Search

A great variety of applications requires to process two-dimensional NMR (2DNMR) data to obtain information about the materials properties. In order to face the increasing request for software to easily process 2DNMR data, in (Bortolotti et al. (2019) [1]), the authors released Upen2dTool, an open source MATLAB software tool implementing nonnegatively constrained uniform penalty locally adapted norm-based regularization for 2DNMR data inversion. This paper presents MUPen2DTool a new open-source MATLAB software tool implementing an unconstrained multipenalty regularization method based on and norms. The new software MUPen2DTool outperforms Upen2dTool since the implemented uniform multipenalty method allows to compute very accurate 2DNMR data inversion at reduced computational cost. By means of MUPen2DTool, the user can choose among several types of NMR experiments, and the free software provides codes that can be used and extended easily. Furthermore, a MATLAB interface makes it easier to include users own data. The practical use is demonstrated in the reported examples of both synthetic and real NMR data.

The protection of stone cultural assets is related to the transformation of the surface characteristic from hydrophilic to hydrophobic/superhydrophobic through the application of a coating. The suitability of a coating depends not only on its capability to dramatically change the surface wettability, but also on other parameters such as the modification of kinetics of water absorption, the permanence of vapor diffusivity, the resistance of the coating to aging and the low volatile organic compound emissions during its application. In this work, an oligo(ethylensuccinamide) containing low molecular pendant perfluoropolyether segments (SC2-PFPE) and soluble in environmentally friendly solvents was tested as a protective agent for historic stone artifacts. Magnetic resonance imaging and relaxometry were employed to evaluate the effects of the surface wettability change, to follow the water diffusion inside the rock and to study the porous structure evolution after the application of SC2-PFPE. A sun-like irradiation test was used to investigate the photo-stability of the product. The results demonstrate that the highly photo-stable SC2-PFPE minimizes the surface wettability of the stone by modifying the water sorptivity without significantly affecting its porous structure and vapor diffusivity. The improved performance of SC2-PFPE in comparison to other traditional coatings makes it a potential candidate as an advanced coating for stone cultural heritage protection.

Numerical simulations are important tools for the assessment of exploiting geothermal energy in heat pump applications. They can be used to evaluate the performance of the system, the long-term production scenarios and the sustainability of the geothermal reservoir. The present work introduces and describes a numerical model, in which a dedicated Matlab script has been realized to allow sequentially coupled simulations of a shallow geothermal reservoir and of a heat pump system. A mathematical model of a dual-source heat pump, working alternatively with the ground or the air as heat source/sink, has been developed in Matlab environment. The heat exchangers of the heat pump have been modelled considering the equations that govern the physical phenomena. The dynamic numerical simulator FEFLOW, based on the finite element method, has been used to simulate the behaviour of the geothermal reservoir, subjected to heat extraction/reinjection by a closed loop vertical heat exchangers field. This methodological approach is useful to evaluate the performance of the coupled system in the long term, and it is important for understanding the advantages and limits of the dual-source heat pump in assuring sustainability over time avoiding the depletion of geothermal resources. The models and their coupling have been calibrated and validated with experimental data from a shallow geothermal plant located in Tribano (Padova, IT). It consists of eight coaxial borehole heat exchangers 30 m deep, connected to a 16 kW dual-source heat pump prototype. The heat pump system provides heating and cooling to an office area. The coupled model has been used to compare the performance of the heat pump when working in air-mode only or in ground-mode only. This allowed the development of a switching control strategy between the two thermal sources. Yearly simulations with the switching strategy have shown that the seasonal performance factor of the dual-source heat pump during the heating mode can be 13.8 % higher compared to the one obtained with a conventional air source heat pump and 3.8 % higher with respect to a ground source heat pump.

