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Articles 1 - 5 of 5
Full-Text Articles in Complex Fluids
Effects Of Hofmeister Ions On Lower Critical Solution Temperatures Of Poly(N-Isopropylacrylamide) And Poly(Vinyl Methyl Ether), Joseph Joaquin
Effects Of Hofmeister Ions On Lower Critical Solution Temperatures Of Poly(N-Isopropylacrylamide) And Poly(Vinyl Methyl Ether), Joseph Joaquin
Williams Honors College, Honors Research Projects
The goal of this study is to compare how four different Hofmeister anions (Cl-, SCN-, F-, and I-) affect the Lower Critical Solution temperature (LCST) on two thermo-responsive polymers: poly(N-isopropylacrylamide) (pNIPAAM) and poly(vinyl methyl ether) (PVME). pNIPAAm is commonly used in the environmental applications such as monitoring, oil-water separations, or antifouling materials, and in medical industry from drug delivery to tissue engineering. When pNIPAAM or PVME reaches a temperature above their LCST, they become hydrophobic, and the polymer chains coiled, leading to their aqueous solutions turn opaque. PVME exhibits a similar LCST as that of pNIPAAM, so it can be …
Matlab Model To Predict Liquid Hydrogen Spill Characteristics And Safety, Amy Gravenstein
Matlab Model To Predict Liquid Hydrogen Spill Characteristics And Safety, Amy Gravenstein
Williams Honors College, Honors Research Projects
The potential of using liquid hydrogen for propulsion is often undermined due to its perilous nature. Hydrogen has a wide flammability range when mixed with air (4.0 - 75.0% hydrogen) and a low ignition energy (0.019 mJ). Liquid hydrogen adds to this high risk as a cryogenic fluid that is to be maintained below -22 K. A liquid hydrogen model has been created in MATLAB that can model various spill scenarios from cryogenic liquid hydrogen vessels. This model takes into consideration the spill rate, spill temperature, air temperature, duration of spill, and air flow conditions to calculate the mass accumulation, …
Relating Modified Ergun's Equation To Hindered Settling Correlations, Ryan Zahniser
Relating Modified Ergun's Equation To Hindered Settling Correlations, Ryan Zahniser
Williams Honors College, Honors Research Projects
Correlations were developed between the Modified Ergun’s and Hindered settling correlations under the condition of dense packing of particles in the bed. As the porosity of the slurry increases, so does the interference between particles in the solution which mimics the behavior of a packed or densely concentrated fluidized bed. The similarity between the two sets of conditions was modeled using mathematical equations to calculate settling velocities and pressure drops by means of the Hindered Settling correlations and Modified Ergun’s equation at porosities ranging from 0.4242 to 0.89. The results showed that a porosity of 0.52 and 0.009 ft particle …
Effects Of Hofmeister Ions On Gelation Of Gelatin And Pluronic Hydrogels, Eric Britton
Effects Of Hofmeister Ions On Gelation Of Gelatin And Pluronic Hydrogels, Eric Britton
Williams Honors College, Honors Research Projects
The purpose of the project was to observe the effects of the Hofmeister series of ions on the gelation of gelatin and Pluronic-127 hydrogels. Hydrogels are semi-solid materials that contain a network of joined molecules through intermolecular interactions which are capable of holding water. Gelatin and Pluronic-127 (PF-127) are thermoreversible, physical crosslinked gels. Gelation occurs when temperature, or other driving forces, reduce the polymer chain solubility until a distinct 2-phase system forms. When aqueous ions are present in solution, they exhibit specific ion effects that have either a stabilizing or destabilizing effect on the solubility of proteins and other polymers. …
Modeling The Effect Thickener Structure Has On The Oil Release Of Grease, Dana Cressman
Modeling The Effect Thickener Structure Has On The Oil Release Of Grease, Dana Cressman
Williams Honors College, Honors Research Projects
Our hypothesis was that the thickener type and micelle concentration of grease affected its viscoelastic properties. Measurements were made using a TA AR G2 rheometer and calculations were made using TA rheometer analysis software to characterize the viscoelastic response of grease under oscillatory shear and frequency tests. The oscillatory frequency tests determined the critical micelle concentration. The oscillatory stress tests were taken at temperatures from 5 to 65 degrees Celsius to create a master curve based on time temperature superposition of the measurements. The crossover points of G’ and G” on the oscillatory stress tests demonstrated where the grease transitions …