Monitoring and preservation of stone cultural heritage using a fuzzy model for predicting salt crystallisation damage.

In this study, a fuzzy model is presented for predicting the possibility of degradation due to salt crystallisation cycles. The formalization of the proposed model has been based on the multivariable approach which considers environmental data (such as temperature, solar radiation, wind speed, rain quantity, relative humidity), characteristic inflection points of specific salts and stone features derived from laboratory characterizations (including mechanical properties, porosity, and mineralogical composition). Modeling results have been compared with experimental data elaborations acquired by monitoring a semi-confined archaeological site situated in the city of Cagliari (Munatius Irenaus cubicle), revealing substantial alignment in the degradation kinetics trends. Moreover, the achieved outcomes show the remarkable capability to identify salt crystallisation phenomenon type (efflorescence or subflorescence).

Salt Crystallization in Limestone: Materials Decay and Chemomechanical Approach.

Salt crystallization is a particularly relevant issue in the conservation of limestones used in Cultural Heritage sites. In this study, various facies of limestones were characterized through porosimetric and mechanical tests. The samples were subjected to experiments to determine their resistance to salt crystallization by verifying the number of cycles at which 50% of them began to lose weight. This number of experimental cycles was compared with the result calculated by the analytical procedure of a chemomechanical model found in the literature. The comparison showed a significant capability of the model to predict the experimental data.

Nanoporous Au Behavior in Methyl Orange Solutions.

Nanoporous (NP) gold, the most extensively studied and efficient NP metal, possesses exceptional properties that make it highly attractive for advanced technological applications. Notably, its remarkable catalytic properties in various significant reactions hold enormous potential. However, the exploration of its catalytic activity in the degradation of water pollutants remains limited. Nevertheless, previous research has reported the catalytic activity of NP Au in the degradation of methyl orange (MO), a toxic azo dye commonly found in water. This study aims to investigate the behavior of nanoporous gold in MO solutions using UV-Vis absorption spectroscopy and high-performance liquid chromatography. The NP Au was prepared by chemical removal of silver atoms of an AuAg precursor alloy prepared by ball milling. Immersion tests were conducted on both pellets and powders of NP Au, followed by examination of the residual solutions. Additionally, X-ray photoelectron spectroscopy and electrochemical impedance measurements were employed to analyze NP Au after the tests. The findings reveal that the predominant and faster process involves the partially reversible adsorption of MO onto NP Au, while the catalytic degradation of the dye plays a secondary and slower role in this system.

Thermal Properties of Eco-Friendly Earthen Materials Stabilized with Bio-Based Polymers: Experimental Data and Modeling Procedure for Improving Mix-Design.

The fight against climate change has delineated new objectives, among which one of the most crucial is the replacement of high-energy-intensity materials in the construction sector with more sustainable and thermally efficient alternatives to reduce indirect emissions. Consequently, the thermal properties of materials assume fundamental importance. In this regard, the large-scale use of earth represents a promising option, not only due to its widespread availability but especially for its minimal embodied energy. However, to enhance its durability, it is necessary to stabilize the mixtures of raw materials. This study analyzes experimental systems based on earth stabilized with bio-based polymers to evaluate their thermal properties and how these vary depending on the selected mix-design. The experimental measurements showed thermal properties comparable to conventional materials. As expected, thermal conductivity increases when porosity decreases. The minimum value is equal to 0.216 W/m·K vs. a porosity of 43.5%, while the maximum is 0.507 W/m·K vs. a porosity of 33.2%. However, the data obtained for individual systems may vary depending on the topological characteristics, which were analyzed through a model for granular materials. The modeling suggests correlations between microstructures and thermal behaviour, which can be useful to develop tools for the mix-design procedure.

New Materials and Technologies for Durability and Conservation of Building Heritage.

