2-D and 3-D tools for electrical imaging in environmental applications

The work presented in this thesis is focused on the characterization of contaminated sites via the application of non-invasive methods, such as electrical resistivity and electromagnetic techniques. With the aim of improving the relationships between geophysical parameters and hydro-geological features of the subsoil, some innovative methods are proposed. In particular, being electrical resistivity tomography an ill-posed and under-determined problem, the solution is computed by an over-parameterization of the model element with respect of the available measured data. The need to improve the resolution of resistivity imaging technique without stressing the intrinsic under-determination of the geo-electrical problem, and to provide more robust results in integrated characterization approaches, guided the work presented in this thesis to works on both “static” 2-D and 3-D problems, and on the inversion of time-lapse data. In addition, joint characterization of contaminated site has been carried out together with chemico-physical and biological analysis. Grid manipulation techniques have been explored and adapted to the inversion of geo-electrical data, in order to solve inversion of resistivity data set trying to improve space resolution without decaying the robustness of the inversion process. Furthermore, results obtained by the testing of a novel code for the inversion of complex resistivity data are presented. The software was implemented on the basis of the Primal-Dual method, which allows flexibility in choosing to minimize the L1- or the L2- norm on both the data and regularization term of the objective function. Strategies related to the inversion of electrical resistivity and IP data have been developed with the aim of improving the interpretability of the results both in space and in time. These activity are part of a common effort for achieving an integrated characterization of contaminated sites, jointly with chemico-physical analysis of soils and groundwater and with measures of presence and degradation activity of hydrocarbon-degrading biomass

P-wave and surface wave survey for permafrost analysis in alpine regions

We discuss the results of seismic survey to delineate temporal and spatial changes of frozen layer in Alpine environments. The seismic characterization allows us to detect changes of soil deformability properties related to the temperature effect on subsoi

Flowmeter and Ground Penetrating Radar: comparison between hydrogeological and geophysical methods

We discuss a comparison between saturated hydraulic conductivity calculated with Electromagnetic Borehole Flowmeter (EBF) and water content obtained by Ground Penetrating Radar (GPR) Zero Offset Profile (ZOP

Deoxygenation of non-edible vegetable oil to produce hydrocarbons over Mg-Al mixed oxides

none7noopenRomero, Max; Pizzi, Andrea; Toscano, Giuseppe; Casazza, Alessandro Alberto; Busca, Guido; Bosio, Barbara; Arato, ElisabettaRomero, Max; Pizzi, Andrea; Toscano, Giuseppe; Casazza, Alessandro Alberto; Busca, Guido; Bosio, Barbara; Arato, Elisabett

Effects of cadmium on viability and function of porcine pre-pubertal Sertoli cells

Cadmium, an ubiquitous environmental pollutant mainly used for industrial purposes, is highly associated with reproductive toxicity. Sertoli cells (SC), by providing an appropriate microenvironment for the development of germ cells, play a pivotal role on spermatogenesis regulation (Geoffroy-Siraudin et al. 2012). Aim of our investigation was to assess the effects of cadmium on high mammalian SC viability and function. Porcine pre-pubertal SC were isolated, according to previously established methods (Fallarino et al. 2009) and treated with 3 different concentrations (5-10-15 μM) of cadmium chloride. The evaluation of SC function in terms of inhibin B and anti-Müllerian hormone (AMH) secretion showed a significant decrease in all SC treated conditions respect as compared to SC control. On the contrary, evaluation of the FSH-R integrity on SC surface, in terms of 17-b-estradiol production under FSH stimulation, showed no difference between SC control and 5 μM cadmium treated SC monolayers in comparison to 10 and 15μM cadmium treated SC monolayers, where FSH-R was impaired. In addition, the apoptotic test showed a significant increase of early (ANNEXIN V-/Propidium Iodide+) (AV-/PI+) and late apoptotic cells (AV+/ PI+) in all cadmium treated SC conditions in comparison with SC control. In conclusion, our data demonstrate that cadmium, even at low dose, exerts toxic effects on Sertoli cells function possibly adversely affecting the spermatogenesis

Nickel oxide nanoparticles exposure as a risk factor for male infertility: “In vitro” effects on porcine pre-pubertal Sertoli cells

