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Loman, Abdullah AlEnzyme Based Processing of Soybean Meal: Production of Enriched Protein Product and Utilization of Carbohydrate as Fermentation Feedstock for Arabitol Production
Doctor of Philosophy, University of Akron, 2016, Chemical Engineering
Soy protein is one of the major components of the diet of food producing animals and is increasingly important in the human diet as well. However, soy protein cannot be used as an ideal protein supplement in foods, because of the presence of high amount of indigestible carbohydrates in the soybean meal. Adverse nutritional and digestion effects have been reported in many animals and fish following the consumption of soybean meal and soybean meal derived products. To enhance the nutritional value of soybean meal in human food and animal feed, it is necessary to improve the protein content and remove the indigestible carbohydrates from the soybean meal during the processing of soy protein diets. This project aims to develop economically feasible technologies and processes for separating, enriching and upgrading soy proteins and carbohydrates from soybean meal. The objective is to separate proteins from carbohydrates (and other minor components) in soybean meal, facilitated by enzymatic hydrolysis of poly- and oligo-meric carbohydrates and other non-protein materials. The enriched proteins obtained are valuable for high-quality feed, food and industrial uses. The hydrolyzed carbohydrates could also be converted via fermentation into bio-fuel related products and other value added chemicals.

Committee:

Lu-Kwang Ju, Dr. (Advisor); George Chase, Dr. (Committee Member); Nic Leipzig, Dr. (Committee Member); Stephen Duirk, Dr. (Committee Member); Thomas Leeper, Dr. (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Enzyme hydrolysis, soy carbohydrate, arabitol, fermentation feedstock

Imbulgoda Liyangahawatte, Gihan Janith MendisHardware Implementation and Applications of Deep Belief Networks
Master of Science in Engineering, University of Akron, 2016, Electrical Engineering
Deep learning is a subset of machine learning that contributes widely to the contemporary success of artificial intelligence. The essential idea of deep learning is to process complex data by abstracting hierarchical features via deep neural network structure. As one type of deep learning technique, deep belief network (DBN) has been widely used in various application fields. This thesis proposes an approximation based hardware realization of DBNs that requires low hardware complexity. This thesis also explores a set of novel applications of the DBN-based classifier that will benefit from a fast implementation of DBN. In my work, I have explored the application of DBN in the fields of automatic modulation classification method for cognitive radio, Doppler radar sensor for detection and classification of micro unmanned aerial systems, cyber security applications to detect false data injection (FDI) attacks and localize flooding attacks, and applications in social networking for prediction of link properties. The work in this thesis paves the way for further investigation and realization of deep learning techniques to address critical issues in various novel application fields.

Committee:

Jin Wei (Advisor); Arjuna Madanayaka (Committee Co-Chair); Subramaniya Hariharan (Committee Member)

Subjects:

Artificial Intelligence; Computer Engineering; Electrical Engineering; Engineering; Experiments; Information Technology

Keywords:

deep belief networks; multiplierless digital architecture; Xilinx FPGA implementations; low-complexity; applications of deep belief networks; spectral correlation function; modulation classification; drone detection; doppler radar; cyber security

Newton, Katherine LExamining the Impact of Military Experience on Crime: Issues of Race and the Life Course
Doctor of Philosophy, University of Akron, 2018, Sociology
Upon returning home from serving, military members experience several hardships including posttraumatic stress disorder, substance and alcohol use, and a higher risk of involvement in crime. There has long been an interest in criminology pertaining to the relationship of military experience and crime. However, the research examining this relationship is largely inconsistent and is made even more unclear when taking combat and race into account. In this dissertation, I address these issues and use a quasi-experimental methodological technique that aims to overcome these inconsistencies. Using life course perspective and data derived from the National Longitudinal Survey of Youth, Child and Young Adult sample (NLSY-CYA) 1986-2014, I examine the impact serving in the military has on individuals and how this varies by race. I do this by first matching individuals based on demographics, cognitive predictors, and childhood experiences and behaviors to obtain propensity scores where the binary treatment indicator is military experience (treatment) and no military experience (control). Then, I examine criminal offending differences between military members and civilians. Finally, I examine just the military sample to develop a greater understanding of the military experience and how combat and race impacts crime. This dissertation contributes not only to the literature in criminology and the life course perspective but also to military research and race literature.

