Geostructural and Geomechanical Study of the Piastrone Quarry (Seravezza, Italy) Supported by Photogrammetry to Assess Failure Mode

The use of non-contact-techniques for rock mass characterization has been growing significantly over the last decade. However, their application to stability assessment of ornamental stone has not yet received much attention from researchers. This study utilizes rock mass data both in terms of slope orientations and degree of fracturing obtained from a point cloud, a set of three-dimensional (3D) points representing a rock mass surface, to (1) investigate the influence of geostructures at different scales and (2) assess quarry stability by determining areas susceptible to different failure types. Multi-resolution point clouds are obtained through several photogrammetric survey techniques to identify important structural elements of the site. By integrating orientation data of discontinuity planes, obtained with a traditional survey, and of traces, outlined on point clouds, several joint sets were identified. Kinematic tests revealed various potential failure modes of the rock slope. Moreover, an analysis of the influence of the discontinuity strength determined by the presence of rock bridges was carried out. The study revealed that the strength of the quarry face is governed by the presence of rock bridges that act to improve the stability condition of the rock fronts

Antiretroviral therapy in HIV/HCV co-infection Italian consensus workshop

About 50% of people living with the HIV infection in Italy are co-infected with HCV. In this group of patients, the primary cause of mortality is liver disease, which accounts for up to 14% of deaths. HIV/HCV co-infection also exposes patients to a higher risk of progression to AIDS, a faster evolution towards cirrhosis, more frequent drug toxicity, and lower tolerance for antiretroviral therapy. Moreover, HCV infection can play a part in increasing immune system depression; neurological, cognitive and renal damage; and bone fragility. Hence an optimal antiretroviral regimen needs to be chosen for co-administration with anti-HCV therapy and timed appropriately to improve the prognosis of co-infected HIV/HCV patients. Unfortunately, however, data on the safety and efficacy of antiretroviral drugs in these patients is scarce, as are studies of pharmacokinetics in patients with advanced liver impairment. Furthermore, restoring adequate immune constitution seems not to slow the progression of liver disease, and the metabolic and hepatic toxicity of some antiretroviral drugs can even contribute to inflammatory and fibrogenic processes. It is therefore essential that HIV/HCV co-infected patients receive only medications capable of ensuring the best immune recovery but possessing the lowest potential to trigger immune reconstitution syndrome or hepatic and metabolic damage

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of $\sqrt s =1.96$ TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is $A_{\mathrm{FB}}^{t\bar{t}} = 0.128 \pm 0.025$. The combined inclusive and differential asymmetries are consistent with recent standard model predictions

Micellization of lithium perfluoroheptanoate and its aggregation on poly(ethylene glycol) oligomers in water

The interaction of lithium perfluoroheptanoate (LiPFHep) with poly(ethylene glycol) (PEG) of different molecular weights (300 < MW < 20 000 Da) was investigated in water at 298.15 and 308.15 K by the isothermal titration calorimetry (ITC). Density and sound velocity measurements were also performed at 288.15, 298.15, and 308.15 K, while viscosity and conductivity data were only collected at 298.15 K. The aggregation process of this surfactant on the PEG polymeric chain was found to be very similar to the process exhibited by the two homologous perfluorooctanoate and perfluorononanoate. Viscosity and ITC data indicated that the formation of polymer-surfactant complexes between PEG and LiPFHep also leads to a conformational change in the polymer. The aggregation of micelles of the lithium perfluoro surfactants on the PEG polymeric chain is characterized by a comparable thermodynamic stability, which results from a balance of enthalpy and entropy contributions, which both increase with the length of the surfactant hydrophobic chain

Selective determination of poly(styrene) and polyolefin microplastics in sandy beach sediments by gel permeation chromatography coupled with fluorescence detection

