electric resistivity tomography (ERT), Multi-channels Analysis of Surface Waves (MASW), FDEM induction, was also carried out in order to verify the usability of GPR and to provide integration of various geophysical methods in the process of regular maintenance and check of the embankments condition. The first part of this thesis is dedicated to the explanation of the state of art concerning the geographic, geomorphologic and geotechnical characteristics of Reno River and its tributaries embankments, as well as the description of some geophysical applications provided on embankments belonging to European and North-American Rivers, which were used as bibliographic basis for this thesis realisation. The second part is an overview of the geophysical methods that were employed for this research, (with a particular attention to the GPR), reporting also their theoretical basis and a deepening of some techniques of the geophysical data analysis and representation, when applied to river embankments. The successive chapters, following the main scope of this research that is to highlight advantages and drawbacks in the use of Ground Penetrating Radar applied to Reno River and its tributaries embankments, show the results obtained analyzing different cases that could yield the formation of weakness zones, which successively lead to the embankment failure. As advantages, a considerable velocity of acquisition and a spatial resolution of the obtained data, incomparable with respect to other methodologies, were recorded. With regard to the drawbacks, some factors, related to the attenuation losses of wave propagation, due to different content in clay, silt, and sand, as well as surface effects have significantly limited the correlation between GPR profiles and geotechnical information and therefore compromised the embankment safety assessment. Recapitulating, the Ground Penetrating Radar could represent a suitable tool for checking up river dike conditions, but its use has significantly limited by geometric and geotechnical characteristics of the Reno River and its tributaries levees. As a matter of facts, only the shallower part of the embankment was investigate, achieving also information just related to changes in electrical properties, without any numerical measurement. Furthermore, GPR application is ineffective for a preliminary assessment of embankment safety conditions, while for detailed campaigns at shallow depth, which aims to achieve immediate results with optimal precision, its usage is totally recommended. The cases where multidisciplinary approach was tested, reveal an optimal interconnection of the various geophysical methodologies employed, producing qualitative results concerning the preliminary phase (FDEM), assuring quantitative and high confidential description of the subsoil (ERT) and finally, providing fast and highly detailed analysis (GPR). Trying to furnish some recommendations for future researches, the simultaneous exploitation of many geophysical devices to assess safety conditions of river embankments is absolutely suggested, especially to face reliable flood event, when the entire extension of the embankments themselves must be investigated.

Styles APA, Harvard, Vancouver, ISO, etc.

10

Forni, Francesca <1979&gt. « Petrology and geochemistry of Lipari Island (Aeolian archipelago) : constraints on magma genesis and evolution ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3785/1/Forni_Francesca_tesi.pdf.

Texte intégral

Résumé :

A full set of geochemical and Sr, Nd and Pb isotope data both on bulk-rock and mineral samples is provided for volcanic rocks representative of the whole stratigraphic succession of Lipari Island in the Aeolian archipelago. These data, together with petrographic observations and melt/fluid inclusion investigations from the literature, give outlines on the petrogenesis and evolution of magmas through the magmatic and eruptive history of Lipari. This is the result of nine successive Eruptive Epochs developing between 271 ka and historical times, as derived from recentmost volcanological and stratigraphic studies, combined with available radiometric ages and correlation of tephra layers and marine terrace deposits. These Eruptive Epochs are characterized by distinctive vents partly overlapping in space and time, mostly under control of the main regional tectonic trends (NNW-SSE, N-S and minor E-W). A large variety of lava flows, scoriaceous deposits, lava domes, coulees and pyroclastics are emplaced, ranging in composition through time from calcalkaline (CA) and high-K (HKCA) basaltic andesites to rhyolites. CA and HKCA basaltic andesitic to dacitic magmas were erupted between 271 and 81 ka (Eruptive Epochs 1-6) from volcanic edifices located along the western coast of the island (and subordinately the eastern Monterosa) and the M.Chirica and M.S.Angelo stratocones. These mafic to intermediate magmas mainly evolved through AFC and RAFC processes, involving fractionation of mafic phases, assimilation of wall rocks and mixing with newly injected mafic magmas. Following a 40 ka-long period of volcanic quiescence, the rhyolitic magmas were lately erupted from eruptive vents located in the southern and north-eastern sectors of Lipari between 40 ka and historical times (Eruptive Epochs 7-9). They are suggested to derive from the previous mafic to intermediate melts through AFC processes. During the early phases of rhyolitic magmatism (Eruptive Epochs 7-8), enclaves-rich rocks and banded pumices, ranging in composition from HKCA dacites to low-SiO2 rhyolites were erupted, representing the products of magma mixing between fresh mafic magmas and the fractionated rhyolitic melts. The interaction of mantle-derived magmas with the crust represents an essential process during the whole magmatic hystory of Lipari, and is responsible for the wide range of observed geochemical and isotopic variations. The crustal contribution was particularly important during the intermediate phases of activity of Lipari when the cordierite-bearing lavas were erupted from the M. S.Angelo volcano (Eruptive Epoch 5, 105 ka). These lavas are interpreted as the result of mixing and subsequent hybridization of mantle-derived magmas, akin to the ones characterizing the older phases of activity of Lipari (Eruptive Epochs 1-4), and crustal anatectic melts derived from dehydration-melting reactions of metapelites in the lower crust. A comparison between the adjacent islands of Lipari and Vulcano outlines that their mafic to intermediate magmas seem to be genetically connected and derive from a similar mantle source affected by different degrees of partial melting (and variable extent of crustal assimilation) producing either the CA magmas of Lipari (higher degrees) or the HKCA to SHO magmas of Vulcano (lower degrees). On a regional scale, the most primitive rocks (SiO2<56%, MgO>3.5%) of Lipari, Vulcano, Salina and Filicudi are suggested to derive from a similar MORB-like source, variably metasomatized by aqueous fluids coming from the slab and subordinately by the additions of sediments.

Styles APA, Harvard, Vancouver, ISO, etc.

11

Forni, Francesca <1979&gt. « Petrology and geochemistry of Lipari Island (Aeolian archipelago) : constraints on magma genesis and evolution ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3785/.

Texte intégral

Résumé :

A full set of geochemical and Sr, Nd and Pb isotope data both on bulk-rock and mineral samples is provided for volcanic rocks representative of the whole stratigraphic succession of Lipari Island in the Aeolian archipelago. These data, together with petrographic observations and melt/fluid inclusion investigations from the literature, give outlines on the petrogenesis and evolution of magmas through the magmatic and eruptive history of Lipari. This is the result of nine successive Eruptive Epochs developing between 271 ka and historical times, as derived from recentmost volcanological and stratigraphic studies, combined with available radiometric ages and correlation of tephra layers and marine terrace deposits. These Eruptive Epochs are characterized by distinctive vents partly overlapping in space and time, mostly under control of the main regional tectonic trends (NNW-SSE, N-S and minor E-W). A large variety of lava flows, scoriaceous deposits, lava domes, coulees and pyroclastics are emplaced, ranging in composition through time from calcalkaline (CA) and high-K (HKCA) basaltic andesites to rhyolites. CA and HKCA basaltic andesitic to dacitic magmas were erupted between 271 and 81 ka (Eruptive Epochs 1-6) from volcanic edifices located along the western coast of the island (and subordinately the eastern Monterosa) and the M.Chirica and M.S.Angelo stratocones. These mafic to intermediate magmas mainly evolved through AFC and RAFC processes, involving fractionation of mafic phases, assimilation of wall rocks and mixing with newly injected mafic magmas. Following a 40 ka-long period of volcanic quiescence, the rhyolitic magmas were lately erupted from eruptive vents located in the southern and north-eastern sectors of Lipari between 40 ka and historical times (Eruptive Epochs 7-9). They are suggested to derive from the previous mafic to intermediate melts through AFC processes. During the early phases of rhyolitic magmatism (Eruptive Epochs 7-8), enclaves-rich rocks and banded pumices, ranging in composition from HKCA dacites to low-SiO2 rhyolites were erupted, representing the products of magma mixing between fresh mafic magmas and the fractionated rhyolitic melts. The interaction of mantle-derived magmas with the crust represents an essential process during the whole magmatic hystory of Lipari, and is responsible for the wide range of observed geochemical and isotopic variations. The crustal contribution was particularly important during the intermediate phases of activity of Lipari when the cordierite-bearing lavas were erupted from the M. S.Angelo volcano (Eruptive Epoch 5, 105 ka). These lavas are interpreted as the result of mixing and subsequent hybridization of mantle-derived magmas, akin to the ones characterizing the older phases of activity of Lipari (Eruptive Epochs 1-4), and crustal anatectic melts derived from dehydration-melting reactions of metapelites in the lower crust. A comparison between the adjacent islands of Lipari and Vulcano outlines that their mafic to intermediate magmas seem to be genetically connected and derive from a similar mantle source affected by different degrees of partial melting (and variable extent of crustal assimilation) producing either the CA magmas of Lipari (higher degrees) or the HKCA to SHO magmas of Vulcano (lower degrees). On a regional scale, the most primitive rocks (SiO2<56%, MgO>3.5%) of Lipari, Vulcano, Salina and Filicudi are suggested to derive from a similar MORB-like source, variably metasomatized by aqueous fluids coming from the slab and subordinately by the additions of sediments.

Styles APA, Harvard, Vancouver, ISO, etc.

12

Catry, Thibault <1985&gt. « Magma injections and destabilization of basaltic volcanoes : a numerical study. Application to La Reunion (Indian ocean, France) and Stromboli (Tyrrhenian sea, Italy) ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3904/1/thibault_catry_tesi.pdf.

