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In this work, the development of novel binary and ternary oxide/Torlon hollow fiber composites comprising zirconia, titania, and silica as amine supports was demonstrated. The resulting binary (Zr-Si/PAI-HF, Ti-Si/PAI-HF) and ternary (Zr-Ti-Si/PAI-HF) composites were then functionalized with monoamine-, diamine-, and triamine-substituted trialkoxysilanes and were evaluated in CO2 capture. Although the introduction of both Zr and Ti improved the CO2 adsorption capacity relative to that with Si/PAI-HF sorbents, zirconia was found to have a more favorable effect on the CO2 adsorption performance than titania, as previously demonstrated for amine sorbents in the powder form. The Zr-Ti-Si/PAI-HF sample with an oxide content of 20 wt % was found to exhibit a relatively high CO2 capacity, that is, 1.90 mmol g(-1) at atmospheric pressure under dry conditions, owing to more favorable synergy between the metal oxides and CO2 . The ternary fiber sorbent showed improved sorption kinetics and long-term stability in cyclic adsorption/desorption runs.

Polyelectrolyte complex nanoparticle (PECNP) systems compatible with produced water were developed to improve supercritical CO2 (scCO2) foam stability and to reduce fluid loss for fracturing applications. Foam viscosity, stability, fluid loss properties and cleanup of injected liquid through the formation were enhanced by PECNP-surfactant systems prepared in produced water medium. Taking advantage of produced water as energized fluids for fracturing requires enhanced compatibility of gas/liquid mixture. Two produced water recipes of 33,333 and 66,666ppm TDS were used to prepare 1 w/w% surfactant solutions. PECNP was formed as a mixture of positively- and negatively- charged polyelectrolytes. Experimental setup was designed to determine the aqueous foam stability at actual reservoir conditions. Rheological measurement was performed to measure the stability of the bulk foam under shear and to evaluate the foam texture properties. The improved viscosity of different proportions of PECNP-Surfactant (9:1, 8:2, 7:3, and 6:4) in aqueous foam mixtures was observed as compared to surfactant stabilized CO2 foam. The flow consistency index observed in the shear thinning region was also increased from 1184.3 to 2916.4 Pa sn in 33,333ppm and from 1035.7 to 1683.1 Pa snin 66,666ppm brine solutions. The view cell results revealed the high stability and longevity of scCO2 foam employing various proportions of surfactant to nanoparticle as oppose to surfactant generated foam in which the foam height shortened faster. The presented scCO2 generated foam can preserve the foam cellular structure in absence of crude oil. The PECNP-Surfactant system successfully lowered the interfacial tension to up to 74% and 93% for 33,333 and 66,666ppm brine salinity, respectively. Fluid loss was measured to evaluate fluid leak-off from a core when the high flow velocity along the core exists. The fluid loss for both CO2 and water leak-off were also lowered employing PECNP- Surfactant containing foam.

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The amount of fresh water used in hydraulic fracturing can be significantly reduced by employing produced water-compatible supercritical CO 2 (scCO 2 ) foams. Foams generated using surfactants only have suffered from long-term stability issues resulting in low viscosity and proppant-carrying problems. In this work, foam lamella stabilization with polyelectrolyte complex nanoparticles (PECNPs) and wormlike micelles (WLMs) is investigated. Electrostatic interactions are studied as the defining factors improving the hydraulic fracturing performance using the PECNP system prepared in produced water. Two oppositely charged polyelectrolytes are investigated to generate a more stable lamellae between the aqueous phase and the scCO 2 while degrading in the presence of crude oil. The generated dry foam system is used as a hydraulic fracturing fluid in a tight shale formation. The strong compatibility of the synthesized PECNPs with zwitterionic surfactants prepared in highly concentrated brine in the form of wormlike micelles above critical micelle concentration (CMC) helps develop a highly viscous, dry foam capable of using produced water as its external phase. This foam system improves fracture propagation and proppant transport fracture cleanup compared to the base case foam system with no PECNPs. The formation of PEC−surfactant nanoparticles was verified via zeta potential, particle size analysis, and transmission electron microscopy; the underlying mechanism was identified as electrostatic rearrangement of WLMs along the PECNP's perimeter or formation of electrostatically bonded micelles with the nanoparticle to create a new enhanced nanoparticle. A Raman spectroscopic model was developed to understand the PECNP−surfactant spectra and subsequent spectroscopic and hence structural changes associated with complexation. Enhanced bulk viscosity and improved foam quality as a result of complexation at the interface was identified with rheometry in addition to sand pack experiments with PECNP−surfactant ratios of 1:9 and 4:6 in 33.3 kppm and 66.7 kppm salinity brine systems, respectively. Enhancement in the shear thinning and cleanup efficiency of the fracturing fluid was observed. Formation damage was controlled by the newly introduced mixtures as fluid loss volume decreased across the tight Kentucky sandstone cores by up to 78% and 35% for scCO 2 foams made with PECNP−WLMs in 33.3 and 66.7 kppm salinity brine, respectively. The produced water compatibility and reduction of water disposal presented the prospect of environmentally friendly scCO 2 foams for hydraulic fracturing of unconventional reservoirs.

The fatigue crack propagation of aluminium panels when repaired with unidirectional glass bre composite laminates was investigated. The stress intensity factor at the crack tip of cracked panels repaired with single-sided and double-sided composite patches was evaluated by developing three-dimensional nite element models (FEMs). A particular surface preparation was used to bond the patches to the aluminium panels, resulting in a cohesive failure mechanism in the specimens. The results show that the stress intensity factor in the aluminium specimens was considerably decreased for double-sided repair, although for singlesided repair specimens the fatigue life was almost doubled compared with the specimens before repair.

Flow-permeable separators underwent surface modification, and their performances were evaluated to determine the impact of an ion-exchange coating on the electrochemical properties of sandwich diffusion batteries. A zinc–alkaline system was used to evaluate this performance at high discharge rates and diffusion overpotentials across the separator. An alkaline-resistant anion-exchange polyelectrolyte was synthesized based on a quaternary ammonia polysulfone system to utilize the coated separators for faster ion and counterion transport, and the obtained functionalized separators were compared with stationary inert porous separators. Accordingly, the discharge behavior of primary battery systems for both inactive and functionalized separators was introduced. According to discharge profiles, the practical voltage range, specific capacity, and utilization of active materials were improved, and ionic conduction was enhanced and verified by electrochemical impedance spectroscopy. Different commercial filter papers were examined to determine the optimal polymer–substrate compatibility.