Sol-gel derived silica: A review of polymer-tailored properties for energy and environmental applications
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36 MATERIALS SCIENCE↗
Engineering topics
Naleway, Steven E.
Publications and source records attributed to Naleway, Steven E..
Thermo-mechanical characterization of shale using nanoindentation
Abstract Shale can be a potential buffer for high-level radioactive nuclear wastes. To be an effective buffer while subject to waste heat, shale's mechanical response at elevated temperature must be known. Many researchers have experimentally characterized the mechanical behavior of various shales at different length scales in adiabatic conditions. However, its mechanical performance at elevated temperatures at the nano-scale remains unknown. To investigate the temperature dependency of nanomechanical properties of shale, we conducted both experimental and numerical studies. In this study, we measured mechanical and fracture properties of shale, such as hardness, elastic modulus, anisotropy, and fracture toughness from 25 °C up to 300 °C at different bedding planes. Statistical analysis of the results suggests that hardness and fracture toughness significantly increased at temperatures from 100 to 300 °C; while, temperature does not have a significant impact on elastic modulus. Data also shows that the bedding plane orientations have a substantial impact on both mechanical and fracture properties of shale at the nano-scale leading to distinct anisotropic behavior at elevated temperature below 100 °C. Additionally, we numerically investigated the mechanical performance of the shale samples at room temperature to gain an insight into its mechanical response through the thickness. Numerical results were validated against the experimental results, confirming the simulation can be used to predict shale deformation at the nano-scale or potentially be used in multi-scale simulations.
36 MATERIALS SCIENCE↗
Bioinspired aligned magnetic features in aerogels for humidity sensing
Many natural plant tissues, such as pinecones, utilize structures to transduce changes in humidity into movement or strain. These often employ layered structures with aligned features in order to create differential stress across the material as different portions swell at different rates. Here, by replicating these types of structures in synthetic materials we can create structures that respond to humidity in a similar manner. Taking these aligned features as inspiration, silica aerogels with tailored humidity reactive properties were created. This behavior was achieved by creating aligned features in these aerogels using a Helmholtz coil to produce a uniform magnetic field that aligned ferrofluid droplets into chains and needle like features. These magnetite-based structures were shown to retain their superparamagnetic properties, allowing them to easily be removed from the aerogels, leaving a large number of aligned channels. Aerogels with the removed needles experienced significantly different strains than both unmodified aerogels and aerogels with the aligned features still in place. Aerogels with these tunable aligned features could be used in humidity sensors that can transduce changes in humidity into strain and could be used in applications such as volatile organic compound capture.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