Texte intégral

Résumé :

Most basaltic volcanoes are affected by recurrent lateral instabilities during their evolution. Numerous factors have been shown to be involved in the process of flank destabilization occurring over long periods of time or by instantaneous failures. However, the role of these factors on the mechanical behaviour and stability of volcanic edifices is poorly-constrained as lateral failure usually results from the combined effects of several parameters. Our study focuses on the morphological and structural comparison of two end-member basaltic systems, La Reunion (Indian ocean, France) and Stromboli (southern Tyrrhenian sea, Italy). We showed that despite major differences on their volumes and geodynamic settings, both systems present some similarities as they are characterized by an intense intrusive activity along well-developed rift zones and recurrent phenomena of flank collapse during their evolution. Among the factors of instability, the examples of la Reunion and Stromboli evidence the major contribution of intrusive complexes to volcano growth and destruction as attested by field observations and the monitoring of these active volcanoes. Classical models consider the relationship between vertical intrusions of magma and flank movements along a preexisting sliding surface. A set of published and new field data from Piton des Neiges volcano (La Reunion) allowed us to recognize the role of subhorizontal intrusions in the process of flank instability and to characterize the geometry of both subvertical and subhorizontal intrusions within basaltic edifices. This study compares the results of numerical modelling of the displacements associated with high-angle and low-angle intrusions within basaltic volcanoes. We use a Mixed Boundary Element Method to investigate the mechanical response of an edifice to the injection of magmatic intrusions in different stress fields. Our results indicate that the anisotropy of the stress field favours the slip along the intrusions due to cointrusive shear stress, generating flank-scale displacements of the edifice, especially in the case of subhorizontal intrusions, capable of triggering large-scale flank collapses on basaltic volcanoes. Applications of our theoretical results to real cases of flank displacements on basaltic volcanoes (such as the 2007 eruptive crisis at La Reunion and Stromboli) revealed that the previous model of subvertical intrusions-related collapse is a likely mechanism affecting small-scale steeply-sloping basaltic volcanoes like Stromboli. Furthermore, our field study combined to modelling results confirms the importance of shallow-dipping intrusions in the morpho-structural evolution of large gently-sloping basaltic volcanoes like Piton de la Fournaise, Etna and Kilauea, with particular regards to flank instability, which can cause catastrophic tsunamis.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Catry, Thibault <1985&gt. « Magma injections and destabilization of basaltic volcanoes : a numerical study. Application to La Reunion (Indian ocean, France) and Stromboli (Tyrrhenian sea, Italy) ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3904/.

Texte intégral

Résumé :

Most basaltic volcanoes are affected by recurrent lateral instabilities during their evolution. Numerous factors have been shown to be involved in the process of flank destabilization occurring over long periods of time or by instantaneous failures. However, the role of these factors on the mechanical behaviour and stability of volcanic edifices is poorly-constrained as lateral failure usually results from the combined effects of several parameters. Our study focuses on the morphological and structural comparison of two end-member basaltic systems, La Reunion (Indian ocean, France) and Stromboli (southern Tyrrhenian sea, Italy). We showed that despite major differences on their volumes and geodynamic settings, both systems present some similarities as they are characterized by an intense intrusive activity along well-developed rift zones and recurrent phenomena of flank collapse during their evolution. Among the factors of instability, the examples of la Reunion and Stromboli evidence the major contribution of intrusive complexes to volcano growth and destruction as attested by field observations and the monitoring of these active volcanoes. Classical models consider the relationship between vertical intrusions of magma and flank movements along a preexisting sliding surface. A set of published and new field data from Piton des Neiges volcano (La Reunion) allowed us to recognize the role of subhorizontal intrusions in the process of flank instability and to characterize the geometry of both subvertical and subhorizontal intrusions within basaltic edifices. This study compares the results of numerical modelling of the displacements associated with high-angle and low-angle intrusions within basaltic volcanoes. We use a Mixed Boundary Element Method to investigate the mechanical response of an edifice to the injection of magmatic intrusions in different stress fields. Our results indicate that the anisotropy of the stress field favours the slip along the intrusions due to cointrusive shear stress, generating flank-scale displacements of the edifice, especially in the case of subhorizontal intrusions, capable of triggering large-scale flank collapses on basaltic volcanoes. Applications of our theoretical results to real cases of flank displacements on basaltic volcanoes (such as the 2007 eruptive crisis at La Reunion and Stromboli) revealed that the previous model of subvertical intrusions-related collapse is a likely mechanism affecting small-scale steeply-sloping basaltic volcanoes like Stromboli. Furthermore, our field study combined to modelling results confirms the importance of shallow-dipping intrusions in the morpho-structural evolution of large gently-sloping basaltic volcanoes like Piton de la Fournaise, Etna and Kilauea, with particular regards to flank instability, which can cause catastrophic tsunamis.

Styles APA, Harvard, Vancouver, ISO, etc.

14

Cinelli, Giorgia <1983&gt. « Indoor and Outdoor Natural Radioactivity in the Vulsini Volcanic District (Central Italy) : Estimation of Doses and Radiological Risks ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4458/1/cinelli_giorgia_tesi.pdf.

Texte intégral

Résumé :

Terrestrial radioactivity for most individual is the major contributor to the total dose and is mostly provided by 238U, 232Th and 40K radionuclides. In particular indoor radioactivity is principally due to 222Rn, a radioactive noble gas descendent of 238U, second cause of lung cancer after cigarettes smoking. Vulsini Volcanic District is a well known quaternary volcanic area located between the northern Latium and southern Tuscany (Central Italy). It is characterized by an high natural radiation background resulting from the high concentrations of 238U, 232Th and 40K in the volcanic products. In this context, subduction-related metasomatic enrichment of incompatible elements in the mantle source coupled with magma differentiation within the upper crust has given rise to U, Th and K enriched melts. Almost every ancient village and town located in this part of Italy has been built with volcanic rocks pertaining to the Vulsini Volcanic District. The radiological risk of living in this area has been estimated considering separately: a. the risk associated with buildings made of volcanic products and built on volcanic rock substrates b. the risk associated to soil characteristics. The former has been evaluated both using direct 222Rn indoor measurements and simulations of “standard rooms” built with the tuffs and lavas from the Vulsini Volcanic District investigated in this work. The latter has been carried out by using in situ measurements of 222Rn activity in the soil gases. A radon risk map for the Bolsena village has been developed using soil radon measurements integrating geological information. Data of airborne radioactivity in ambient aerosol at two elevated stations in Emilia Romagna (North Italy) under the influence of Fukushima plume have been collected, effective doses have been calculated and an extensive comparison between doses associated with artificial and natural sources in different area have been described and discussed.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Cinelli, Giorgia <1983&gt. « Indoor and Outdoor Natural Radioactivity in the Vulsini Volcanic District (Central Italy) : Estimation of Doses and Radiological Risks ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4458/.

Texte intégral

Résumé :

Terrestrial radioactivity for most individual is the major contributor to the total dose and is mostly provided by 238U, 232Th and 40K radionuclides. In particular indoor radioactivity is principally due to 222Rn, a radioactive noble gas descendent of 238U, second cause of lung cancer after cigarettes smoking. Vulsini Volcanic District is a well known quaternary volcanic area located between the northern Latium and southern Tuscany (Central Italy). It is characterized by an high natural radiation background resulting from the high concentrations of 238U, 232Th and 40K in the volcanic products. In this context, subduction-related metasomatic enrichment of incompatible elements in the mantle source coupled with magma differentiation within the upper crust has given rise to U, Th and K enriched melts. Almost every ancient village and town located in this part of Italy has been built with volcanic rocks pertaining to the Vulsini Volcanic District. The radiological risk of living in this area has been estimated considering separately: a. the risk associated with buildings made of volcanic products and built on volcanic rock substrates b. the risk associated to soil characteristics. The former has been evaluated both using direct 222Rn indoor measurements and simulations of “standard rooms” built with the tuffs and lavas from the Vulsini Volcanic District investigated in this work. The latter has been carried out by using in situ measurements of 222Rn activity in the soil gases. A radon risk map for the Bolsena village has been developed using soil radon measurements integrating geological information. Data of airborne radioactivity in ambient aerosol at two elevated stations in Emilia Romagna (North Italy) under the influence of Fukushima plume have been collected, effective doses have been calculated and an extensive comparison between doses associated with artificial and natural sources in different area have been described and discussed.

Styles APA, Harvard, Vancouver, ISO, etc.

16

Kralj, Martina <1981&gt. « Effects of Resources Exploitation on Water Quality : case studies in Salt Water Intrusion and Acid Mine Drainage ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4812/1/Kralj_Martina_Tesi.pdf.

Texte intégral

Résumé :

Throughout the world, pressures on water resources are increasing, mainly as a result of human activity. Because of their accessibility, groundwater and surface water are the most used reservoirs. The evaluation of the water quality requires the identification of the interconnections among the water reservoirs, natural landscape features, human activities and aquatic health. This study focuses on the estimation of the water pollution linked to two different environmental issues: salt water intrusion and acid mine drainage related to the exploitation of natural resources. Effects of salt water intrusion occurring in the shallow aquifer north of Ravenna (Italy) was analysed through the study of ion- exchange occurring in the area and its variance throughout the year, applying a depth-specific sampling method. In the study area were identified ion exchange, calcite and dolomite precipitation, and gypsum dissolution and sulphate reduction as the main processes controlling the groundwater composition. High concentrations of arsenic detected only at specific depth indicate its connexion with the organic matter. Acid mine drainage effects related to the tin extraction in the Bolivian Altiplano was studied, on water and sediment matrix. Water contamination results strictly dependent on the seasonal variation, on pH and redox conditions. During the dry season the strong evaporation and scarce water flow lead to low pH values, high concentrations of heavy metals in surface waters and precipitation of secondary minerals along the river, which could be released in oxidizing conditions as demonstrated through the sequential extraction analysis. The increase of the water flow during the wet season lead to an increase of pH values and a decrease in heavy metal concentrations, due to dilution effect and, as e.g. for the iron, to precipitation.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Kralj, Martina <1981&gt. « Effects of Resources Exploitation on Water Quality : case studies in Salt Water Intrusion and Acid Mine Drainage ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amsdottorato.unibo.it/4812/.

