Extended Identification of Mechanical Parameters and Boundary Conditions by Digital Image Correlation

Abstract This paper represents a further contribution to the study of identification procedures for material mechanics resting on kinematic measurements provided by 2D Digital Image Correlation (DIC) at the microscale. Reference is made to non-conventional experiments on adhesively bonded assemblies industrially manufactured for aerospace applications. For calibration purposes a local approach is considered under plane stress conditions, focusing on a small sub-domain on the sample surface, in which mixed mode debonding is monitored. As a novelty, both the (cohesive) mechanical parameters of the interface and the actual boundary conditions prescribed at different time instants during the test are considered as unknowns to be estimated on the basis of full-field data. In this way, data smoothing and parameter identification procedures, so far usually performed in a sequence, are tackled simultaneously in a coupled framework. Since the inverse problem generalized as mentioned above turns out to be severely ill-posed, suitable regularizing provisions are applied, concerning the a priori regularity of (kinematic) displacement fields, from which boundary data are sampled, and the equilibrium (Neumann) conditions along the cracked part of the interface

Indirect Electrografting of Aryl Iodides

International audienceThe electrografting of 4-iodonitrobenzene that is not possible directly is demonstrated whilst that of 5-iodo-2-amino-pyridine, 4-iodoaniline and iodobenzene is performed with a decrease of overpotential > 2 V. The electrografting of aryl iodides is achieved through a iodine abstraction reaction: in the presence of a sterically hindered diazonium salt (2,6-dimethylbenzenediazonium), the aryl iodide is grafted to gold at the much less negative reduction potential of the diazonium salt

Couplage électro-elastique et adsorption : vers une nouvelle instrumentation en chimie analytique

On utilise des poutres de dimensions micrométriques comme capteurs de leur environnement. Toute modification de l'état électrochimique d'une face introduit alors une flexion du levier. On a montré par ailleurs qu'en utilisant un dispositif interférométrique de mesure de champ et une technique d'identification adaptée, on peut construire une modélisation du couplage électro-élastique. On montre ici comment la relation de couplage est modifiée par l'adsorption de molécules neutres à la surface, et on propose d'exploiter cet effet en chimie analytique

Electrochemical Investigation of Nitinol/Tantalum Hybrid Surfaces Modified by Alkylphosphonic Self-Assembled Monolayers

The surface characteristics of bare and modified nickel-titanium samples (NiTi) are investigated by spectroscopic, microscopic and electrochemical techniques. The successful electrodeposition of a tantalum coating on NiTi and the effective grafting of 1-dodecylphosphonic acid SAMs on both pristine and Ta-covered NiTi surfaces are evidenced and quantified by XPS and SEM. Cyclic voltammetry performed on the different NiTi-based electrodes highlights their specificities regarding electron transfer to a redox probe present in solution (here ruthenium(III) hexamine). Finally, the samples electrochemical characteristics at a local scale are investigated by scanning electrochemical microscopy (SECM). The impact of the surface modifications on mass transport of the redox probe is analyzed through approach curves in the feedback mode, while the recording of current maps in feedback as well as in substrate-generation/tip-collection modes leads to the qualitative identification of electrochemically-active areas corresponding to precursor pitting corrosion sites

Identification du couplage électro-élastique à partir de mesures de champs régularisées par les conditions d'équilibre

Les capteurs micromécaniques présentent de grands intérêts dans les domaines de la biologie et chimie. Leur stimulation électrochimique permet d'améliorer la mesure de flexion induite par l'adsorption de molécules ainsi que la reproductibilité des mesures. On modélise ici le couplage électro-élastique par une couche virtuelle d'épaisseur très petite devant celle du levier et contrainte à se déformer avec celui-ci. Afin de déterminer les paramètres mécaniques de ce système une méthode d'identification et régularisation à partir de mesures de champs est proposée

ECLectic. WP2 Electrochemiluminescence Mechanism Performance Optimisation. T2.1 Optimization Reagents

The presented dataset, part of the Horizon Europe project ECLectic, contains data (simulated and experimental) produced in the framework of the ECLectic project, regarding the electrochemiluminescence (ECL) of [Ru(bpy)3](2+), [Ir(sppy)3]3-, and the mixing of the two emitters ([Ru(bpy)3](2+) and [Ir(sppy)3]3-). The data are useful to decipher the coreactant mechanism for the electrochemiluminescence signal generation. In addition data are useful to optimize the signal in the case of freely diffusing [Ru(bpy)3](2+) complex and Ir(III) mediators to determine the key properties of effective ECL enhancers

Key Requirements for Advancing Machine Learning Approaches in Single Entity Electrochemistry

Despite the noteworthy progress in Single Entity Electrochemistry (SEE) in the last decade, the field still must undergo further advancements to attain the requisite maturity for facilitating and propelling machine learning (ML)-based discoveries. This mini-review presents an analysis of the required developments in the domain, using the success of AlphaFold in biology as a benchmark for future progress. The first essential requirement is the creation and support of high-quality, centralized, and open-access databases on the electrochemical properties of single entities. This should be facilitated through the automation and standardization of experiments, promoting high-throughput output and facilitating comparison between datasets. Finally, the creation of a new type of interdisciplinary specialist, trained to pinpoint critical issues in SEE and implement solutions from applied informatics, is vital for ML approaches to flourish in the SEE field

Reflective microscopy for mechanistic insights in corrosion research

Reflective microscopy (RM) is a robust, label free optical imaging technique that allows fast operando measurements of structural changes on metal interfaces at nanoscale in a wide field. Based on the analysis of the reflected light, RM can be simply understood as “video camera” to produce optical photographs of studied interfaces and thus, it has been used for many years as a complementary tool for the visual inspection. However, recent developments in the optical models and refining the experimental design provided means for the quantitative conversion of reflected light intensities into the variations in roughness, thickness of surface films, chemical composition etc., all indispensable for the surface sciences. This review highlights recent advances and contemporary challenges in the methodological developments of RM specifically tailored for the corrosion research