The increase in concrete structures' durability is a milestone to improve the sustainability of buildings and infrastructures. In order to ensure a prolonged service life, it is necessary to detect the deterioration of materials by means of monitoring systems aimed at evaluating not only the penetration of aggressive substances into concrete but also the corrosion of carbon-steel reinforcement. Therefore, proper data collection makes it possible to plan suitable restoration works which can be carried out with traditional or innovative techniques and materials. This work focuses on building heritage and it highlights the most recent findings for the conservation and restoration of reinforced concrete structures and masonry buildings.

Effects of the Parent Alloy Microstructure on the Thermal Stability of Nanoporous Au.

Nanoporous (NP) metals represent a unique class of materials with promising properties for a wide set of applications in advanced technology, from catalysis and sensing to lightweight structural materials. However, they typically suffer from low thermal stability, which results in a coarsening behavior not yet fully understood. In this work, we focused precisely on the coarsening process undergone by NP Au, starting from the analysis of data available in the literature and addressing specific issues with suitably designed experiments. We observe that annealing more easily induces densification in systems with short characteristic lengths. The NP Au structures obtained by dealloying of mechanically alloyed AuAg precursors exhibit lower thermal stability than several NP Au samples discussed in the literature. Similarly, NP Au samples prepared by annealing the precursor alloy before dealloying display enhanced resistance to coarsening. We suggest that the microstructure of the precursor alloy, and, in particular, the grain size of the metal phases, can significantly affect the thermal stability of the NP metal. Specifically, the smaller the grain size of the parent alloy, the lower the thermal stability.

Chemical effects induced by the mechanical processing of granite powder.

Starting from 1970s, the use of mechanical forces to induce chemical transformations has radically changed vast areas of metallurgy and materials science. More recently, mechanochemistry has expanded to core sectors of chemistry, showing the promise to deeply innovate chemical industry while enhancing its sustainability and competitiveness. We are still far, however, from unveiling the full potential of mechanical activation. This study marks a step forward in this direction focusing on the chemical effects induced on the surrounding gaseous phase by the mechanical processing of granite. We show that fracturing granite blocks in oxygen can result in the generation of ozone. The refinement of coarse granite particles and the friction between fine ones are also effective in this regard. Combining experimental evidence related to the crushing of large granite samples by uniaxial compression and the ball milling of coarse and fine granite powders, we develop a model that relates mechanochemical ozone generation to the surface area effectively affected by fracture and frictional events taking place during individual impacts. We also extend the investigation to gaseous phases involving methane, oxygen, benzene and water, revealing that chemical transformations occur as well.

Estimation of Nanoporous Au Young's Modulus from Serial Block Face-SEM 3D-Characterisation.

Nanoporous Au has been subjected to serial block face-scanning electron microscopy (SBF-SEM) 3D-characterisation. Corresponding sections have been digitalized and used to evaluate the associated mechanical properties. Our investigation demonstrates that the sample is homogeneous and isotropic. The effective Young's modulus estimated by an analytical multiscale approach agrees remarkably well with the values stated in the literature.

Hardening of Nanoporous Au Induced by Exposure to Different Gaseous Environments.

This work focuses on the mechanical behaviour of nanoporous Au samples alternately exposed to ozone and carbon dioxide. Nanoporous Au was fabricated by freely corroding the Ag70Au30 parent alloys prepared by mechanical alloying in the form of powder and subsequently compacted by cold pressing. Dealloying was performed in acidic solution, and conditions were suitably adjusted to obtain fine nanoporous Au structures with ligaments about 15 nm thick. Nanoporous Au samples with increasingly thicker ligaments, up to about 40 nm, were fabricated by annealing the pristine nanoporous Au structure for different time intervals at 473 K. For all of the samples, the cyclic variation of gaseous atmosphere results in a macroscopic strain variation due to the occurrence of surface oxidation and reduction processes. We show that the reiterated cyclic exposure to the different gases also induces the progressive hardening of nanoporous Au, which can be ascribed to irreversible strain contributions. For nanoporous Au samples with ligaments that are 15 nm thick, after 50 exposure cycles, the yield strength increases approximately from 49 MPa to 57 MPa. A systematic investigation on coarser nanoporous Au structures indicates that, with the same exposure cycles, the degree of hardening decreases with the ligament thickness.