During CO2 injection operation start-up, strong transient flow occurs. It may lead to sudden changes in CO2 flowing pressure and temperature profiles, and possible phase transition. Moreover, wellbore flow behaviour affects the temperature at which CO2 enters the reservoir posing operational risks such as hydrates precipitation in the reservoir, ice formation around the wellbore, and thermal shocks of the casing. This indicates the importance of a reliable simulation of the coupled wellbore and reservoir flow to design the injection operations. The T2Well-ECO2M coupled wellbore-reservoir simulator allows the modelling of three-phase flow with the possible coexistence of liquid and gaseous CO2. T2Well-ECO2M offers a numerical and a semi-analytical approach to calculate heat exchange between the wellbore and surrounding formation. The full numerical approach is the most accurate, however, it requires building and solving spatial grids with many additional discretisation elements just for the modelling of heat conduction. The semi-analytical approach for wellbore heat exchange is based on the Ramey’s method with or without time-convolution. The numerical and the semi-analytical option with time-convolution approach options were compared with reference to the simulation of dry CO2 injection at constant wellhead rate and enthalpy in a simple 1D radial reservoir containing CO2 and immobile brine. The conceptual model, considered in both approaches, assumes a reservoir at depth of 3067 m with a radial extension of 2000 m. The evolution of flowing pressure and temperature profiles as well as the radial distribution of reservoir thermodynamic conditions are compared. The computation time to solve the time-convolution semi-analytical case was approximately 2.5 % of the time necessary to solve the numerical case with, overall, a good approximation of the numerical solution.

The changes in the surface wettability of many materials are receiving increased attention in recent years. It is not too hard to fabricate resistant hydrophobic surfaces through products bearing both hydrophobic and reactive hydrophilic end groups. More challenging is obtaining resistant nonwetting surfaces through noncovalent reversible bonds. In this work, a fluorinated oligo(ethylenesuccinamide), soluble in solvent benign for operators and environment, has been synthesized. It contains two opposite functional groups (perfluoropolyether segments and amidic groups) (SC2-PFPE) that provide water repellency while hydrophilicity is retained. Its performance has been tested on porous calcarenite and investigated by magnetic resonance imaging, water capillary absorption, and vapor diffusivity tests. The results demonstrate that SC2-PFPE modifies the wettability of porous substrates in a drastic and durable way and reduces the vapor condensation inside the pore space due to the perfluoropolyether segments that act at the air/surface interface.

not available

The Almopias and Paikon "sub-zones" in northern Greece represent the easternmost part of the Vardar Domain. Volcanic sequences in the Paikon subzone largely consist of calc-alkaline volcanic rocks with very minor normal-type (N-) mid-ocean ridge basalts (MORB) and boninites. These data confirm that the Paikon volcanics have originated in a volcanic arc setting developed during the Middle to Late Jurassic times on the westernmost continental margin of the European plate. The Almopias "sub-zone" consists of several ophiolite-bearing tectonic units showing a complex combination of different metamorphic, litho-stratigraphical, and age characteristics. The Liki, Nea Zoi, and Vrissi units (central Almopias) are ophiolitic mélanges, the Mavrolakkos and Krania units (eastern Almopias) consist of volcanic sequences, and the Ano Garefi unit (eastern Almopias) includes serpentinized peridotites and overlying basaltic lavas. The Liki unit underwent metamorphism and deformation under amphibolite-facies condition and includes rocks showing N-MORB and low-K island arc tholeiitic affinities. The Nea Zoi unit incorporates N-MORBs of unknown age and Late Triassic calc-alkaline rocks. The Vrissi unit includes an incomplete volcanic sequence consisting of MORB-type volcanics cross cut by arc-type dyke and Middle-Late Jurassic arc-type volcanic rocks. The Mavrolakkos unit consists of sheeted dykes, lavas, and individual dykes with N-MORB affinity, which are crosscut by dykes showing volcanic arc affinity. The Krania unit consists of Middle-Late Jurassic N-MORB series tectonically associated with calc-alkaline volcanics and dykes. Basalts of the Ano Garefi unit have alkaline affinity, whereas dikes cutting the peridotites show enriched-type MORB chemistry. Our data show the occurrence in the Almopias units of Middle-Late Jurassic N-MORB lavas associated with overlying coeval volcanic arc-type lavas and/or intruded by volcanic arc-type dykes. A major point arising from this paper is that some of the Almopias ophiolitic units do not correlate with the other ophiolitic units in the Dinaride-Hellenide belt and some could correlate with the northernmost extension of the Vardar zone in the South Apuseni - Transylvanian ophiolitic belt in Romania.

Fino ad anni recenti la Risonanza Magnetica Nucleare non era stata sostanzialmente impiegata per lo studio di materiali di interesse per i Beni Culturali. Ora le tecniche di Rilassometria NMR per i materiali porosi sono divenute un importante strumento di indagine della struttura dello spazio poroso, delle sua alterazioni, e del contenuto di acqua. Vengono mostrati esempi di integrazione tra le tecniche NMR ed altre tecniche tradizionali.

