A 2-D FEM thermal model to simulate water flow in a porous media: Campi Flegrei caldera case study

Abstract. Volcanic and geothermal aspects both exist in many geologically young areas. In these areas the heat transfer process is of fundamental importance, so that the thermal and fluid-dynamic processes characterizing a viscous fluid in a porous medium are very important to understand the complex dynamics of the these areas. The Campi Flegrei caldera, located west of the city of Naples, within the central-southern sector of the large graben of Campanian plain, is a region where both volcanic and geothermal phenomena are present. The upper part of the geothermal system can be considered roughly as a succession of volcanic porous material (tuff) saturated by a mixture formed mainly by water and carbon dioxide. We have implemented a finite elements approach in transient conditions to simulate water flow in a 2-D porous medium to model the changes of temperature in the geothermal system due to magmatic fluid inflow, accounting for a transient phase, not considered in the analytical solutions and fluid compressibility. The thermal model is described by means of conductive/convective equations, in which we propose a thermal source represented by a parabolic shape function to better simulate an increase of temperature in the central part (magma chamber) of a box, simulating the Campi Flegrei caldera and using more recent evaluations, from literature, for the medium's parameters (specific heat capacity, density, thermal conductivity, permeability). A best-fit velocity for the permeant is evaluated by comparing the simulated temperatures with those measured in wells drilled by Agip (Italian Oil Agency) in the 1980s in the framework of geothermal exploration. A few tens of days are enough to reach the thermal steady state, showing the quick response of the system to heat injection. The increase in the pressure due to the heat transport is then used to compute ground deformation, in particular the vertical displacements characteristics of the Campi Flegrei caldera behaviour. The vertical displacements range from 1 cm to 10 cm in accordance with the mini uplift, characterizing the recent behaviour of the caldera. The time needed to move fluid particles from the bottom to the upper layer (years) is compatible with the timing of the mini uplift

ACCORDI DI COESISTENZA TRA MARCHI

Gli accordi di coesistenza sono strumenti molto diffusi per la composizione di controversie attuali o potenziali. Presentano tuttavia ancora molti interrogativi irrisolti. Il lavoro analizza alcune tematiche chiave che hanno interessato o che tuttora interessano gli accordi di coesistenza, considerando in primo luogo il punto di vista dell\u2019ordinamento italiano, facendo anche ricorso alla comparazione con l\u2019esperienza e le soluzioni offerte dagli ordinamenti di altri paesi. Viene in primo luogo analizzato il tema della validit\ue0 degli accordi di coesistenza: un tempo considerati nulli, sono stati successivamente riconosciuti validi sia dalla dottrina che dalla giurisprudenza, con prospettazioni poi assecondate anche dal legislatore. Viene inoltre analizzato il contenuto tipico degli accordi di coesistenza, con una rassegna delle principali obbligazioni (limitazioni merceologiche, spartizioni territoriali, modifiche all\u2019aspetto grafico o denominativo del segno, etc.), e sono individuati i profili critici sui quali pi\uf9 frequentemente le parti possono trovarsi successivamente a discutere. \uc8 infatti noto l\u2019adagio secondo cui gli accordi di coesistenza sarebbero i sistemi pi\uf9 diffusi per risolvere controversie attuali, rinviando la lite a controversie future. Il lavoro approfondisce inoltre il tema della rilevanza degli accordi di coesistenza rispetto ai terzi, e i problemi che possono scaturire dalla qualificazione giuridica degli accordi di coesistenza quali i contratti aventi efficacia meramente obbligatoria, e quindi vincolanti solo per le parti che lo hanno sottoscritto. Infine, viene esaminato l\u2019atteggiamento dell\u2019EUIPO e dell\u2019UIBM rispetto agli accordi di coesistenza, nello specifico nell\u2019ambito delle procedure di opposizione. Nell\u2019ordinamento italiano il tema \ue8 ancora pressoch\ue9 inesplorato, e risulta solo un caso portato all\u2019attenzione dell\u2019UIBM che ha avuto esiti opposti nei due gradi di giudizio davanti alla Divisione di Opposizione e alla Commissione Ricorsi.Trademark co-existence agreements are very popular tools to avoid/settle trademark disputes. However, many questions concerning these agreements remain unanswered. This thesis explores some of the most relevant issues from an Italian legal standpoint and the solutions offered by other countries. The thesis starts by analysing the issue of the validity of co-existence agreements (they were once considered void, were then accepted as valid by some courts and then finally also by the legislator). The thesis then analyses the typical content of co-existence agreements, with an overview of the main provisions (limitation to products and services, territorial divisions, modifications to the signs, etc.), with a focus on some wording that the parties may have further discussions on. Also examined is the relationship between co-existence agreements and third parties and the issues that can arise from the legal qualification of co-existence agreements as being binding only on the parties to it. The thesis closes with an analysis of the impact of co-existence agreements in opposition proceedings by examining the European and Italian trademark offices\u2019 main caselaw

