Matching Items (5)
Filtering by
- All Subjects: Flow
- Creators: Emady, Heather
Description
Characterization of particulate process and product design is a difficult field because of the unique bulk properties and behaviors of particles that differ from gasses and liquids. The purpose of this research is to develop an equation to relate the angle of repose and flowability, the ability of the particle to flow as it pertains to particulate processes and product design. This research is important in multiple industries such as pharmaceuticals and food processes.
ContributorsNugent, Emily Rose (Author) / Emady, Heather (Thesis director) / Marvi, Hamidreza (Committee member) / Materials Science and Engineering Program (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
This thesis investigates the effects of differing diameters, removal of antistatic forces, and varying moisture content on the shear stress properties of granular glass beads through use of a Freeman FT4 Powder Rheometer. A yield locus results from plotting the experimental shear stress values (kPa) vs. the applied normal stress value (kPa). From these yield loci, Mohr’s Circles are constructed to quantitatively describe flowability of tested materials in terms of a flow function parameter.
By testing 120-180 µm, 120-350 µm, 250-350 µm, and 430-600 µm dry glass bead ranges, an increase in diameter size is seen to result in both higher shear stress values and an increasing slope of plotted shear stress vs. applied normal stress. From constructed Mohr’s Circles, it is observed that flow function is quite high amongst tested dry materials, all yielding values above 20. A high flow function value (>10) is indicative of a good flow.1 Flow function was observed to increase with increasing diameter size until a slight drop was observed at the 430-600 µm range, possibly due to material quality or being near the size limitation of testing within the FT4, where materials must be less than 1000 µm in diameter.However, no trend could be observed in flowability as diameter size was increased.
Through the use of an antistatic solution, the effect of electrostatic forces generated by colliding particles was tested. No significant effect on the shear stress properties was observed.
Wet material testing occurred with the 120-180 µm glass bead range using a deionized water content of 0%, 1%, 5%, 15%, and 20% by mass. The results of such testing yielded an increase in shear stress values at applied normal stress values as moisture content is increased, as well as a decrease in the resulting flow function parameter. However, this trend changed as 20% moisture content was achieved; the wet material became a consistent paste, and a large drop in shear stress values occurred along with an increase in flowability.
By testing 120-180 µm, 120-350 µm, 250-350 µm, and 430-600 µm dry glass bead ranges, an increase in diameter size is seen to result in both higher shear stress values and an increasing slope of plotted shear stress vs. applied normal stress. From constructed Mohr’s Circles, it is observed that flow function is quite high amongst tested dry materials, all yielding values above 20. A high flow function value (>10) is indicative of a good flow.1 Flow function was observed to increase with increasing diameter size until a slight drop was observed at the 430-600 µm range, possibly due to material quality or being near the size limitation of testing within the FT4, where materials must be less than 1000 µm in diameter.However, no trend could be observed in flowability as diameter size was increased.
Through the use of an antistatic solution, the effect of electrostatic forces generated by colliding particles was tested. No significant effect on the shear stress properties was observed.
Wet material testing occurred with the 120-180 µm glass bead range using a deionized water content of 0%, 1%, 5%, 15%, and 20% by mass. The results of such testing yielded an increase in shear stress values at applied normal stress values as moisture content is increased, as well as a decrease in the resulting flow function parameter. However, this trend changed as 20% moisture content was achieved; the wet material became a consistent paste, and a large drop in shear stress values occurred along with an increase in flowability.
ContributorsKleppe, Cameron Nicholas (Author) / Emady, Heather (Thesis director) / Vajrala, Spandana (Committee member) / Chemical Engineering Program (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2018-12
Description
Ionic liquids (ILs), or low-temperature liquid salts, are a class of materials with unique and useful properties. Made up entirely of ions, ILs are remarkably tunable and diverse as cations and anions can be mixed and matched to yield desired properties. Because of this, IL/water systems range widely—from homogeneous mixtures to multiphasic systems featuring ionic liquid/liquid interfaces. Even more diversity is added when particles are introduced to these systems, as hard particles or soft-matter microgels interact with both ILs and water in complex ways. This work examines both miscible ionic liquid/water mixture and two-phase, immiscible ionic liquid/water systems. Extensive molecular dynamics (MD) simulations are utilized in conjunction with physical measurements to inform theoretical understanding of the nature of these systems, and this theoretical understanding is related to practical applications—in particular, the development of a low-temperature liquid electrolyte for use in molecular electronic transducer (MET) seismometers, and particle self-assembly and transport at ionic liquid/liquid interfaces such as those in Pickering emulsions.
The homogenous mixture of 1-butyl-3-methylimidazolium iodide and water is examined extensively through MD as well as physical characterization of properties. Molecular ordering within the liquid mixture is related to macroscopic properties. These mixtures are then used as the basis of an electrolyte with unusual characteristics, specifically a wide liquid temperature range with an extremely low lower bound combined with relatively low viscosity allowing excellent performance in the MET sensor. Electrolyte performance is further improved by the addition of fullerene nanoparticles, which dramatically increase device sensitivity. The reasons behind this effect are explored by testing the effect of graphene surface size and through MD simulations of fullerene and a silica nanoparticle (for contrast) in [BMIM][I]/water mixtures.
