ABSTRACT
This study presents an innovative and effective solution for recycling PET bottles as raw for producing anion exchange membranes (AEMs) for electrochemical applications. This approach reduces the demand for pristine materials, a key principle of the circular economy and sustainability. PET was subjected to chemical modification by introducing cationic functional groups followed by methylation and OH- exchange process. The amination synthesis was optimized based on reaction time. The results indicate that ion exchange capacity, water uptake, and swelling ratio properties mainly depend on the degree of cationic functionalization. The optimized AEM exhibits ionic conductivity of 5.3 × 10-2 S·cm-1 and alkaline stability of 432 h in 1 M KOH at 80 °C. The membrane properties before and after the alkaline treatment were investigated using Fourier-transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy analysis. Computational chemistry analysis was employed to gain further insights into the membrane degradation mechanisms and pathways under alkaline conditions. This research and its findings are a step toward using recycled materials in the field of AEM technology.
ABSTRACT
Geographic profiling, or locus operandi, is a scientific approach that has been applied to forensic investigations for several years. However, it has never been applied to a phenomenon as complex as the search for missing persons. This article presents three Italian case studies in which geographic profiling was used to narrow the areas to search for missing persons. The geographical data were mapped and processed on a geographic information system platform using computational geometry analysis. However, these disappearances occurred during the Italian lockdown period, imposed to address the COVID-19 outbreak, which made the searches slower and more complex than usual.
ABSTRACT
Air permeability measurements according to the Hagen-Poiseuille equation, Scanning Electron Microscopy (SEM) and mercury intrusion porosimetry (MIP) tests were conducted on samples of cementitious mortar at different curing times to study the correlation between the increased crystallization and their microstructure. The mortar samples were prepared with a commercial fast-setting premix containing calcium silicates and quartz. The average permeability coefficient (K) was 2.96 × 10-15 m2 after 3 days and decreased to 3.07 × 10-17 m2 after about one month. The continuous C-S-H nucleation in the capillary pores of the cement mortar changes their shape and improves the mortar's impermeability. The SEM images showed the development of crystals that refine the pore size distribution of the cement paste, with more of the smallest pores, and fewer of the largest, as demonstrated by the MIP measurements. Adding a superabsorbent polyacrylate (SA-PA) in the amount of 0.5% wt of dry powder, without adding any extra water, makes a mortar less fluid but not faster-setting. Twenty-four hours after mixing and casting, it is still plastic and, with time, the pore size distribution differs from that of standard mortar. Over time in air, permeability remains high, but in water it could be low due to swelling of SA-PA residues.
ABSTRACT
Cu2ZnSnS4 (CZTS) nanocrystals in oleylamine (OLA) and 1-dodecanethiol (1-DDT) solvents were successfully prepared via hot-injection method, to produce inks for the deposition of absorber layers in photovoltaic cells. In this process, 1-DDT acts as a coordinating ligand to control the nucleation and growth of CZTS nanocrystals, whereas lower amounts of OLA promote a homogeneous growth of the grains in the absorber layer. X-Ray Diffraction (XRD) revealed both tetragonal and hexagonal phases of CTZS in films obtained after soft thermal treatments (labeled TT0). In particular, 1-DDT is responsible for the formation of a greater percentage of the hexagonal phase (ZnS-wurtzite type) than that formed when only OLA is used. The thermal treatments have been varied from 500 °C to 600 °C for improving crystallization and eliminating secondary phases. Both features are known to promote CZTS thin films with band gap values typical of CZTS (1.5-1.6 eV) and suitable resistivity. This study let to compare also the CZTS post-annealing without (TT1) and with sulfur vapor (TT2) in a tubular furnace. Only tetragonal CZTS phase is observed in the XRD pattern of CZTS thin films after TT2. A small presence of localized residues of secondary phases on the same samples was revealed by µRaman measurements. The best values of band gap (1.50 eV) and resistivity (1.05 ohm.cm) were obtained after thermal treatment at 500 °C, which is suitable for absorber layer in photovoltaic application.
ABSTRACT
Ground penetrating radar (GPR) investigations have the potential to non-destructively detect buried or hidden targets and are therefore often used in forensic research. This study presents a particular application of GPR methods to search for a missing person in a specific subsurface environment: a natural cave. The search for missing people in Italy is a problematic and delicate task that needs improvement. Results of this study highlight not only the ability to detect both hollow and forensic targets, but also precisely locate and define their geometries. Moreover, GPR findings efficiently focus archaeological excavation and body recovery in an exact area and help to minimise time digging in erroneous places.
ABSTRACT
Novel inorganic-organic hybrid copolymers based on vinyl- or (3-mercaptopropyl)-trimethoxysilane and an organically modified zirconium-oxocluster were investigated as a wood preservation treatment. The copolymers were prepared using a modified sol-gel strategy not involving alkoxysilane pre-hydrolysis and were applied on wood through a dip coating method. Even though the copolymers were mainly present on the surface of the wood, EDX analysis showed also a uniform distribution of silicon and zirconium in the cell wall but not in the lumina. The grafting of the copolymers on wood was confirmed through FTIR, (13)C and (29)Si MAS NMR analysis. The copolymer obtained from (3-mercaptopropyl)trimethoxysilane was post-functionalized with the methacrylic ester of thymol; introduced for testing as a biocide. Preliminary accelerated biological tests against the brown rot fungus Coniophora puteana, showed resistance to the fungus for the samples coated with the vinyltrimethoxysilane copolymer, while uneven results were obtained for the samples coated with the (3-mercaptopropyl)trimethoxysilane copolymer, even when functionalized with the ester of thymol.