Microplastics generated by plastics waste degradation are ubiquitous in marine and freshwater basins, posing serious environmental concerns. Raman and FTIR spectroscopies, along with techniques such as pyrolysis-GC/MS, are typically used for their identification. We present a procedure based on gel permeation chromatography (GPC) coupled with fluorescence detection for semi-quantitative selective determination of the most common microplastics found in marine shoreline sediments: poly(styrene) (PS) and partially degraded polyolefins (LDPEox). By operating the detector at either 260/280 or 370/420 nm excitation/emission wavelengths PS can be distinguished from LDPEox upon GPC separation. Semi-quantitative determination of microplastics contents is also possible: dichloromethane extracts of PS and LDPEox yield linear plots of fluorescence peak area vs concentration (0-5.0 mg/mL range) and were used as reference materials for quantification of the plastics content in sand samples collected in the winter berm and dune sectors of a Tuscany beach in Italy

Thermodynamic study of organic compounds in di-n-butyl ether. Enthalpy and Gibbs energy of solvation

The Gibbs energies and enthalpies of solvation of some hydrocarbons (n-hexane, n-octane, cyclohexane), alcohols (methanol, propan-1-ol, butan-1-ol, butan-2-ol), ethers (diethyl ether, tetrahydrofuran), ketones (propanone, pentan-3-one, cyclopentanone), amines (n-propylamine, n-butylamine), and acetonitrile in di-n-butyl ether have been determined at 298.15 K from vapour-liquid equilibrium measurements and from limiting enthalpies of solution. The data obtained have been compared with the corresponding values of the solvation functions in octan-1-ol and hexadecane. The phenomenology has been discussed in terms of a simple group additivity scheme. The interaction effects of polar and non-polar groups with the solvents have been deduced from the above group contributions combined with the cavity terms estimated through the scaled particle theory. The linear solvation energy relationships (LSER) have also been used for correlating the thermodynamic solvation function to the structural features of the solutes. All the approaches consistently highlight that the hydrophobic groups exhibit interactions with the solvent of nearly the same strength in the three media, while clearly different interactions are shown by polar groups

Thermal behavior of Sicilian clay-based geopolymers

Geopolymers have been recently proposed for restoration of built heritage to substitute traditional mortars. Local materials and industrial wastes from the Italian region Sicily showed their potential as low-cost aluminosilicate sources for the preparation of geopolymers. Here, a set of Sicilian clays was studied by Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC), and its mineralogical composition was evaluated by X-ray diffraction (XRD). The raw materials were used to prepare geopolymers by alkaline activation with or without the addition of silicate. The thermal degradation profile of the final materials was studied by TGA and compared with that of the precursors, and the energetics of dehydration were investigated by DSC. Two statistical analyses (made by Principal Component Analysis) were performed on the TG data of raw materials and geopolymers and on the TG data of geopolymers and their mineralogical composition, respectively. The last analysis in particular showed a correlation between the mineralogical composition of the materials and the samples' thermal properties. Additional studies of samples subject to accelerated aging by UV irradiation and exposure to acetic acid vapors highlighted the different effects of these two agents on the samples' stability

Building geopolymers for CuHe part I: thermal properties of raw materials as precursors for geopolymers

This paper presents the results obtained from the thermal analysis of a set of geomaterials (clays, pyroclastic materials, and industrial recycled materials) to be used as raw materials for the synthesis of geopolymers, specifically designed for the conservation of Cultural Heritage (CH) buildings, particularly in seismic hazard zones such as Sicily. X-ray diffraction and gas volumetric analysis (calcimetry) were applied to this set of raw materials in order to characterize the materials from the chemical and structural point of view. Thermogravimetric analysis (TG), TG coupled to Fourier transform infrared spectroscopy (TG-FTIR), and differential scanning calorimetry were used to characterize their thermal behavior. The statistical treatment of the thermogravimetric data by principal component analysis and hierarchical clustering analysis highlights the direct relation between the thermal data and the material composition that will be exploited for the selection of the best materials to obtain geopolymers specifically designed for the conservation of CH buildings