Role of surface states in the Casimir force between semiconducting films

We present results of first principle calculations of the Casimir force between Si films of nanometric size, which show that it depends significantly upon the configuration of the surface atoms, and give evidence of the importance of surface states.Comment: to be published on J.Phys.

A fully customizable data management system for Built Cultural Heritage surveys through NDT

The diagnosis of Built Cultural Heritage using non-invasive methods is useful to deepen the understanding of building characteristics, assessing the state of conservation of materials, and monitoring over time the effectiveness of restoration interventions. Ultrasonic and sonic tests are Non-Destructive Techniques widely used to evaluate the consistency of historic masonry and stone elements and to identify on-site internal defects such as voids, detachments, fractures. These tests, in addition to being suitable for Cultural Heritage because they are non-invasive, provide a fundamental preliminary screening useful to better address further analysis. Ultrasonic and Sonic velocity tests performed on monuments involve a lot of different information obtained from many surveys. It is therefore important to optimize the amount of data collected both during documentation and diagnostic phase, making them easily accessible and meaningful for analysis and monitoring. In addition, investigations set-up should be following a standard methodology, repeatable over time, suitable for different types of artifacts, and prepared for comparison with other techniques. An integrated data management system is then also useful to support the decision-making processes behind maintenance actions. This work proposes the development of a complete management IT solution for the Ultrasonic and Sonic measurements of different types of masonry, and stone artifacts. The system consists of a browser-based collaboration and document management platform, a mobile/desktop application for data entry, and a data visualization and reporting tool. This set of tools enable the complete processing of data, from the on-site survey to their analysis and visualization. The proposed methodology allows the standardization of the data entry workflow, and it is scalable, so it can be adapted to different types of masonry and artifacts. Moreover, this system provides real-time verification of data, optimizes survey and analysis times, and reduces errors. The platform can be integrated with machine learning models, useful to gain insight from data. This solution, aimed to improve the approach to diagnostics of Cultural Heritage, has been successfully applied by the LAM Laboratory of the Department of Earth Sciences (University of Florence) on different case studies (e.g., ashlar, frescoed walls, plastered masonries, stone columns, coat-of-arms, etc.) belonging to many important monuments

Assessing weathering damage in Arenitic Rock using Non-Destructive Testing: the case study of the stone coats of arms of Palazzo Ricasoli in Florence

The conservation of architectural heritage often involves studying the effects of weathering on stone materials exposed to polluted environments with characteristics unfavorable to their preservation. The decay phenomena that occur in urban environments can lead to destructive effects on stone material, resulting in the need for specific analysis to assess the mechanical properties of these artifacts. In this study, we analyzed three stone coats of arms that decorate the facade of Palazzo Ricasoli in Florence using non-destructive diagnostic techniques (NDTs) to assess their degree of weathering. Palazzo Ricasoli is a historic Renaissance palace, located in the center of Florence, that features three stone coats of arms on its façade that are currently in critical condition, showing signs of very advanced degradation. The stone of which they are composed is a type of local sandstone rock commonly used in Florentine historical architecture. To investigate the properties of the material we used in situ techniques, such Sonic test and 3D scanning. The results obtained with these techniques were then compared with those obtained from laboratory analysis of micro-samples using methods such as Fourier transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray Fluorescence (XRF), and optical microscopy. Using NTDs we were able to gather data and insights on the mechanical properties of weathered rock used in historical buildings, obtaining crucial information that can be used to develop appropriate and detailed conservation strategies to ensure the long-term stability of these materials in their environmental conditions

The Mortars of Florence Riverbanks: Raw Materials and Technologies of Lungarni Historical Masonry

The study of structural masonry joined to geohydrological hazards in cultural heritage represents a multidisciplinary theme, which requires consideration of several aspects, among them the characterization of the materials used. In this paper, a first complete chemical, minero-petrographic, and physico-mechanical characterization of core samples taken from the masonry of two Florence riverbanks (Lungarno degli Acciaiuoli and Lungarno delle Grazie) is performed in order to identify the raw materials, technologies, and state of conservation and to support the planning of maintenance and restoration interventions. The physico-mechanical characterization of the riverbanks allows their stability to be determined. Such investigations allow identification of the level of compactness and cohesion of masonry; this information is useful for planning emergency interventions and for supporting planned restoration activities. The results provide valid support for the design of riverbank safety projects, to mitigate the risk of their collapse and to decrease the flood risk in the historic center of Florence

The link between sustainable business models and Blockchain: A multiple case study approach

The paper investigates the relationship between Blockchain technology and new sustainable business models (SBMs). The literature notes a lack of empirical classifications and successful case studies. Using a multiple case studies methodology, our research article aims to answer the research question (RQ): How can Blockchain enable new SBMs and support the United Nations Sustainable Development Goals (SDGs)? We present 20 business stories extracted from a combined analysis of the databases coinmarketcap.com and icobench.com, demonstrating how Blockchain can be used for environmental management. Notably, our analysis finds out four broad research clusters related to (i) smart energy management, (ii) climate change, (iii) waste management, and (iv) sustainable production. Mainly, an actual application of Blockchain toward SBMs is related to supply chain cost reduction. Finally, the research includes investments and their social scalability with Blockchain. Then, the final research cluster discovers social and proof sustainability. This study adds to the empirical literature evidence of SBMs offering a connection with the SDGs

Multi-analytical methodology to indagate the Pietraforte sandstone risk assessment

Pietraforte sandstone is one of the most important stone material used during Renaissance in Historic Center of Florence, a UNESCO World Heritage Site. One of its main uses as building material is rusticated block facades, a peculiar masonry technique typical of many historical Florentine palace (ie. Palazzo Pitti, Palazzo Medici Riccardi, Palazzo Strozzi, etc.). The characteristic color of Pietraforte, ranging from grey to yellow-ochreous, is a distinctive feature of the urban landscape of Florence. Stone rusticated blocks constitute elements with different overhangs which make them subject to decay phenomena due to weathering that, together with their intrinsic characteristics, can lead to detachment and loss of blocks (even of considerable size). The study of Pietraforte as a geoheritage with its morphological, mechanical, physical, mineralogical, and petrographic characterization is an important starting point to understand the possible evolution of decay processes. A multi-analytical characterization of this stone in several study cases allow the comparison of Florentine rusticated blocks used in different architectural registers (rough-hewn, smooth-faced and pillow rusticated), highlighting different behaviors of Pietraforte in distint architectural contexts. For example, convolute laminations and calcite veins (Pecchioni et al. 2007, Pecchioni et al. 2020), typical macroscopic characteristics of Pietraforte, show different behavior depending on the type of rusticated blocks. A multi-analytical methodology has been developed including sampling for physical, petrographic and mineralogical characterization and Non Destructive Techniques (NTD), using ultrasonic pulse velocity and sclerometric tests for mechanical behaviors (Salvatici et al. 2020, Centauro et al. 2022, Calandra et al. 2023). The main morphological features of Pietraforte from a geological point of view are investigated pondering each rusticated blocks as a rock mass and applied some methods of rock slope stability analysis. The study performed in this work aims to protect and preserve geoheritage stones finding a new and sustainable restoration and conservation approach for Pietraforte built Cultural Heritage weaknesses. Furthermore this multi analytical approach allow the diagnosis of the vulnerability of the stone material to detachments of scales, fragments and whole blocks that represent a damage to the monuments and a danger for people

Characterization protocol of Florentine historical mortars for absolute dating

The raw materials used in the realization of a mortar provide information on the supply areas, original recipes and ancient technologies used to realize a building or an artefact. The raw materials utilized may vary over time, so they may be useful to give an indication of its relative dating. In this field, from the pioneering studies of Labeyrie and Delibrias, (1964) and Stuiver and Smith, (1965), was evaluated the possibilities to radiocarbon dating of historical mortars; this research field still open, since may present many issues in its application. In principle, the carbon fraction datable is represented by calcite (CaCO3) resulting from the hardening of the quicklime (calcium hydroxide, Ca(OH)2) that reacts with CO2 from the atmosphere. The lime binder and lump (un-mixed portion of lime in an aerial mortar) represent the portions that must be isolated from other carbon sources to accurately date mortars. Previous research shows that suitable and proper sampling of mortar samples is of fundamental importance for a conclusive radiocarbon analysis. In recent years, a complete characterization of the mortar before radiocarbon dating was strongly encouraged (Cantisani et al. 2021). The minero-petrographic characterization is the first step to identify the type of mortar and to develop an efficient analytical approach that allows to select the most suitable component of mortar for absolute dating. This work is aimed at mortar characterizing of an important architectural Cultural Heritage in Florence (Italy), Palazzo Medici Riccardi, to understand the building technique, the choice of raw materials, the history of its construction and, possibly, the presence of mortar datable fraction. A correct sampling and characterization procedures allow to know the composition of the binder, the nature of the aggregate, the presence of lumps, the carbonate origins etc. Therefore, to reduce the cost and time of dating, it is necessary to utilize always a fully characterized sample, consisting of a calcite binder, to be subjected subsequently to analysis to accelerator mass spectrometry (AMS) for dating. The research proposes on operative protocol applied on 12 mortar masonry samples of Palazzo Medici Riccardi, composed by: i) a preliminary in-depth characterization of mortar specimens, by means of multi-analytical techniques such as OM, XRPD, TGA, SEM-EDS, OM-CL for a chemical, minero-petrographic and physical characterization fields; ii) non-destructive analyses of datable samples selected, using XRPD, OM-CL and ATR-FTIR (Calandra et al. 2022). The combined use of characterization techniques is the key to obtaining more evidence regarding the composition of the samples to be dated. The selection protocol has made it possible to choose several samples for dating, thanks to which the history of the construction of Palazzo Medici Riccardi will be further explored

How resistant are levodopa-resistant axial symptoms? Response of freezing, posture and voice to increasing levodopa intestinal infusion rates in Parkinson's disease

Treatment of freezing of gait (FoG) and other Parkinson's disease (PD) axial symptoms is challenging. Systematic assessments of axial symptoms at progressively increasing levodopa doses are lacking. We sought to analyze the resistance to high levodopa doses of FoG, posture, speech, and altered gait features presenting in daily-ON therapeutic condition