In questo lavoro, la tecnica di Imaging a Risonanza magnetica Nucleare (MRI) è stata impiegata per studiare in modo quantitativo, non invasivo, non distruttivo, la cinetica di assorbimento capillare di acqua in campioni di Pietra di Lecce, una biocalcarenite omogenea nella quale il fronte di bagnamento avanza pressoché piatto. MRI permette di misurare in funzione del tempo l’altezza raggiunta dal fronte in qualunque sezione interna del campione. Al fine di studiare l’anisotropia del fenomeno dovuta ad eventuali strati sedimentari, alcuni esperimenti sono stati effettuati variando l’asse principale di assorbimento (ortogonale al piano dove avviene l’assorbimento) attraverso la semplice rotazione del campione cubico. Le differenze osservate nella cinetica di assorbimento a seguito di trattamenti con prodotti idrorepellenti permettono di studiare l’efficacia dei trattamenti stessi. Le misure sono state ripetute dopo il trattamento con una resina acrilica (Paraloid B72) comunemente usata per tali trattamenti. I dati ottenuti sono stati interpretati mediante il modello di Washburn per la risalita capillare. Nell’intervallo di tempo esaminato è stata osservata la prevista dipendenza lineare dell’altezza di risalita dalla radice quadrata del tempo, sia per assorbimento dalla faccia trattata, sia per assorbimento da quella non trattata. I valori del coefficiente angolare (sorptivity, S) ottenuti nelle diverse condizioni permettono di trarre conclusioni circa l’efficacia del trattamento. Quando il litotipo è molto eterogeneo, come nel caso di una biocalcarenite proveniente da una cava nei pressi dell’area archeologica di Agrigento, MRI evidenzia un avanzamento stocastico del fluido, come confermato da immagini ottenute mediante tomografia computerizzata.

In this paper, we present the preliminary data on the age of the radiolarian cherts deposited on top of basalts belonging to the Eastern Ankara Mélange (part of the Izmir-Ankara Mélange). Petrological studies on the basalts were carried out in order to constrain the tectonic setting of the studied basalt-chert sequences. Nine sections were sampled East and Northeast of Ankara and twenty seven samples were collected for biostratigraphic and geochemical analyses. The oldest radiolarian cherts dated in the present paper are referable to the Late Triassic (Section 6: late Norian) and are associated with basaltic rocks of OIB character. OIB type volcanic rocks are also found in other sections, associated with cherts of Late Jurassic (Section 3: middle-late Oxfordian to late Kimmeridgian- early Tithonian) and Early Cretaceous (Section 1: late Valanginian to late Hauterivian) ages. E-MORB type rocks are associated with radiolarian cherts of Cretaceous age (Section 4: middle late Barremian-early early Aptian and Section 7: Valanginian to middle Aptian-early Albian), whereas the oldest N-MORBs were found in a section of Late Jurassic age (Section 5: early-early late Tithonian). Other N-MORBs are associated with radiolarian cherts of Early Cretaceous age (Section 8: late Valanginian-early Barremian). P-MORBs type rocks were found only in a section of Middle Jurassic age (Section 2: early-middle Bajocian to late Bathonian-early Callovian age). In this work, we document the occurrence of Late Triassic OIB-type rocks and of rocks showing different geochemical affinities (N-, E-, P-MORBs and OIB) generated within the same time span (Middle-Late Jurassic - Early Cretaceous). N-MORBs are compatible with composition of melts generated by partial melting of a depleted MORB mantle source. In contrast, OIBs are compatible with partial melting of an enriched-type mantle source. E-MORBs may have derived from mantle source slightly enriched with respect to a DMM source, whereas P-MORBs are compatible with melts generated from a mantle source significantly enriched, compared to DMM.

