Modelling a Coupled Thermoelectromechanical Behaviour of Contact Elements via Fractal Surfaces

A three-dimensional coupled thermoelectromechanical model for electrical connectors is here proposed to evaluate local stress and temperature distributions around the contact area of electric connectors under different applied loads. A micromechanical numerical model has been developed by merging together the contact theory approach, which makes use of the so-called roughness parameters obtained from experimental measurements on real contact surfaces, with the topology description of the rough surface via the theory of fractal geometry. Particularly, the variation of asperities has been evaluated via the Weierstrass-Mandelbrot function. In this way the micromechanical model allowed for an upgraded contact algorithm in terms of effective contact area and thermal and electrical contact conductivities. Such an algorithm is subsequently implemented to construct a global model for performing transient thermoelectromechanical analyses without the need of simulating roughness asperities of contact surfaces, so reducing the computational cost. A comparison between numerical and analytical results shows that the adopted procedure is suitable to simulate the transient thermoelectromechanical response of electric connectors

Contact-damage coupled modelling of FRP reinforcements under variable loading times

In the last years FRP (Fiber Reinforced Polymer) technology has been developed to repair damaged concrete structures. In this work it is proposed to investigate the complex mechanism of stress-strain evolution at the FRP interface, during different loading programs (short or long-time loadings), until complete debonding. This study has been performed by means of a fully threedimensional approach within the context of damage mechanics, to appropriately catch transversal effects as well as normal stresses, developing a realistic and comprehensive study of the delamination process. The adhesion properties have been reconstructed through a contact model incorporating an elastic-damage constitutive law, relating inter-laminar stresses acting in the sliding direction. A F.E. research code (FRPCON) has been developed, including a numerical procedure accounting for Mazars’s damage law inside the contact algorithm. The code is able to describe the delamination process considering the different surface preparation of the concrete part as well. The long-time behaviour of these composite structures has been studied by means of two visco-elastic formulations: i) Bazant’s B3 law has been considered for the concrete component, where creep effect is composed by three different terms, i.e. the elastic part, basic creep and drying creep; ii) for FRP’s fibres and matrix a micromechanical approach has been implemented. The experimental results of long-time bending tests have been used to calibrate and validate the numerical models

Aggregate behaviour in concrete materials under high temperature conditions

Concrete under high temperature conditions is a topic of wide interest for applications in several engineering fields, from nuclear to civil as well as building engineering

Neoadjuvant therapy for breast cancer

Objective: To evaluate the frequency of neoadjuvant therapy (NT) in women with stage I–III breast cancer in Italy and whether it is influenced by biological characteristics, screening history, and geographic area. Methods: Data from the High Resolution Study conducted in 7 Italian cancer registries were used; they are a representative sample of incident cancers in the study period (2009–2013). Included were 3546 women aged <85 years (groups <50, 50–69, 70–64, and 75+) with stage I–III breast cancer at diagnosis who underwent surgery. Women were classified as receiving NT if they received chemotherapy, target therapy, and/or hormone therapy before the first surgical treatment. Logistic models were built to test the association with biological and contextual variables. Results: Only 8.2% of women (290 cases) underwent NT; the treatment decreases with increasing age (14.5% in age <50 and 2.2% in age 75+), is more frequent in women with negative receptors (14.8%), HER2-positive (15.7%), and triple-negative (15.6%). The multivariable analysis showed the probability of receiving NT is higher in stage III (odds ratio [OR] 3.83; 95% confidence interval [CI] 2.83–5.18), luminal B (OR 1.87; 95% CI 1.27–2.76), triple-negatives (OR 1.88; 95% CI 1.15–3.08), and in symptomatic cancers (OR 1.98; 95% CI 1.13–3.48). Use of NT varied among geographic areas: Reggio Emilia had the highest rates (OR 2.29; 95% CI 1.37–3.82) while Palermo had the lowest (OR 0.41; 95% CI 0.24–0.68). Conclusions: The use of NT in Italy is limited and variable. There are no signs of greater use in hospitals with more advanced care

Euromediterranean Biomedical Journal: the renewed journal of young doctors aims even higher.

In January 2006, a new journal, Capsula Eburnea, was born in the Italian scientific pub-lishing scene, with the initial goal of creating, at the same time, “an open scientific forum and a blog”. Until December 2009, the vast majority of manuscripts was still published in Italian, restricting the number of readers. From the end of 2009, the journal has undergone extensive changes, becoming indexed in the main scientific search engines (Scopus, Directory of Open Access Journal, Google Scholar, Ulrich Periodical Directory), and renewing its Editorial Team with a role reassign-ment and expanding the Editorial Board to up to 40 young doctors with proven scientific experience from 15 countries around the world, working as researchers, PhD students, senior medical staff, research fellows or doctors in specialist training. Finally, the journal has progressively encouraged the publication of articles in English, through an endorsed English translation service provided by native English speaking translators. This service became mandatory for all peer-reviewed articles accepted by the Journal in 2011. At the same time, the Editorial Board unanimously decreed to change the name of the journal into “Euromediterranean Biomedical Journal for young doctors (formerly: Capsula Eburnea)” from January 2012. Today, the journal is fully open access (including the archives of Capsula Eburnea) with the possibility to download articles for free, and the publication process involves a blind peer review of each article by at least two scientists. During its first two years of activity, the Euromediterranean Biomedical Journal (EMBJ) published 48 scientific articles (17 origi-nal articles, 14 reviews, 13 case report, two technical reports and two commentaries) and one edition of Conference Proceedings

