Experimental Evaluation of Engineering Behavior of Soft Bangkok Clay under Elevated Temperature

This paper presents the results of a systematic well designed experimental investigation carried out to study the engineering properties of the soft Bangkok clay heated up to 90°C from room temperature (25°C). Details of modified oedometer and triaxial test apparatus that can handle temperatures up to 100°C are also presented. In the range of temperatures investigated, soft Bangkok clay exhibited temperature induced volume changes that depend mainly on the stress history, reduction in the conventional elastic zone, stiffening, and increased hydraulic permeability with increasing temperature as well as apparent overconsolidation state after subjecting the normally consolidated specimen to heating/cooling cycle. The results of this study provide additional data that can enhance the understanding of the thermohydromechanical behavior concepts of saturated clays.     

Development and characterization of clay facial mask containing turmeric extract solid dispersion

Objective: To develop clay facial mask containing turmeric extract solid dispersion (TESD) for enhancing curcumin water solubility and permeability and to determine suitable clay based facial mask.

Methods: The TESD were prepared by solvent and melting solvent method with various TE to polyvinylpyrrolidone (PVP) K30 mass ratios. The physicochemical properties, water solubility, and permeability were examined. The effects of clay types on physical stability of TESD, water adsorption, and curcumin adsorption capacity were evaluated.

Results: The TESD prepared by solvent method with a TE to PVP K30 mass ratio of 1:2 showed physically stable, dry powders, when mixed with clay. When TESD was dissolved in water, the obtained TESD micelles showed spherical shape with mean size of ～100?nm resulting in a substantial enhancement of curcumin water solubility,?～5?mg/ml. Bentonite (Bent) and mica (M) showed the highest water adsorption capacity. The TESD’s color was altered when mixed with Bent, titanium dioxide (TiO₂) and zinc oxide (ZnO) indicating curcumin instability. Talcum (Talc) showed the greatest curcumin adsorption followed by M and kaolin (K), respectively. Consequently, in vitro permeation studies of the TESD mixed with Talc showed lowest curcumin permeation, while TESD mixed with M or K showed similar permeation profile as free TESD solutions. The developed TESD-based clay facial mask showed lower curcumin permeation as compared to those formulations with Tween 80.

Conclusion: The water solubility and permeability of curcumin in clay based facial mask could be improved using solid dispersion technique and suitable clay base composed of K, M, and Talc.