In the Argolis, the Basal Sequence, constituting the eastern Pelagonian margin which bordered the Maliac-Vardar oceanic domain, includes shallow-water carbonates of Late Triassic-Early Jurassic, condensed pelagic limestones of Early-Middle Jurassic, radiolarian cherts of late Middle-Late Jurassic age and siliceous mudstones and sandstones rich in ophiolite fragments. Up-section, coarse breccias, including clasts of boninites derived from the ophiolite obducted onto the Pelagonian margin in Late Jurassic times crop out. Near Angelokastron a small quarry exposes pervasively sheared dark reddish-brown, radiolarian-bearing cherty shales with disrupted fragments of chert and chert nodules impregnated by ferro-manganese oxides. These shales occur in the footwall of a thrust bringing them into contact with the Pantokrator Limestone of the Basal Sequence. We collected more than 30 samples of the chert fragments and the shaly matrix. Thirteen nodules and one matrix sample yielded determinable radiolarians. Low to non-detectable concentrations of trace metals such as Co, Cr, Cu, Ni, Zn, and Pb indicate a hydrothermal origin of the ferro-manganese mineralization. The radiolarian taxa found indicate four age groups for the nodules that are embedded in the siliceous shale matrix that yielded a Middle Jurassic age (middle Bathonian). The first group includes a nodule of Late Triassic age (late Norian to Rhaetian); the second group nodules of Early Jurassic age (late early to late Pliensbachian and probably middle-late Toarcian); the third group nodules of early Middle Jurassic age (Aalenian-Bajocian); the last group finally includes nodules of late Middle Jurassic age (Bajocian-Bathonian). The presence of Upper Triassic to Middle Jurassic Mn-impregnated chert nodules in a Middle Jurassic matrix indicates a deep oceanic environment of deposition outside the Pelagonian realm (easternmost Adria Plate), which at that time was a shallow-water carbonate platform with a thin pelagic limestone cover. The chert nodules are with all certainty derived from the oceanic Maliac-Vardar domain and were, together with their host formation, tectonically emplaced onto the Pelagonian margin. We speculate that these nodules, more lithified than their matrix, were exhumed on the slope of an intra-oceanic accretionary wedge and were redeposited in the Middle Jurassic siliceous mudstones on the floor of the subducting Maliac-Vardar Ocean.

L'escursione geologica proposta si svolge nell'Appennino bolognese, sino alle aree di crinale e propone una serie di stop illustranti i caratteri salienti delle unità a forte deformazione (tettoniti) e delle ofioliti delle unità liguri e le principali unità della successione epiligure.

A mafic dike is intruded into two SW-NE trending normal faults, and crosscuts the Mt. Alpe Cherts and the Nisportino Fm. in the Monte Castello area, Elba Island, Tuscan Archipelago. The dike is dark grey to brownish in colour, it has a porphyritic texture with phenocrysts of plagioclase + clinopyroxene + olivine, and seldom xenocrysts of large k-feldspar. The original mineralogy is strongly altered and replaced by secondary minerals. Clinopyroxene and plagioclase in some cases are still preserved, whereas olivine is entirely replaced by smectite aggregates. Euhedral Mg-chromite inclusions occur in the olivine ghosts. In the freshest samples the groundmass is made up of clinopyroxene, k-feldspar, plagioclase, magnetite and apatite. Large k-feldspar xenocrysts probably scavenged from a monzogranite are also present. No olivine analyses are available due to strong weathering. Mg-chromites hosted by olivine ghosts have a mild residual character with a Cr# between 0.40 and 0.65. Plagioclases range in composition from An75 to An65, although those enclosed in the k-feldspar xenocrysts have a compositional range from An39 to An35. Clinopyroxenes are mainly sub-calcic diopside (augite) with an Mg# ranging from 0.88 to 0.83. Step-heating 40Ar/39Ar dating was performed on the k-feldspar-rich groundmass of the less altered sample. The result establishes a date of 5.83±0.14 Ma (~70% of the released 39Ar), although the slightly radiogenic initial Ar isotopic composition and the scatter observed during the release of Ar at low temperature make the result only indicative of the age. Secondary minerals are ubiquitous even in the freshest samples, the whole rock compositions indicate that the parental magma has a shoshonitic composition, with a clear alkaline-potassic affinity. Mineral chemistry of k-feldspar and clinopyroxene crystals indicate that the magma belongs to the Italian Potassic Suites, with a strong resemblance to the potassic rocks cropping out at the Capraia Island and in the Southern Tuscany. The presence of olivine ghosts with euhedral Mg-chromite inclusions suggest that the magma has a strong primitive composition, with an alkaline character. Initial Sr-isotope values are in the range between 0.70878-0.70900, which indicate that the parental magma of the dike has not been contaminated with the monzogranite but the radiogenic Sr has been diluted by small scale magma-wall rock interaction. The presence of xenocrysts from a monzogranite, and lack of reaction paragenesis clearly indicates that the mafic magma intruded the monzogranite successively to its cooling. The 5.8 Ma age of this dike constitutes a very important datum: in fact it indicates that block tectonics should began in the Island before this date, and could be contemporaneous or also older of the gravitational detachments triggered by the Monte Capanne pluton uplift.