Coupling of mechanical deformation and reaction in mechanochemical transformations.

Driven by the promise of alternative synthetic routes to fine chemicals and pharmaceuticals, mechanochemistry is going through a period of intense growth. Mechanical forces are successfully utilized to activate chemical reactions involving an ever-growing variety of inorganic and organic substances with the aim of developing solvent-less processes to be used in the greener chemical industry of tomorrow. Down this path, the proper understanding of the relationships between processing variables, macroscopic transformation kinetics and microscopic chemistry represents one of the fundamental challenges to face. In this work, we develop a kinetic model that, taking into account the intrinsic statistical nature of the mechanical processing of powders by ball milling, combines a phenomenological description of the rheological behaviour of molecular solids with the chemistry of interface reactions. Specifically, we use discrete deformation maps to account for the co-deformation of molecular solids and the consequent increase of the interface area between initially segregated reactants. We assume that the chemical reaction only occurs, with a certain probability, when reactants come into contact due to relocations induced by shearing. No diffusion is allowed. The systematic variation of the amount of powder involved in individual impacts, the composition of powder mixtures and the reaction probability at the interface provide us with a complete overview of the kinetic scenario. In particular, we present the different kinetic curves that can be originated from interface reaction, pointing out how statistical, mixing and chemical factors affect the mechanochemical kinetics. Eventually, we suggest how experimental findings can be used to gain information on the underlying mechanochemistry based on the outcomes of our kinetic modeling.

Nurses' Behavior Regarding Pain Treatment in an Emergency Department: A Single-Center Observational Study.

PURPOSE: The aim of this prospective study was to assess the behavior of emergency department (ED) nurses with regard to pain and their role in pain management in a real-life clinical setting. METHODS: A total of 509 consecutive patients were enrolled during a 6-week period. A case-report form was used to collect data on nurses' approaches to pain, time to analgesia provision, and patient-perceived quality of analgesia. RESULTS: Triage nurses actively inquired about pain in almost every case, but they did not estimate pain intensity in a third of patients. In the majority of cases, triage nurses did not report pain-related findings to the physician, who was the only professional that could prescribe analgesia to patients. The assignment of the color-coding of triage by nurses appears to be related to the perceived severity of the clinical case and a more comprehensive evaluation of pain. More than half of patients were at least fairly satisfied with analgesia. CONCLUSION: Pain is increasingly screened during triage, but its comprehensive assessment and management still lack systematic application. We believe that further education and implementation of analgesia protocols may empower nurses to manage ED patients' pain more effectively and in a more timely manner.

Ag surface segregation in nanoporous Au catalysts during CO oxidation.

The present study focuses on the modification of surface compositional profiles induced in nanoporous (NP) Au catalysts by the catalytic oxidation of carbon monoxide to carbon dioxide in the presence of oxygen. The phenomenon has deep implications concerning the catalytic behavior of NP Au foams in particular, and more in general for the design of more efficient catalysts. Aimed at gaining deeper insight into the mechanisms governing surface segregation, we exposed NP Au foams containing residual Ag to a mixture of gaseous carbon monoxide and oxygen at different temperature. Structural and surface composition analyses pointed out the concomitant occurrence of both NP Au coarsening and Ag surface segregation processes. Experimental findings suggest for Ag surface segregation a two-stage kinetics. During the initial, rapid coarsening of the NP Au structure, Ag surface segregation is mediated by surface rearrangements, which allow the Ag atoms to reach the surface at anomalously fast rate. As coarsening decelerates, the slower diffusion of buried Ag atoms towards the surface predominates, due to favorable chemical interactions with adsorbed oxygen. This novel mechanism's understanding can benefit strategic areas of science and technology.

