Separation of azeotropic mixtures using protic ionic liquids as extraction solvents

IF/00190/2014; IF/00210/2014; PTDC/EQU-EQU/29737/2017; PTDC/QEQ-FTT/3289/2014; IF/00210/2014/CP1244/CT0003; UID/QUI/50006/2019; POCI-01-0145-FEDER-007265; University of Pamplona, Internal Project 2-2017.The aim of this work is to evaluate the separation of hydrocarbons (hexane and heptane) from their azeotropic mixtures with ethanol using protic ionic liquid (PIL) as extraction solvents. With this goal in mind, PILs were synthesized and their thermal and physical characterization were carried out. Experimental determination of the phase equilibrium for the ternary systems hydrocarbons + ethanol + PIL at 298.15 K and 101.2 kPa were also carried out in order to evaluate the feasibility of this application. The solute distribution ratio and the selectivity were also determined to compare the solvent capacity of these PILs. The NRTL equation was used to correlate the experimental data. Furthermore, this paper provides a comparison of the solvent capacity of these PILs with different extraction solvents (ionic liquids (ILs), ILs mixtures and deep eutectic solvents) available in the literature. Then, a critical review for the separation of these azeotropic mixtures was carried out using the extraction processes data obtained through the simulation using a conventional software.preprintpublishe

El futuro del envejecimiento: Opciones de política pública

A partir de la metodología de las Cuentas Nacionales de Transferencia (CNT), este documento presenta nueve estudios nacionales (Argentina, Estado Plurinacional de Bolivia, Brasil, Chile, Colombia, Costa Rica, El Salvador, México y Perú) que analizan los cambios en la estructura etaria de la población y presentan escenarios ilustrativos, con opciones de políticas públicas para hacer frente a los desafíos del envejecimiento, centradas en: extensión de la vida laboral, eliminación de la brecha de género en materia de ingreso laboral, aumento de los impuestos e inversión en educación, para aumentar los años de escolaridad.Resumen .-- Introducción .-- I. El futuro del envejecimiento en Argentina .-- II. El futuro del envejecimiento en el Estado Plurinacional de Bolivia .-- III. El futuro del envejecimiento en Brasil .-- IV. El futuro del envejecimiento en Colombia .-- V. El futuro del envejecimiento en Costa Rica .-- VI. El futuro del envejecimiento en Chile .-- VII. El futuro del envejecimiento en El Salvador .-- VIII. El futuro del envejecimiento en México .-- IX. El futuro del envejecimiento en el Per

Fog interception by Ball moss (<i>Tillandsia recurvata</i>)

Interception losses are a major influence in the water yield of vegetated areas. For most storms, rain interception results in less water reaching the ground. However, fog interception can increase the overall water storage capacity of the vegetation and once the storage is exceeded, fog drip is a common hydrological input. Fog interception is disregarded in water budgets of semiarid regions, but for some plant communities, it could be a mechanism offsetting evaporation losses. <i>Tillandsia recurvata</i> is a cosmopolitan epiphyte adapted to arid habitats where fog may be an important water source. Therefore, the interception storage capacity by <i>T. recurvata</i> was measured in controlled conditions and applying simulated rain or fog. Juvenile, vegetative specimens were used to determine the potential upperbound storage capacities. The storage capacity was proportional to dry weight mass. Interception storage capacity (<i>C</i>_min) was 0.19 and 0.56 mm for rainfall and fog respectively. The coefficients obtained in the laboratory were used together with biomass measurements for <i>T. recurvata</i> in a xeric scrub to calculate the depth of water intercepted by rain. <i>T. recurvata</i> contributed 20 % to the rain interception capacity of their shrub hosts: <i>Acacia farnesiana</i> and <i>Prosopis laevigata</i> and; also potentially intercepted 4.8 % of the annual rainfall. Nocturnal stomatic opening in <i>T. recurvata</i> is not only relevant for CO₂ but for water vapor, as suggested by the higher weight change of specimens wetted with fog for 1 h at dark in comparison to those wetted during daylight (543 ± 77 vs. 325 ± 56 mg, <i>p</i> = 0.048). The storage capacity of <i>T. recurvata</i> leaf surfaces could increase the amount of water available for evaporation, but as this species colonise montane forests, the effect could be negative on water recharge, because potential storage capacity is very high, in the laboratory experiments it took up to 12 h at a rate of 0.26 l h⁻¹ to reach saturation conditions when fog was applied

Snap-Off Criteria for Dynamic Flow Conditions in Constricted Circular Capillaries

One of the main mechanisms of emulsion formation in porous media is the snap-off; invasion of the wetting phase flowing adjacent to the pore wall within a constriction mostly occupied by the non-wetting phase, causing breakup into isolated drops of this phase. The current approaches to determine the occurrence of this phenomenon have been formulated for quasistatic flow conditions, where the mechanisms governing the flow are controlled by the geometry of the capillary. However, some studies suggest that the drop breakup does not occur above a capillary number threshold and given a certain viscosity ratio, even if the static breakup criteria are met. In this paper, we extend the current numerical analysis of the capillary number upper limit (Calim), in which the snap-off is inhibited, by considering the effect of viscosity ratio on the dynamics of immiscible two-phase flow through constricted circular capillaries. Based on the results of this study, empirical mathematical expressions that relate the main physical variables of the flow were established as breakup criteria for dynamic flow conditions. The dynamic breakup criteria takes into account, jointly: some aspects of rheology of the two-phase system, such as the viscosity ratio; the dynamic factors of the flow, encapsulated in the local capillary number; and an integral form of the capillary geometry, represented by a parameter that relates both radii and the distance between them