Matching Items (9)
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- All Subjects: Membranes
- All Subjects: Materials
- Creators: Materials Science and Engineering Program
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
Due to the environmental problems caused by global warming, it has become necessary to reduce greenhouse gas emissions across the planet. Biofuels, such as ethanol, have proven to release cleaner emissions when combusted. However, large scale production of these alcohols is uneconomical and inefficient due to limitations in standard separation processes, the most common being distillation. Pervaporation is a novel separation technique that utilizes a specialized membrane to separate multicomponent solutions. In this research project, pervaporation utilizing ZIF-71/PDMS mixed matrix membranes are investigated to see their ability to recover ethanol from an ethanol/aqueous separation. Membranes with varying nanoparticle concentrations were created and their performances were analyzed. While the final results indicate that no correlation exists between nanoparticle weight percentage and selectivity, this technology is still a promising avenue for biofuel production. Future work will be conducted to improve this existing process and enhance membrane selectivity.
ContributorsHoward, Chelsea Elizabeth (Author) / Lind, Mary Laura (Thesis director) / Nielsen, David (Committee member) / Greenlee, Lauren (Committee member) / Barrett, The Honors College (Contributor) / Chemical Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor)
Created2015-05
Description
Dry and steam NanoBonding™ are conceived and researched to bond Si-based surfaces, via nucleation and growth of a two-dimensional SiOxHy or hydrated SiOxHy interphase connecting surfaces at the nanoscale across macroscopic domains. The motivation is to create strong, long lasting, hermetically bonded sensors with their electronics for the development of an artificial pancreas and to bond solar cells to glass panels for robust photovoltaic technology. The first step in NanoBonding™ is to synthesize smooth surfaces with 20 nm wide atomic terraces via a precursor phase, ß-cSiO2 on Si(100) and oxygen-deficient SiOx on the silica using the Herbots-Atluri process and Entrepix’s spin etching. Smooth precursor phases act as geometric and chemical template to nucleate and grow macroscopic contacting domains where cross bridging occurs via arrays of molecular strands in the hydrated SiOxHy interphase. Steam pressurization is found to catalyze NanoBonding™ consistently, eliminating the need for direct mechanical compression that limits the size and shape of wafers to be bonded in turn, reducing the cost of processing. Total surface energy measurements via 3 Liquids Contact Angle Analysis (3L CAA) enables accurate quantitative analysis of the total surface energy and each of its components. 3L CAA at each step in the process shows that surface energy drops to 42.4 ± 0.6 mJ/m2 from 57.5 ± 1.4 mJ/m2 after the Herbots-Atluri clean of an “As Received” wafer. 3L CAA after steam pressurization Nanobonding™ shows almost complete elimination from 13.8 mJ/m2 ± 1.0 to 0.002 ±- 0.0002 mJ/m2 in the contribution of acceptors to the total free surface energy, and an increase from 0.2 ± .03 to 23.8± 1.6 mJ/m2 in the contribution of donors. This is consistent with an increase in hydroxylation of the ß-cSiO2 surface as a consistent precursor phase for cross-bridging. This research optimizes the use of glycerin, water, and α-bromo-naphtalene in the use of 3L CAA to effectively quantify the components of total free surface energy which helps to better understand the most consistent method for NanoBonding™.
ContributorsBennett-Kennett, Ross Buchanan (Author) / Culbertson, Robert (Thesis director) / Herbots, Nicole (Committee member) / Foy, Joseph (Committee member) / Barrett, The Honors College (Contributor) / Materials Science and Engineering Program (Contributor) / Department of Physics (Contributor) / School of Historical, Philosophical and Religious Studies (Contributor)
Created2013-05
Description
Acute Kidney Injury (AKI) may be detected through biomarkers in urine. This research is being done to develop a membrane for use in separating urine biomarkers to monitor their level. A hydrophobic membrane was treated to improve separation of the desired biomarker for colorimetric sensing. This method was tested with model solutions containing the biomarker. Future work will extend to testing with real urine.
