Energy harvesting from electrospun piezoelectric nanowires for structural health monitoring of a cable-stayed bridge

Wireless monitoring could greatly impact the fields of structural health assessment and infrastructure asset management, but some technological challenges pose unsolved issues toward its reliable use in continuous large-scale applications. Among the others, it is worth highlighting that power supply by means of batteries is usually implemented within wireless sensor networks, even though it causes practical concerns that heavily prevent the development of efficient monitoring systems for large structures and infrastructures. Conversely, scavenging ambient energy can alleviate or eventually eliminate the problem of electrical supply by batteries, a strategy that has emerged in recent years as a promising technological solution for bridges. Within this framework, the present work proposes to harvest ambient-induced vibrations of bridge structures using a new class of piezoelectric textiles. The considered case study is an existing cable-stayed bridge located in Italy along the high-speed road that connects Rome and Naples, for which a recent monitoring campaign has allowed to record the dynamic responses of deck and cables. In order to enhance the electric energy that can be converted from wind- and traffic-induced bridge vibrations, the energy harvester exploits a piezoelectric nanogenerator built using arrays of piezoelectric electrospun nanofibers. Particularly, several fiber arrangements are studied at the nano/micro-scale leading to different macro constitutive laws and different electric energy output. A computational study is performed to demonstrate that such nanogenerator is able to provide higher energy levels from recorded dynamic loading time histories than a standard piezoelectric energy harvester. The feasibility of this piezoelectric nanogenerator for bridge monitoring applications is finally discussed

Disfunctions in the anthocyanin accumulation of Vitis vinifera L. varieties studied by a targeted resequencing approach

BACKGROUND: The pathway of anthocyanin biosynthesis, and its alterations leading to berry colour modification, are well known in grape skin. This variability could affect both quantity and quality of pigment accumulation. OBJECTIVE: The present work is focused on 15 grapevine cultivars selected to represent a high variability in the phenotypical colour traits in order to highlight new polymorphisms related to the flavonoid pathway. METHODS: Twenty-one genes involved in the biosynthetic pathway of anthocyanins were studied via targeted resequencing and were correlated with phenotypic data ( anthocyanin profiles and spectroscopy indices). RESULTS: Single nucleotide polymorphism (SNP) and InDel (insertion/deletion) polymorphisms were detected. Out of 1751 polymorphic loci, 68% were SNPs and 32% were InDels (568). Cluster analysis and SPLS-DA were used to investigate the genetic relationships among the cultivars, confirming the large range of phenotypical variability. Statistically significant correlations were detected between accumulation of 3\u2019 anthocyanins and genetic polymorphisms in two structural genes and one transcription factor putatively involved in the anthocyanin biosynthetic pathway. CONCLUSIONS: The understanding of the polymorphisms related to the anthocyanin accumulation could support future selection of new pink table grape varieties with increased appeal on the consumers

A consistency assessment of coupled cohesive zone models for mixed-mode debonding problems

Due to their simplicity, cohesive zone models (CZMs) are very attractive to describe mixed-mode failure and debonding processes of materials and interfaces. Although a large number of coupled CZMs have been proposed, and despite the extensive related literature, little attention has been devoted to ensuring the consistency of these models for mixed-mode conditions, primarily in a thermodynamical sense. A lack of consistency may affect the local or global response of a mechanical system. This contribution deals with the consistency check for some widely used exponential and bilinear mixed-mode CZMs. The coupling effect on stresses and energy dissipation is first investigated and the path-dependance of the mixed-mode debonding work of separation is analitically evaluated. Analytical predictions are also compared with results from numerical implementations, where the interface is described with zero-thickness contact elements. A node-to-segment strategy is here adopted, which incorporates decohesion and contact within a unified framework. A new thermodynamically consistent mixed-mode CZ model based on a reformulation of the Xu-Needleman model as modified by van den Bosch et al. is finally proposed and derived by applying the Coleman and Noll procedure in accordance with the second law of thermodynamics. The model holds monolithically for loading and unloading processes, as well as for decohesion and contact, and its performance is demonstrated through suitable examples

Genetic analysis of the VvMybA1 gene in Armenian grapevines (V. Vinifera L.)

Research Not

Analysis of VvMybA1 and VvMybA2 genes in grape bud sports

Berry skin colour is a fundamental qualitative trait of grape varieties, which has become largely diversified during the centuries of viticulture. Colour mutations in grape berry, resulting in black, red, pink, grey, green and yellow fruits, were relatively frequent events. In the Carpathian Basin there are several berry colour variant groups named conculta, members of which contain bud sports differing in skin colour. In most cases, this difference cannot be detected by microsatellite analysis, therefore we examined the variations of the VvMybA1 and VvMybA2 genes related to anthocyanin biosynthesis. Based on the results of the allelic polymorphisms, we have discriminated the conculta members among the old Hungarian and several other foreign varieties. Based on our results, it was possible to find molecular differences in 10 out of 14 concultas

Evidence for a Sympatric Origin of Ribolla gialla, Gouais Blanc and Schiava cultivars (V. vinifera L.)