Texte intégral

Résumé :

Throughout the world, pressures on water resources are increasing, mainly as a result of human activity. Because of their accessibility, groundwater and surface water are the most used reservoirs. The evaluation of the water quality requires the identification of the interconnections among the water reservoirs, natural landscape features, human activities and aquatic health. This study focuses on the estimation of the water pollution linked to two different environmental issues: salt water intrusion and acid mine drainage related to the exploitation of natural resources. Effects of salt water intrusion occurring in the shallow aquifer north of Ravenna (Italy) was analysed through the study of ion- exchange occurring in the area and its variance throughout the year, applying a depth-specific sampling method. In the study area were identified ion exchange, calcite and dolomite precipitation, and gypsum dissolution and sulphate reduction as the main processes controlling the groundwater composition. High concentrations of arsenic detected only at specific depth indicate its connexion with the organic matter. Acid mine drainage effects related to the tin extraction in the Bolivian Altiplano was studied, on water and sediment matrix. Water contamination results strictly dependent on the seasonal variation, on pH and redox conditions. During the dry season the strong evaporation and scarce water flow lead to low pH values, high concentrations of heavy metals in surface waters and precipitation of secondary minerals along the river, which could be released in oxidizing conditions as demonstrated through the sequential extraction analysis. The increase of the water flow during the wet season lead to an increase of pH values and a decrease in heavy metal concentrations, due to dilution effect and, as e.g. for the iron, to precipitation.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Resmi, Umberto <1956&gt. « Dinamica dell’intrusione salina nella costa ravennate : aspetti idrogeochimici ed evoluzione attesa ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5278/1/resmi_umberto_tesi.pdf.

Texte intégral

Résumé :

Nell’ambito del progetto multidisciplinare “Coastal Salt Water Intrusion”, che si propone di indagare “l’Intrusione salina nella costa ravennate con i conseguenti impatti territoriali-ambientali, connessi al previsto innalzamento del livello marino per cause climatiche e di subsidenza”, si inserisce il presente studio con l’obiettivo di fornire una caratterizzazione idrogeochimica delle acque di falda e superficiali e un modello geochimico generale sui processi di salinizzazione o desalinizzazione in atto nella falda freatica costiera della costa ravennate. E’ stato fatto un confronto fra tre metodiche di estrazione del complesso di scambio della matrice solida dell’acquifero che utilizzano rispettivamente acetato di ammonio, cloruro di bario e argento-tiourea. Sono stati posizionati 5 transetti perpendicolari alla linea di costa per un totale di 44 punti di campionamento con due campagne di prelievi, al termine della primavera e al termine dell’estate. La caratterizzazione dei processi di mixing e scambio ionico con la matrice solida dell’acquifero è avvenuta mediante analisi dei cationi ed anioni fondamentali, determinazione della CEC sulla matrice solida dell’acquifero, modellizzazione mixing/scambio ionico, modellizzazione della composizione teorica della frazione scambiabile in funzione della composizione acqua all’equilibrio e interpolazione geostatistica dei dati raccolti e costruzione di mappe geochimiche (curve di iso-concentrazione). La metodologia di estrazione che utilizza il bario-cloruro è risultata la più affidabile. Le acque prelevate dalla falda superficiale evidenziano miscelazione in varie proporzioni acqua marina/acqua dolce, scambi ionici per interazione acqua/sedimento, dissoluzione di CaSO4.2H2O. I processi di salinizzazione e/o addolcimento mostrano una significativa variabilità nello spazio (variabilità legata alla distanza dalla costa, al profilo topografico e alla distribuzione dei corpi sabbiosi litoranei) e nel tempo (variabilità legata alla piovosità e alla gestione delle acque superficiali e del sottosuolo). La complessa variabilità spazio-temporale dei processi in atto nella falda superficiale non consente di evidenziare una complessiva prevalenza di fenomeni di salinizzazione rispetto a quelli di addolcimento.
The present study is inserted within the multidisciplinary project “Coastal Salt Water Intrusion” , that aims at investigating “the salt water intrusion in the ravennate coast with the consequent territorial-environmental impacts connected to the anticipated raising of the sea level for climatic and subsidence causes. Its objective is to show a hydrogeochemistry characterisation of the top freshwater and a general geochemistry model of the salinisation/refreshening. It is based on a comparison among three methods of extraction of the exchange complex of the aquiferous solid matrix, that respectively use ammonium acetate, barium chloride and silver-tiourea. Five perpendicular profiles to the line coast have been located for a total of 44 sampling points with two countries of collecting, and this at the end of spring and at the end of summer. The characterisation of the processes of mixing and ionic exchange with the aquiferous solid matrix took place through fundamental cations and anions analysis, mixing and ionic exchange modelling, theoretical composition of exchangeable fraction of the composition water to the equilibrium and geostatistic interpolation of the data collected with geochemistry maps construction (iso-concentration curves). The methodology of extraction that makes use of the barium-chloride results as the most reliable. The withdrawn waters to the top of the aquiferous show mixing in various proportions seawater/freshwater, ionic exchanges for water/sediment interaction, CaSO4.2H2O dissolution. The salinisation/refreshening process presents a meaningful variability in the space (a variability linked to the distance from the coast, to the topographical profile and the distribution of the coast sandy bodies) and in the time (a variability linked to the rainfall and the management of the superficial and subsoil waters). The complex variability space-storm of the trials in action at the top of the aquiferous doesn’t allow to underline a general prevalence of salinisation phenomena in comparison to those of refreshening.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Resmi, Umberto <1956&gt. « Dinamica dell’intrusione salina nella costa ravennate : aspetti idrogeochimici ed evoluzione attesa ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5278/.

Texte intégral

Résumé :

Nell’ambito del progetto multidisciplinare “Coastal Salt Water Intrusion”, che si propone di indagare “l’Intrusione salina nella costa ravennate con i conseguenti impatti territoriali-ambientali, connessi al previsto innalzamento del livello marino per cause climatiche e di subsidenza”, si inserisce il presente studio con l’obiettivo di fornire una caratterizzazione idrogeochimica delle acque di falda e superficiali e un modello geochimico generale sui processi di salinizzazione o desalinizzazione in atto nella falda freatica costiera della costa ravennate. E’ stato fatto un confronto fra tre metodiche di estrazione del complesso di scambio della matrice solida dell’acquifero che utilizzano rispettivamente acetato di ammonio, cloruro di bario e argento-tiourea. Sono stati posizionati 5 transetti perpendicolari alla linea di costa per un totale di 44 punti di campionamento con due campagne di prelievi, al termine della primavera e al termine dell’estate. La caratterizzazione dei processi di mixing e scambio ionico con la matrice solida dell’acquifero è avvenuta mediante analisi dei cationi ed anioni fondamentali, determinazione della CEC sulla matrice solida dell’acquifero, modellizzazione mixing/scambio ionico, modellizzazione della composizione teorica della frazione scambiabile in funzione della composizione acqua all’equilibrio e interpolazione geostatistica dei dati raccolti e costruzione di mappe geochimiche (curve di iso-concentrazione). La metodologia di estrazione che utilizza il bario-cloruro è risultata la più affidabile. Le acque prelevate dalla falda superficiale evidenziano miscelazione in varie proporzioni acqua marina/acqua dolce, scambi ionici per interazione acqua/sedimento, dissoluzione di CaSO4.2H2O. I processi di salinizzazione e/o addolcimento mostrano una significativa variabilità nello spazio (variabilità legata alla distanza dalla costa, al profilo topografico e alla distribuzione dei corpi sabbiosi litoranei) e nel tempo (variabilità legata alla piovosità e alla gestione delle acque superficiali e del sottosuolo). La complessa variabilità spazio-temporale dei processi in atto nella falda superficiale non consente di evidenziare una complessiva prevalenza di fenomeni di salinizzazione rispetto a quelli di addolcimento.
The present study is inserted within the multidisciplinary project “Coastal Salt Water Intrusion” , that aims at investigating “the salt water intrusion in the ravennate coast with the consequent territorial-environmental impacts connected to the anticipated raising of the sea level for climatic and subsidence causes. Its objective is to show a hydrogeochemistry characterisation of the top freshwater and a general geochemistry model of the salinisation/refreshening. It is based on a comparison among three methods of extraction of the exchange complex of the aquiferous solid matrix, that respectively use ammonium acetate, barium chloride and silver-tiourea. Five perpendicular profiles to the line coast have been located for a total of 44 sampling points with two countries of collecting, and this at the end of spring and at the end of summer. The characterisation of the processes of mixing and ionic exchange with the aquiferous solid matrix took place through fundamental cations and anions analysis, mixing and ionic exchange modelling, theoretical composition of exchangeable fraction of the composition water to the equilibrium and geostatistic interpolation of the data collected with geochemistry maps construction (iso-concentration curves). The methodology of extraction that makes use of the barium-chloride results as the most reliable. The withdrawn waters to the top of the aquiferous show mixing in various proportions seawater/freshwater, ionic exchanges for water/sediment interaction, CaSO4.2H2O dissolution. The salinisation/refreshening process presents a meaningful variability in the space (a variability linked to the distance from the coast, to the topographical profile and the distribution of the coast sandy bodies) and in the time (a variability linked to the rainfall and the management of the superficial and subsoil waters). The complex variability space-storm of the trials in action at the top of the aquiferous doesn’t allow to underline a general prevalence of salinisation phenomena in comparison to those of refreshening.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Lancianese, Valerio <1985&gt. « Stream sediments analysis for geochemical mapping of Romagna Apennines (Northern Italy) : monitoring and management tool of environmental resources at various scales ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6521/1/Lancianese_PhD.pdf.

Texte intégral

Résumé :

Geochemical mapping is a valuable tool for the control of territory that can be used not only in the identification of mineral resources and geological, agricultural and forestry studies but also in the monitoring of natural resources by giving solutions to environmental and economic problems. Stream sediments are widely used in the sampling campaigns carried out by the world's governments and research groups for their characteristics of broad representativeness of rocks and soils, for ease of sampling and for the possibility to conduct very detailed sampling In this context, the environmental role of stream sediments provides a good basis for the implementation of environmental management measures, in fact the composition of river sediments is an important factor in understanding the complex dynamics that develop within catchment basins therefore they represent a critical environmental compartment: they can persistently incorporate pollutants after a process of contamination and release into the biosphere if the environmental conditions change. It is essential to determine whether the concentrations of certain elements, in particular heavy metals, can be the result of natural erosion of rocks containing high concentrations of specific elements or are generated as residues of human activities related to a certain study area. This PhD thesis aims to extract from an extensive database on stream sediments of the Romagna rivers the widest spectrum of informations. The study involved low and high order stream in the mountain and hilly area, but also the sediments of the floodplain area, where intensive agriculture is active. The geochemical signals recorded by the stream sediments will be interpreted in order to reconstruct the natural variability related to bedrock and soil contribution, the effects of the river dynamics, the anomalous sites, and with the calculation of background values be able to evaluate their level of degradation and predict the environmental risk.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Lancianese, Valerio <1985&gt. « Stream sediments analysis for geochemical mapping of Romagna Apennines (Northern Italy) : monitoring and management tool of environmental resources at various scales ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6521/.