EUROMEDITERRANEAN BIOMEDICAL JOURNAL: THE RENEWED MANUSCRIPT LAYOUT AND WEB RENDERING FORESHADOW FURTHER JOURNAL IMPROVEMENT

In January 2006, a new journal, Capsula Eburnea, was born into the Italian scientific publishing scene with the initial goal of creating, at the same time, \u201can open scientific forum and a blog\u201d, based on the premise that \u201cin medicine, nothing should be considered stable, immutable or unsusceptible to critical review at any time, by any scientist\u201d. The Editorial Team progressively sought to improve the quality of the manuscripts published, introducing the requirement for all articles to be written in English, and changed the Journal\u2019s name to EuroMediterranean Biomedical Journal in 2012. Over the last five years, approximately 125 articles by young doctors (including original articles, reviews, commentaries, notes, and abstract books) have been published. The editorial board are confident that the new publishing layout and the renewed web-portal of the journal, introduced in this editorial, represent an essential upgrade after over 10 years of editorial activity, and that these improvements will be appreciated by our authors and, especially, our readers

Numerical modelling of ellipsoidal inclusions

Within the framework of numerical algorithms for the threedimensional random packing of granular materials this work presents an innovative formulation for polydispersed ellipsoidal particles, including an overlapping detection algorithm for an optimized simulation of the mesostructure of geomaterials, particularly concrete. Granular composite cement-based materials can be so reconstructed with adequate precision in terms of grain size distribution. Specifically, the algorithm performance towards the assumed inclusion shape (ellipsoidal or spheric) and degree of regularity (round or irregular) is here discussed. Examples on real grading curves prove that this approach is effective. The advantages of the proposed method for computational mechanics purposes are also disclosed when properly interfaced with visualization CAD (Computer Aided Design) tools

Investigation of stress-strain behaviour in concrete materials through the aid of 3D advanced measurement techniques

This work deals with the investigation of the mechanical behaviour of cementitious materials, following a mesoscopic approach where aggregates, grains and cement paste are explicitly represented, and the strict comparison between the numerical results and the experimental results from uniaxial tests is carried out. For this purpose, solid models are created with the support of advanced techniques of measurement and detection, such as laser scanners or computer tomography (CT). The 3D laser- scanning technique in fact allows to acquire the exact shape of the grains added to the concrete mix design while, through the adoption of an ad-hoc random distribution algorithm, a realistic disposition of the inclusions is guaranteed. The industrial CT instead, is able to reproduce exactly the tested specimens; the geometry of the inclusions and their placement. Once reconstructed realistic geometries for the models, the mechanical behaviour of concrete under uniaxial compression tests is numerically studied. A specific constitutive behaviour is assigned to each component; an elasto-plastic law with damage is assumed for the cement matrix while the aggregates are conceived to behave elastically. The implemented damage-plasticity model consists in the combination of the non-associated plasticity model by Men\ue9trey-Willam, where the yield surface is described in function of the second and the third invariant of the deviatoric stress tensor and the scalar isotropic damage model by Mazars. Comparisons between numerical and experimental results fairly prove the correctness of the suggested approach

Nonlinear Modelling, Design, and Test of Steel Blast-Resistant Doors

The nonlinear dynamic response for steel blast-resistant doors is here described, referring to an innovative experience at both national and international level requiring an ad hoc design and specific numerical simulations. The elements capability to sustain thermal loads due to fire hazards is additionally accounted for. The study has been conducted to define and characterize the nonlinear behaviour of a large number of doors, with the objective of sustaining dynamic loads from explosive hazards of fixed magnitude, as well as variable design and clearing times. The local overcome of the material strength limit (with correspondent plastic response) and possible formation of plastic hinges has been critically discussed. Numerical models have allowed for refining first design sketches and subsequently understanding the real thermomechanical behaviour for the investigated elements. Some experimental tests have been additionally performed, verifying the correctness of the already available numerical results, validating the adopted procedures, and correspondingly guaranteeing the doors' structural efficiency even under dynamic loads higher than design ones

Age-dependent association of white matter abnormality with cognition after TIA or minor stroke

ObjectiveTo investigate if the association between MRI-detectable white matter hyperintensity (WMH) and cognitive status reported in previous studies persists at older ages (>80 years), when some white matter abnormality is almost universally reported in clinical practice.MethodsConsecutive eligible patients from a population-based cohort of all TIA/nondisabling stroke (Oxford Vascular Study) underwent multimodal MRI, including fluid-Attenuated inversion recovery and diffusion-weighted imaging, allowing automated measurement of WMH volume, mean diffusivity (MD), and fractional anisotropy (FA) in normal-Appearing white matter using FSL tools. These measures were related to cognitive status (Montreal Cognitive Assessment) at age 6480 vs >80 years.ResultsOf 566 patients (mean [range] age 66.7 [20-102] years), 107 were aged >80 years. WMH volumes and MD/FA were strongly associated with cognitive status in patients aged 6480 years (all p < 0.001 for WMH, MD, and FA) but not in patients aged >80 years (not significant for WMH, MD, and FA), with age interactions for WMH volume (pinteraction = 0.016) and MD (pinteraction = 0.037). Voxel-wise analyses also showed that lower Montreal Cognitive Assessment scores were associated with frontal WMH in patients 6480 years, but not >80 years.ConclusionMRI markers of white matter damage are strongly related to cognition in patients with TIA/minor stroke at younger ages, but not at age >80 years. Clinicians and patients should not overinterpret the significance of these abnormalities at older ages