Emulsions are a type of metastable colloid composed of two or more immiscible liquids. These systems are widely used in a variety of applications, such as cosmetics, drug delivery, food, etc. Although there exist theoretical foundations which offer insights into these systems, industry practices often favor empirical methods. In this work a multiscale approximation is used for the study of water-in-oil (W/O) emulsions. This approach allows for the analysis of interrelationships among macroscopic, microscopic, process, and formulation variables. Additionally, the emulsions were modeled with Computational Fluid Dynamics (CFD), which permitted a better understanding of the role process variables plays. It was possible to establish relationships among incorporated energy, elastic modulus, mean droplet diameter, and stability measurements. In addition, differences in impeller geometry were found to have an effect in the aforementioned variables. Finally, the CFD model allowed for the observation of gradients in relative viscosity, droplet diameter, and dispersed phase volume fraction.

Emulsions are widely used in different industries such as oil, food, pharmaceutics, and cosmetics. These systems, however, exhibit high degrees of complexity due to the interactions between the dispersed and continuous phase on different levels (i.e., molecular and microscopic) and the emergent properties generated by said interactions. In this work, the interrelationships among macroscopic, microscopic, molecular, process, and formulation variables in oil-in-water (O/W) emulsions were analyzed via a multiscale analysis. Furthermore, Computational Fluid Dynamics (CFD) was implemented in order to gain a better understanding of the link between process variables and other relevant responses. Relationships among elastic modulus, mean droplet diameter, zeta potential, stability, and incorporated energy measurements could be established. The simulation allowed for the observation of three-dimensional gradients in relative viscosity, droplet diameter, and dispersed phase volume fraction, as well as flow details for two of the studied impeller geometries.

Rheology control is essential during the period in which cement and concrete pastes are encountered in the fresh state, due to the fact that it directly affects workability, initial placement and the structural performance of the hardened material. Optimizations of clinker formulations and reductions in cement-to-water ratios induced by economic and environmental considerations have a significant effect in rheology, which invokes the need for mechanistic models capable of describing the effect of multiple relevant phenomena on the observed paste flow. In this work, the population balance framework was implemented to develop a model able to relate the transient microstructural evolution of cement pastes under typical experimental conditions with its macroscopic rheological responses. Numerical details and performance are assessed and discussed. It was found that the model is capable of reproducing experimentally observed flow curves by using measured cluster size distribution information. It is also able to predict the complex rheological characteristics typically found in cement pastes. Furthermore, a spatially resolved scheme was proposed to investigate the nature of flow inside a parallel-plates rheometer geometry with the objective of assessing the ability of the model of qualitatively predicting experimentally observed behavior and to gain insight into the effect of possible secondary flows.

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