Quantum Pairing of Impurities in Quantum Crystals

We calculated the time of pairing by quantum diffusion of ortho-H2 impurities in solid para-H2. The important feature of the pairing process is a strong directional bias associated with the dependence of the hopping rates on energy mismatches caused by the interaction of the pairing particles. This bias at moderate temperatures is against a mutual approach of particles and creates a ‘‘kinetic barrier.’’ At lower temperatures, the corresponding diffusion mechanism freezes out, which leads to a rapid increase in pairing rates. This explains a well-developed, experimentally observed maximum in the pairing time as a function of temperature: a maximum that exists in spite of a monotonic temperature dependence of individual hopping rates. Our results are in good agreement with experimental data

GPS time series at Campi Flegrei caldera (2000-2013)

The Campi Flegrei caldera is an active volcanic system associated to a high volcanic risk, and represents a well known and peculiar example of ground deformations (bradyseism), characterized by intense uplift periods, followed by subsidence phases with some episodic superimposed mini-uplifts. Ground deformation is an important volcanic precursor, and, its continuous monitoring, is one of the main tool for short time forecast of eruptive activity. This paper provides an overview of the continuous GPS monitoring of the Campi Flegrei caldera from January 2000 to July 2013, including network operations, data recording and processing, and data products. In this period the GPS time series allowed continuous and accurate tracking of ground deformation of the area. Seven main uplift episodes were detected, and during each uplift period, the recurrent horizontal displacement pattern, radial from the “caldera center”, suggests no significant change in deformation source geometry and location occurs. The complete archive of GPS time series at Campi Flegrei area is reported in the Supplementary materials. These data can be usefull for the scientific community in improving the research on Campi Flegrei caldera dynamic and hazard assessment

Topography and structural heterogeneities in surface ground deformation: a simulation test for Somma-Vesuvius volcano

Abstract. We simulate the deformation of Somma-Vesuvius volcano due to some overpressure sources by means of a finite element 3D code. The main goal of these simulations is to investigate the influence of topography and structural heterogeneity on ground deformation. In our model the sources of deformation are embedded in an elastic linear isotropic medium and located at various depths. Geometry (shape and lateral extension) of the sources is mainly constrained by the results coming from recent seismic tomography studies. The structural heterogeneity has been modelled in terms of dynamic elastic parameters (Young's modulus) retrieved from previous seismic tomography and gravity studies. A high-resolution digital terrain model is used for the topography of the volcano subaerial edifice. Evidences from our results suggest that real topography and structural heterogeneities are key factors governing the ground deformation, which often turns being one of the most relevant problems in volcano monitoring. A large deviation from the axially symmetrical model of the displacement field is the main result of our modelling. Such an asymmetry is routinely unaccounted for when Mogi's simplistic modelling in a homogeneous medium with simplified topography is used. Our study clearly demonstrate that a better knowledge of deformation patterns can significantly help in the location of monitoring sensors as well as in the design of an efficient geodetic network

