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Full-Text Articles in Engineering
Towards Long Term Colloid Suspension In A Vertically Rotated System., Md Mahmudur Rahman
Towards Long Term Colloid Suspension In A Vertically Rotated System., Md Mahmudur Rahman
Electronic Theses and Dissertations
Within a colloidal suspension gravity may compromise the observation of governing physical interactions, especially those that are weak and/or take significant time to develop. Conducting the experiment in a long-term microgravity environment is a viable option to negate gravitational effects, though significant resources are required to do so. While it may not be possible to simulate long-term microgravity terrestrially, particles can resist quick sedimentation in a confined suspension system rotating vertically with appropriate rotation speed. The goal of the investigation is to demonstrate the existence of long-term particle suspension regime for a certain colloidal suspension while characterizing colloidal behavior due …
Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil
Image Analysis Of Charged Bimodal Colloidal Systems In Microgravity., Adam J. Cecil
Electronic Theses and Dissertations
Colloids are suspensions of two or more phases and have been topics of research for advanced, tunable materials for decades. Stabilization of colloids is typically attributed to thermodynamic mechanisms; however, recent studies have identified transport or entropic mechanisms that can potentially stabilize a thermodynamically unstable colloidal system. In this study, suspensions of silsesquioxane microparticles and zirconia nanoparticles were dispersed in a nitric acid solution and allowed to aggregate for 8-12 days in microgravity aboard the International Space Station. The suspensions were subsequently imaged periodically at 2.5x magnification. Due to the inadequacy of existing image analysis programs, the python package “Colloidspy” …
Investigation Of Stabilization Mechanisms For Colloidal Suspension Using Nanoparticles., Qingwen He
Investigation Of Stabilization Mechanisms For Colloidal Suspension Using Nanoparticles., Qingwen He
Electronic Theses and Dissertations
Over the past decade, charged nanoparticles have been found to enhance the stability of colloidal suspensions. One promising explanation of this stabilization mechanism is “Nanoparticle Haloing”- the formation of a non-adsorbing nanoparticle layer surrounding neutral colloids that would induce an effective electrostatic repulsion between them. The objective of this work was to investigate the effect of additional charged nanoparticles on the interaction between neural colloids in nanoparticle-regulated complex fluids. Firstly, colloidal probe Atomic Force Microscopy (CP-AFM) is used to directly measure the interaction force in such system with nanoparticle volume fractions varying from 10-6 to 10-2. It is found that …