Committee:

Stacey Nofziger, Ph.D. (Advisor); Juan Xi, Ph.D. (Committee Member); Matthew Lee, Ph.D. (Committee Member); Toni Bisconti, Ph.D. (Committee Member)

Subjects:

Criminology; Military Studies; Social Research; Sociology

Keywords:

military; crime; propensity score matching; race

Wang, KaiHIGH PERFORMANCE SOLUTION-PROCESSED PEROVSKITE HYBRID SOLAR CELLS THROUGH DEVICE ENGINEERING AND NOVEL
Doctor of Philosophy, University of Akron, 2017, Polymer Engineering
ABSTRACT Efficiently and economically harnessing the solar energy via solar cell devices is one of promising solutions to address the global energy crisis. This thesis mainly focuses on a novel family of photoactive layer materials, namely organic-inorganic lead halide perovskite hybrids, and their corresponding solar cell devices, due to their potential for achieving outstanding power conversion efficiency and low-cost processibility. Specifically, the main research themes of this thesis are to achieve high performance perovskite hybrid solar cells through optimizing device structures, developing novel functional perovskite materials, and elucidating the underlying physics and mechanisms for guiding us to construct high performance solution-processed perovskite hybrid solar cells. This dissertation contains four parts and 10 chapters. In PART I, a broaden overview on both solar cell device and material is given, which specifically reviews the importance of solar energy and solar cells, comparison between previous-generation solar cells and perovskite hybrid solar cells, history of perovskite hybrid materials for solar cell application in Chapter 1 and describes the theoretical background of solar cell devices and material used for fabrication of solar cells in Chapter 2. PART II mainly includes the detailed projects on solar cell device engineering. Firstly, in Chapter 3, we employ a highly electrical conductive, polyethylene oxide (PEO)-doped poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) as the hole extraction layer (HEL) for the planar heterojunction (PHJ) perovskite hybrid solar cells (pero-HSCs). The dramatically enhanced electrical conductivity of the PEO-doped PEDOT:PSS HEL provides an efficient pathway for the hole extraction, transport, and collection from the perovskite active layer to the anode. As a result, a significantly enhanced short-circuit current (JSC) of 23.42 mA cm-2, a slightly enlarged open-circuit voltage (VOC) of 0.88 V, an enhanced FF of 80.10% and a correspondingly dramatically enhanced power conversion efficiency (PCE) of 16.52%, which is a ~45% enhancement as compared with that from the PHJ pero-HSCs incorporated with the pristine PEDOT:PSS HEL, are observed. In Chapter 4, we utilize a solution-processed ultrathin layer of an ionomer, 4-lithium styrenesulfonic acid/styrene copolymer (LiSPS), to re-engineer the interface of methylammonium lead iodide (CH3NH3PbI3) in PHJ pero-HSCs. The ionomer can sufficiently modify the rough surface of the perovskite and optimize the charge extraction efficiency between perovskite photoactive layer and the charge transport layer. As a result, PHJ pero-HSCs with an increased photocurrent density of 20.90 mA cm-2, an enlarged ¿ll factor of 77.80%, a corresponding enhanced power conversion ef¿ciency of 13.83%, high reproducibility, and low photo-current hysteresis, are achieved. In Chapter 5, because one major limitation to increasing the efficiency of pero-HSCs is the fact that the diffusion length of the electrons is shorter than that of the holes, to facilitate the electron extraction efficiency in pero-HSCs and to make this efficiency comparable with that of the holes, we fabricated BHJ pero-HSCs by mixing perovskite materials with water-/alcohol soluble fullerene derivatives. The observed enhanced JSC and enlarged FFs were a result of the balance in the charge carrier extraction efficiency and the enlarged interfacial area between the perovskite materials and the fullerene derivatives. Significantly improved power conversion efficiencies were obtained for these BHJ pero-HSCs. A greater than 22% increase in power conversion efficiency was observed for the BHJ pero-HSCs compared with planar heterojunction pero-HSCs. A remarkable 86.7% FF, the highest reported value for pero-HSCs, was observed for the BHJ pero-HSCs. Our strategy of using a BHJ structure in pero-HSCs offers an efficient and simple way to further increase the performance of these devices. PART III mainly discusses the detailed projects on novel perovskite materials development. To fabricate homogeneous and high-quality perovskite thin ¿lms via low-temperature solution processing is always a challenge to realizing high-ef¿ciency pero-HSCs, in Chapter 6, we firstly report a development of an approach to realize smooth surface morphology of CH3NH3PbI3 perovskite thin ¿lms via using strong-polar ethanol solution rather than less-polar isopropanol solution, which was previously used as the solvent for preparing perovskite thin ¿lms. In comparison with the pero-HSCs processed from isopropanol solution, more than 40% enhanced ef¿ciency is observed from pero-HSCs processed from ethanol solution. The enhanced ef¿ciency is attributed to a homogeneous high-quality perovskite thin ¿lm with dramatically low root-mean-square roughness and completely conversion of lead (II) iodide (PbI2) to CH3NH3PbI3. In Chapter 7, we report the development and investigation of novel CH3NH3PbI3: x Nd3+(where x = 0, 0.1, 0.5, 1.0, and 5.0 mol%) perovskite hybrid materials, where Pb2+ is partially substituted by an inequivalent rare-earth metal cation, neodymium (Nd3+), which was never reported in previous studies. By conducting the charge carrier mobility measurements and film morphology studies, it is found that solution-processed CH3NH3PbI3: x Nd3+ thin films exhibit significantly improved and more balanced charge carrier mobilities, and superior film quality with dramatically reduced trap-states and pin-holes, as compared with pristine CH3NH3PbI3 thin film. As a result, a descent power conversion efficiency of 20.56% for solar cells and a superior photodetectivity of ~ 1014 cm Hz1/2 W-1 from 375 nm to 800 nm at room temperature for photodetector, are observed from solution-processed perovskite photovoltaics by novel CH3NH3PbI3: x Nd3+ thin films. All these results demonstrate that our method provides a simple and facial way to boost the device performance of perovskite photovoltaics. In Chapter 8, we report the utilization of polyethylene oxide additives to anchoring the ions in the perovskite lattice to suppress the formation of point defect or the migration of ions/vacancy, for simultaneously enhancing device efficiency, minimizing photocurrent hysteresis and enhancing device stability. Consequently, efficient solar cell devices with power conversion efficiency of 19.01% with extremely low hysteresis index of 0.001 and long-term device shelf half-life time of 504 hrs (without encapsulation, stored in 50% humidity air) have been achieved. Chemical, structural and morphological analysis show that the PEO additive acts as a crosslink between neighboring perovskite crystal domains via the strong hydrogen bonding of `-OH…I-’ and `O…H-NH2CH3+’ to the perovskite. In PART IV, a brief summerization on our works in terms of both device and material engineering is presented in Chapter 9, that is, for optimizing the device configuration as well as address critical issues in previously wide-applied hybrid perovskite thin films, we mainly developed novel ideas on: (i) modifying anode buffer layer for efficient hole extraction; (ii) modifying the interfacial electrical coherence on the i-n junction; (iii) developing a bulk heterojunction concept for efficient charge extraction; for novel materials part, we also focused on three major parts: (i) optimizing the thin film quality of perovskite; (ii) tuning the crystal lattice structure by inequivalent metal doping; (iii) anchoring the ion within the perovskite lattice for reducing hysteresis and improving device stability. Finally, an outlook is given in the Chapter 10 for guiding our future work.

