90 research outputs found
Riforma e problematiche della portualita'
No full textL’analisi effettuata nel capitolo, la cui redazione è stata coordinata da F. Munari, muove dagli scenari globali, europei e nazionali sui mercati e i flussi di traffico caratterizzanti il trasporto marittimo e porti (par. 1, redatto da L. Antonellini e P. Costa). Tali scenari vengono confrontati sia coi documenti programmatici del Governo (il Piano Strategico Nazionale sui Porti e la Logistica, l’Allegato Infrastrutture 2017 al DEF), sia con le norme adottate a livello nazionale (d.lgs. n. 169/2016 di riforma della l. n. 84/1994) ed europeo (Regolamento 352/2017), evidenziandone gli elementi positivi e le criticità (par. 2 di L. Antonellini e F. Munari; par. 4 di F. Munari; par. 5 di P. Costa). Sulla riforma portuale, pur dando atto delle buone intenzioni del legislatore, il rapporto evidenzia ritardi e imperfezioni attuative, che potrebbero pregiudicarne le potenzialità e dovrebbero quindi essere rimediate quanto prima (par. 2 di L. Antonellini e F. Munari e par. 4 di F. Munari). Particolare attenzione viene quindi rivolta alla pianificazione e alle modalità di scelta di finanziamento delle dotazioni infrastrutturali (par. 3 e 5 redatti rispettivamente da P. Spirito e P. Costa): con taluni distinguo anche rispetto agli interventi da compiere, si sottolinea l’assoluta necessità di criteri e metodologie obiettive e credibili nella selezione degli interventi infrastrutturali, tanto più considerati (a) i vincoli di finanza pubblica e l’esigenza di non disperdere risorse e tempi con (annunci di) interventi «a pioggia» e non ancorati ad alcun disegno strategico né sistemico e (b) la circostanza che le non-scelte risultano ulteriormente penalizzanti nel contesto globale dove altri si muovono invece rapidamente. Presupposti comunque necessari per una politica degli investimenti in infrastrutture portuali e logistiche appaiono, da un lato, una valutazione ex ante delle loro ricadute al servizio di una policy non limitata ai porti, bensì funzionale all’intera catena logistica, agli stessi centri produttivi del Paese, e ai flussi prospettici dei grandi traffici globali; dall’altro lato, una visione strategica degli investimenti da compiersi, in due direzioni: (a) svincolarsi da logiche prevalentemente conservative e al massimo migliorative di infrastrutture esistenti (molte delle quali comunque inadeguate a sostenere nel lungo periodo una presenza importante del nostro Paese nella catena produttiva e logistica globale); (b) puntare su obiettivi di eccellenza e di ampio respiro, capaci di segnare una discontinuità rispetto alle inadeguatezze del nostro sistema infrastrutturale, a costo di operare scelte selettive marcate. Ciò non significa puntare esclusivamente a intercettare progetti globali, come lo One Belt One Road, ma sviluppare anche la posizione mediterranea del nostro Paese e la vocazione dell’Italia a porsi come punto di riferimento per il Nord Africa e il Medio Oriente
Impact of groundwater salinity on vegetation species richness in the coastal pine forests and wetlands of Ravenna, Italy
No full textIn the coastal pine forests (Pinus pinea and Pinus pinaster) of Ravenna (Italy) along the Adriatic coast, many pine trees are stressed or dying. In this paper we present ground elevation, depth to watertable, salinity of groundwater and vegetation species richness data within one of the coastal pine forests and some wetlands north of the Bevano River between LAT. 44°23′10″ and LAT. 44°20′21″ and between LONG. 12°17′25″ and LONG. 12°19′33″. The data are presented areally and along a 50 m long transect perpendicular to the coast to study the cause of distress in the pine forest and in different water pools within the wetlands. The findings were compared to published values of tolerance to salinity for 39 plant species typical of the area and incorporated into a web application to help nature managers in assessing or adjusting water salinity in relation to the vegetation species present. The pine trees are relatively tolerant to salinity (up to 12 g/l) but cannot survive a shallow watertable. On the other hand, species richness or biodiversity in this area is promoted by a shallow watertable and low salinity
Characterization of sub-seismic resolution structural diagenetic heterogeneities in porous sandstones: Combining ground-penetrating radar profiles with geomechanical and petrophysical in situ measurements (Northern Apennines, Italy)
No full textDeformation bands and structurally-related diagenetic heterogeneities, here named Structural Diagenetic Heterogeneities (SDH), have been recognized to affect subsurface fluid flow on a range of scales and potentially promoting reservoir compartmentalization, influencing flow buffering, and sealing during production. Their impact on reservoir hydraulic properties depends on many factors, such as their permeability contrast with respect to the undeformed reservoir rock, their anisotropy, thickness, geometry as well as their physical connectivity and arrangement in the subsurface. We used the Ground Penetrating Radar (GPR) for detection and analysis of the assemblage of deformation bands – carbonate nodules, in high-porosity arkose sandstone in Northern Apennines of Italy. 