Texte intégral

Résumé :

Geochemical mapping is a valuable tool for the control of territory that can be used not only in the identification of mineral resources and geological, agricultural and forestry studies but also in the monitoring of natural resources by giving solutions to environmental and economic problems. Stream sediments are widely used in the sampling campaigns carried out by the world's governments and research groups for their characteristics of broad representativeness of rocks and soils, for ease of sampling and for the possibility to conduct very detailed sampling In this context, the environmental role of stream sediments provides a good basis for the implementation of environmental management measures, in fact the composition of river sediments is an important factor in understanding the complex dynamics that develop within catchment basins therefore they represent a critical environmental compartment: they can persistently incorporate pollutants after a process of contamination and release into the biosphere if the environmental conditions change. It is essential to determine whether the concentrations of certain elements, in particular heavy metals, can be the result of natural erosion of rocks containing high concentrations of specific elements or are generated as residues of human activities related to a certain study area. This PhD thesis aims to extract from an extensive database on stream sediments of the Romagna rivers the widest spectrum of informations. The study involved low and high order stream in the mountain and hilly area, but also the sediments of the floodplain area, where intensive agriculture is active. The geochemical signals recorded by the stream sediments will be interpreted in order to reconstruct the natural variability related to bedrock and soil contribution, the effects of the river dynamics, the anomalous sites, and with the calculation of background values be able to evaluate their level of degradation and predict the environmental risk.

Styles APA, Harvard, Vancouver, ISO, etc.

22

Colombani, Nicolo <1977&gt. « Hydrogeochemical monitoring and modelling of saltwater intrusion in lowlands (Ferrara, IT) ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6851/1/Colombani_Nicolo_tesi.pdf.

Texte intégral

Résumé :

Because of the potentially irreversible impact of groundwater quality deterioration in the Ferrara coastal aquifer, answers concerning the assessment of the extent of the salinization problem, the understanding of the mechanisms governing salinization processes, and the sustainability of the current water resources management are urgent. In this light, the present thesis aims to achieve the following objectives: Characterization of the lowland coastal aquifer of Ferrara: hydrology, hydrochemistry and evolution of the system The importance of data acquisition techniques in saltwater intrusion monitoring Predicting salinization trends in the lowland coastal aquifer Ammonium occurrence in a salinized lowland coastal aquifer Trace elements mobility in a saline coastal aquifer
A causa dell'impatto potenzialmente irreversibile del deterioramento della qualità delle risorse idriche , l'obiettivo primario di questa tesi è stato quello di ottenere una comprensione quantitativa dei processi che hanno causato la salinizzazione delle acque sotterranee nella falda acquifera costiera ferrarese. In secondo luogo si è voluto indagare l’impatto che i cambiamenti climatici potranno avere sul processo di salinizzazione in atto e le eventuali conseguenze che un aumento di salinità possono avere sulla mobilizzazione di contaminanti sia maggiori che in tracce. Alla luce di quanto detto sin qui, lo studio in oggetto si propone di raggiungere i seguenti obiettivi: - Caratterizzazione della falda acquifera costiera della pianura di Ferrara: idrologia, idrochimica ed evoluzione del sistema - Importanza di tecniche di monitoraggio nella comprensione dei processi di salinizzazione - L’influenza della salinizzazione sui trend di concentrazione dell’ammonio e degli elementi nell’acquifero costiero - Previsione dei trend di salinizzazione della falda acquifera costiera

Styles APA, Harvard, Vancouver, ISO, etc.

23

Colombani, Nicolo <1977&gt. « Hydrogeochemical monitoring and modelling of saltwater intrusion in lowlands (Ferrara, IT) ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6851/.

Texte intégral

Résumé :

Because of the potentially irreversible impact of groundwater quality deterioration in the Ferrara coastal aquifer, answers concerning the assessment of the extent of the salinization problem, the understanding of the mechanisms governing salinization processes, and the sustainability of the current water resources management are urgent. In this light, the present thesis aims to achieve the following objectives: Characterization of the lowland coastal aquifer of Ferrara: hydrology, hydrochemistry and evolution of the system The importance of data acquisition techniques in saltwater intrusion monitoring Predicting salinization trends in the lowland coastal aquifer Ammonium occurrence in a salinized lowland coastal aquifer Trace elements mobility in a saline coastal aquifer
A causa dell'impatto potenzialmente irreversibile del deterioramento della qualità delle risorse idriche , l'obiettivo primario di questa tesi è stato quello di ottenere una comprensione quantitativa dei processi che hanno causato la salinizzazione delle acque sotterranee nella falda acquifera costiera ferrarese. In secondo luogo si è voluto indagare l’impatto che i cambiamenti climatici potranno avere sul processo di salinizzazione in atto e le eventuali conseguenze che un aumento di salinità possono avere sulla mobilizzazione di contaminanti sia maggiori che in tracce. Alla luce di quanto detto sin qui, lo studio in oggetto si propone di raggiungere i seguenti obiettivi: - Caratterizzazione della falda acquifera costiera della pianura di Ferrara: idrologia, idrochimica ed evoluzione del sistema - Importanza di tecniche di monitoraggio nella comprensione dei processi di salinizzazione - L’influenza della salinizzazione sui trend di concentrazione dell’ammonio e degli elementi nell’acquifero costiero - Previsione dei trend di salinizzazione della falda acquifera costiera

Styles APA, Harvard, Vancouver, ISO, etc.

24

Bartholini, Gabriella <1974&gt. « Influenza della sostanza organica nella diagenesi precoce dei sedimenti del mare Adriatico e Ionio ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6936/1/Bartholini_Gabriella_tesi.pdf.

Texte intégral

Résumé :

Lo studio dei processi biogeochimici che avvengono all’interfaccia acqua-sedimento riveste grande importanza per comprendere quali fattori ambientali siano responsabili di un eventuale modifica nel bilancio del carbonio organico e di altri elementi maggiori o minori e può` fornire un' indicazione su quali siano le aree più sensibili a tali processi. In questo studio sono stati analizzati i meccanismi che guidano la mineralizzazione della sostanza organica in aree caratterizzate da differenti condizioni idrodinamiche, batimetriche e trofiche nel Mediterraneo centrale. In particolare sono state prelevate carote di sedimento e analizzate le acque interstiziali in siti localizzati nell'Adriatico centro-meridionale, caratterizzati da basse profondità, alti tassi di sedimentazione e elevati apporti di sostanza organica, e in siti localizzati nello Ionio centro-settentrionale, caratterizzati da profondità crescenti, minori tassi di sedimentazione e ridotti apporti fluviali. L'analisi dei processi di degradazione della sostanza organica evidenzia differenze regionali tra il bacino adriatico e quello ionico: processi di mineralizzazione ossica e subossica appaiono intensi nei sedimenti adriatici, diversamente il bacino ionico appare caratterizzato principalmente da processi di degradazione ossica della sostanza organica. Inoltre, relativamente ai flussi bentici di Carbonio Inorganico Disciolto (DIC) flussi inversi sono stati registrati nei due bacini: i sedimenti adriatici si comportano come sourse di DIC, mentre i sedimenti Ionici si comportano come dei sink di DIC suggerendo una possibile precipitazione di carbonati nel bacino ionico.
It is known that the burial of organic carbon (OC) in marine sediments is one of the major long-term sinks of reduced carbon on Earth and the long-term sink of particulate OC in marine sediments contribute to moderate atmospheric CO2 levels on geological time scales. For this reason several efforts have been made to understand early diagenetic zonation and evaluate the associated benthic fluxes. In this study we investigate the features controlling the early diagenetic processes in areas of different sedimentation in the central Mediterranean Sea. Sediments core were collected in 7 stations characterized by different bathymetry, hydrological setting and trophic conditions. Northern stations, located in the central and southern Adriatic depressions, are characterized by shallow depths, higher sedimentation rates and higher organic matter inputs. Southern stations, located in the Northern and Central Ionian Sea, are characterized by increasing depths, different provenances of terrigenous sediments, lower productivity, lower sedimentation rates and organic matter inputs. The early diagenesis processes recorded in the Adriatic and Ionian seas showed regional differences between the Adriatic and Ionian basins. Higher inputs of reactive organic matter promote a northern-southern and shallow-deep trend in Adriatic sediments. These sediments are characterized by oxic-suboxic degradation processes and a lowering of remineralization processes in accord with distance from terrestrial inputs is evident. In the Ionian basin the remineralization processes takes place mainly by means of oxic reactions. The inputs of reactive organic matter in this area are lower for the lower productivity of this basin and for the higher distance from fluvial inputs. However, inverse DIC fluxes occur, Adriatic sediments are a net source of DIC while Ionian sediments show a sink of DIC suggesting a possible precipitation of carbonate in the Ionian basin.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Bartholini, Gabriella <1974&gt. « Influenza della sostanza organica nella diagenesi precoce dei sedimenti del mare Adriatico e Ionio ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/6936/.

