Correction to: FTIR-ATR analysis of the H-bond network of water in branched polyethyleneimine/TEMPO-oxidized cellulose nano-fiber xerogels

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Evaluating spintronics-compatible implementations of Ising machines

The commercial and industrial demand for the solution of hard combinatorial optimization problems push forward the development of efficient solvers. One of them is the Ising machine which can solve combinatorial problems mapped to Ising Hamiltonians. In particular, spintronic hardware implementations of Ising machines can be very efficient in terms of area and performance, and are relatively low-cost considering the potential to create hybrid CMOS-spintronic technology. Here, we perform a comparison of coherent and probabilistic paradigms of Ising machines on several hard Max-Cut instances, analyzing their scalability and performance at software level. We show that probabilistic Ising machines outperform coherent Ising machines in terms of the number of iterations required to achieve the problem s solution. Nevertheless, high frequency spintronic oscillators with sub-nanosecond synchronization times could be very promising as ultrafast Ising machines. In addition, considering that a coherent Ising machine acts better for Max-Cut problems because of the absence of the linear term in the Ising Hamiltonian, we introduce a procedure to encode Max-3SAT to Max-Cut. We foresee potential synergic interplays between the two paradigms.Comment: 26 pages, 6 Figures, submitted for publication in Phys. Rev. Applied (it will be presented at intermag 2023 in Japan

New insights to assess the consolidation of stone materials used in built heritage: the case study of ancient graffiti (Tituli Picti) in the archaeological site of Pompeii

Abstract Tituli Picti are an ancient form of urban graffiti very common in the archaeological site of Pompeii (Naples, South—Italy). They are generally made of red pigments applied on walls of Campanian ignimbrite. This paper deals with a scientific investigation aimed to their conservation. This is a challenging task since it requires a multidisciplinary approach that includes restorers, archaeologists and conservation scientists. The study has provided suggestions on the proper way to conserve Tituli Picti over time. In the present work, several specimens of Campanian ignimbrite were painted with red earth pigment; lime and Arabic gum have been used as binders as well. Such painted stones were treated with three consolidants: a suspension of reactive nanoparticles of silica, ethyl silicate and an acrylic microemulsion. Treated and untreated specimens were subjected to thermal aging, artificial solar radiation and induced crystallization decay. It has been assessed the colorimetric variations induced by treatments. Moreover, the micromorphologic features of the consolidated surfaces have been highlighted by means of electron microscope observations. The scotch tape test allowed to compare the superficial cohesion induced by the three used products. According to the results, ethyl silicate seems to represent the most successful product

Diagnostic investigation of the Cycle of the new church of Sarria (Floriana, Malta) by Mattia Preti

In the present paper, we present the main results of a diagnostic investigation on different paintings by Mattia Preti, belonging to the Cycle of the New Church of Sarria, located inside the Church of the Immaculate Conception of Sarria (Floriana) in Malta. The analysis was carried out on the occasion of the restoration process and, due to the short time available, only on some representative areas of each painting. A multi-technique approach was applied in situ, employing X-ray fluorescence spectroscopy (XRF) and Raman microscopy. The aim was to achieve information on the execution technique, in a completely non-invasive way, following the requirements of the restorers.peer-reviewe

Digital reconstruction and scientific analysis prior the restoration of two paintings by Mattia Preti in the Church of the Immaculate Conception of Sarria (Floriana, Malta)

The paper presents the results of scientific investigations carried out in support of a professionally executed restoration on two paintings by Mattia Preti, located in the Church of the Immaculate Conception of Sarria in Floriana, Malta. In particular, the attention was mainly paid on a combined approach, using 2D/3D survey in order to formulate hypothetic reconstruction, and XRF spectroscopy in order to get more information on how the master prepared the various types of materials, with particular regard to the painting preparation, the pigments palette and the formulation of shades and highlights.peer-reviewe

Scientific investigation of The Conversion of St Paul painting (Mdina, Malta)

The paper presents the results of two different approaches applied to the newly-restored painting The Conversion of St Paul, the main altarpiece in the Cathedral of Mdina in Malta. This large, dramatic painting is work of the Baroque artist Mattia Preti, il Cavaliere Calabrese. As is normal with a professionally executed restoration, several scientific methods have been used before, during and at completion, in the framework of a global analytical strategy. In particular, we focus on the results of the digital photogrammetric survey which uses image-based approaches for 2D/3D models reconstruction enormously. The model was used to quantify and measure important features on the painting as well extensions of areas restored. In addition, portable Raman spectroscopy was used to identify, in non-destructive way, the nature of the painting materials with the final goal of reconstructing the color palette of the artist.peer-reviewe

Valorizing underground cultural heritage through the use of virtual reality

This paper presents the results of scientific investigations carried out at the Batia Church which is located in the small village of Tortorici (Messina, Sicily, Italy). We performed several geophysical surveys, as well as geomatics approaches, were used in order to reconstruct 2D and 3D digital models of the monument mainly using digital photogrammetry. Previous geophysical investigations have shown the presence of a crypt which was ultimately surveyed and digitally reconstructed. Here, we present the potential of valorizing the site and its underground structures by the means of advanced technologies and digital reconstructions.peer-reviewe

Proprieta' dinamiche in liquidi associati

Dottorato di ricerca in fisica. 7. ciclo. Coordinatore e Tutore P. MigliardoConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7, Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

2D Correlation Spectroscopy (2DCoS) Analysis of Temperature-Dependent FTIR-ATR Spectra in Branched Polyethyleneimine/TEMPO-Oxidized Cellulose Nano-Fiber Xerogels

Fourier transform infrared spectroscopy in attenuated total reflectance geometry (FTIR-ATR), combined with a 2D correlation analysis, was here employed to investigate temperature-induced spectral changes occurring in a particular type of novel cellulosic-based nano-material prepared using 2,2,6,6-tetramethyl-piperidine-1-oxyl (TEMPO) oxidized and ultra-sonicated cellulose nano-fibers (TOUS-CNFs) as three-dimensional scaffolds, and branched polyethyleneimine (bPEI) as cross-linking agent. The aim was to highlight the complex sequential events involving the different functional groups of the polymeric network, as well as to gain insight into the interplay between the amount of bPEI and the resulting sponge-like material, upon increasing temperature. In this framework, synchronous and asynchronous 2D spectra were computed and analyzed in three wavenumber regions (900–1200 cm−1, 1500–1700 cm−1 and 2680–3780 cm−1), where specific vibrational modes of the cellulosic structure fall, and over a T-range between 250 K and 340 K. A step-by-step evolution of the different arrangements of the polymer functional groups was proposed, with particular regard to how the cooperativity degree of inter- and intramolecular hydrogen bonds (HBs) changes upon heating. Information acquired can be useful, in principle, in order to develop a next-generation, T-sensitive novel material to be used for water remediation applications or for drug-delivery nano-vectors