An automatic and fast procedure for the numerical analysis of curved masonry structures

A fast and innovative discrete model approach coupled with homogenization procedure is here presented. The method is able to comply with the main features required for an accurate simulation of masonry curved elements, such as the orthotropy and the typical in- and-out-of-plane coupled behavior exhibited by masonry vaults. Furthermore, homogenization techniques directly implemented in the method allows reducing consistently the number of variables, leading to a fair combination of accuracy and reasonable computational time. The discrete model is an assembly of elastic units joint by non-linear interfaces. These latter are modeled with 3D linear brick elements and Concrete Damage Plasticity (CDP) is used for modeling the non-linear mechanical properties coming from the homogenization step. In order to overcome potential difficulties during the preparation of the model, the discretized mesh is obtained automatically by means of an ad-hoc script implemented by the Authors. The proposed approach is validated taking advantage of numerical data already available on a cloister vault. The numerical comparison shows the reliability of the method and its efficacy in the simulation of both global behavior and crack pattern, requiring a low computational effort.(undefined

Experimental and Numerical Analysis of a FRCM Reinforced Parabolic Tuff Barrel Vault

An experimental and numerical analysis of the structural behaviour of a barrel tuff masonry vault strengthened by a Fiber Reinforced Cementitious Matrix (FRCM) reinforcement system it is proposed. The geometry and the materials of the vault are representative of some historical constructions in Apulia (Italy). The vault, under the action of the self-weight and of a distributed load representative of the infill, has been first damaged by differential settlement of abutments, and then repaired and strengthened by FRCM composites. Finally the structure has been subjected to a increasing concentrated load on the extrados. A 3D heterogeneous FE Abaqus numerical model describing the above mentioned experimental conditions is carried out in order to reproduce the response of the FRCM reinforced vault. The obtained experimental and numerical results allows for discussing the structural behaviour of the reinforced vault, and then the effectiveness of the employed reinforcement

Lattice Distortions Around a Tl+ Impurity in NaI:Tl+ and CsI:Tl+ Scintillators. An Ab Initio Study Involving Large Active Clusters

Ab initio Perturbed Ion cluster-in-the-lattice calculations of the impurity centers NaI:Tl+ and CsI:Tl+ are pressented. We study several active clusters of increasing complexity and show that the lattice relaxation around the Tl+ impurity implies the concerted movement of several shells of neighbors. The results also reveal the importance of considering a set of ions that can respond to the geometrical displacements of the inner shells by adapting selfconsistently their wave functions. Comparison with other calculations involving comparatively small active clusters serves to assert the significance of our conclusions. Contact with experiment is made by calculating absorption energies. These are in excellent agreement with the experimental data for the most realistic active clusters considered.Comment: 7 pages plus 6 postscript figures, LaTeX. Submmited to Phys, Rev.

Ab Initio Calculation of the Lattice Distortions induced by Substitutional Ag- and Cu- Impurities in Alkali Halide Crystals

An ab initio study of the doping of alkali halide crystals (AX: A = Li, Na, K, Rb; X = F, Cl, Br, I) by ns2 anions (Ag- and Cu-) is presented. Large active clusters with 179 ions embedded in the surrounding crystalline lattice are considered in order to describe properly the lattice relaxation induced by the introduction of substitutional impurities. In all the cases considered, the lattice distortions imply the concerted movement of several shells of neighbors. The shell displacements are smaller for the smaller anion Cu-, as expected. The study of the family of rock-salt alkali halides (excepting CsF) allows us to extract trends that might be useful at a predictive level in the study of other impurity systems. Those trends are presented and discussed in terms of simple geometric arguments.Comment: LaTeX file. 8 pages, 3 EPS pictures. New version contains calculations of the energy of formation of the defects with model clusters of different size

Biodiversity of Indigenous Saccharomyces Populations from Old Wineries of South-Eastern Sicily (Italy): Preservation and Economic Potential

In recent years, the preservation of biodiversity has become an important issue. Despite much public discussion, however, current practices in the food industry seldom take account of its potential economic importance: on the contrary, the introduction of industrialized agriculture practices over large areas has often resulted in a dramatic reduction in biodiversity

Silencing of PINK1 Expression Affects Mitochondrial DNA and Oxidative Phosphorylation in DOPAMINERGIC Cells