Processing and Investigation Methods in Mechanochemical Kinetics.

The present work focuses on the challenges that emerge in connection with the kinetics of mechanically activated transformations. This is an important topics to comprehend to enable the full exploitation of mechanical processing in a broad spectrum of areas related to chemistry and materials science and engineering. Emerging challenges involve a number of facets regarding materials and material properties, working principles of ball mills and milling conditions, and local changes occurring in series in processed materials. Within this context, it is highly desirable to relate the nature and rate of observed mechanochemical transformations to individual collisions and then to the processes induced by mechanical stresses on the molecular scale. Hence, it is necessary to characterize the milling regimes that can establish in ball mills regarding frequency and energy of collisions, map the relationship between milling dynamics and transformation kinetics, and obtain mechanistic information through proper time-resolved investigations in situ. A few specific hints are provided in this respect.

Prospective study on prevalence, intensity, type, and therapy of acute pain in a second-level urban emergency department.

AIM: Pain represents the most frequent cause for patient admission to emergency departments (EDs). Oligoanalgesia is a common problem in this field. The aims of this study were to assess prevalence and intensity of pain in patients who visited a second-level urban ED and to evaluate the efficacy of pharmacological treatment administered subsequent to variations in pain intensity. METHODS: A 4-week prospective observational study was carried out on 2,838 patients who visited a second-level urban ED. Pain intensity was evaluated using the Numeric Rating Scale at the moment of triage. The efficacy of prescribed analgesic therapy was evaluated at 30 and 60 minutes, and at discharge. Data concerning pain intensity were classified as absent, slight, mild, or severe. Pain was evaluated in relation to the prescribed therapy. RESULTS: Pain prevalence was 70.7%. Traumatic events were the primary cause in most cases (40.44%), followed by pain linked to urologic problems (13.52%), abdominal pain (13.39%), and nontraumatic musculoskeletal pain (7.10%). Only 32.46% of patients were given pharmacological therapy. Of these, 76% reported severe pain, 19% moderate, and 5% slight, and 66% received nonsteroidal anti-inflammatory drugs or paracetamol, 4% opioids, and 30% other therapies. A difference of at least 2 points on the Numerical Rating Scale was observed in 84% of patients on reevaluation following initial analgesic therapy. CONCLUSION: Pain represents one of the primary reasons for visits to EDs. Although a notable reduction in pain intensity has been highlighted in patients who received painkillers, results show that inadequate treatment of pain in ED continues to be a problem.

Mental disorders and HIV infection in the emergency department: epidemiology and gender differences.

The management of patients with HIV infection who have comorbidity with psychiatric disorders, is a problem that is encountered relatively frequently in Emergency Departments. This retrospective study aims to evaluate the characteristics of HIV-infected patients who have been admitted for mental disorders and other conditions to an Emergency Department (ED) of Sardinia, Italy, in 2013. Regarding the associated psychiatric condition (25.5% of total sample) 46.3% had mood disorders, 38.9% psychotic disorders and 14.8% anxiety disorders, with no significant gender differences (p = 0.329). The analysis of the sample showed drug abuse in 29.2%. A concomitant infection with HBV or HCV was found in the history of almost half of the patients. Only in 24.5% of cases was there a drug treatment in administered urgently, and an admission to hospital was necessary in 34.3% of the total sample of patients. Among the admissions, 70.4% were admitted to a department of infectious diseases, but of these, only 54.4% had at the admission to the ED signs of acute infection. The management of those who had gained access to emergency services required not only the management of acute disease, but also consideration of which would be the most appropriate department to solve the main problem (infection, fever, agitation, decompensated cirrhosis). Poor patient compliance often makes it difficult to manage, as the analysis of the data shows, a relevant percentage of patients appeared to leave before completion.