Raman identification of cuneiform tablet pigments. Emphasis and colour technology in ancient Mesopotamian mid-third millennium

In the modern age, there is a large number of ways to manage a written text, from bolding or underlining some words with the preferred PC editing software down to animated gifs or emoticons for short edited text of mobile messaging and social posting. The task is to catch the eye and rapidly convey the important message. Besides the almost endless opportunities of high-tech displays, to put emphasis on a text written on a hard support mainly relies on changing the editing style, by applying bold, italic or underline style to selected words or phrases and exploiting the characteristic of human eye to be sensible to the change of brightness into a written text

Fresco Paintings: Development of an Aging Model from 1064 nm Excited Raman Spectra

In this study, we proposed a preliminary kinetic model applied to the carbonation process of fresh lime with the intention to realize a diagnostic tool for aged fresco paintings. The model can be useful, in particular, in the fields of conservation and restoration of ancient lime wall paintings. The dating procedure was achieved through the analysis of 1064 nm excited Raman spectra collected on artificially aged lime samples in addition to ancient samples taken from literature and covering a period of two thousand years. The kinetic model was developed monitoring the concentration of emitting defective centers related to the intensity of 780 cm−1 calcium hydroxide band as a function of the time and depth. This preliminary model shows how Raman spectroscopy, especially NIR micro-Raman, is advantageous for diagnostics and conservation in the cultural heritage field

All-organic, low voltage, transparent and compliant organic field-effect transistor fabricated by means of large-area, cost-effective techniques

The development of electronic devices with enhanced properties of transparency and conformability is of high interest for the development of novel applications in the field of bioelectronics and biomedical sensing. Here, a fabrication process for all organic Organic Field-Effect Transistors (OFETs) by means of large-area, cost-effective techniques such as inkjet printing and chemical vapor deposition is reported. The fabricated device can operate at low voltages (as high as 4 V) with ideal electronic characteristics, including low threshold voltage, relatively high mobility and low subthreshold voltages. The employment of organic materials such as Parylene C, PEDOT:PSS and 6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) helps to obtain highly transparent transistors, with a relative transmittance exceeding 80%. Interestingly enough, the proposed process can be reliably employed for OFET fabrication over different kind of substrates, ranging from transparent, flexible but relatively thick polyethylene terephthalate (PET) substrates to transparent, 700-nm-thick, compliant Parylene C films. OFETs fabricated on such sub-micrometrical substrates maintain their functionality after being transferred onto complex surfaces, such as human skin and wearable items. To this aim, the electrical and electromechanical stability of proposed devices will be discussed

Critical issues and key points from the survey to the creation of the historical building information model: The case of Santo Stefano Basilica

The new era of designing in architecture and civil engineering applications lies in the Building Information Modeling (BIM) approach, based on a 3D geometric model including a 3D database. This is easier for new constructions whereas, when dealing with existing buildings, the creation of the BIM is based on the accurate knowledge of the as-built construction. Such a condition is allowed by a 3D survey, often carried out with laser scanning technology or modern photogrammetry, which are able to guarantee an adequate points cloud in terms of resolution and completeness by balancing both time consuming and costs with respect to the request of final accuracy. The BIM approach for existing buildings and even more for historical buildings is not yet a well known and deeply discussed process. There are still several choices to be addressed in the process from the survey to the model and critical issues to be discussed in the modeling step, particularly when dealing with unconventional elements such as deformed geometries or historical elements. The paper describes a comprehensive workflow that goes through the survey and the modeling, allowing to focus on critical issues and key points to obtain a reliable BIM of an existing monument. The case study employed to illustrate the workflow is the Basilica of St. Stefano in Bologna (Italy), a large monumental complex with great religious, historical and architectural assets

Optimizing the Mechanoluminescent Properties of CaZnOS:Tb via Microwave-Assisted Synthesis: A Comparative Study with Conventional Thermal Methods

Recent developments in lighting and display technologies have led to an increased focus on materials and phosphors with high efficiency, chemical stability, and eco-friendliness. Mechanoluminescence (ML) is a promising technology for new lighting devices, specifically in pressure sensors and displays. CaZnOS has been identified as an efficient ML material, with potential applications as a stress sensor. This study focuses on optimizing the mechanoluminescent properties of CaZnOS:Tb through microwave-assisted synthesis. We successfully synthesized CaZnOS doped with Tb3+ using this method and compared it with samples obtained through conventional solid-state methods. We analyzed the material's characteristics using various techniques to investigate their structural, morphological, and optical properties. We then studied the material's mechanoluminescent properties through single impacts with varying energies. Our results show that materials synthesized through microwave methods exhibit similar optical and, primarily, mechanoluminescent properties, making them suitable for use in photonics applications. The comparison of the microwave and conventional solid-state synthesis methods highlights the potential of microwave-assisted methods to optimize the properties of mechanoluminescent materials for practical applications