Ribolla gialla is an autochthonous grape variety cultivated in Friuli Venezia Giulia (Italy) and in Slovenia,and probably originated in Eastern Central Europe. Just like Ribolla gialla, the Gouais blanc and Schiavacultivars also appear to have originated in the same geographical area. To verify this hypothesis, a poolof varieties probably sharing the same historical and geographical origin were taken into account. Thefingerprinting, by 35 SSR loci, of Gouais blanc, Ribolla gialla, Schiava grossa and Schiava lombarda(synonyms of Schiava bresciana), is presented and the correlation among historical, geographical andgenetic information of these cultivars was investigated. Gouais blanc and Traminer, already suggested askey varieties in the development of European grape diversity and as parents for some French varieties,interestingly enough seems to be linked to Ribolla gialla. The putative parentage was verified using 58microsatellite markers. The genetic results suggest a common geographical origin for Gouais blanc,Ribolla gialla and the Schiava group: these cultivars appear to be related through sympatric origin. Thehypothesis of Ribolla gialla as a progeny of Gouais blanc and Traminer was ruled out. The data proved asecond-degree relationship between Gouais blanc and Ribolla gialla and a third or more distant degree ofrelationships between Ribolla gialla and Traminer

A comparative evaluation of coupled mixed-mode cohesive zone laws for interfacial debonding

WCCM XI, 11th World Congress on Computational Mechanics, Barcelona, Spain, 20-25 July 2014

Stochastic phase-field modeling of brittle fracture: computing multiple crack patterns and their probabilities

In variational phase-field modeling of brittle fracture, the functional to be minimized is not convex, so that the necessary stationarity conditions of the functional may admit multiple solutions. The solution obtained in an actual computation is typically one out of several local minimizers. Evidence of multiple solutions induced by small perturbations of numerical or physical parameters was occasionally recorded but not explicitly investigated in the literature. In this work, we focus on this issue and advocate a paradigm shift, away from the search for one particular solution towards the simultaneous description of all possible solutions (local minimizers), along with the probabilities of their occurrence. Inspired by recent approaches advocating measure-valued solutions (Young measures as well as their generalization to statistical solutions) and their numerical approximations in fluid mechanics, we propose the stochastic relaxation of the variational brittle fracture problem through random perturbations of the functional. We introduce the concept of stochastic solution, with the main advantage that point-to-point correlations of the crack phase fields in the underlying domain can be captured. These stochastic solutions are represented by random fields or random variables with values in the classical deterministic solution spaces. In the numerical experiments, we use a simple Monte Carlo approach to compute approximations to such stochastic solutions. The final result of the computation is not a single crack pattern, but rather several possible crack patterns and their probabilities. The stochastic solution framework using evolving random fields allows additionally the interesting possibility of conditioning the probabilities of further crack paths on intermediate crack patterns

Microvascular heart involvement in systemic autoimmune diseases: The purinergic pathway and therapeutic insights from the biology of the diseases

Heart involvement \u2013 often asymptomatic \u2013 is largely underestimated in patients with systemic autoimmune diseases (SADs). Cardiovascular events are more frequent in patients with SADs compared to the general population, owing to the consequences of inflammation and autoimmunity and to the high prevalence of traditional risk factors. Coronary microvascular disease (CMD) is a form of cardiac involvement that is increasingly recognised yet still largely neglected. CMD, the incapacity of the coronary microvascular tree to dilate when myocardial oxygen demand increases or when there is a microvascular spasm (or subclinical myocarditis), is increasingly reported because of the widespread use of new cardiac imaging tools, even in a subclinical phase. The assessment of myocardial coronary flow reserve (CFR) emerged as the most effective clinical tool to detect microvascular damage. The potential causes of microvascular damage, molecular and cellular inflammation along with a pathological CD39-CD73 axis, need always to be considered because data show that they play a role in the occurrence of acute coronary syndromes, heart failure and arrhythmias, even in the early asymptomatic stage. Data suggest that controlling disease activity by means of methotrexate, biologic drugs, antimalarial medications, statins and aspirin, according to indication, might reduce the cardiovascular risk related to macrovascular and microvascular damage in most patients with SADs, provided that they are used early and timely to control diseases. The need of new biomarkers and a careful assessment of myocardial CFR emerged as the most effective clinical tool to detect microvascular damage