Ground deformation analysis at Campi Flegrei (Southern Italy) by CGPS and tide-gauge network

Campi Flegrei caldera is located 15 km west of the city of Naples, within the central-southern sector of a large graben called Campanian Plain. It is an active volcanic area marked by a quasi-circular caldera depression, formed by a huge ignimbritic eruption occurred about 37000 years ago. This caldera was generated by several collapses produced by strong explosive eruptions (the last eruption, occurred in 1538, built an about 130 m spatter cone called Mt. Nuovo). Campi Flegrei area periodically experiences significant deformation episodes, with uplift phenomena up to more than 3.5 m in 15 years (from 1970 to 1984), which caused during 1983-84 the temporary evacuation of about 40000 people from the ancient part of Pozzuoli town. The deformation field obtainable by CGPS and tidegauge stations plays an important role for the modelling and interpretation of volcanic phenomena, as well as for forecasting purposes. The structural complexity of the Campi Flegrei area, together with the evidence of a strong interaction between magmatic chamber and shallow geothermal system, calls for a detailed characterization of the substructure and of magma-water interaction processes. The incoming experiment of deep drilling, down to about 4 km, will give detailed structural and physical constraints able to resolve the intrinsic ambiguities of geophysical data and in particular geodetic ones. In this poster we describe the recent ground deformations at Campi Flegrei area by means of GPS technique and tide gauge stations, discussing the possible interpretations also in light of further constraints likely coming from the next CFDDP (Campi Flegrei Deep Drilling) deep drilling experiment

Characterization of GPS time series at the Neapolitan volcanic area by statistical analysis

The GPS time series recorded at the Neapolitan volcanic area reveals a very peculiar behavior. When a clear deformation is observed, the amplitude distribution evolves from a super‐Gaussian to a broader distribution. This behavior can be characterized by evaluating the kurtosis. Spurious periodic components were evidenced by independent component analysis and then removed by filtering the original signal. The time series for all stations was modeled with a fifth‐order polynomial fit, which represents the deformation history at that place. Indeed, when this polynomial is subtracted from the time series, the distributions again become super‐Gaussian. A simulation of the deformation time evolution was performed by superposing a Laplacian noise and a synthetic deformation history. The kurtosis of the obtained signals decreases as the superposition increases, enlightening the insurgence of the deformation. The presented approach represents a contribution aimed at adding further information to the studies about the deformation at the Neapolitan volcanic area by revealing geologically relevant data

Chemical diffusivity and wave propagation in surface reactions: Lattice-gas model mimicking CO-oxidation with high CO-mobility

We analyze the spatiotemporal behavior in a lattice-gas model for the monomer-dimer reaction on surfaces. This model, which mimics catalytic CO-oxidation, includes a mobilemonomer adspecies (representing CO), an immobile dissociatively adsorbed dimer species (representing O), and afinitereaction rate (for CO2 production). We characterize in detail the propagation of the chemical wave or reaction front produced when the stable reactive steady-state of the model displaces the metastable CO-poisoned state. In the regime of high CO-mobility, such propagation can be described directly within a “hydrodynamic” reaction-diffusion equation formalism. However, we show that the chemical diffusivity of CO is dependent on the O coverage, reflecting the percolative nature of CO-transport through a background of immobile O. We also emphasize that gradients in the coverage of immobile O induce a diffusive flux in the highly mobile CO. These features significantly influence wave propagation and reaction front structure. In addition, our analysis accounts for the feature that in this hydrodynamic regime, correlations persist in the distribution of adsorbed immobile O, and that these influence the reaction kinetics, the steady states, and the percolation and diffusion properties. To this end, we utilize a “hybrid” approach which incorporates a mean-field reaction-diffusion treatment of adsorbed CO, coupled with a lattice-gas treatment of adsorbed O [Tammaro et al., J. Chem. Phys. 103, 10277 (1995)].The following article appeared in Journal of Chemical Physics 108, 2 (1998): 762 and may be found at doi: 10.1063/1.475436.</p