Fused Filament Fabrication is a promising manufacturing technology for the circularity of space missions. Potential scenarios include in-orbit applications to maximize mission life and to support long-term exploration missions with in situ manufacturing and recycling. However, its adoption is restricted by the availability of engineering polymers displaying mechanical performance combined with resistance to space conditions. Here, a thermotropic Liquid Crystal Polymer (LCP) is reported as a candidate material with extrusion 3D printing. To expand its scope of applicability to structural parts for space applications, four different exposure conditions are studied: thermal cycling under vacuum, atomic oxygen, UV, and electron irradiations. While 1 MeV-electron irradiation leads to a green coloration due to annealable color centers, the mechanical performance is only slightly decreased in dynamic mode. It is also found that increased printing temperature improves transverse strength and resistance to thermal cycling with the trade-off of tensile stiffness and strength. Samples exposed to thermal cycling and the highest irradiation dose at lower printing temperatures still display a Young's modulus of 30 GPa and 503 MPa of tensile strength which is exceptionally high for a 3D-printed polymer. For the types of exposure studied, overall, the results indicate that LCP 3D-printed parts are well suited for space applications.@en

Dispersed and solubilized oil can impact bulk foam stability differently. Though aromatic components are more soluble in water than straight-chain aliphatic components, solubilized aromatics do not necessarily impact bulk foam stability, whereas straight-chain aliphatic components can have a detrimental impact (Lee et al., “Stability of Aqueous Foams in the Presence of Oil: On the Importance of Dispersed vs Solubilized Oil”, Ind. Eng. Chem. Res., 52,pp. 66−72, 2013). However, to our knowledge there is no research on the impact of solubilized oil on foam in porous media. The impact of the crude oil, as a separate oleic phase, was studied by co-injection of crude oil, surfactant solution and gas in coreflood, on steady-state mobility, captured by the pressure drop across the core. To investigate if the behaviour of steady-state foam with dispersed crude oil can be explained by the solubilized oil components, we perform foam-flooding experiments with surfactant solution previously equilibrated with crude oil. Furthermore, we conduct foam-flooding experiments with solubilized hexane in surfactant solution, to determine if the straight-chain aliphatic components can explain the behaviour of the solubilized crude oil on steady-state foam mobility as it impacts bulk foam in the literature. The crude oil , as a separate oleic phase, reduces the pressure gradient across the core by a factor of twenty compared to the case without oil. Nonetheless, this pressure gradient was about a factor three higher than we observed by co-injecting crude oil, water without surfactant, and gas, which indicates that some weak foam and emulsion was generated by co-injecting surfactant, crude oil, and gas. In contrast, with solubilized crude oil and with solubilized hexane, the pressure gradient is in the same order of magnitude for co-injection gas and surfactant with and without solubilized oil. These results indicate that solubilized crude oil cannot explain the impact of the crude oil as a separate oleic phase on foam mobility in our case. Furthermore, the impact of solubilized crude oil on steady-state foam mobility cannot be explained as the effect of a solubilized straight-chain aliphatic component such as hexane. The major result of our work is that the impact of solubilized crude oil on foam does not explain the detrimental impact of crude oil in a separate oleic phase on foam in a porous media. Another result is that though co-injected water, gas and crude oil might not generate strong foam, it can result in somewhat higher pressure gradients with surfactant in the aqueous phase than without surfactant. This is possibly caused by smaller oil droplets in presence of surfactant and a weak foam.@en

Foam can be applied as an Enhanced Oil Recovery (EOR) process. Foam stability in porous mediadecreases with decreasing surfactant concentration. It is also known that foam collapses belowa “limiting water saturation” in porous media. However, there isn’t a complete theory for the relationship between surfactant concentration and the water saturation below which foam coarsens ina specific porous medium. The aim of this study was to find a relationship between the surfactantconcentration, the foam bubble radius, and the limiting water saturation. This research gathersand analyses experimental data from the literature on foam properties in porous media. The foamswere stabilized with the same anionic surfactant (AOS), at different surfactant concentrations andporous media.The experimental data shows that for a specific porous medium, the limiting water saturation exponentially decreases with increasing surfactant concentration. These results can be explainedby the surfactant depletion from the solution to the gas-water interface. This work shows that thelimiting water saturation approximates the water saturation for which the gas-water interfacial-areais equal to the surface-area that could be covered by the surfactant molecules in the surfactant solution in the given porous medium. A fundamental assumption in this calculation is that gas bubblesin the porous medium correspond to pore size, as is thought to apply to foams at water saturationsabove the limiting water saturation.The general implication of these results is that from two known parameters, the third parameter canbe calculated (the three parameters are surfactant concentration, the average foam bubble sizeand limiting water saturation). A possible implication on the modelling of the foam flood in porousmedia was investigated in this research. The observed relationship was applied to a simulation ofsurfactant-alternating-gas injection in a homogenous reservoir with a uniform residual oil saturation. In this simulation the limiting water saturation was a function of the foam bubble size and thesurfactant concentration@en

We present the results of an experimental investigation of the effect of gas type and composition on foam transport in porous media. Steadystate foam strengths with respect to three cases of distinct gases and two cases containing binary mixtures of these gases were compared. The effects of gas solubility, the stability of lamellae, and the gas diffusion rate across the lamellae were examined. Our experimental results showed that the steady-state foam strength is inversely correlated with the gas permeability across a liquid lamella, a parameter that characterizes the rate of mass transport. The results are also in good agreement with existing observations that the foam strength for a mixture of gases is correlated with the less soluble component. Three hypotheses with different predictions of the underlying mechanism that explain the role of gas type and composition in foam strength are discussed in detail. @en