Temperature Distribution in Fluidized Beds of Porous Particles with Liquid Injection

Liquid injection in fluidized beds is used to add reactants or to improve the heat management in the reactor. This injection will increase the complexity of reactor due to the formation of agglomerates. In this work the effect of the injection on the particle temperature distribution in a fluidized bed of porous particles is determined experimentally using particle image velocimetry and infra-red thermography. The main property of the porous particles influencing the distribution is the specific surface area. In addition, the porosity has a large effect on the defluidization of the fluidized bed.     

Regulating Zinc Nucleation Sites and Electric Field Distribution to Achieve High-Performance Zinc Metal Anode via Surface Texturing

Understanding zinc (Zn) deposition behavior and improving Zn stripping and plating reversibility are significant in developing practical aqueous Zn ion batteries (AZIBs). Zn metal is abundant, cost-effective, and intrinsically safe compared with Li. However, their similar inhomogeneous growth regime harms their practicality. This work reports a facile, easily scalable, but effective method to develop a textured Zn with unidirectional scratches on the surface that electrochemically achieves a high accumulated areal capacity of 5530 mAh cm⁻² with homogenized Zn deposition. In symmetric cells, textured Zn presents a stable cycling performance of 1100 hours (vs 250 h of bare Zn) at 0.5 mA cm⁻² for 0.5 mAh cm⁻² and lower nucleation and plating overpotentials of 120.5 and 41.8 mV. In situ optical microscopy and COMSOL simulation disclose that the textured surface topography can 1) homogenize the electron field distribution on the Zn surface and regulate Zn nucleation and growth, and 2) provides physical space to accommodate Zn deposits, prevent the detachment of “dead” Zn, and improve the structural sufficiency of Zn anode. Moreover, differential electrochemical mass spectrometry analysis find that the textured Zn with regulated interfacial electron activity also presents a higher resistance toward hydrogen evolution and other parasitic reactions.     

An improved correlation for dry pressure losses across static mixers at high Reynolds numbers

Corrugated (SMV-style) static mixers are industrially important for process intensification and can promote gas–liquid mass transfer in processes such as sour gas sweetening. Current correlations for pressure loss are limited to Reynolds numbers (Re) below 40 000, far below the ranges encountered in natural gas systems (10⁵ < Re < 10⁷). An experimental and numerical study of pressure drop across multiple corrugated mixers in the range of 10⁴ < Re <2 × 10⁵ encompassing different configurations (aligned, rotated), pipe diameters (1–4 in.), and sand grain surface roughness values (10–5000 μm) is reported here. Our previous correlation for pressure loss across a single corrugated element is shown to be extendable to multiple corrugated mixing elements. Through the inclusion of mixer tortuosity (τ), porosity (ε), and macro-scale (geometric) wall roughness (e), the correlation also matches historical pressure drop data (at different τ, ε) reported in literature, thereby demonstrating the utility of these variables as parameters that can help optimize mixer performance. Experiments and computational fluid dynamics (CFD) modelling revealed that the rotated configuration increased the residence time by up to 13% in comparison to the aligned configuration. This may have implications on the selective absorption of sour gas components that are based on fast kinetics. In addition, the role of wall roughness (both pipe housing and mixer) was demonstrated to be significant in this study (accounting for 55% of the pressure losses) and must be accurately accounted for when scaling laboratory measurements.     

Structure-Property Relationships Governing Membrane-Penetrating Behaviour of Complex Coacervates

Complex coacervates are phase-separated liquid droplets composed of oppositely charged multivalent molecules. The unique material properties of the complex coacervate interior favours the sequestration of biomolecules and facilitates reactions. Recently, it is shown that coacervates can be used for direct cytosolic delivery of sequestered biomolecules in living cells. Here, it is studied that the physical properties required for complex coacervates composed of oligo-arginine and RNA to cross phospholipid bilayers and enter liposomes penetration depends on two main parameters: the difference in ζ-potential between the complex coacervates and the liposomes, and the partitioning coefficient (K_p) of lipids into the complex coacervates. Following these guidelines, a range of complex coacervates is found that is able to penetrate the membrane of living cells, thus paving the way for further development of coacervates as delivery vehicles of therapeutic agents.