Mechanochemical Reactions from Individual Impacts to Global Transformation Kinetics

Typically induced by the mechanical processing of powders in ball mills, mechanochemical transformations are considered to result from the application of mechanical force to solid reactants. However, the undeniable deep connection between the dynamic compaction of powders during impacts and the overall transformation degree has yet to be disclosed. In the present work, we show that the square planar bis(dibenzoylmethanato)Ni-II coordination compound undergoes trimerization when its powder experiences even a single ball impact. Based on systematic experiments with individual ball impacts and analysis by Raman spectroscopy, we provide here quantitative mapping of the transformation in the powder compact and deduce bulk reaction kinetics from multiple individual impacts

Selecting molecular or surface centers in carbon dots-silica hybrids to tune the optical emission: A photo-physics study down to the atomistic level

In this work, we unveil the fluorescence features of citric acid and urea-based Carbon Dots (CDs) through a photo-physical characterization of nanoparticles synthesized, under solvent-free and open-air condi-tions, within silica-ordered mesoporous silica, as a potential host for solid-state emitting hybrids. Compared to CDs synthesized without silica matrices and dispersed in water, silica-CD hybrids display a broader emission in the green range whose contribution can be increased by UV and blue laser irradi-ation. The analysis of hybrids synthesized within different silica (MCM-48 and SBA-15) calls for an active role of the matrix in directing the synthesis toward the formation of CDs with a larger content of graphitic N and imidic groups at the expense of N-pyridinic molecules. As a result, CDs tuned in size and with a larger green emission are obtained in the hybrids and are retained once extracted from the silica matrix and dispersed in water. The kinetics of the photo-physics under UV and blue irradiation of hybrid samples show a photo-assisted formation process leading to a further increase of the relative contribution of the green emission, not observed in the water-dispersed reference samples, suggesting that the porous matrix is involved also in the photo-activated process. Finally, we carried out DFT and TD-DFT calcula-tions on the interaction of silica with selected models of CD emitting centers, like surface functional groups (OH and COOH), dopants (graphitic N), and citric acid-based molecules. The combined experimen-tal and theoretical results clearly indicate the presence of molecular species and surface centers both emitting in the blue and green spectral range, whose relative contribution is tuned by the interaction with the surrounding media

Defect-assisted photoluminescence in hexagonal boron nitride nanosheets

The development of functional optoelectronic applications based on hexagonal boron nitride nanosheets (h-BNNs) relies on controlling the structural defects. The fluorescent emission, in particular, has been observed to depend on vacancies and substitutional defects. In the present work, few-layerh-BNNs have been obtained by sonication-assisted liquid-phase exfoliation of their bulk counterpart. The as-prepared samples exhibit a weak fluorescent emission in the visible range, centred around 400 nm. Tailored defects have been introduced by oxidation in air at different temperatures. A significant increase in the fluorescent emission of the oxidatedh-BNNs has been observed with maximum emissive intensity for the samples treated at 300 degrees C. A further increase in temperatures (>300 degrees C) determines a quenching of the fluorescence. We investigated, by means of detailed microscopic and spectroscopic analysis, the relationship between the optical properties and defects ofh-BNNs. The investigation of the optical properties as a function of treatment temperature highlights the critical role of hydroxyl groups created by the oxidation process. Onlyh-BN exfoliated in water allows introducing OH groups with consequent enhancement of fluorescence emission. Quantum chemical calculations support the experimental findings

Copper chloro-complexes concentrated solutions: An electrochemical study

Basic studies on concentrated solutions are becoming more and more important due to the practical industrial and geological applications. The use in redox flow batteries is one of the most important applications of these solutions. Specifically, in this paper we investigated high-concentrated copper chloro-complexes solutions with different additives. The concentration of ligands and additives affects the physicochemical and electrochemical properties of 2 M solutions of Cu(I) and Cu(II). Solutions with calcium chloride and HCl as Cl- source were investigated with Cu:Cl ratios of 1:5 and 1:7, the 1:5 Cu:Cl ratio being the best performing. The substitution of calcium chloride with ammonium chloride increased the conductivity. However, while the effect on the positive electrode process was not very evident, the reversibility of the copper deposition-stripping process was greatly improved. Orthophosphoric acid could be a viable additive to decrease the complexation of calcium with chloride anions and to improve the stability of Cu(II) chloro-complexes. Absorption spectroscopy demonstrated that phosphate ions do not coordinate copper(II) but lead to a shift in the distribution of copper chloro-complexes toward more coordinated species. Electrochemically, the increased availability of chloride anions in solution stabilized the Cu(II)-rich solution and led to increased reversibility of the Cu(II)/Cu(I) redox process