The accretion of ice on aircraft wings, sensors, and engines presents a serious hazard to flight safety, underscoring the need for durable and energy-efficient ice protection strategies. Among emerging strategies, porous icephobic surfaces (PISs) have attracted considerable research interest due to the favorable durability, excellent icephobic performance, and low energy requirements. Nevertheless, critical aspects such as design objectives, theoretical foundations, fabrication techniques, and durability test standards for PISs have not yet been systematically examined, resulting in unclear research directions and motivating this review. This article first provides a comprehensive overview of existing aircraft ice protection strategies, establishing a broader context for the development of PIS. Through extensive literature analysis, the review then identifies contact angle hysteresis and icephobic durability as two key design parameters for PISs. Foundational principles related to lubricant transport, heat transfer, and wetting behavior in porous media are also introduced to furnish a solid theoretical basis for PIS design. Subsequently, slippery liquid-infused porous surfaces (SLIPS) are discussed as a prominent and successful example of PIS in ice protection applications, covering their fabrication methods, failure modes, and icing characteristics. However, SLIPS are prone to lubricant depletion under shear flow and rain erosion, which can substantially compromise their icephobic performance. Recent advances in PIS design have therefore incorporated strategies such as antifreeze agent release, lubricant replenishment, and covalent anchoring to reduce lubricant loss and enhance durability. To bridge the gap between simplified laboratory durability tests and the multifaceted testing required for aeronautical applications, this review outlines essential durability evaluation protocols for aeronautical implementation. Furthermore, the potential of artificial intelligence (AI) in accelerating the development and optimization of PIS is explored. Beyond offering a thorough synthesis of recent progress in PIS technology for anti-icing, this work also highlights PIS as a promising next-generation, durable, and energy-efficient candidate for aircraft ice protection.

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Xanthan gum (XG) is a biopolymer used in various industries as a thickener and stabilizer. However, its tendency to agglomerate and form lumps during dispersion in water is an industry issue. The present work investigates the effect of ethanol acting as an XG dispersant in an aqueous solution and whether the dispersant affects the solution´s stability and rheological properties. The study proposes different concentrations of XG (0.1 %, 0.5 %, and 1 % wt) dissolved in water and an ethanol-water mixture. The results show that ethanol promotes faster and more effective hydration and dispersion of xanthan gum. This effect is particularly evident at intermediate (0.5 wt%) and high (1.0 wt%) concentrations, where the observed increase in viscosity suggests improved initial dispersion and enhanced rheological stability over time. The FTIR analysis indicates that ethanol disrupts hydrogen bonds, promotes polymer-polymer interactions, and increases dispersion homogeneity. Additionally, the zeta potential shows that ethanol increased the electrostatic stability of XG dispersions by augmenting the particles´ repulsion and thus preventing clustering, which results in more stable systems than water-alone solutions. The TGA analysis revealed that ethanol slightly enlarged the thermal stability of XG solutions due to stronger polymer-polymer interactions. Therefore, ethanol is an efficient, accessible, and environmentally friendly dispersant for improving XG dissolution, reducing processing time, and showing promising potential for industrial applications.

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This study presents an experimental investigation into the startup flow of waxy crude oils in pipelines. An experimental rig was assembled with two syringe pumps connected to a 56.6-meter-long pipeline with an internal diameter of 10.3 mm. The experimental setup was placed within a thermal chamber to control the system temperature. The system was able to control thermal and shear history. The primary objective was to evaluate the start-up pressure required when initiating flow at a constant inlet flow rate. Unlike most prior works in the open literature, which discuss the rheological properties of crude oils at low temperatures, the current work explores the effect of the shear history, initial cooling temperature, aging time, and final cooling temperature in a startup flow loop. We also show in a pioneering experimental analysis that pressurizing the pipeline during the cooling evinces the effect of compressibility due to shrinkage on the startup of waxy crude oil.

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This work investigates transient non-colloidal suspension flows in cone-and-plate, plate-plate, and cylindrical geometries to assess particle motion’s impact on viscosity measurement. Mass and momentum conservation equations model the two-phase liquid–solid flow, with both phases treated as continuous in an Euler-Euler approach. Findings demonstrate rheometric flow induces particle motion, affecting suspension homogeneity and viscosity measurement over time. Both buoyancy and inertia effects drive particle motion, with buoyancy dominating at low shear rates and inertia at high shear rates. Particle volume fractions, shear rates, and liquid viscosity notably influence viscosity measurements. Measurements with concentric cylinders are the least affected by particle motion. Additionally, we propose a time limit and a critical Reynolds number in which particle motion does not affect the measurement of the suspension viscosity.

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This work aims at modeling the forces acting on the drill string assembly during its pull-out from the hole. Such forces arise from the interaction between equipment and both the cuttings bed and the well walls. The model is based on the continuity and momentum equations and the interactions with the cuttings bed are determined using concepts of granular materials. Comparisons with laboratory experimental data show the forces computed by the model are similar to that observed experimentally for different cuttings bed heights and drill bit areas. In addition, the model is able to predict whether a plug is formed or not. Finally, a case study was carried out by coupling the proposed model to an existing drag model to show the model’s potential for the detection of field problems.

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The current work puts forward a numerical study of non-colloidal suspension flows in a parallel-plate geometry. The inhomogeneous Euler-Euler model applied to the continuity and momentum equations is used to solve the two-phase flow problem. The aim is at the investigation of particle motion in the suspensions flow and its consequence on the measured apparent viscosity. In contrast with prior works that dealt with neutrally buoyant flows, buoyancy is now taken into account. Good agreement was obtained between measured and computed particle distributions. Analysis of this distribution reveals that not only the particle motion but also the apparent viscosity depends on whether the lower or the upper plate is rotating. Comparisons between buoyant and non-buoyant flows were performed to understand the reasons behind the particle motion. Numerical experiments were conducted by rotating the upper or lower parallel plates and varying Reynolds number, particle volume fraction, density ratio and particle size. It can be anticipated that the particle motion in buoyant flows is mainly driven by a combination of gravity and a secondary flow perpendicular to the main circumferential flow.

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