The cold neutron imaging and diffraction instrument IMAT at the second target station of the pulsed neutron source ISIS is currently being commissioned and prepared for user operation. IMAT will enable white-beam neutron radiography and tomography. One of the benefits of operating on a pulsed source is to determine the neutron energy via a time of flight measurement, thus enabling energy-selective and energy-dispersive neutron imaging, for maximizing image contrasts between given materials and for mapping structure and microstructure properties. We survey the hardware and software components for data collection and image analysis on IMAT, and provide a step-by-step procedure for operating the instrument for energy-dispersive imaging using a two-phase metal test object as an example.

The interaction of oxygen with alkalis (Na, K) on Ni(111) was studied by high-resolution electron energy loss spectroscopy. Loss measurements revealed for the first time a softening of the O–Ni bond and, simultaneously, a strengthening of the alkali-Ni bond in the alkali+O coadsorbed phase, in perfect agreement with recent theoretical calculations. The weakening of the O–Ni bond was ascribed to the alkali-induced filling of the O 2pz antibonding orbitals. Different physical mechanisms were discussed for explaining the strengthening of the alkali-substrate bond whenever alkalis are coadsorbed with O adatoms.

The obsidian of Sierra de las Navajas is well known for its green color and gold hue. In order to relate these features with compositional and microtextural characteristics, we have carried out a microanalytical study by Wave Dispersion System associated to Electron Probe Micro-Analyzer, Scanning Electron Microscope observation, and X-rays micro-tomographic analyses of samples showing different colors (dark to light green, sometimes with bands of different color intensity) and hues (changing, uniform, no hue). In accordance with previous studies, the green color of the obsidian seems to be related to a high iron content, probably in its reduced state. However, no significant difference in composition occurs between dark and light green samples. The SEM observation and microtomographic study revealed the absence of microcrystals and the occurrence of vesicles of different size, shape, and orientation. Lighter green colors are shown by highly vesiculated surfaces, whereas non-vesiculated samples are darker. On the surfaces with a high concentration of coarse vesicles, a uniform golden hue is observed. Decreasing vesiculation gives a hue changing with the angle of incident light. However, when the vesicularity approaches zero, no hue is visible. The iso-orientation of vesicles along preferential directions and their distribution in bands determine the variation in color intensity and hue on differently oriented surfaces. Microvesiculation also influences other characteristics that were important features for the use of obsidian in the past, such as fracture, transparency, and roughness.

The target for European decarburization encourages the use of renewable energy sources and H₂ is considered the link in the global energy system transformation. So, research studies are numerous, but only few facilities can test materials and components for H₂ storage. This work offers a brief review of H₂ storage methods and presents the preliminary results obtained in a new facility. Slow strain rate and fatigue life tests were performed in H₂ at 80 MPa on specimens and a tank of AISI 4145, respectively. Besides, the storage capacity at 30 MPa of a solid-state system, they were evaluated on kg scale by adsorption test. The results have shown the H₂ influence on mechanical properties of the steel. The adsorption test showed a gain of 26% at 12 MPa in H₂ storage with respect to the empty condition. All samples have been characterized by complementary techniques in order to connect the H₂ effect with material properties.

We present an in situ x-ray absorption study of hydrogen absorption into the bulk of an electrode material while it is operating in an electrochemical cell. The active material is an overstoichiometric ${\mathrm{AB}}_2-\mathrm{type}$ alloy, namely, $\mathrm{Zr}({\mathrm{V}}_{0.29}{\mathrm{Ni}}_{0.71}{)}_3,$ with a cubic $C15\mathrm{}$ Laves phase structure. Hydrogen absorption induces both structural and electronic changes due to the bonding between interstitial H atoms and each alloy element. The role of each element is revealed, allowing us to determine the inert role of Ni atoms and the dominant effect of the H-V interaction on the hydride formation process. Comparison between the alloyed element behavior and the H affinity of each pure element allows us to determine the influence of structural and alloying effects on bonding formation.