Ductile metals and alloys undergo plastic yielding at room temperature, during which they exhibit work-hardening and the generation of surface instabilities that lead to necking and failure. We show that pure nanocrystalline copper behaves differently, displaying near-perfect elastoplastic behavior characterized by Newtonian flow and the absence of both work-hardening and neck formation. We observed this behavior in tensile tests on fully dense large-scale bulk nanocrystalline samples. The experimental results further our understanding of the unique mechanical properties of nanocrystalline materials and also provide a basis for commercial technologies for the plastic (and superplastic) formation of such materials.

The present paper reviews and analyses different models that could be used to describe the adsorption equilibrium of pure gases. The adsorption equilibrium of hydrogen, nitrogen and methane is characterised and modelled. Several thermodynamic conceptions have been selected and tested for the calculation of physico-chemical parameters. The model of Dubinin has been selected to estimate the pseudo-saturation vapour pressure. The best results for the molar volume of the adsorbate have been obtained by using Do’s equation. Eight models, namely Langmuir, Freundlich, Sips, Toth, Jovanovic, UNILAN, OBMR and Potential Theory, describing the adsorption equilibrium of pure gases, have been tested and compared with experimental data obtained from the literature at three different temperatures (283 K, 298 K and 313 K). In order to determine the best fit, the correlation coefficient and the standard errors for each parameter have been used to evaluate the data. All the models used in this study, except for Freundlich’s equation in the case of nitrogen or methane adsorption, are in good agreement between experiment and modelling for the adsorption isotherms.

As part of the ongoing transition from fossil fuels to renewable energies, advances are particularly expected in terms of safe and cost-effective solutions. Publicising instances of such advances and emphasising global safety considerations constitute the rationale for this communication. Knowing that high-strength steels can prove economically relevant in the foreseeable future for transporting hydrogen in pipelines by limiting the pipe wall thickness required to withstand high pressure, one advance relates to a bench designed to assess the safe transport or renewable-energy-related buffer storage of hydrogen gas. That bench has been implemented at the technology readiness level TRL 6 to test initially intact, damaged, or pre-notched 500 mm-long pipe sections with nominal diameters ranging from 300 to 900 mm in order to appropriately validate or question the use of reputedly satisfactory predictive models in terms of hydrogen embrittlement and potential corollary failure. The other advance discussed herein relates to the reactivation of a previously fruitful applied research into safe mass solid-state hydrogen storage by magnesium hydride through a new public–private partnership. This latest development comes at a time when markets have started driving the hydrogen economy, bearing in mind that phase-change materials make it possible to level out heat transfers during the absorption/melting and solidification/desorption cycles and to attain an overall energy efficiency of up to 80% for MgH₂-based compacts doped with expanded natural graphite.

A new procedure for quantitative characterization of different types of solid materials is proposed. The technique is based on the Scanning Electron Microscopy (SEM) analysis results of porous materials and their processing by the software ^ImageJ. Several types of porous adsorbents AX21, AC35, GAC250, ACENO and IRH3 activated carbons were investigated. Based on SEM analysis, different characteristics of the samples such as porosity, pore size distribution, bed particles porosity can be obtained. In this study, the particle size, the average macropore size and pore size distributions (PSD) of samples were determined with a new procedure for SEM analysis treatment using ^ImageJ software. Three distribution functions (Gamma, Weibull and Lognormal) were selected to describe the experimental results. The Lognormal distribution fitted more accurately the experimental data.