Texte intégral

Résumé :

Lo studio dei processi biogeochimici che avvengono all’interfaccia acqua-sedimento riveste grande importanza per comprendere quali fattori ambientali siano responsabili di un eventuale modifica nel bilancio del carbonio organico e di altri elementi maggiori o minori e può` fornire un' indicazione su quali siano le aree più sensibili a tali processi. In questo studio sono stati analizzati i meccanismi che guidano la mineralizzazione della sostanza organica in aree caratterizzate da differenti condizioni idrodinamiche, batimetriche e trofiche nel Mediterraneo centrale. In particolare sono state prelevate carote di sedimento e analizzate le acque interstiziali in siti localizzati nell'Adriatico centro-meridionale, caratterizzati da basse profondità, alti tassi di sedimentazione e elevati apporti di sostanza organica, e in siti localizzati nello Ionio centro-settentrionale, caratterizzati da profondità crescenti, minori tassi di sedimentazione e ridotti apporti fluviali. L'analisi dei processi di degradazione della sostanza organica evidenzia differenze regionali tra il bacino adriatico e quello ionico: processi di mineralizzazione ossica e subossica appaiono intensi nei sedimenti adriatici, diversamente il bacino ionico appare caratterizzato principalmente da processi di degradazione ossica della sostanza organica. Inoltre, relativamente ai flussi bentici di Carbonio Inorganico Disciolto (DIC) flussi inversi sono stati registrati nei due bacini: i sedimenti adriatici si comportano come sourse di DIC, mentre i sedimenti Ionici si comportano come dei sink di DIC suggerendo una possibile precipitazione di carbonati nel bacino ionico.
It is known that the burial of organic carbon (OC) in marine sediments is one of the major long-term sinks of reduced carbon on Earth and the long-term sink of particulate OC in marine sediments contribute to moderate atmospheric CO2 levels on geological time scales. For this reason several efforts have been made to understand early diagenetic zonation and evaluate the associated benthic fluxes. In this study we investigate the features controlling the early diagenetic processes in areas of different sedimentation in the central Mediterranean Sea. Sediments core were collected in 7 stations characterized by different bathymetry, hydrological setting and trophic conditions. Northern stations, located in the central and southern Adriatic depressions, are characterized by shallow depths, higher sedimentation rates and higher organic matter inputs. Southern stations, located in the Northern and Central Ionian Sea, are characterized by increasing depths, different provenances of terrigenous sediments, lower productivity, lower sedimentation rates and organic matter inputs. The early diagenesis processes recorded in the Adriatic and Ionian seas showed regional differences between the Adriatic and Ionian basins. Higher inputs of reactive organic matter promote a northern-southern and shallow-deep trend in Adriatic sediments. These sediments are characterized by oxic-suboxic degradation processes and a lowering of remineralization processes in accord with distance from terrestrial inputs is evident. In the Ionian basin the remineralization processes takes place mainly by means of oxic reactions. The inputs of reactive organic matter in this area are lower for the lower productivity of this basin and for the higher distance from fluvial inputs. However, inverse DIC fluxes occur, Adriatic sediments are a net source of DIC while Ionian sediments show a sink of DIC suggesting a possible precipitation of carbonate in the Ionian basin.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Funari, Valerio <1987&gt. « The Critical Raw Materials Potential of Anthropogenic Deposits : Insights from Solid Residues of Municipal Waste Incineration ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7426/1/Funari_PhDThesis%28AMS%29.pdf.

Texte intégral

Résumé :

Due to the current and foreseen global growth of raw material demand, the sustainable supply of minerals and metals for high-tech applications, the so-called critical raw materials (Co, Cr, Ga, Nb, Rare Earth Elements, Sb, W, Platinum Group Elements), is of general concern. Industrial wastes have the potential to become an alternative source (flow) of strategic metals and, consequently, their valorisation can be seen as a move towards resources efficiency and circular economy. In this 3-years study I aimed to decipher the critical raw materials potential from solid residues produced by Municipal Solid Waste Incineration (MSWI), namely bottom and fly ashes. These solid residues, coming from different leading companies of MSWI in northern Italy, have been selected because they can be accounted for urban mining purposes and represent high elements flows, still poorly explored. In the present work I address the potential of MSWI solid residues as an alternative source of critical raw materials by studying the material chemistry, its resources flow and the evaluation of metals upgrading and recovery. Finally, I tackle some environmental and economic issues.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Borghesi, Fabrizio <1969&gt. « Environmental Pollution and Hunting : Exposure of Birds to Metals in their Trophic Areas, and of Humans to Lead in Game Birds ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7547/1/borghesi_fabrizio_tesi.pdf.

Texte intégral

Résumé :

This doctorate is focused on birds and their relationships with trace elements (MTEs). The Mediterranean coast hosts millions migratory birds every year. However, Mediterranean countries are among the most influenced in the world by human pressure. There is a strong impulse by GOs and NGOs operating in the European Union to improve methods and standardization in studies on contaminants involving birds. Birds are potential biomonitors of change in the environment and feathers has proven to be a very informative tool. On the other hand, there is the need to improve methods in order to avoid errors in interpretation of concentrations in feathers. It is the case of external contamination on feathers due to lithic particles adhered to the surface. Intake of MTEs naturally present in their environment occurs to birds, as well as assumption of anthropogenic MTEs in polluted areas. Furthermore, birds are exposed to lead due to the ammunition shot by hunters, which can be assumed from sediments and preys which have lead pieces embedded in their body. Aim of this doctorate is to improve the possibility to use birds as biomonitors of metal exposure through non-invasive methods adopting a multidisciplinary approach. In particular, the studies included in this work achieved these objectives: 1) some wetlands in the Northern Adriatic coast very important for colonial waterbirds, have been investigated for their geochemical characteristics for any future ecotoxicological studies; 2) a new geochemical approach has been proposed for studies on MTE bioaccumulation in Greater flamingo feathers, in order to reduce biases caused by environmental (external) contamination; 3) new information about type, frequency and distribution of Pb particles embedded in two small-sized bird species (European starling and Eurasian woodcock) killed by hunters has been given. This work is structured in six scientific articles and one short communication.

Styles APA, Harvard, Vancouver, ISO, etc.

28

Hense, Peter <1989&gt. « Development and Optimization of a Thermo-Chemical Process for Recycling Waste Electrical and Electronic Equipment ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/7900/1/Hense_Peter_tesi.pdf.

Texte intégral

Résumé :

In this thesis, a process and a corresponding bench-scale plant for a thermo-chemical treatment of different fractions from WEEE were developed and optimized, with the aim to accumulate and/or extract metals from different feedstocks to enable downstream recycling as well as to dehalogenate pyrolysis products. From tests with shredder residues, best results regarding metal accumulation and dehalogenation were achieved at a pyrolysis temperature of 650 °C and a residence time of 30 min. Most metals were part of the pyrolysis solid products, but, for instance, Cd, In, and Mo were strongly mobilized to pyrolysis vapor. In addition, levels of polyhalogenated dibenzo-p-dioxins and -furans (PXDD/F) in the solid products were minimized, going even below threshold values of corresponding legal requirements. PXDD/F decomposition in liquid products was achieved using blends of polypropylene and a metal compound resulting in a complete decomposition of polyhalogenated dioxins. For a following dehalogenation, a novel filter-material was developed, which was able to absorb more than 90 wt.-% of Br2 and HBr in preliminary tests. In order to investigate efficiencies of selective mobilizations of metals, different pyrolysis approaches with Liquid Crystal Displays (LCD) as feedstock were conducted and allocations of metals analyzed. Tests clearly revealed that co-pyrolysis with polyvinylchloride could be used to completely mobilize As while pyrolysis of PVC with LCD in vapor-phase mode enabled a selective extraction of In. In contrast, from pyrolysis of Ta capacitors at 550 °C in combination with sieving at 500 µm, a targeted enrichment of nearly 90 wt.-% Ta in pyrolysis solid products <500 µm was achieved. In an ecological and an economical assessment, the performance of a prospective, continuous pyrolysis process for shredder residues was compared to a treatment following the status quo. The process could result in strong ecological exonerative effects and a high economic performance.

Styles APA, Harvard, Vancouver, ISO, etc.

29

Pignotti, Emanuela <1989&gt. « Contaminants of Emerging Concern : occurrence and distribution in aquatic environments ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amsdottorato.unibo.it/8462/1/PhD_thesis.pdf.

Texte intégral

Résumé :

The aim of this PhD study was to assess the occurrence, behavior and fate of Contaminants of Emerging Concern, and more specifically Endocrine Disrupting Compounds (EDCs) in natural freshwater and saltwater environments. To this purpose, estrogens, perfluorinated compounds (PFCs) and phenolic compounds were analysed in the freshwater environment of the Romagna area (Italy). Two sampling campaigns were carried out in two following years during summer. Wastewater treatment plant effluents were the main source of introduction of PFCs in the water compartment, whereas phenolic compounds occurrence was likely related to the presence of industrial activities. Both PFCs and phenolic compounds were persistent in the aquatic compartment during the monitoring periods. On the contrary, estrogens occurrence was not constant over time, suggesting local sporadic events of contamination. Sediments were mainly affected by the occurrence of the phenolic group, whose presence was controlled by sediment size and organic carbon content. Analysis on the surrounding transitional environment of the Pialassa Baiona revealed salinity to be a relevant element controlling their partition between water and sediment. PFCs were also analysed in the transitional environment of the Ebro delta (NE Spain) during three sampling campaigns (autumn, winter, spring-summer). PFCs were confirmed to be persistent in the water compartment over the year. On the contrary, concentrations in sediments were highly influenced by seasonality. Nevertheless, a greater partition of PFCs between water and sediment was registered in the Ebro delta, in contrast with their almost absence in riverine sediments of the Romagna area, as a consequence of PFCs lower solubility in saline environments. Analyses of PFCs in both seawater and freshwater fish pointed out a higher PFCs accumulation in the freshwater species, with perfluorocarboxylic acids being more concentrated than sulfonates.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Ricci, Andrea <1989&gt. « Geochemistry of C-bearing gas compounds in natural fluids under crustal conditions : insights into deep and shallow processes ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amsdottorato.unibo.it/9007/1/ricci_andrea_tesi.pdf.