ContributorsBrown, Stephanie Ann (Author) / Lind, Mary Laura (Thesis director) / Yin, Huidan (Committee member) / Materials Science and Engineering Program (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Zeolite thin films and membranes are currently a promising technology for pervaporation, gas separation and water purification. The main drawback with these technologies is that the synthesis is not consistent leading to varied and unreproducible results. The Langmuir-Blodgett technique is a robust method for transferring monolayers of molecules or crystals to a solid substrate. By measuring the surface pressure and controlling the area, reliable results can be achieved by transferring monolayers to different solid substrates. It has been shown previously that various types of zeolites can be functionalized and dispersed on the top of water. This is done by using an alcohol to form a hydrophobic coating on the surface of zeolite. The Langmuir-Blodgett can be used to create thin, compact films of zeolites for synthesizing and growing zeolite films. For the first reported time, cubic LTA Zeolites monolayers have been assembled with the Langmuir-Blodgett technique with multiple solvents and different sizes of zeolites. These films were characterized with Scanning Electron Microscopy and Pressure-Area Isotherms generated from the Langmuir-Blodgett. It was found that linoleic acid is a required addition to the zeolite dispersions to protect the mechanical stability during agitation. Without this addition, the LTA zeolites are broken apart and lose their characteristic cubic structure. This effect is discussed and a theory is presented that the interparticle interactions of the long alkane chain of the linoleic acid help reduce the shear stress on the individual zeolite particles, thus preventing them from being broken. The effect of size of the zeolites on the monolayer formation was also discussed. There seemed to be little correlation between the monolayer quality and formation as size was changed. However, to optimize the process, different concentrations and target pressures are needed. Lastly, the effect of the solvent was explored and it was found that there is a different between monolayer formations for different solvents likely due to differing interparticle interactions. Overall, LTA zeolites were successfully fabricated and the important factors to consider are the zeolite size, the solvent, and the amount of surfactant stabilizer added.
ContributorsDopilka, Andrew Michael (Author) / Lind, Mary Laura (Thesis director) / Cay, Pinar (Committee member) / Materials Science and Engineering Program (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
One of the more difficult portions of our capstone project has been identifying a potential market for our Clay Metal—whether there even is a potential market. To that end, I plan to use the strategies discussed in MSE482 to complete a feasibility study and market analysis for our two clay metal systems to determine if our alloys are viable as a product in any market and to determine what steps we might need to take to bring our material to that market. While we have done some preliminary research similar to a feasibility study, a more comprehensive understanding of our problem and its existing solutions will help us optimize our design with respect to desirable properties and cost. There are various metrics used to identify what materials properties are most desirable for consumers; the exact metric we use will become clearer when I have identified our demographic.
ContributorsMandzuk, Kevin Paul (Author) / Adams, Jim (Thesis director) / Krause, Stephen (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
The story of graphene truly began in what was simply a stub in the journal Physical Review not two years after the end of World War II. In 1947, McGill University physicist P.R. Wallace authored “The Band Theory of Graphite” and attempted to develop a foundation on which the structure-property relationship of graphite could be explored; he calculates the number of free electrons and conductivity of what he describes as “a single hexagonal layer” and “suppos[es] that conduction takes place only in layers” in bulk graphite to predict wave functions, energies at specific atomic sites in the hexagonal lattice, and energy contours using a tight binding approximation for a hypothesized version of what we now call ‘armchair-style’ graphene. While Wallace was the first to explore the band structure and Brillouin Zones of single-layer graphite, the concept of two-dimensional materials was not new. In fact, for years, it was dismissed as a thermodynamic impossibility.
Everything seemed poised against any proposed physical and experimental stability of a structure like graphene. “Thermodynamically impossible”– a not uncommon shutdown to proposed novel physical or chemical concepts– was once used to describe the entire field of proposed two-dimensional crystals functioning separately from a three-dimensional base or crystalline structure. Rudolf Peierls and Lev Davoidovich Landau, both very accomplished physicists respectively known for the Manhattan Project and for developing a mathematical theory of helium superfluidity, rejected the possibility of isolated monolayer to few-layered crystal lattices. Their reasoning was that diverging thermodynamic-based crystal lattice fluctuations would render the material unstable regardless of controlled temperature. This logic is flawed, but not necessarily inaccurate– diamond, for instance, is thermodynamically metastable at room temperature and pressure in that there exists a slow (i.e. slow on the scale of millions of years) but continuous transformation to graphite. However, this logic was used to support an explanation of thermodynamic impossibility that was provided for graphene’s lack of isolation as late as 1979 by Cornell solid-state physicist Nathaniel David Mermin. These physicists’ claims had clear and consistent grounding in experimental data: as thin films become thinner, there exists a trend of a decreasing melting temperature and increasing instability that renders the films into islands at somewhere around ten to twenty atomic layers. This is driven by the thermodynamically-favorable minimization of surface energy.
