Matrix transformation of lunar regolith and its use as a feedstock for additive manufacturing.

Building a sustainable human habitat on the Moon requires advances in excavation, paving, and additive manufacturing to construct landing pads, surface transportation arteries, resilient shelters, and scientific outposts. Construction of infrastructure elements on the lunar surface necessitates exploration of the interfacial reactivity of locally sourced regolith and the adaptation of Earth-based construction techniques. Various crosslinking frameworks and sintering methods have been proposed as a means of consolidating lunar regolith into load-bearing structures but each have challenges related to incomplete understanding of reaction chemistry, excessive thermal budgets, and lack of universal applicability to different mineral components of regolith. We describe here a versatile experimental and computational study of the consolidation of a regolith simulant through formation of siloxane networks enmeshing mineral particles by surface dissolution-precipitation and polycondensation reactions. Furthermore, by tailoring the rheological properties of the formulation an additive manufacturing feedstock can be developed for the construction of lunar infrastructure.

Textured ceramic membranes for desilting and deoiling of produced water in the Permian Basin.

Oil production in the Permian Basin gives rise to large volumes of produced water contaminated by silt, emulsified oil, and additives used for enhanced oil recovery. There is intense interest in the design of membrane modules as sustainable alternatives for produced water treatment to enable the reuse of produced water for agricultural applications, injection into aquifers, and redeployment in oil recovery. Here, we report a hierarchically textured cement-based membrane exhibiting orthogonal wettability, specifically, superhydrophilic and underwater superoleophobic characteristics. The in situ formation of ettringite needles accompanied by embedding of glass spheres imbues multiscale texturation to stainless-steel mesh membranes, enabling the separation of silt and oil from produced water at high flux rates (1600 L h-1Û°m-2, at ca. 2.7 bar). Oil concentration is reduced as low as 1 ppb with an overall separation efficiency of 99.7% in single-pass filtration. The membranes show outstanding mechanical resilience and retention of performance across multiple cycles.

Characterizing the low strain complex modulus of asphalt concrete specimens through optimization of frequency response functions.

Measured and finite element simulated frequency response functions are used to characterize the low strain (~10(-7)) complex moduli of an asphalt concrete specimen. The frequency response functions of the specimen are measured at different temperatures by using an instrumented hammer to apply a load and an accelerometer to measure the dynamic response. Theoretical frequency response functions are determined by modeling the specimen as a three-dimensional (3D) linear isotropic viscoelastic material in a finite element program. The complex moduli are characterized by optimizing the theoretical frequency response functions against the measured ones. The method is shown to provide a good fit between the frequency response functions, giving an estimation of the complex modulus between minimum 500 Hz and maximum 18|000 Hz depending on the temperature. Furthermore, the optimization method is shown to give a good estimation of the complex modulus master curve.