Texte intégral

Résumé :

The PhD research project was aimed to improve the scientific knowledge of the origin and fate of C-bearing gas compounds released from active volcanoes, hydrothermal systems and tectonically active sedimentary basins. The first goal was to investigate the primary source(s) of CH4 and light hydrocarbons in volcanic-hydrothermal gases under crustal conditions. This objective was achieved by comparing the composition of low molecular weight organic fraction (C1-C4) and associated CO2 and H2O in fumarolic gases and geothermal wells from different study areas around the world. We demonstrated that these hydrocarbons derive from biotic sources, i.e., predominantly from the thermal decomposition of organic matter. Meteoric waters and seawater circulating through the crust shuttle organic matter from Earth’s surface into the reservoir rocks. There, high temperature pyrolysis of organic matter and open system degassing generates n-alkanes with isotopic compositions previously classified as being indicative for abiogenesis. These results led us to question the dogma of crustal production of abiotic hydrocarbons and highlighted the potential of n-alkanes to become sensitive indicators of life on habitable (exo)planets. The second goal was to study the secondary processes affecting the composition of CO2, CH4 and light hydrocarbons in natural fluids during their uprising from the deep reservoirs to the surface in different geologic setting, ranging from active volcanoes to sedimentary basins. Under magmatic-hydrothermal conditions, catalytic organic reactions may strongly affect volatile organic compounds, drastically changing alkanes-alkenes-aromatics relative abundances and isotopic composition of C1–C4 hydrocarbons. At peripheral areas of volcanic systems and tectonically active sedimentary basins, composition of CO2 and CH4 in interstitial soil gases and dissolved gases in groundwater are mainly controlled by supergene mechanisms, such as calcite precipitation and microbial-driven processes. These secondary processes likely play a major role in regulating the ultimate release of C-bearing gas compounds into the atmosphere.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Toller, Simone <1991&gt. « Water and sediments geochemistry and elemental fluxes on a Large Dam : case study of Ridracoli reservoir ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9782/1/toller_simone_tesi.pdf.

Texte intégral

Résumé :

Since the study of Large Dam Reservoirs is of worldwide interest, in this PhD project we investigated the Ridracoli reservoir, one of the main water supply in Emilia-Romagna (north-eastern Italy). This work aims to characterize waters and sediments to better understand their composition, interactions and any process that occurs, for a better geochemical and environmental knowledge of the area. Physical and chemical analyses on the water column have shown an alternation of stratification and mixing of water in the reservoir’s water body due to seasonal variations in temperature and density. In particular, it was observed the establishment, in late summer, of anoxic conditions at the bottom, which in turn affects the concentration and mobility of some elements of concern (e.g. Fe and Mn) for the water quality. Sediments within the reservoir and from surrounding areas were analysed for organic matter, total inorganic composition and grain size, assessing the inter-element relationship, grain size, geological background and damming influences on their chemistry, through descriptive statistics, Principal Component Analysis and Cluster Analysis. The reservoir’s area was also investigated by pseudo total composition (Aqua Regia digestion), degree of elements extractability, and enrichment factors, then analysed and compared to limits by law and literature. Sediment cores, interstitial waters, and benthic chamber data from the bottom were of great interest due to organic matter degradation, early diagenesis, mineral formation at water-sediment interface and observed flows. Finally, leaching test and extraction procedures, of environmental interest, showed peculiar partitioning, both regarding spatial and in-depth distribution, and the absence of pollution. Collectively, our results are useful for the comprehension of processes that occur in water and sediments of Ridracoli reservoir, providing important knowledges on the site that could be relevant for the management of the resource and the planning of future interventions.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Meschiari, Sara <1992&gt. « Eruptive and depositional processes of widely dispersed volcanic ash : Insights from the Brown Tuffs (Aeolian Islands) ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amsdottorato.unibo.it/9970/1/Meschiari_Sara_tesi.pdf.

Texte intégral

Résumé :

This is a multidisciplinary study of the Brown Tuffs (BT) ash deposits of the Aeolian Islands in northern Sicily and representing the most voluminous and widely distributed tephra deposit in this region. A large dataset of major and minor elements of the BT glass has defined a range from K-series basaltic-andesites and trachy-andesites through to tephri-phonolites and trachytes that is consistent with the Vulcano magmatic system. Combined with stratigraphic information and new radiocarbon ages, four stratigraphic macro-units are defined: the Lower (80-56 ky; LBT), Intermediate (56-27 ky; IBT), Intermediate-upper (26-24 ky; IBT-upper) and Upper BT (24-6 ky; UBT). Glass compositional data provide constraints on proximal-distal correlations of the BT with deep-sea tephra layers in the Tyrrhenian and Adriatic Seas and new insights on the definition of the dispersal area of the BT eruptions. Sedimentological evidence of massive to stratified deposits and shear-related structures, coupled with grain-size and componentry analyses, have allowed to interpret the BT as the result of laterally-spreading, concentrated ash-rich PDCs, with a high potential of erosion of the substratum. Shear-structures similar to those observed in the field in the BT deposits have been reproduced by small-medium scale laboratory experiments carried out on ash granular flows, which have also allowed to describe the behaviour of ash-rich PDcs and their mobility depending on variations of slope-ratio, grain size and flow channelization. The resulting integrated dataset provides a contribution to the knowledge of the BT eruptions and insights on long-term hazard assessment in the study area. The eruptive dynamics of the BT may have a role in characterizing the whole magmatic system of the La Fossa Caldera on Vulcano, in the light of the geochemical link highlighted between the UBT macrounit and the early products of the La Fossa cone.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Cappuzzo, Adriano <1976&gt. « La componente ambientale nella gestione del territorio : dalla ricerca sul territorio all'analisi dell'impatto ambientale ». Doctoral thesis, Università Ca' Foscari Venezia, 2009. http://hdl.handle.net/10579/276.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

34

Masiol, Mauro <1978&gt. « Caratterizzazione geochimica dell'aerosol naturale e di background nell'area costiera della laguna di Venezia attraverso l'utilizzo di nuove tecnologie applicate all'ambiente ». Doctoral thesis, Università Ca' Foscari Venezia, 2009. http://hdl.handle.net/10579/354.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

35

Cazzaro, Marta <1989&gt. « Caratterizzazione geochimica del particolato fine PM2.5 ; confronto tra un sito urbano ed un sito aeroportuale ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2014. http://hdl.handle.net/10579/5150.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

36

Beaubien, Stanley Eugene <1965&gt. « The mapping and quantification of CO2 leakage and its potential impact on groundwater quality ». Doctoral thesis, Università Ca' Foscari Venezia, 2014. http://hdl.handle.net/10579/6509.

Texte intégral

Résumé :

The present study relates to CO2 leakage from the deep subsurface towards the atmosphere. Work involved writing a computer code to study the impact of different sampling strategies and densities on the capability of a gas flux survey to find and quantify the leakage of CO2, with simulations being performed using both synthetic and real data. In addition, the potential impact of a CO2 leak on drinking water quality was studied by measuring groundwater chemistry along a transect through a major natural CO2 leakage area. The research detailed here relates to both natural leaking systems as well as to man-made systems where leakage may hypothetically occur (such as carbon capture and storage, CCS, projects).

Styles APA, Harvard, Vancouver, ISO, etc.

37

Dreossi, Giuliano <1981&gt. « A recent past temperature reconstruction based on oxygen and hydrogen stable isotopes in Alpine ice cores ». Doctoral thesis, Università Ca' Foscari Venezia, 2015. http://hdl.handle.net/10579/8336.

Texte intégral

Résumé :

Nelle carote di ghiaccio gli isotopi stabili di ossigeno e idrogeno sono utilizzati per le ricostruzioni climatiche. Nel 2011 quattro carote sono state estratte sul Monte Ortles, a 3859 m s.l.m. Nell'ambito di questo dottorato la carota #1 è stata studiata, processata e analizzata per tutta la sua lunghezza per d18O e dD; i profili isotopici ottenuti sono stati comparati con quelli della carota #2, analizzata presso l’Ohio State University, creando un record composito degli isotopi. I record isotopici sono stati confrontati con i dati di temperatura del sito di studio, al fine di determinare la sensibilità del termometro isotopico, per poter estendere la ricostruzione di temperatura oltre la copertura dei dati strumentali. I dati isotopici di campionamenti superficiali fatti nella stessa area sono stati discussi per comprendere i processi post-deposizionali che modificano il contenuto isotopico della neve e complicano l’interpretazione climatica di questo proxy.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Shah, Syed Asif Ali <1990&gt. « Reconstruction of past atmospheric deposition of trace elements in a coastal Antarctic ice core climate archive ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2017. http://hdl.handle.net/10579/10526.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

39

Feller, Edoardo <1991&gt. « Analisi e monitoraggio dei metalli pesanti nel particolato atmosferico nei principali siti di monitoraggio della regione Veneto ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2017. http://hdl.handle.net/10579/10532.

Texte intégral

Résumé :

Con questo lavoro di tesi si vuole indagare l'andamento dei principali metalli pesanti presenti nel particolato atmosferico (PM10) campionato nei principali siti di monitoraggio della regione Veneto. In particolare si cercherà di porre l'evidenza sulle eventuali omogeneità e differenze di concentrazione degli inquinanti fra i siti di campionamento, anche confrontando i dati ottenuti durante lo svolgimento delle analisi con i dati storici acquisiti da ARPAV negli anni precedenti. Nei mesi di gennaio e febbraio 2017 ci sarà un'estensione del pannello di analisi dei metalli, per poter avere una visione più complessiva, e non limitata ai soli metalli normati dal decreto legislativo 155 del 2010. Verranno poi studiate le eventuali interazioni fra le concentrazioni di particolato atmosferico e le condizioni meteo.

Styles APA, Harvard, Vancouver, ISO, etc.

40

Zannoni, Daniele <1983&gt. « Caratterizzazione geochimica di vapor d’acqua nella Laguna di Venezia ». Doctoral thesis, Università Ca' Foscari Venezia, 2017. http://hdl.handle.net/10579/12905.