2D GPR surveys allowed the description of the SDH spatial organization, their geometry, and their continuity in the subsurface. Petrophysical (air-permeability) and mechanical (uniaxial compressive strength) properties of host rock, deformation bands, and calcite-cement nodules were evaluated along a 30-m thick stratigraphic log to characterize the permeability and strength variations of those features. The assemblage “deformation bands – nodules” degrade porosity and permeability and produce a strengthening effect of the rock volume, imparting a strong mechanical and petrophysical heterogeneity to the pristine rock. Different textural, petrophysical, and geomechanical properties between deformation bands, nodules, and host rock result in different GPR response (permittivity). Thus, GPR response could be used to extend outcrop data (petrophysical and geomechanical) of SDH to 3D subsurface volumes in a way to reconstruct realistic and detailed outcrop analogs of faulted aquifers and reservoirs in porous sandstones
The role of deformation bands, stylolites and sheared stylolites in fault development in carbonate grainstones of Majella Mountain, Italy
No full textIn this paper we document deformation processes in porous carbonate grainstones of Cretaceous age in Majella Mountain in the central Apennines of Italy by detailed mapping of meso- and microstructural features as well as thin section observations and image analyses. We distinguished three main deformation mechanisms: (i) deformation bands developed by compaction and shear strain localization, (ii) stylolites formed by pressure solution, and (iii) subsequent shearing of stylolites. The deformation bands occur in six sets: five sets are compactive shear bands at high angles to bedding and one, which is the oldest, occurs parallel to bedding and is interpreted to be a compaction band. Stylolites localize along and within all six sets of deformation bands and are commonly sheared, as evidenced by striated surfaces and detectable offsets.
These sheared stylolites are in many cases associated with one or two sets of subsidiary stylolites, oblique to the major set. The band-parallel sheared stylolites, together with the associated oblique sets of stylolites, form a tabular zone of fine grained cataclastic material within the compactive shear bands and accommodate slip in the range of 5–75 cm.
The bed-parallel compaction bands and bed-parallel stylolites, which are kinematically compatible, are interpreted to be pre-tilting structures developed in response to the overburden, whereas the five sets of compactive shear bands and the associated stylolites and sheared stylolites likely occurred during the syn- and post-tilting deformation phases recorded in the Majella anticline
Groundwater Management in the Northern Adriatic Coast (Ravenna, Italy): New Strategies to Protect the Coastal Aquifer From Saltwater Intrusion.
No full textGroundwater (GW) is one of the most valuable natural resources and for that reason, the GW protection and management is vital for human evolution, socio-economic development and ecological diversity. During the last decades, the continuously increasing need of water has led to a rapidly growing awareness in the field of GW management. At the same time over exploitation and pollution of water resources are threatening the ecosystems. The combination of these two problems which have acquired worldwide dimensions has forced many scientists working in relative fields to search new, multidisciplinary approaches to address them. Effective management and protection of groundwater resources require detail knowledge and quantitative/qualitative characterization of aquifers. Thus, modeling and planning of the GW through the use of modern technologies and approaches have become of high priority towards this direction. This book provides leading-edge research on this field
Chert nodules in pelagic limestones as paleo-stress indicators: A 3D geomechanical analysis
No full textThe objective of this study is to explain the occurrence and paleo-stress significance of 3D joint clustering in chert nodules (inclusions) within a layered pelagic limestone sequence. The difference in stiffness between chert and limestone is about one order of magnitude. Field observations show that fracture localization occurs mostly in chert nodules as opposed to the limestone matrix. We show with a novel three-dimensional geomechanical modelling analysis how the inclusion (ellipsoid) axes ratio influences fracture intensity and propagation within and outside the chert nodules and how the nodules record different deformation phases under different remote stress conditions. From field observations, we recognize two joint sets in the chert nodules: joints parallel and normal to the plane containing the two major axes of the nodule (bedding plane). In the nodules, the normal-to-bedding joints are interpreted to be younger than the parallel-to-bedding ones. The modelling of the 3D Eshelby solution for the stress field inside the chert nodule and in the surrounding matrix is consistent with our field observations and it suggests a strong differential stress during deformation (σminr/σmaxr < 0.3). Chert nodules in a deformed carbonate sequence, therefore, can provide important clues on the paleo-stress conditions, the temporal sequence of events, and fracture distribution heterogeneity
Application of analytical diffusion models to outcrop observations: Implications for mass transport by fluid flow through fractures
