This paper reports the production of intermetallic microrods and microtubes from the decomposition of an intermetallic compound in an AlTiFe system. The intermetallic compound was obtained by mechanosynthesis of elemental powders of Al, Ti and Fe over 300 h at 400 rpm, sintering from compacted powder particles at 300 MPa per minute and at 900 °C for 3600 s in an argon atmosphere. The milled and sintered samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The intermetallic AlTi₃ and Fe₃Al phases were obtained during the milling process. After sintering, a decomposition of these intermetallic phases was found—Al₃Ti_0.75Fe_0.25, Al₃Ti, FeTi, AlTi₃, Ti₉Al₂₃, Fe₂Ti, Al₈₆Fe₁₄ and Al_0.4Fe_0.6. As a result of the decomposition, we observed the formation of hexagonal rods with intercalated phases of AlTi₃ and Fe₂Ti.

Based on a recently published theoretical model, in this work we experimentally studied the problem of gravity water drainage due to continuous steam injection into an elliptical porous chamber made of glass beads and embedded in a metallic, quasi-2D, massive cold slab. This configuration mimics the process of steam condensation for a given time period during the growth stage of the steam-assisted gravity drainage (SAGD) process, a method used in the recovery of heavy and extra-heavy oil from homogeneous reservoirs. Our experiments validate the prediction of the theoretical model regarding the existence of an optimal injected steam mass flow rate per unit length, ${\varphi }_{opt}$, to achieve the maximum recovery of a condensate (water). We found that the recovery factor is close to 85% when measured as the percentage of the mass of water recovered with respect to the injected mass. Our results can be extended to actual oil-saturated reservoirs because the model involves the formation of a film of condensates close to the chamber edge that allows for gravity drainage of a water/oil emulsion into the recovery well.

This paper experimentally analyzes the collapse of conical granular columns made out of non-cohesive granular materials. Dimensionless run-out lengths were found, as a function of the aspect ratio a, similar to those occurring in the collapse of cylindrical columns, although in the case of conical columns of high aspect ration, at the end of the collapse, a layer of grains that rotates around the cone axis appears and it affects the final profiles of the mounds.

We report a theoretical study to determine the temperature profiles due to the continuous and constant injection of hot water through a line source, into a homogeneous fluid-saturated porous medium which has had initially a constant temperature T∞. In our treatment we have taken in to account the simultaneous injection of constant fluxes of volume fluid, q, and of heat, φ. By using a far-field description, we found similarity solutions for the dimensionless temperature depending on the Peclet number, P e, as the single parameter of the problem.

In this work, the performance of a low-temperature solar collector (LTSC) is evaluated, using carbon nanoparticles in water as working fluid. The nanoparticles used are crystallized fullerenes, with a red parameter of 1.42 nm ± 0.5 nm, with different volume fractions in water. The thickness of the carbon film was approximately 140 to 520 nm. The study is divided into three parts: modeling and simulation of an LTSC, low-cost production and characterization of nanoparticles, and thermal evaluation of the LTSC. For the study, fullerenes were produced by microwave synthesis from a terpenoid resin (Camphor) and the nanoparticles were characterized by scanning electron microscopy (SEM) and High-Resolution Transmission (HRTEM). Tests were carried out with different volumetric flow rates, 0.0111 LT/s, 0.0166 LT/s and 0.0194 L/s, and two volumetric concentrations, 0.035% and 0.063%. The results obtained from the fullerene nanofluid showed an improvement in the thermophysical properties compared to the properties of water. The performance results showed that the efficiency increases up to 47.2% compared to that of water, with a volume fraction of 0.063%, and a flow rate of 0.0194 LT/s.

By using sandpaper of different grit, we have scratched up smooth sheets of acrylic to cover their surfaces with disordered but near parallel micro-grooves. This procedure allowed us to transform the acrylic surface into a functional surface; measuring the capillary rise of silicone oil up to an average height $\overline{h}$, we found that $\overline{h}$ evolves as a power law of the form $\overline{h}\sim t^n$, where t is the elapsed time from the start of the flow and n takes the values 0.40 or 0.50, depending on the different inclinations of the sheets. Such behavior can be understood alluding to the theoretical predictions for the capillary rise in very tight, open capillary wedges. We also explore other functionalities of such surfaces, as the loss of mass of water sessile droplets on them and the generic role of worn surfaces, in the short survival time of SARS-CoV-2, the virus that causes COVID-19.