Daniele Moro

The present study reports the variation of the mechanical properties of engineered metakaolin-based geopolymers synthetized using NaOH-KOH alkali activators and sodium disilicate, investigated after 7 and 28 days of aging by means of unconfined compression tests for mechanical strength analysis. The geopolymers were synthetized by mixing KOH and NaOH in different proportions in the alkaline activating solution, from 0% to 100% of KOH addition, fixing the Si/Al ratio and water content. The binders were synthetized with different curing temperatures. A novel composition using quarry-derived materials (silt from sedimentation lakes) was developed to realize an innovative composite. The materials were characterized by XRD, ESEM-EDS and unconfined compression tests. The mechanical results underlined that the addition of the filler tends to preserve the mechanical properties of the composite. Generally, curing at 40 °C followed by a 28-day aging period for the mixed Na-K geopolymers demonstrated the highest mechanical strength of all the synthesized products, with a maximum strength of 21 MPa. Mixed NaOH-KOH composites generally exhibited lower performances compared to sample consisting solely of 100% NaOH when cured at a temperature of 85 °C. Nonetheless, the synthetized composites reported in this study can have diverse applications across various technological fields requiring low-strength materials.

Purpose: This study examines adherence to the Mediterranean diet (MD) among Italian adults, identifying meaningful determinants, including socioeconomic factors, health and sustainability-related practices, environmental concerns, and psychological well-being. Design/methodology/approach: Data consist of 103,447 adult individual-level observations from the Multipurpose Household Survey (MHS) collected by the Italian National Institute of Statistics (ISTAT) from a representative sample of Italian households during years 2019–2021. Adherence is measured through three indexes: the Mediterranean Diet Score (MDS), the Mediterranean Diet Serving Score (MDSS), and the Mediterranean Diet Composite Score (MDCS). Ordered logit models have been used to assess the impact of individual, household, and health behaviors. Findings: The cross-sectional analysis reveals that higher MD adherence is positively associated with older age, female gender, higher education, and elevated socioeconomic status. Individuals engaged in health-promoting behaviors, such as regular physical activity and non-smoking, and those with greater environmental awareness and pro-environmental behaviors are more likely to follow the MD. Psychological well-being plays a relevant role, as lower levels of psychological distress correspond with higher MD adherence. Household characteristics, including marital status and the presence of preschool children, also play a role in adherence patterns. Research limitations/implications: These findings underline the importance of integrating health behaviors, environmental sustainability, and psychological well-being into public health strategies to promote the MD. Practical implications: Results emerging from this research can assist policymakers to encourage a diet that supports both human and environmental health, in line with the Farm to Fork strategy's objectives and the promotion of sustainable, healthy food systems. Originality/value: This study offers a novel, integrative analysis of MD adherence by jointly examining psychological well-being, pro-environmental behaviors, and socio-economic characteristics within a single empirical model. Using a nationally representative sample of over 100,000 Italian adults (2019–2021), it captures subclinical psychological distress in a non-clinical population, extending beyond traditional socio-demographic analyses. The study is also the first to simultaneously explore psychological and environmental factors during the COVID-19 period and to compare three widely used MD adherence indices (MDS, MDSS, MDCS), demonstrating how index choice affects prevalence estimates and associations, thus providing key methodological insights for research and policy.

This study is part of a broader conservation and restoration project of the 17th-century statue “Santissimo Salvatore” attributed to the Bolognese sculptor Gabriele Brunelli (1615–1682). This sculpture was traditionally classified as a marble statue, i.e., primarily composed of calcium carbonate. However, the careful diagnostic analyses conducted during the present work of restoration revealed that, instead, the sculpture is made of gypsum alabaster, a material predominantly composed of calcium sulphate hydrate (CaSO₄·2H₂O). In the present research, a multi-analytical investigation was carried out using X-Ray Powder Diffraction (XRPD), Field Emission Environmental Scanning Electron Microscopy (FE-ESEM) with Energy-Dispersive X-ray Spectroscopy (EDS), and confocal Raman microspectrometry. Here, we report detailed and updated analytical data of the material constituting the “Santissimo Salvatore” statue by Gabriele Brunelli. These data were found extremely useful to plan and accomplish the restoration work in detail: (i) the suitable conservation project of the artwork, (ii) the reassessment of the knowledge on the artist’s sculptural production, and (iii) gaining more information about the material used in the 17th-century Bolognese sculptural context.