Texte intégral

Résumé :

Gli isotopi stabili di idrogeno e ossigeno sono ottimi traccianti dei processi atmosferici del ciclo idrologico. Recentemente si è osservato un forte interesse della comunità scientifica verso la composizione isotopica del vapore acqueo nella bassa troposfera grazie ai recenti sviluppi nel campo della spettroscopia. In questa tesi la composizione isotopica del vapore acqueo viene indagata assieme alle principali fasi con cui esso può interagire all’interno del PBL veneziano, cioè le acque superficiali della Laguna di Venezia e le precipitazioni. L’obiettivo dello studio è quindi determinare quali siano i principali processi che governano la composizione isotopica del vapore in una laguna costiera, spaziando da quelli vicino all’interfaccia acqua-aria a quelli di trasporto a lunga distanza. Il vapore acqueo è stato campionato sia in maniera discreta (intrappolamento criogenico) che analizzato in continuo mediante Cavity Ring-Down Spectroscopy. In aggiunta alle analisi isotopiche sono state effettuate anche alcune analisi chimiche esplorative sui campioni ottenuti con intrappolamento criogenico. Ne risulta che il contributo dell’evaporazione delle acque superficiali all’umidità nella bassa troposfera è il processo principale che governa la composizione isotopica nell’area di studio. Eventuali contributi dall’atmosfera libera sono risultati importanti in condizioni di alta pressione. L’analisi chimica dei campioni di vapore ha invece evidenziato alcune potenziali sorgenti di inquinamento nell’area di studio.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Gallo, Alba <1986&gt. « Dal suolo alla tavola : elementi per la tracciabilità di prodotti della filiera agroalimentare ». Doctoral thesis, Università Ca' Foscari Venezia, 2018. http://hdl.handle.net/10579/15001.

Texte intégral

Résumé :

Negli ultimi anni la tracciabilità dei prodotti agroalimentari ha assunto sempre più importanza, soprattutto tra i consumatori desiderosi di conoscere non solo il valore nutrizionale dei cibi ma soprattutto la loro autenticità e provenienza. Lo scopo di questa ricerca è riconoscere quali sono le caratteristiche geochimiche del prodotto tipico considerato (radicchio rosso di Treviso) che riflettono le peculiarità del suolo di provenienza. Per questo motivo si sono adoperati marker geochimici “stabili” in modo da fornire indicazioni attendibili circa l’area di origine dei prodotti tipici considerati. Oltre a determinare le caratteristiche chimico–fisiche basilari del suolo (pH, carbonio organico, calcare totale, tessitura e capacità di scambio cationico) si sono valutati il contenuto di macronutrienti (come Ca, K, Mg, N, Na P, S) e di micronutrienti (es. Cu, Zn, Mn, B, Fe) per avere informazioni riguardo la fertilità del suolo di produzione, gli isotopi stabili (es. δ18O, δ13O, D, δ13C, δ34S, δ15N) come elementi di riferimento geopedologici, e i metalli pesanti presenti (es. Al, Cd, Co, Cr, Ni, Pb, V). Per capire la variabilità dei siti investigati si sono considerati diverse matrici ambientali: suolo, pianta, concimi, precipitazioni e acque di irrigazione.

Styles APA, Harvard, Vancouver, ISO, etc.

42

Khan, Ishaq <1989&gt. « Climate-related variability of isotopic records in a coastal Antarctic ice core ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2019. http://hdl.handle.net/10579/15637.

Texte intégral

Résumé :

Polar ice cores, both in Greenland and Antarctica, provide an improved understanding of past climatic variations through ⸹18O and ⸹D records, which are considered a proxy of surface temperature. This study focusses on the isotopic records obtained from four ice cores drilled in a coastal site of East Antarctica (GV7), characterized by a relatively high snow accumulation rate (237 mm of water equivalent). At this site different cores have been retrieved, one of which reached a depth of 250 m, while others reached shallow (5-12 m) or intermediate (55 m) depths, covering different time periods; this allows to calculate a stacked record for this site, in order to reduce the stratigraphic noise. The co-isotopic analysis allows the definition of the deuterium excess (d=⸹D-8*⸹18O), which is a proxy of climatic conditions (relative humidity, sea surface temperature, and wind speed) in the moisture source regions of precipitation. Since the isotopic records are not only related to temperature but also to other factors (precipitation intermittency, snow redistribution by winds and post-depositional effects), we compare the mean annual GV7 values of ⸹18O,⸹D, d and snow accumulation rate, all of which determined after an annual layer dating approach, to re-analysis data over the 1979-2012 period. For validating the proxy records, we used the ERA-Interim reanalysis data of temperature and precipitation, as well as the ECHAM5-wiso model data, which includes also the stable isotopes. We found that ERA-Interim over-estimates the precipitation data at GV7, which is already known in literature in coastal areas of Antarctica, while the ECHAM5-wiso under-estimates them. The simulated temperature data from ECHAM5-wiso were found in strong agreement with stable isotopes from GV7 ice cores, when using a 3-year moving average, except for one of them. Furthermore, we also compared the d-excess records with sea ice extent, finding a contrasting behavior in the most recent period. We also investigated the snow accumulation records in relation to simulated temperature, finding an agreement between the two variables from 1979 to 1996, while they appear not correlated afterward. The main climatic indices for the Southern Hemisphere, El Niño 3.4 and the Antarctic Oscillation, were also compared to stable isotopes and simulated temperatures. The overall model-data comparison in this study and for this area, shows a relatively good agreement, both in terms of absolute values and variability.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Posocco, Vittoria <1993&gt. « Variazioni stagionali e inter-annuali della composizione isotopica delle precipitazioni all’interno del Plateau Antartico ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2021. http://hdl.handle.net/10579/19651.

Texte intégral

Résumé :

I record isotopici delle perforazioni profonde in Antartide sono tra i principali proxy a nostra disposizione per la ricostruzione delle paleotemperature. In special modo il plateau Antartico è considerato un’area strategica per i siti di carotaggio e ospiterà il progetto Beyond Epica-Oldest Ice che mira a ricostruire il clima degli ultimi 1.5 milioni di anni. Si rende necessario quindi migliorare la comprensione della relazione esistente fra la composizione isotopica delle precipitazioni e la temperatura. Per questa finalità vengono effettuate analisi isotopiche dei campioni giornalieri di precipitazioni raccolte su banchino e a terra presso la base italo-francese di Concordia, a cui verranno associati i rispettivi dati meteorologici, facendo un confronto delle variabilità stagionali ed inter-annuali delle precipitazioni all’interno del plateau antartico. In questo lavoro di tesi saranno analizzati più di 400 campioni risalenti all’anno 2017 a cui verranno aggiunti, per un confronto, i dati dei campioni precedenti dal 2008 al 2016. Inoltre, verrà fatta una comparazione preliminare dei dati osservati con i dati meteorologici simulati dal modello generale di circolazione atmosferica ERA-5 e i dati isotopici simulati dai modelli ECHAM5-wiso e ECHAM6-wiso, che implementano la diagnostica per gli isotopi stabili di ossigeno e idrogeno nel ciclo idrologico. Ciò che ci si aspetta è una miglior comprensione della relazione δ/T in Antartide e dei processi che la determinano, nonché una possibile validazione dei modelli GCM ai quali è stata applicata la diagnostica isotopica.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Salitore, Alessio <1996&gt. « Indicazioni paleoclimatiche da record isotopici e di levoglucosano nella carota di ghiaccio di SolarIce (Dome C, Antartide orientale) ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2021. http://hdl.handle.net/10579/19672.

Texte intégral

Résumé :

Questo studio si prefigge di valutare le variazioni climatiche e ambientali che si sono succedute nell’area di Dome C nel corso della seconda parte dell’attuale interglaciale, denominato Olocene, mediante l’utilizzo di proxy di temperatura ( 18 O e/o D) e di combustione di biomasse (levoglucosano), avvalendosi del confronto con il record isotopico della carota di Epica Dome C e di quello del levoglucosano della carota di TALDICE. Per interpretare le variazioni climatiche del passato sono stati utilizzati i dati isotopici ottenuti dall’analisi di campioni ad alta risoluzione (5 cm) della carota di SolarIce, prelevata a Dome C nell’ambito del progetto PNRA SolarIce, tra 50 m e 204 m di profondità e corrispondenti ad un’età compresa tra circa 2000 e 6100 anni BP. Le analisi isotopiche sono state condotte attraverso spettroscopia laser CRDS e spettrometria di massa IRMS; una parte dei campioni del dataset utilizzato è stata analizzata dal centro di ricerca francese dell’LSCE e dall’Università di Parma, partner del progetto SolarIce Per interpretare l’andamento delle combustioni di biomasse nel passato, sono state utilizzate le variazioni di concentrazione del levoglucosano, considerato un tracciante specifico di questo tipo di combustioni. I campioni analizzati sono compresi tra i 90 e i 110 m di profondità, range corrispondente a circa 2100-2800 anni BP. Il record ad alta risoluzione (5 cm), è stato messo a confronto, per il periodo di sovrapposizione, con quello ottenuto dalla carota di ghiaccio di TALDICE, prelevata a Talos Dome, sempre in Antartide orientale, ma a una distanza inferiore dall’oceano meridionale. Per determinare la concentrazione di levoglucosano, i campioni di ghiaccio sono stati sottoposti a decontaminazione e analizzati mediante la tecnica analitica ifenata HPLC-MS/MS; la quantificazione è stata effettuata attraverso l’utilizzo di levoglucosano marcato 13 C 6 come standard interno.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Ammirati, Maddalena <1995&gt. « Applicazione dell’idrologia isotopica alla viticultura nell’ambito del progetto ACQUAVITIS ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2021. http://hdl.handle.net/10579/19818.

Texte intégral

Résumé :

I cambiamenti climatici in atto stanno causando un aumento delle temperature, più accentuato nei mesi estivi e si sta inoltre evidenziando un mutamento nella distribuzione annuale delle piogge. Bisogna pertanto riuscire a valutarne quanto prima i possibili impatti sul settore agricolo e della viticoltura, per poter intervenire adeguatamente per preservare le caratteristiche dei prodotti, prevedendo inoltre un efficientamento dell’utilizzo della risorsa idrica. Il seguente progetto di tesi si inserisce nel progetto Interreg Italia-Slovenia ACQUAVITIS: soluzioni innovative per l’uso efficiente dell’acqua in viticultura transfrontaliera. In questa tesi è stata analizzata la composizione isotopica dell’ossigeno e dell’idrogeno di campioni di precipitazioni, acqua contenuta nel suolo e linfa xilematica relativi a 3 vigneti sperimentali, in contesti geografici e climatici differenti tra di loro, nella regione Friuli-Venezia Giulia: il Carso classico, l’area isontina e la bassa pianura del Tagliamento, raccolti nel corso della stagione produttiva delle viti del 2020. I dati isotopici sono utilizzati come traccianti al fine di identificare l’origine e le possibili variazioni dell’acqua di approvvigionamento delle viti.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Mario, Giovanni <1995&gt. « Caratterizzazione del regime idrologico e del bacino di alimentazione di due sorgenti situate nelle pendici sud-occidentali del Cansiglio ». Master's Degree Thesis, Università Ca' Foscari Venezia, 2022. http://hdl.handle.net/10579/20778.