Lately, nickel oxide nanoparticles (NiO NPs) have been employed in different industrial and biomedical fields. Several studies have reported that NiO NPs may affect the development of reproductive organs inducing oxidative stress and, resulting in male infertility. We investigated the in vitro effects of NiO NPs on porcine pre-pubertal Sertoli cells (SCs) which undergone acute (24 h) and chronic (from 1 up to 3 weeks) exposure at two subtoxic doses of NiO NPs of 1 μg/ml and 5 μg/ml. After NiO NPs exposure we performed the following analysis: (a) SCs morphological analysis (Light Microscopy); (b) ROS production and oxidative DNA damage, gene expression of antioxidant enzymes (c) SCs functionality (AMH, inhibin B Real-time PCR analysis and ELISA test); (d) apoptosis (WB analysis); (e) pro-inflammatory cytokines (Real-time PCR analysis), and (f) MAPK kinase signaling pathway (WB analysis). We found that the SCs exposed to both subtoxic doses of NiO NPs didn’t sustain substantial morphological changes. NiO NPs exposure, at each concentration, reported a marked increase of intracellular ROS at the third week of treatment and DNA damage at all exposure times. We demonstrated, un up-regulation of SOD and HO-1 gene expression, at both concentrations tested. The both subtoxic doses of NiO NPs detected a down-regulation of AMH and inhibin B gene expression and secreted proteins. Only the 5 μg/ml dose induced the activation of caspase-3 at the third week. At the two subtoxic doses of NiO NPs a clear pro-inflammatory response was resulted in an up-regulation of TNF-α and IL-6 in terms of mRNA. Finally, an increased phosphorylation ratio of p-ERK1/2, p-38 and p-AKT was observed up to the third week, at both concentrations. Our results show the negative impact of subtoxic doses NiO NPs chronic exposure on porcine SCs functionality and viability

Staggered grid inversion of cross hole 2-D resistivity tomography

We apply the staggered grid method (referred to as SGERT in this paper) to the inversion of electrical resistivity 16 data in order tominimize ambiguity and smearingwhen inverting a datasetwith a unique grid. Artefacts are typ- 17 ical drawbacks in inversion of cross-hole resistivity data, especially in the zones of the image characterized by 18 poorer model resolution, in presence of noisy data or when sound a-priori information is poor or not available. 19 SGERT is based on a reiterated inversion of the same resistivity dataset on a series of grids obtained by staggering 20 a starting one. The application of the SGERT tends to limit the formation of artefacts, as it roughly operates as a 21 moving average. Moreover, the SGERT permits to estimate the standard deviation of each resistivity value 22 (pixel) in the resulting image. This datum improves the quantitative information of the inverted resistivity 23 image.We run a set of tests applying SGERT to the inversion of 2-D synthetic electrical resistivity data comparing 24 the final results to the ones obtained using a standard single grid inversion. The SGERT reveals a reduction of ar- 25 tefacts, and shows amore robust reconstruction of the syntheticmodel.We also apply the SGERT to a cross-hole 26 resistivity field dataset collected for characterizing and monitoring a contaminated sit

3D inversion of ERT data on an archaeological site using GPR reflection and 3D inverted magnetic data as a priori information

Non-destructive geophysical prospecting methods are increasingly used for the investigation of archaeological sites, where a detailed physical and geometrical reconstruction of structures is required prior to any excavation work. In 1996, at the Archaeological Test Site of the Sabine Necropolis at Research Area of National Research Council of Rome (Montelibretti, Italy), a small area had been selected to test the integration of magnetic, ground-penetrating radar, and electrical resistivity tomography techniques. The magnetic data were acquired as the vertical gradient of the total magnetic field and were inverted by minimizing an L-2 norm. The ground-penetrating radar data were acquired as singleoffset measurements on a regular grid and processed to obtain time slices of reflection amplitude. The electrical resistivity tomography data were acquired with dipole-dipole array along parallel profiles in both east-west and north-south directions. In this work, we reprocessed the data collected in 1996 performing a three-dimensional inversion of electrical resistivity tomography data using ground-penetrating radar data and three-dimensional inversion results of the magnetic data. We inverted electrical resistivity tomography data according to L2 and L1 norm minimization. Both the mean apparent resistivity and different resistivity distributions derived from processed ground-penetrating radar and three-dimensional inversion of the vertical gradient of the total magnetic field data were used as a starting model. The results were then compared in the volume under the surveyed area: merits and shortcomings of the different techniques are pointed out and analyzed. From the results of the different applied techniques, it comes that both electrical resistivity tomography and vertical gradient of the total magnetic field locate the searched tomb as a volume, whereas ground-penetrating radar mainly identified the ceiling of the tomb. Vertical gradient of the total magnetic field data inversion obtained from minimization of the L2 norm properly locates both the chamber and the corridor but produces smeared overestimated volumes. Three-dimensional inversions of electrical resistivity tomography data with a priori information give an accurate picture of the chamber and delineates the corridor, even if the resistivity values are underestimated if compared with the expected resistivity of void. Results are compared with the archaeological findings as the area was unearthed and verified in 200