Physicochemical Properties and its Variation Law of Microemulsion Phase When Microemulsion Flooding

The composition change of microemulsion system in microemulsion flooding will inevitably cause the change of phase behavior. Microemulsion with different phase types directly affects its performance and displacement efficiency of microemulsion flooding. Therefore, in order to accurately describe this change, this paper, starting from the composition of microemulsion, gives the physicochemical properties characterization methods of microemulsion phase density, viscosity and interfacial tension, and simulates the change of physicochemical properties of microemulsion phase caused by microemulsion entering the high water-oil ratio zone in the process of flooding. The research results are of great significance for screening microemulsion systems and determining the displacement efficiency.

Parametric Study of Droplet Formation and Characteristics Within Microfluidic Devices — A Case Study

Droplet-based microfluidics technologies hold great attention in a wide range of applications, including chemical analysis, drug screening, and food industries. This work aimed to describe the effects of different physical properties of the two immiscible phases on droplet formation in a flow-focusing microfluidic device and determining proper flow rates to form a droplet within the desired size range. A numerical model was developed to solve the governing equations of two-phase flow and the results were validated with previous experimental results. The results demonstrate different types of droplet formation regimes from dripping to jetting and different production rates of droplets as a consequence of the impact of each property on fluid flow, including the viscosity ratio, density, interfacial tension, and the flow rate ratio. Based on the results, flow rate, viscosity, and interfacial tension strongly affect the droplet formation regime as well as its size and shape. Droplet diameter increases by increasing the dispersed to continuous phase flow rate as well as the interfacial tension while it decreases by increasing the viscosity ratio and the continuous phase density. Moreover, the formation of satellite droplets was modeled, and the effect of interfacial tension, the viscosity of the dispersed phase and the continuous phase density were found to be important on the conditions that the satellite droplets are suppressed. Since the formation of the satellite droplets induces polydispersity in droplet size, this phenomenon is avoided. Collectively, choosing appropriate aqueous and oil phases with proper physical properties is crucial in forming monodisperse droplets with defined size and shape.

Observations of tetrel bonding between sp3-carbon and THF

sp3-C⋯THF tetrel bonding was observed in the crystalline state and in the gas phase. Density functional calculations revealed interaction energies up to −11.2 kcal mol−1 and showed that these adducts are held together mainly by electrostatics.