Everything seemed poised against any proposed physical and experimental stability of a structure like graphene. “Thermodynamically impossible”– a not uncommon shutdown to proposed novel physical or chemical concepts– was once used to describe the entire field of proposed two-dimensional crystals functioning separately from a three-dimensional base or crystalline structure. Rudolf Peierls and Lev Davoidovich Landau, both very accomplished physicists respectively known for the Manhattan Project and for developing a mathematical theory of helium superfluidity, rejected the possibility of isolated monolayer to few-layered crystal lattices. Their reasoning was that diverging thermodynamic-based crystal lattice fluctuations would render the material unstable regardless of controlled temperature. This logic is flawed, but not necessarily inaccurate– diamond, for instance, is thermodynamically metastable at room temperature and pressure in that there exists a slow (i.e. slow on the scale of millions of years) but continuous transformation to graphite. However, this logic was used to support an explanation of thermodynamic impossibility that was provided for graphene’s lack of isolation as late as 1979 by Cornell solid-state physicist Nathaniel David Mermin. These physicists’ claims had clear and consistent grounding in experimental data: as thin films become thinner, there exists a trend of a decreasing melting temperature and increasing instability that renders the films into islands at somewhere around ten to twenty atomic layers. This is driven by the thermodynamically-favorable minimization of surface energy.
ContributorsShulman, Neal Arthur (Author) / Adams, James (Thesis director) / Islam, Rafiqul (Committee member) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Metal-organic frameworks (MOFs) are a new set of porous materials comprised of metals or metal clusters bonded together in a coordination system by organic linkers. They are becoming popular for gas separations due to their abilities to be tailored toward specific applications. Zirconium MOFs in particular are known for their high stability under standard temperature and pressure due to the strength of the Zirconium-Oxygen coordination bond. However, the acid modulator needed to ensure long range order of the product also prevents complete linker deprotonation. This leads to a powder product that cannot easily be incorporated into continuous MOF membranes. This study therefore implemented a new bi-phase synthesis technique with a deprotonating agent to achieve intergrowth in UiO-66 membranes. Crystal intergrowth will allow for effective gas separations and future permeation testing. During experimentation, successful intergrown UiO-66 membranes were synthesized and characterized. The degree of intergrowth and crystal orientations varied with changing deprotonating agent concentration, modulator concentration, and ligand:modulator ratios. Further studies will focus on achieving the same results on porous substrates.
ContributorsClose, Emily Charlotte (Author) / Mu, Bin (Thesis director) / Shan, Bohan (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
One of the grand challenges of engineering is to provide access to clean water because it is predicted that by 2025 more than two thirds of the world’s population will face severe water shortages. To combat this global issue, our lab focuses on creating a novel composite membrane to recover potable water from waste. For use as the water-selective component in this membrane design Linde Type A zeolites were synthesized for optimal size without the use of a template. Current template-free synthesis of zeolite LTA produces particles that are too large for our application therefore the particle size was reduced in this study to reduce fouling of the membrane while also investigating the nanoparticle synthesis mechanisms. The time and temperature of the reaction and the aging of the precursor gel were systematically modified and observed to determine the optimal conditions for producing the particles. Scanning electron microscopy, x-ray diffraction, and energy dispersive x-ray analysis were used for characterization. Sub-micron sized particles were synthesized at 2 weeks aging time at -8°C with an average size of 0.6 micrometers, a size suitable for our membrane. There is a limit to the posterity and uniformity of particles produced from modifying the reaction time and temperature. All results follow general crystallization theory. Longer aging produced smaller particles, consistent with nucleation theory. Spinodal decomposition is predicted to affect nucleation clustering during aging due to the temperature scheme. Efforts will be made to shorten the effective aging time and these particles will eventually be incorporated into our mixed matrix osmosis membrane.
ContributorsKing, Julia Ann (Author) / Lind, Mary Laura (Thesis director) / Durgun, Pinar Cay (Committee member) / Chemical Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
This project sought to analyze the effects of recycling Inconel 718 powder for Direct Metal Laser Sintering (DMSL) for additive manufacturing by testing low cycle fatigue tensile samples ranging from virgin to ten times recycled. Fracture generally occurs at the sample surface where persistent slip planes form and accumulate to cause a sudden fracture leading to signature markings for various phases of crack growth. Effects caused by contamination would be found in the first region of crack growth at the initiation site as the cause stress concentration. Tensile strength and fatigue life were compared to initiation site size found from fracture images obtained using scanning electron microscope imaging which found no significant deviations from the expected surface cracking and LCF region of slip plane buildups. Contamination was not found at any initiation site indicating that fracture life was not impacted by the amount of powder recycling. LCF life ranged from 60,000 to 250,000 which the majority experiencing fractures near 120,000 cyclic loadings. If defect effects were to be found than the low fatigue life sample would exhibit them however its fracture surface did not exhibit contamination but a slight increase in porosity found in the phase III cracking region. The In 718 powders were also analyzed to determine that the primary powder contaminates were brush fibers used to sweep away unused powders during processing however these were not seen in the final DMLS samples.
ContributorsLaws, Alec Ky (Author) / Tasooji, Amaneh (Thesis director) / Eylon, Daniel (Committee member) / Materials Science and Engineering Program (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05