Immiscible ionic liquid/water systems are explored through MD studies of particles at IL/water interfaces. By increasing the concentration of hydrophobic nanoparticles at the IL/water interface, one study discovers the formation of a commingled IL/water/particle pseudo-phase, and relates this discovery to previously-observed unique behaviors of these interfaces, particularly spontaneous particle transport across the interface. The other study demonstrates that IL hydrophobicity can influence the deformation of thermo-responsive soft particles at the liquid/liquid interface.
The homogenous mixture of 1-butyl-3-methylimidazolium iodide and water is examined extensively through MD as well as physical characterization of properties. Molecular ordering within the liquid mixture is related to macroscopic properties. These mixtures are then used as the basis of an electrolyte with unusual characteristics, specifically a wide liquid temperature range with an extremely low lower bound combined with relatively low viscosity allowing excellent performance in the MET sensor. Electrolyte performance is further improved by the addition of fullerene nanoparticles, which dramatically increase device sensitivity. The reasons behind this effect are explored by testing the effect of graphene surface size and through MD simulations of fullerene and a silica nanoparticle (for contrast) in [BMIM][I]/water mixtures.
Immiscible ionic liquid/water systems are explored through MD studies of particles at IL/water interfaces. By increasing the concentration of hydrophobic nanoparticles at the IL/water interface, one study discovers the formation of a commingled IL/water/particle pseudo-phase, and relates this discovery to previously-observed unique behaviors of these interfaces, particularly spontaneous particle transport across the interface. The other study demonstrates that IL hydrophobicity can influence the deformation of thermo-responsive soft particles at the liquid/liquid interface.
ContributorsNickerson, Stella Day (Author) / Dai, Lenore L (Thesis advisor) / Yu, Hongyu (Committee member) / Lind, Mary Laura (Committee member) / Mu, Bin (Committee member) / Emady, Heather (Committee member) / Arizona State University (Publisher)
Created2016
Description
This work describes the development of a device for measuring CO2 in breath, which has applications in monitoring a variety of health issues, such as Chronic Obstructive Pulmonary Disease (COPD), asthma, and cardiovascular disease. The device takes advantage of colorimetric sensing technology in order to maintain a low cost and high user-friendliness. The sensor consists of a pH dye, reactive element, and base coated on a highly porous Teflon membrane. The transmittance of the sensor is measured in the device via a simple LED/photodiode system, along with the flow rate, ambient relative humidity, and barometric pressure. The flow is measured by a newly developed flow meter described in this work, the Confined Pitot Tube (CPT) flow meter, which provides a high accuracy with reduced flow-resistance with a standard differential pressure transducer. I demonstrate in this work that the system has a high sensitivity, high specificity, fast time-response, high reproducibility, and good stability. The sensor has a simple calibration method which requires no action by the user, and utilizes a sophisticated, yet lightweight, model in order to predict temperature changes on the sensor during breathing and track changes in water content. It is shown to be effective for measuring CO2 waveform parameters on a breath-by-breath basis, such as End-Tidal CO2, Alveolar Plateau Slope, and Beginning Exhalation Slope.
ContributorsBridgeman, Devon (Author) / Forzani, Erica S (Thesis advisor) / Nikkhah, Mehdi (Committee member) / Holloway, Julianne (Committee member) / Raupp, Gregory (Committee member) / Emady, Heather (Committee member) / Arizona State University (Publisher)
Created2017
Description
Functional materials can be characterized as materials that have tunable properties and are attractive solutions to the improvement and optimization of processes that require specific physiochemical characteristics. Through tailoring and altering these materials, their characteristics can be fine-tuned for specific applications. Computational modeling proves to be a crucial methodology in the design and optimization of such materials. This dissertation encompasses the utilization of molecular dynamics simulations and quantum calculations in two fields of functional materials: electrolytes and semiconductors. Molecular dynamics (MD) simulations were performed on ionic liquid-based electrolyte systems to identify molecular interactions, structural changes, and transport properties that are often reflected in experimental results. The simulations aid in the development process of the electrolyte systems in terms of concentrations of the constituents and can be invoked as a complementary or predictive tool to laboratory experiments. The theme of this study stretches further to include computational studies of the reactivity of atomic layer deposition (ALD) precursors. Selected aminosilane-based precursors were chosen to undergo density functional theory (DFT) calculations to determine surface reactivity and viability in an industrial setting. The calculations were expanded to include the testing of a semi-empirical tight binding program to predict growth per cycle and precursor reactivity with a high surface coverage model. Overall, the implementation of computational methodologies and techniques within these applications improves materials design and process efficiency while streamlining the development of new functional materials.
ContributorsGliege, Marisa Elise (Author) / Dai, Lenore (Thesis advisor) / Derecskei-Kovacs, Agnes (Thesis advisor) / Muhich, Christopher (Committee member) / Emady, Heather (Committee member) / Zhuang, Houlong (Committee member) / Arizona State University (Publisher)
Created2021