Texte intégral

Résumé :

Il Massiccio Cansiglio-Cavallo è un altipiano carsico con diverse geomorfologie superficiali tipiche di questi ambienti e un complicato sistema idrogeologico. Sebbene le precipitazioni siano abbondanti, queste vengono rapidamente convogliate nel sottosuolo e drenate principalmente verso le pendici sudorientali dove emergono importanti sorgenti (Molinetto, Santissima e Gorgazzo). Tuttavia sul versante sudoccidentale sono presenti due sorgenti di modesta portata, Laron e Canchero, sfruttate dalla rete idrica del comune di Fregona (TV). Il loro bacino di alimentazione non è noto, così come manca una valutazione della vulnerabilità dei rispettivi acquiferi. Questo studio, svolto in collaborazione con Piave Servizi S.p.A. e basato su dati forniti anche da ARPAV, si propone di (i) caratterizzare il regime idrologico delle sorgenti Laron e Canchero; (ii) valutare la possibile estensione dell’area di ricarica e (iii) valutarne la vulnerabilità mediante l’applicazione di modelli. Le sorgenti sono state monitorate in continuo tramite l’impiego di sonde per la misura di portata, temperatura e conducibilità elettrica ed inoltre sono stati raccolti campioni per analisi chimiche (alcalinità, conducibilità, durezza, pH, bicarbonato, F-, Cl-, Br-, NO3-, NO2-, PO43-, SO42-, Na+, Mg2+, K+, Ca2+ e Si) e dei valori di δ18O e δ2H. Inoltre sono stati installati due pluviometri (località di Vittorio Veneto e Pian Cansiglio) per la raccolta delle acque meteoriche e la determinazione di δ18O e δ2H.

Styles APA, Harvard, Vancouver, ISO, etc.

47

AGOSTINI, CLAUDIA. « Crystallization kinetics : a probe of magmatic and eruptive processes for Stromboli and Pantelleria volcanic systems ». Doctoral thesis, Università degli Studi di Camerino, 2013. http://hdl.handle.net/11581/401842.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

48

BONACINA, GRETA. « Improve Source Rock Evaluation using Inorganic Geochemistry (ISRIG) ». Doctoral thesis, Università degli studi di Pavia, 2021. http://hdl.handle.net/11571/1423374.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

49

SESSA, GIANLUCA. « GEOCHEMISTRY OF AMPHIBOLE FROM ARCHEAN AND EARLY PROTEROZOIC ULTRAMAFIC ROCKS : IMPLICATIONS FOR THE SECULAR EVOLUTION OF THE EARTH¿S MANTLE ». Doctoral thesis, Università degli Studi di Milano, 2019. http://hdl.handle.net/2434/609805.

Texte intégral

Résumé :

Since its formation at 4.5 Ga, the Earth underwent a complex evolution that progressively differentiated its original composition into the reservoirs that we presently know. Our knowledge on the composition and differentiation mechanisms active in the Early and Ancient Earth are still fragmentary for the paucity of suitable preserved rock records. The poor knowledge on the Archean mantle composition arises a series of problems spanning from the effective chondritic composition of the Earth to how volatile elements (hydrogen, oxygen, chlorine and fluorine) were added to the Earth. For the unavailability of mantle sectors preserving the Archean geochemical signature, valuable information on the Archean mantle composition can be exclusively extracted from Archean mantle-derived igneous rocks. In the Archean greenstone belts, different products of mantle melting are found as lavas and sills spanning in composition from tholeiites through Fe-picrites to komatiites. All these rocks are generally affected by extensive alteration which prevent the bulk rocks to be fully informative on the primary mantle melt composition and particularly on its volatile element contents. However, in some of these rocks primary igneous mineral phases such as amphibole are preserved that may be useful to constrain the primary melt composition including its volatile budgets. In this thesis amphibole-bearing ultramafic rocks of late Archean and Early Proterozoic age (Stone et al., 2003; Fiorentini et al., 2004; Fiorentini et al., 2008) were selected. For comparison amphibole-bearing ultramafic rocks from different tectonic settings of the Phanerozoic were also considered. The Archean and Early Proterozoic rocks share many petrographic and textural similarities with hornblendites and amphibole-bearing pyroxenites from Phanerozoic orogenic settings. In all studied rocks the crystallisation of amphibole follows that of the early crystallising minerals: olivine + spinel ± orthopyroxene + clinopyroxene. The chemical composition of Archean and Early Proterozoic amphiboles is more similar to that of amphibole from alkaline lavas than that of amphibole in orogenic settings. The geobarometric calculations on Archean and Early Proterozoic rocks yield large uncertainty on the pressure of crystallisation with values between 0 and >3 Kbar, which are not conclusive about the deep or shallow origin of amphibole. In the Archean and Early Proterozoic rocks amphibole is in clear disequilibrium with the early crystallizing clinopyroxene. Modelling of melt differentiation suggests that amphibole crystallized from a melt percolating the cumulate pile. Such melt evolved by crystallization of olivine and pyroxene and subsequently modified its composition in response to olivine assimilation. A major problem in the studied Archean and Early Proterozoic rocks is about the origin of the H2O necessary to stabilize amphibole. The H2O concentrations in the Archean and early Proterozoic amphiboles are comparable to those of either subduction-related or amphibole megacrysts from alkaline lavas, thus suggesting that melts in equilibrium with amphiboles possessed almost the same water contents irrespective of age. According to the composition of amphibole in fluid-mobile elements (e.g., F, Cl, B and Sr) a contribution of seawater-derived fluid in the Archean and Early Proterozoic rocks is unlikely. The range of δD values of the Archean and Paleoproterozoic amphiboles is between -99.5 ‰ and -129.8 ‰, that is slightly lower than the mantle range but still consistent with a magmatic origin for water. The hypothesis of a crustal contribution in the origin of the amphiboles (and in turn a crustal origin of water) contrasts with the oxygen isotope signature of amphibole showing δ18O values lighter than those of the mantle. Because the involvement of recycled crustal materials, able to provide the required seawater-like geochemical anomalies, is unlikely for the genesis of the studied amphiboles, the light δ18O signature is interpreted as a primary feature of the mantle source. In order to monitor possible changes marked by amphibole in the secular evolution of the Earth’s mantle, the trace element composition of the melt in equilibrium with amphibole from Archean and Early Proterozoic rocks was calculated and compared with that of melts produced nowadays at the different geodynamic settings. Equilibrium melts show increasing Nb/Y ratios from komatiites through tholeiites to Fe-picrites that are in agreement with the increased alkalinity of the parental melt as inferred from the literature. All calculated melts share an incompatible trace element pattern paralleling that of present-day OIB. The comparison of the water content in primary melts calculated from Archean-early Proterozoic amphiboles and present-day primary mantle melts reveals that the mantle source of the Archean komatiites had a much higher water content than that characterizing present day OIB. The highly variable water contents in Fe-picrites however suggest a large heterogeneity in the composition of the mantle source. The comparison between the Archean-early Proterozoic amphiboles and those from the Phanerozoic has also revealed heterogeneities in the Nb/Ta ratios of the mantle through the Earth’s history. Some of the calculated melts (since early Proterozoic) show an enriched Nb/Ta signature that is independent from space (geological setting) and time and that was interpreted as a primary feature of the different mantle sources. The observed heterogeneous Nb/Ta signature of the Earth’s mantle was interpreted as related to the addition of extra-terrestrial material after the mantle-core equilibration prior to 4.4 Ga and to an incomplete equilibration of these domains during the Earth’s evolution. In conclusion, the data of this thesis suggest that the Earth’s mantle is much more heterogeneous than commonly assumed. The occurrence in the Archean and Early Proterozoic of mantle domains enriched in volatile elements but unrelated to subduction processes has been documented. An extra-terrestrial signature for some mantle domains was also reported and I do not exclude that the light oxygen isotope signature of the Archean and Early Proterozoic rocks is also a reminiscence of extra-terrestrial inputs possibly related to the meteoritic Late Veneer.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Innocente, Elena <1982&gt. « Caratterizzazione della componente batterica nel particolato atmosferico e studio delle relazioni con i parametri ambientali ». Doctoral thesis, Università Ca' Foscari Venezia, 2013. http://hdl.handle.net/10579/4661.

Texte intégral

Résumé :

Negli ultimi anni sono aumentati gli studi sull’inquinamento atmosferico a causa di una maggiore consapevolezza dei suoi numerosi effetti avversi. Nonostante la composizione chimica e la frazione biogenica dell’aerosol siano argomento di diversi studi, sono ancora poco chiare e studiate le relazioni fra queste due componenti dell’aerosol. Con questo lavoro di tesi si è tentato di: mettere a punto una tecnica che permettesse di raccogliere campioni validi sia per determinazioni chimiche che per determinazioni biologiche, identificare la composizione delle comunità batteriche in atmosfera, determinare la composizione chimica del particolato atmosferico, descrivere un’eventuale relazione fra la composizione chimica del particolato atmosferico e la composizione in specie dei batteri del medesimo, trovare una relazione fra l’approccio biologico e l’approccio chimico allo studio dell’aerosol.
Recently studies about atmospheric pollution are increased, due to the awareness about many adverse effects of particulate matter in air. In spite of chemical composition and the biogenic portion of atmospheric aerosol are the focus of many studies, the relationship between chemical composition and biological fraction has been poorly investigated and at today appear not clear. The aim of this study is: improve a sampling method to collect a valid PM sample both for chemical and biological analysis, identify the composition of bacterial population in air Particulate Matter, determinate the chemical composition of air Particulate Matter; describe the relationship between bacterial population and PM chemical composition and find a connection between those different approach of aerosols study.

Styles APA, Harvard, Vancouver, ISO, etc.

Thèses sur le sujet « GEO/08 »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres