Consolidation of Stone Materials by Organic and Hybrid Polymers: An Overview

Historic stone buildings and monuments undergo a gradual, unstoppable, and episodic deterioration due to environmental or climatic impact, biological or mechanical deterioration, or, in the case of better-preserved structures, inadequate maintenance. Water infiltration, freezing and thawing, carbonation, wind erosion, acid rain, and graffiti/vandalism are the key “environmental” issues that strongly impact cultural heritage and therefore must be limited or even prevented. This interaction leads to the occurrence of different phenomena, possibly involving blistering phenomena on the stone surface, its gradual weather away, leaving a sound surface behind, or the dropping away of the bulk material, because of prolonged weathering, in a single event. It is noteworthy that, quite often, the stone may appear perfectly intact to the naked eye, though it is losing its cohesion beneath its surface. Therefore, it becomes necessary to either efficiently protect the stone substrates to prolong their life, or to fix the damage that already occurred by means of effective, reliable, and long-lasting consolidation/restoration strategies. This work aims at summarizing the current state-of-the-art referring to the use of monomeric/oligomeric or polymeric consolidants, providing the reader with some perspectives for the next future

Insights into Induction Heating Processes for Polymeric Materials: An Overview of the Mechanisms and Current Applications

In polymer systems, induction heating (IH) is the physical outcome that results from the exposure of selected polymer composites embedding electrically-conductive and/or ferromagnetic fillers to an alternating electromagnetic field (frequency range: from kHz to MHz). The interaction of the applied electromagnetic field with the material accounts for the creation of magnetic polarization effects (i.e., magnetic hysteresis losses) and/or eddy currents (i.e., Joule losses, upon the formation of closed electrical loops), which, in turn, cause the heating up of the material itself. The heat involved can be exploited for different uses, ranging from the curing of thermosetting systems, the welding of thermoplastics, and the processing of temperature-sensitive materials (through selective IH) up to the activation of special effects in polymer systems (such as self-healing and shape memory effects). This review aims at summarizing the current state-of-the-art of IH processes for polymers, providing readers with the current limitations and challenges, and further discussing some possible developments for the following years

LA GIURISDIZIONE ECCLESIASTICA MATRIMONIALE IN ITALIA: EVOLUZIONE STORICA E PROFILI ATTUALI

Tesi sui rapporti tra giurisdizione ecclesiastica e civile in materia matrimonialeThe present dissertation examines the relation between the civil matrimonial jurisdiction and the ecclesiastic matrimonial jurisdiction

Stochastic effects on the dynamics of a resonant MEMS magnetometer: a Monte Carlo investigation

In the design of Lorentz force MEMS magnetometers, the coupled thermo-electro-magneto-mechanical fields governing the dynamics of the relevant compliant structures can be appropriately exploited to enhance their performances. In recent works, we showed that reduced-order models for the dynamics of the said movable structures can be recast in the form of the Duffing equation, where nonlinear terms arise from the multi-physics governing the problem. As stochastic effects may play a role due to the micrometric dimensions of the device, an investigation of the link between the statistics of sensor imperfections and output is here carried out. The said imperfections at the microscopic length-scale are modeled in terms of: overetch thickness, assumed to feature a uniform distribution in a proper interval matching available experimental data; and elastic properties of the vibrating polycrystalline silicon film, as obtained through a numerical homogenization procedure over a representative film volume. To get insights into the effects of the parameters governing the nonlinear dynamics of the resonant structure, a Monte Carlo analysis is adopted

Modeling Impact-induced Failure of Polysilicon MEMS: A Multi-scale Approach

Failure of packaged polysilicon micro-electro-mechanical systems (MEMS) subjected to impacts involves phenomena occurring at several length-scales. In this paper we present a multi-scale finite element approach to properly allow for: (i) the propagation of stress waves inside the package; (ii) the dynamics of the whole MEMS; (iii) the spreading of micro-cracking in the failing part(s) of the sensor. Through Monte Carlo simulations, some effects of polysilicon micro-structure on the failure mode are elucidated

A hybrid Structural Health Monitoring approach based on reduced-order modelling and deep learning

Recent advances in sensor technologies coupled with the development of machine/deep learning strategies are opening new frontiers in Structural Health Monitoring (SHM). Dealing with structural vibrations recorded with pervasive sensor networks, SHM aims at extracting meaningful damage-sensitive features from the data, shaped as multivariate time series, and taking real-time decisions concerning the safety level. Within this context, we discuss an approach able to detect and localize a structural damage avoiding any pre-processing of the acquired data. The method takes advantage of the capability of Deep Learning of Fully Convolutional Networks, trained during an offline SHM phase. As a hybrid model- and data-based solution is looked for, Reduced Order Models are also built in the offline phase to reduce the computational burden of the whole monitoring approach. Through a numerical benchmark test, we show how the proposed method can recognize and localize different damage states

On the nanoscopic structural heterogeneity of liquid n-alkyl carboxylic acids

Herein we report the first in-depth structural characterisation of simple linear carboxylic acids with alkyl tail length ranging from one to six carbon atoms. By means of the SWAXS technique, a pronounced nanoscopic heterogeneity evolving along the aliphatic portion of the molecule is highlighted. Via classical molecular dynamics, the origin of such heterogeneity is unambiguously assigned to the existence of aliphatic domains resulting from the self-segregation of the polar and apolar portions of the molecules. Furthermore, the structural correlation of aliphatic-separated polar domains is responsible for observing the so-called “pre-peak” in the SAXS region

Genetic Variability and Management in Nero di Parma Swine Breed to Preserve Local Diversity

Nero di Parma is an endangered swine breed reared in the North of Italy which nowadays counts 1603 alive pigs. The aims of this study were (i) to explore the genetic diversity of the breed at pedigree level to determine the actual genetic structure, (ii) to evaluate the effectiveness of the breeding recovery project and (iii) to potentially propose breeding strategies for the coming generations. The pedigree dataset contained 14,485 animals and was used to estimate demographic and genetic parameters. The mean equivalent complete generations was equal to 6.47 in the whole population, and it reached a mean value of 7.94 in the live animals, highlighting the quality of the available data. Average inbreeding was 0.28 in the total population, whereas it reached 0.31 in the alive animals and it decreased to 0.27 if only breeding animals were considered. The rate of inbreeding based on the individual increase in inbreeding was equal to 7%. This study showed the effectiveness of the recovery project of the breed. Nevertheless, we found that inbreeding and genetic diversity have reached alarming levels, therefore novel breeding strategies must be applied to ensure long-term survival of this breed