The present research investigates the possibility to create a silt-waste reinforced composite through a NaOH-activated, metakaolin-based geopolymerization process. In this regard, we used thermal exo–endo analysis, X-ray diffraction (XRD), and oedometric mechanical tests to characterize the produced composites. In our experimental conditions, the tested material mixtures presented exothermic peaks with maximum temperatures of about 100 °C during the studied geopolymerization process. In general, the XRD analyses showed the formation of amorphous components and new mineral phases of hydrated sodalite, natrite, thermonatrite and trona. From oedometric tests, we observed a different behavior of vertical deformation related to pressure (at RT) for the various produced composites. The present work indicated that the proposed geopolymerization process to recycle silt-waste produced composite materials with various and extended mineralogy and chemical–physical properties, largely depending on both the precursors and the specific alkaline-activating solution. Thermal analysis, XRD, and oedometric mechanical tests proved to be fundamental to characterize and understand the behavior of the newly formed composite material.

Calcite (CaCO₃, space group Rc) is a solid phase whose well-known highly anisotropic physical properties can be exploited to compare and calibrate various theoretical simulation methods. In this work, to benchmark different ab initio Density Functional Theory approaches that include for the first time corrections for dispersive forces, a systematic analysis of structural, electronic, dielectric, optical and vibrational properties of calcite is performed. The simulations considered the generalized-gradient approximation functional PBE and the hybrid B3LYP and PBE0, whereas the DFT-D2 and DFT-D3 schemes were adopted to account for the long-range interactions. This study suggests an overall better agreement between the theoretical results obtained with the DFT functionals corrected for the dispersive forces, with a better performance of hybrid functionals over PBE.

The focus of the present study is on fibre-reinforced geopolymer composites, whose optimization and application necessarily need a detailed chemical characterization at the micro-nanoscale. In this regard, many geopolymer composites presenting micro and nanometric architectures pose a challenge for scanning electron microscopy with energy dispersive X-ray microanalysis (SEM-EDS) quantification, because of several potential sources of errors. For this reason, the present work reports a SEM-EDS Monte Carlo approach to carefully investigate the complex physical phenomena related to the cited quantification errors. The model used for this theoretical analysis is a simplified fibre-reinforced geopolymer with basalt-derived glass fibres immersed in a potassium-poly(sialate-siloxo) matrix. The simulated SEM-EDS spectra showed a strong influence on the measured X-ray intensity of (i) the sample nano-to-micro architecture, (ii) the electron beam probing energy and (iii) the electron probe-sample-EDS detector relative position. The results showed that, compared to a bulk material, the X-ray intensity for a nano-micrometric sized specimen may give rise to potential underestimation and/or overestimation of the elemental composition of the sample. The proposed Monte Carlo approach indicated the optimal instrumental setup depending on the sample and on the specific SEM-EDS equipment here considered.

The aim of this study was the morphological evaluation of root surfaces subjected to manual (curette) and ultrasonic (conventional and diamond tips) scaling. The surface was then polished with a rubber cup and three medium-sized pastes. Ninety teeth were randomly divided into three groups of 30 and subjected to three different root instrumentation: (1) manual instrumentation with a Gracey^® curette; (2) ultrasonic instrumentation with a standard steel tip (Universal Perio S-SERIES: USU, Hu-Friedy, Chicago, IL, USA) at a power equal to 50%; and (3) with a diamond tip (Punta Piezo Serie E Scaling, Hu-Friedy, Chicago, IL, USA) at a power of 20%. Each group of the instrumented teeth was then divided in three subgroups of 10 and subjected to 30 s of rubber polishing with three different polishing pastes with medium grain sizes in single-dose cups: (1) Ultrapro Tx cool mint medium^®; (2) Stomyprox media^®; and (3) Nupro medium orange^®. Polyether root surface replicas were then taken from all 90 samples and analyzed by SEM to evaluate surface morphology after scaling and polishing procedures. All scaling techniques caused an alteration of the root surface without statistically significant difference, whereas polishing resulted in maintenance or improvement of the surface texture.

Hard tissues (e.g., bone, enamel, dentin) in vertebrates perform various and different functions, from sustaining the body to haematopoiesis. Such complex and hierarchal tissue is actually a material composite whose static and dynamic properties are controlled by the subtle physical and chemical interplay between its components, collagen (main organic part) and hydroxylapatite-like mineral. The knowledge needed to fully understand the properties of bony and dental tissues and to develop specific applicative biomaterials (e.g., fillers, prosthetics, scaffolds, implants, etc.) resides mostly at the atomic scale. Among the different methods to obtains such detailed information, atomistic computer simulations (in silico) have proven to be both corroborative and predictive tools in this subject. The authors have intensively worked on quantum mechanical simulations of bioapatite and the present work reports a detailed review addressed to the crystal-chemical, physical, spectroscopic, mechanical, and surface properties of the mineral phase of bone and dental tissues. The reviewed studies were conducted at different length and time scales, trying to understand the features of hydroxylapatite and biological apatite models alone and/or in interaction with simplified collagen-like models. The reported review shows the capability of the computational approach in dealing with complex biological physicochemical systems, providing accurate results that increase the overall knowledge of hard tissue science.