Background: Mitochondrial dysfunction has been implicated in the pathogenesis of Parkinson's disease (PD). Impairment of the mitochondrial electron transport chain (ETC) and an increased frequency in deletions of mitochondrial DNA (mtDNA), which encodes some of the subunits of the ETC, have been reported in the substantia nigra of PD brains. The identification of mutations in the PINK1 gene, which cause an autosomal recessive form of PD, has supported mitochondrial involvement in PD. The PINK1 protein is a serine/threonine kinase localized in mitochondria and the cytosol. Its precise function is unknown, but it is involved in neuroprotection against a variety of stress signalling pathways.Methodology/Principal Findings: In this report we have investigated the effect of silencing PINK1 expression in human dopaminergic SH-SY5Y cells by siRNA on mtDNA synthesis and ETC function. Loss of PINK1 expression resulted in a decrease in mtDNA levels and mtDNA synthesis. We also report a concomitant loss of mitochondrial membrane potential and decreased mitochondrial ATP synthesis, with the activity of complex IV of the ETC most affected. This mitochondrial dysfunction resulted in increased markers of oxidative stress under basal conditions and increased cell death following treatment with the free radical generator paraquat.Conclusions: This report highlights a novel function of PINK1 in mitochondrial biogenesis and a role in maintaining mitochondrial ETC activity. Dysfunction of both has been implicated in sporadic forms of PD suggesting that these may be key pathways in the development of the disease

Observation of gravitational waves from the coalescence of a 2.5–4.5 M ⊙ compact object and a neutron star

We report the observation of a coalescing compact binary with component masses 2.5–4.5 M ⊙ and 1.2–2.0 M ⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal GW230529_181500 was observed during the fourth observing run of the LIGO–Virgo–KAGRA detector network on 2023 May 29 by the LIGO Livingston observatory. The primary component of the source has a mass less than 5 M ⊙ at 99% credibility. We cannot definitively determine from gravitational-wave data alone whether either component of the source is a neutron star or a black hole. However, given existing estimates of the maximum neutron star mass, we find the most probable interpretation of the source to be the coalescence of a neutron star with a black hole that has a mass between the most massive neutron stars and the least massive black holes observed in the Galaxy. We provisionally estimate a merger rate density of 55−47+127Gpc−3yr−1 for compact binary coalescences with properties similar to the source of GW230529_181500; assuming that the source is a neutron star–black hole merger, GW230529_181500-like sources may make up the majority of neutron star–black hole coalescences. The discovery of this system implies an increase in the expected rate of neutron star–black hole mergers with electromagnetic counterparts and provides further evidence for compact objects existing within the purported lower mass gap

A Micro-Modeling Approach Applied to the TRM Debonding on Concave Masonry Substrates

The intrinsic vulnerability affecting curved masonry structures, when subjected to loads different from the static vertical ones, pushed the researchers and practitioners to conceive reinforcement techniques enable to provide a tangible increase in terms of peak strength and ultimate ductility. However, such features are not enough if the reinforcement does not provide full compatibility with the original material. In this context, the application of composite innovative materials coupled with lime/cementitious-based mortar (TRM/FRCM reinforcement) met the requirements discussed deeply in the ISCARSAH guidelines. Recently, several works focused on the debonding phenomena which can occur in the case of masonry structures reinforced with TRM technique. On the other hand, few experimental works are available in the literature concerning the influence of substrate curvature on the debonding process and its modality of activation. An advanced heterogeneous FE approach is used for the numerical analysis of three TRM-reinforced curved specimens. The difference in terms of peak load is highlighted and finally, a brief discussion with useful suggestions for practice applications is provided

A rational simplified procedure for modelling TRM reinforcement on curved masonry elements

The vulnerability of masonry structures, especially when subjected to a changing of the load and boundary conditions, was evident since the antiqueness when the first interventions of reinforcement were designed. Lately, with the easy provision of innovative materials, the upgrade of the structural performance is often accomplished through the application of composite systems as FRP (fiber reinforced polymer) and TRM (textile reinforced mortar). In TRM systems, fibers having a high strength under tensions are embedded within an inorganic matrix. The wide range of materials (carbon, PBO, glass, basalt) that the industry put at disposal makes difficult a correct definition of the efficacy of such kind of reinforcement technique. Indeed, the literature showed the several failure typologies that can be encountered when a masonry element is reinforced with TRM. In the case of arches and vaults, the curvature itself complicates furthely a correct prediction. The paper wants to provide a reasonable way to model numerically curved masonry structures reinforced with TRM and explore the advantages and detriment of advanced simulation and simplified approaches