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The load cell is an indispensable component of many engineering machinery and industrial automation for measuring and sensing force and torque. In this article, we propose to investigate a force sensor design combining surface acoustic wave (SAW) strain sensor with binocular load cell structure. For this purpose, we use a binocular test body instrumented with both resistive strain gauge as a reference and SAW strain sensor. The system enables the generation of extremely localized and accurate positive and negative strains. Static and dynamic measurements are performed using calibrated weights and a shock hammer respectively. For SAW sensor, a one-port resonator with frequency operation in the range of 410 MHz was fabricated and mounted on the test body. For electronic conditioning, we use a low-cost RF electronic conditioning based on radar architecture using the integrated circuit AD8302. The system enables the measurement of ${S}_{{11}}$ reflection coefficient (module and phase) with sensitivity and noise spectral density of (29 mV/dB, 250 nV/ $\surd $ Hz) and (10 mV/°, 83 nV/ $\surd $ Hz) respectively. The SAW sensor mounted on body proof was successfully tested in static and dynamic mode using this electronic architecture. The results show good linearity, sensitivity values of 0.023 and 0.09 mV/ppm were obtained for amplitude and phase measurements respectively. The dynamic response was performed using a shock hammer and a comparison with conventional strain gauge shows a good agreement.

In this work, we addressed the local degradation mechanisms limiting the prelaunch environmental durability of thin-layered silver stacks for demanding space mirror applications. Local initiation and propagation of tarnishing were studied by combined surface and interface analysis on model stack samples consisting of thin silver layers supported on lightweight SiC substrates and protected by thin SiO2overcoats, deposited by cathodic magnetron sputtering and submitted to accelerated aging in gaseous H2S. The results show that tarnishing is locally initiated by the formation of Ag2S columns erupting above the stack surface. Ag2S growth is promoted at high aspect ratio defects (surface pores) of the SiC substrate as a result of an imperfect protection by the SiO2overcoat. Channels most likely connect the silver layer to its environment through the protection layer, which enables local H2S entry and Ag2S growth. The silver sulfide columns grow in number and size eventually leading to coalescence with increasing H2S exposure. In more advanced stages, tarnishing slows down owing to saturation of all pre-existing imperfectly protected sites of preferential sulfidation. However, it progresses radially at the basis of the Ag2S columns underneath the protection layer, consuming the metallic silver layer and deteriorating the protecting overcoat.

Organic coatings are often required for the protection of metals against environmental degradation. Despite their extensive use, only limited information is available on the initial stages of adsorption and formation of protective films, especially at the molecular and atomic levels. As a model system for coating formation, this study investigates the adsorption of glycerol molecules on the single-crystalline Cu(111) surface. A combined electrochemical and scanning tunneling microscopy study in NaOH aqueous solution enabled following the adsorption process in detail, providing molecular information on the glycerol film structure. A potential-driven adsorption of glycerol was observed, suppressing the adsorption of hydroxyl molecules and copper oxidation. The adsorbed species assembled in a nearest neighbor arrangement fitting a (√3 × √3) R30° hexagonal structure with respect to the Cu(111) lattice. This experimentally observed configuration was confirmed by density functional theory (DFT) calculations. DFT modeling indicates that a mixed adsorption mode involving the two primary alcohol groups adsorbed at different z-positions relative to the surface is the most favorable. This mixed configuration enabled the formation of an extended network of hydrogen bonds that aids in stabilization of the glycerol film. This implies that interactions between glycerol molecules have a non-negligible effect on the growth process of such an organic film, allowing the formation of organic layers in the absence of strong interfacial interactions.