No full textA pavement outcrop with excellent exposure of spatial relationships among joints, veins, small offset normal faults, and associated alteration halos (redox fronts) provided an opportunity to compare predictions of analytical models for reaction front propagation in a fracture-matrix system with a real-field situation. The results have important implications for fluid flow and pollutant transport through a fractured medium. The alteration halos observed suggest that all joints of different sets and most small faults are conductive to meteoric water at shallow depth. On the other hand, veins are local barriers to mass transport by diffusion. By using petrologic and petrophysical data, analytical modeling, and the width of the alteration halos, it was possible to estimate when the fracture network was open to fluid flow. The inferred time for fluid flow and diffusion through the fracture network is sensitive to the porosity n of the rock matrix used in the analytical solutions: 2200 ± 500 years with n = 0.08, 4600 ± 900 years with n = 0.05, and 16,000 ± 4000 with n = 0.02. The second and third age determinations are consistent with the landscape evolution of the area since the end of the last Wűrmian ice age and with the timing required to fill the fractures observed in outcrop. We suggest that analytical modeling is an important tool for the determination of transport and reaction time scales in fractured formations where it is constrained by a robust petrophysical and chemical properties data set
Metodi matematici per l'esplorazione ambientale sostenibile
No full textUno degli obiettivi principali della nostra ricerca risiede nella ottimizzazione di algoritmi per la modellazione e la stima di local ties a partire da osservazioni topografiche di angoli azimutali, zenitali e distanze inclinate, o attraverso il posizionamento tridimensionale GPS di precisione. In particolare intendiamo migliorare il modello geometrico della stima del punto invariante per le grandi antenne VLBI a partire da sequenze rotazionali di mire topografiche applicate alla struttura del radiotelescopio installate a differenti altezze e distanza dagli assi di rotazione.
Il problema matematico si può ridurre ad una stima minimi quadrati di un sistema di equazioni linearizzate che rispettino vincoli geometrici di appartenenza a determinate superfici nello spazio
Assessment of Water Resources Availability and Groundwater Salinization in Future Climate and Land use Change Scenarios: A Case Study from a Coastal Drainage Basin in Italy
No full textThe joint effect of changes in climate and land use on the future availability of water resources was assessed under the SRES A1B and A2 climate scenarios as well as five land use scenarios for the 2080–2100 time-frame in an Italian coastal watershed. The study area is a small coastal polder (100 km2) characterized by irrigated agriculture, urban expansion, drainage, quarrying and sensitivity to salt-water intrusion. The hydroclimatic budget and the GALDIT index have been computed for assessing water resources availability and groundwater vulnerability to salinization, respectively. The methodology developed is integrated into a tool based on ExcelTM, which supported the development of scenarios in participatory processes. The conclusions emerged from the analysis are the following: (1) climate change is more effective than land use change in controlling future freshwater availability and amplifies the imbalance between winter surplus and summer deficits, (2) freshwater availability in the summer will likely be affected by an increase in evaporation from open water surfaces due to increased temperature, whereas winter surplus would increase, (3) the vulnerability of the coastal aquifer to salinization will probably moderately increase but an inherent limitation of the GALDIT index to land use change parameters prevents a sound assessment. Strategies that may be proposed to administrators and stakeholders are based on increasing storage of seasonal water surplus
Effects of outcrop-scale structural and diagenetic heterogeneities on flow and mass transport in a porous sandstone aquifer
No full textWe apply outcrop-based structural and in-situ petrophysical properties measurements for the construction of flow and mass transport calibrated numerical models in a porous sandstone aquifer. The hydraulic conductivity in this aquifer is influenced by the presence of deformation bands and related carbonate nodules. These heterogeneities are shown to decrease the hydraulic conductivity of the host rock by 2-3 orders of magnitude. The result obtained is robust, given that the models were calibrated with hydrologic field data. Our upscaling methodology for hydraulic conductivity allows inclusion of outcrop-scale structures and diagenetic features by means of inversion of the advective velocity for conservative particles. This approach can be used for easily implementing field data in aquifers or other geofluids reservoir simulators. Our experiments show that the use of an equivalent isotropic hydraulic conductivity approach fails to correctly account for mass transport in porous sandstone aquifers and we recommend implementing, as much as possible, the local heterogeneities and anisotropies in hydraulic conductivity within the model to be able to have a more realistic and conservative estimate of advection and dispersion. Our findings should be helpful to those scientists dealing with geofluids modeling and groundwater pollution
- …
