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This study aims to fine-tune the plasma composition with a particular emphasis on reactive nitrogen species (RNS) including nitrogen dioxide (NO 2 ), dinitrogen pentoxide (N 2 O 5 ), and nitrous oxide (N 2 O), produced by a self-constructed cylindrical dielectric barrier discharge (CDBD). We demonstrated the effective manipulation of the plasma chemical profile by optimizing electrical properties, including the applied voltage and frequency, and by adjusting the nitrogen and oxygen ratios in the gas mixture. Additionally, quantification of these active species was achieved using Fourier transform infrared spectroscopy. The study further extends to exploring the aerosol polymerization of acrylamide (AM) into polyacrylamide (PAM), serving as a model reaction to evaluate the reactivity of different plasma-generated species, highlighting the significant role of NO 2 in achieving high polymerization yields. Complementing our experimental data, molecular dynamics (MD) simulations, based on the ReaxFF reactive force field potential, explored the interactions between reactive oxygen species, specifically hydroxyl radicals (OH) and hydrogen peroxide (H 2 O 2 ), with water molecules. Understanding these interactions, combined with the optimization of plasma chemistry, is crucial for enhancing the effectiveness of DBD plasma in environmental applications like air purification and water treatment.

Engineered artificial minerals (EnAMs) are the core of a new concept of designing scavenger compounds for the recovery of critical elements from slags. It requires a fundamental understanding of solidification from complex oxide melts. Ion diffusivity and viscosity play vital roles in this process. In the melt, phase separations and ion transport give rise to gradients/increments in composition and, with it, to ion diffusivity, temperature, and viscosity. Due to this complexity, solidification phenomena are yet not well understood. If the melt is understood as increments of simple composition on a microscopic level, then the properties of these are more easily accessible from models and experiments. Here, we obtain these data for three stoichiometric lithium aluminum oxides. LiAlO 2 is a promising EnAM for the recovery of lithium from lithium-ion battery pyrometallurgical processing. It is obtained through the addition of aluminum to the recycling slag melt. The high temperature properties spanning from below to above the liquidus temperature of three stoichiometric Li-Al-Oxides: Li 5 AlO 4 , LiAlO 2 , and LiAl 5 O 8 are determined using molecular dynamic simulations. The compounds are also synthesized via the sol-gel route. The Li + ion exhibits the largest diffusivity. They are quite mobile already below the liquidus temperature, i.e., for LiAlO 2 at T = 1700 K, the diffusion coefficient of the lithium ion equals D = 3.0 × 10 -9 m 2 s -1 . The other ions Al 3+ and O 2- do not move considerably at that temperature. The diffusivity of Li + is largest in the lithium-rich compound Li 5 AlO 4 with D = 32 × 10 -9 m 2 s -1 at 2500 K. The lower the viscosity, the higher the lithium content. The Li 5 AlO 4 exhibits a viscosity of η = 2.2 mPa s at 1328 K which matches well with the experimentally determined 2.5 mPa s at this temperature. The viscosity of LiAlO 2 at 1800 K is more than two times higher. These data sets can help to describe the melts on a microscopic level and understand how the melt properties will change due to gradients in the Li/Al concentration., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The plastic response of the Senkov HfNbTaTiZr high-entropy alloy is explored by means of simulated nanoindentation tests. Both a random alloy and an alloy with chemical short-range order are investigated and compared to the well understood case of an elementary Ta crystal. Strong differences in the dislocation plasticity between the alloys and the elementary Ta crystal are found. The high-entropy alloys show only little relaxation of the indentation dislocation network after indenter retraction and only negligible dislocation emission into the sample interior. Short-range order-besides making the alloy both stiffer and harder-further increases the size of the plastic zone and the dislocation density there. These features are explained by the slow dislocation migration in these alloys. Also, the short-range-ordered alloy features no twinning plasticity in contrast to the random alloy, while elemental Ta exhibits twinning under high stress but detwins considerably under stress relief. The results are in good qualitative agreement with our current knowledge of plasticity in high-entropy alloys., (© 2024. The Author(s).)

Bridging the gap between the material and geometrical aspects of a structure is critical in lightweight construction. Throughout the history of structural development, shape rationalization has been of prime focus for designers and architects, with biological forms being a major source of inspiration. In this work, an attempt is made to integrate different phases of design, construction, and fabrication under a single framework of parametric modeling with the help of visual programming. The idea is to offer a novel free-form shape rationalization process that can be realized with unidirectional materials. Taking inspiration from the growth of a plant, we established a relationship between form and force, which can be translated into different shapes using mathematical operators. Different prototypes of generated shapes were constructed using a combination of existing manufacturing processes to test the validity of the concept in both isotropic and anisotropic material domains. Moreover, for each material/manufacturing combination, generated geometrical shapes were compared with other equivalent and more conventional geometrical constructions, with compressive load-test results being the qualitative measure for each use case. Eventually, a 6-axis robot emulator was integrated with the setup, and corresponding adjustments were made such that a true free-form geometry could be visualized in a 3D space, thus closing the loop of digital fabrication.