Herein, we report for the first time the successful preparation of a gold(III) nitrate [Au(NO₃)₃] water‐based precursor for use in a bottom‐up ultrasonic spray pyrolysis (USP) process. Due to its limited solubility in water, the precursor was prepared under reflux conditions with nitric acid (HNO₃) as the solvent and ammonium hydroxide (NH₄OH) as a neutralizer. This precursor enabled the USP synthesis of gold nanoparticles (AuNPs) and the in situ formation of low concentrations of NO₂⁻ and NO₃⁻ ions, which were caught directly in deionized water in a collection system. These ions were proven to act as stabilizers for the AuNPs. Investigations showed that the AuNPs were monodispersed and spherically shaped with a size distribution over three groups: the first contained 5.3 % AuNPs with diameters (2 r) 200 nm. UV/Vis spectroscopy revealed the maximum absorbance band of the AuNPs at λ=528 nm. Additionally, scanning transmission electron microscopy (STEM) observations of the smallest AuNPs (2 r<5 nm) revealed atomically resolved coalescence phenomena induced by interaction with the electron beam. Four stages of the particle‐growth process were distinguished: 1) movement and rotation of the AuNPs; 2) necking mechanism; 3) orientated attachment at matching facets; 4) reshaping of the AuNPs by surface diffusion. This provided important insight into the formation/synthesis process of the AuNPs.

Nowadays friction surfacing (FS) has become a popular solid state surface coating technology suitable for a range of substrates. The technology has the ability to produce coatings with marginal dilution and good metallurgical bonding....

Ultrasonic Spray Pyrolysis (USP) possesses a great potential for production of higher quantities of gold nanoparticles (AuNPs), thus overcoming the problem of batch-to-batch variations in their properties. Recently, we demonstrated that USP with an additional evaporation chamber (modular USP) led to a better size control of AuNPs. However, their morphology, stability, toxicity, and immunomodulatory properties have not been investigated completely. Here, two types of spherical AuNPs were produced by using different USP parameters, followed by their stabilization in Na-citrate solution. No significant changes in their size, agglomeration, andz-potential occurred 3 months after their initial production in citrate solution. However, the conditioning of AuNPs in serum-containing cell culture media for 24 h induced an increase in the AuNPs’ hydrodynamic size and a red shift in their Surface Plasmon Resonance, pointing to their instability in biological media. Cytocompatibility tests showed that the produced AuNPs were internalized by L929 cells and primary human monocytes and were not cytotoxic at the concentrations lower than 200 μg/mL, but they exhibited antiproliferative and anti-inflammatory effects, respectively. AuNPs reduced the percentage of CD14⁺CD16⁺but not CD14^lowCD16⁺monocytes in vitro and reduced the expression of CD86, HLA-DR, TNF-α, and IL-12/IL-23 by these cells. These results indicate that the anti-inflammatory effects of citrate-capped AuNPs produced by modular USP could be beneficial for their application in the treatment of inflammatory conditions.

In this article, the review on different modeling approaches used for the dispersion of conductive slurries is presented. It comprises three parts: state‐of‐the‐art dispersion process, physiochemical properties, and different modelling approaches. The first part explains the physical mechanism involved in the mixing process and gives an in‐depth understanding of the applicability of the current techniques available commercially with respect to lab‐scale, pilot plant, and industrially upscaled production of these conductive slurries. The main challenges in slurry formulation prevent the formation of agglomerates and breaking down the preexisting agglomerates. It can be understood by studying the role of process parameters such as mixing time and stirring speed involved in the dispersion process. The second part focusses on the important physiochemical properties such as solid content, particle size distribution, and rheology that influences the electrode performance. The third part focusses on the available modelling approaches based on computational‐fluid‐dynamics‐ and coarse‐grained‐molecular‐dynamics‐based on the need as well as the complexity involved. The important aspects such as accuracy, computational cost, advantages, and limitations for both these approaches are discussed that will help the readers to select an appropriate technique in the modelling paradigm to reduce the energy consumption in the dispersion process.