Matching Items (7)
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- All Subjects: chemical engineering
- Creators: Emady, Heather
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
This report investigates the effects of autolyzing, fermentation medium, fermentation temperature, and proofing medium on the growth and porosity of 50% whole wheat sourdough bread. A model was designed using a 24 statistical design of experiment with replicates to screen and quantify the individual and combined effects of the aforementioned factors on the area of a 1 cm cross-sectional cut from each loaf. Fermentation temperature had the single largest effect, with colder fermented loaves being on average 10 cm2 larger than their warmer fermented counter parts. Autolyzing had little individual effect, but the strengthened gluten network abated some of the degassing and overproofing that is a consequent handling the dough or letting it ferment too much. This investigation quantifies how to maximize gluten development and yeast growth to create the airiest whole wheat sourdough, a healthier and easier to digest bread than many commercially available.
ContributorsLay, Michael Loren (Author) / Emady, Heather (Thesis director) / Adepu, Manogna (Committee member) / School of Sustainability (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Layered double hydroxides (LDHs), also known as hydrotalcite-like materials, are extensively used as precursors for the preparation of (photo-)catalysts, electrodes, magnetic materials, sorbents, etc. The synthesis typically involves the transformation to the corresponding mixed metal oxide via calcination, resulting in atomically dispersed mixed metal oxides (MMOs). This process alters the porosity of the materials, with crucial implications for the performance in many applications. Yet, the mechanisms of pore formation and collapse are poorly understood. Combining an integrated in situ and ex situ characterization approach, here we follow the evolution of porosity changes during the thermal decomposition of LDHs integrating different divalent (Mg, Ni) and trivalent (Al, Ga) metals. Variations in porous properties determined by high-resolution argon sorption are linked to the morphological and compositional changes in the samples by in situ transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, which is facilitated by the synthesis of well crystallized LDHs of large crystal size. The observations are correlated with the phase changes identified by X-ray diffraction, the mass losses evidenced by thermogravimetric analysis, the structural changes determined by infrared and nuclear magnetic resonance spectroscopy, and the pore connectivity analyzed by positron annihilation spectroscopy. The findings show that the multimetallic nature of the LDH governs the size and distribution (geometry, location, and connectivity) of the mesopores developed, which is controlled by the crystallization of the MMO phase, providing key insights for the improved design of porous mixed metal oxides.
ContributorsMurty, Rohan Aditya (Author) / Deng, Shuguang (Thesis director) / Nielsen, David R. (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Rotary drums are commonly used for their high heat and mass transfer rates in the manufacture of pharmaceuticals, cement, food, and other particulate products. These processes are difficult to model because the particulate behavior is governed by the process conditions such as particle size, particle size distribution, shape, composition, and operating parameters, such as fill level and rotation rate. More research on heat transfer in rotary drums will increase operating efficiency, leading to tremendous energy savings on a global scale. This study investigates the effects of drum fill level and rotation rate on the steady-state average particle bed temperature. 3 mm silica beads and a stainless steel rotary drum were used at fill levels ranging from 10 \u2014 25 % and rotation rates from 2 \u2014 10 rpm. Four heat guns were used to heat the system via conduction and convection, and an infrared camera was used to record temperature data. A three-level, two-factor, full-factorial design of experiments was employed to determine the effects of each factor on the steady-state average bed temperature. Low fill level and high rotation rate resulted in higher steady-state average bed temperatures. A quantitative model showed that rotation rate had a larger impact on the steady-state bed temperature than fill level.
ContributorsBoepple, Brandon Richard (Author) / Emady, Heather (Thesis director) / Adepu, Manogna (Committee member) / W.P. Carey School of Business (Contributor) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
This thesis analyzed Canon GPR-30 Black Standard Yield Toner in hopes to gain better understanding of the additives and plastic used in a popular photocopier toner formulation. By analyzing the toner’s composition from the perspective of its recyclability and potential to be manufactured using recycled plastic, this thesis hoped to fill a gap in current literature regarding how toner fits into a circular economy. While the analysis of the selected toner was ultimately inconclusive, three hypotheses about the toner’s composition are put forth based upon data from differential scanning calorimetry (DSC), solubility analysis, and Fourier Transform Infrared (FTIR) spectroscopy experimentation. It is hypothesized that the toner is most likely composed of either polymethyl methacrylate (PMMA) or polyethylene terephthalate (PET). Both of these polymers have characteristic FTIR peaks that were exhibited in the toner spectra and both polymers exhibit similar solubility behavior to toner samples. However, the glass transition temperature and melting temperature of the toner sampled were 58℃ and 74.5℃ respectively, both of which are much lower than that of PMMA and PET. Thus, a third hypothesis that would better support DSC findings is that the toner is primarily composed of nylon 6,6. While DSC data best matches this polymer, FTIR data seems to rule out nylon 6,6 as an option because its characteristic peaks were not found in experimental data. Thus, the Canon GPR-30 Black Standard Yield Toner is probably made from either PMMA or PET. Both PMMA and PET are 100% recyclable plastics which are commonly repurposed at recycling facilities, however, unknowns regarding toner additives make it difficult to determine how this toner would be recycled. If the printing industry hopes to move towards a circular economy in which plastic can be recycled to use towards toner manufacturing and toner can be “unprinted” from paper to be recycled into new toner, it is likely that monetary incentives or government regulations will need to be introduced to promote the sharing of toner formulations for recycling purposes.
ContributorsChase, Jasmine (Author) / Green, Matthew (Thesis director) / Emady, Heather (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2023-05
ContributorsChase, Jasmine (Author) / Green, Matthew (Thesis director) / Emady, Heather (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2023-05
ContributorsChase, Jasmine (Author) / Green, Matthew (Thesis director) / Emady, Heather (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Mechanical and Aerospace Engineering Program (Contributor)
Created2023-05
Description
Membrane-based technology for gas separations is currently at an emerging stage of advancement and adoption for environmental and industrial applications due to its substantial advantages like lower energy and operating costs over the conventional gas separation technologies. Unfortunately, the available polymeric (or organic) membranes suffer a trade-off between permeance and selectivity. Mixed matrix membranes (MMMs) containing two-dimensional (2D) metal-organic frameworks (MOFs) as fillers are a highly sought approach to redress this trade-off given their enhanced gas permeabilities and selectivities compared to the pure polymeric membrane. These MMMs are increasingly gaining attention by researchers due to their unique properties and wide small- and large-scale gas separation applications. However, straightforward and scalable methods for the synthesis of MOFs nanosheets have thus far been persistently elusive. This study reports the single-phase preparation, and characterization of MMMs with 2D MOFs nanosheets as fillers. The prepared MOF and the polymer matrix form the ‘dense’ MMMs which exhibit increased gas diffusion resistance, and thus improved separation abilities. The single-phase approach was more successful than the bi-phase at synthesizing the MOFs. The influence of sonication power and time on the characteristics and performance of the membranes are examined and discussed. Increasing the sonication power from 50% to 100% reduces the pore size. Additionally, the ultimate effect on the selectivity and permeance of the MMMs with different single gases is reported. Analysis of results with various gas mixers indicates further performance improvements in these MMMs could be achieved by increasing sonication time and tuning suitable membrane thicknesses. Reported results reveal that MMMs are excellent candidates for next-generation gas mixture separations, with potential applications in CO2 capture and storage, hydrogen recovery, alkene recovery from alkanes, and natural gas purification.
ContributorsNkuutu, John (Author) / Mu, Bin (Thesis director) / Shan, Bohan (Committee member) / Chemical Engineering Program (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05