Committee:

Xiong Gong (Advisor); Matthew Becker (Committee Member); Alamgir Karim (Committee Member); Nicole Zacharia (Committee Chair); Jie Zheng (Committee Member)

Subjects:

Electrical Engineering; Energy; Nanoscience; Physics; Polymers

Keywords:

Energy Conversion; Photovoltaics; Lead Halide Perovskite; High Performance; Device Physics; Material Science

Das, Suma RaniInvestigation of Design and Operating Parameters in Partially-Filled Rubber Mixing Simulations
Master of Science, University of Akron, 2016, Mechanical Engineering
The modern rubber industry is always in pursuit of improvements in the properties of the final product resulting from the mixing of the rubber compounds with different fillers and additives. Depending on the functional characteristics of the final product and thus the compounding ingredients, different types of mixers can be used for the rubber mixing process. Hence, the choice of an appropriate mixer is critical in achieving the proper distribution and dispersion of fillers in rubber, and a consistent product quality, as well as is the attainment of high productivity. Besides rotor design, operational parameters such as speed ratio and the orientation of the mixing rotors with respect to each other also play significant role in the mixing performance. With the availability of high-performance computing resources and high-fidelity computational fluid dynamics tools, understanding the flow field and mixing characteristics associated with rotor orientations, speed ratios and complex rotor geometries, has become more feasible over the last two decades. As part of this effort, all the simulations here are carried out in a 75% fill chamber with two counter-rotating rotors using a CFD code. In the phase angle and rotor design studies conducted here, the rotors rotate at 20 rpm even speed, whereas for speed ratio study, only the left rotor rotates at 20 rpm and the right rotor rotates at a speed, which is a multiple of 20 rpm by the speed ratio specified. The computational models used in this research are based on a finite volume method to simulate a partially filled mixer equipped with different tangential rotor types. The model solves for transient, isothermal and incompressible set of governing fluid equations for the mixing of non-Newtonian high-viscosity rubber. The research here considers phase angles of 45°, 90° and 180°, speed ratios of 1.0, 1.125 and 1.5, and rotor designs including 2-wing, 4-wing A and the 4-wing B rotors. Investigation of each parameter type carried out separately. The flow field is analyzed via pressure and velocity contours, mass flow patterns, velocity vectors and particle trajectories. Dispersive mixing is evaluated through histograms of mixing index, joint probability density functions of mixing index and shear rate, and cumulative probability distribution functions of maximum shear stress experienced by the particles. Distributive mixing is quantified statistically using cluster distribution index, axial distribution, inter-chamber particles transfer, segregation scale and length of stretch. The results helped in understanding the mixing process and material movement, thereby generating information that could potentially improve the productivity and efficiency in tire manufacturing process.

Committee:

Abhilash Chandy, Ph.D. (Advisor); Povitsky Alex, Ph.D. (Committee Member); Choi Jae-Won, Ph.D. (Committee Member)

Subjects:

Fluid Dynamics; Industrial Engineering; Mechanical Engineering; Polymers

Keywords:

Dispersive mixing; Distributive mixing; Speed ratio; Phase angle; Rotor design; Segregation scale; Cluster distribution; Length of stretch; Partially filled; non-Newtonian; Numerical simulation; Polymer processing; Rubber Processing; Tire materials

Qian, JinQUARTZ CRYSTAL MICROBALANCE WITH DISSIPATION MEASUREMENTS OF BINDER SWELLING AND SALTS EFFECTS ON PHYSICAL CROSSLINK HYDROGEL
Master of Science, University of Akron, 2018, Polymer Engineering
Advanced active materials, such as Si, for lithium ion battery electrodes are becoming highly engineered, but their cycling performance can be significantly impacted by the mechanical, transport, and electrochemical properties of the polymeric binder in the electrode. The swelling and plasticization of most widely used binder poly(vinylidene difluoride) (PVDF), poly(acrylic acid) (PAA), branched polyethylenimine (BPEI) and potential binder sulfonated ethylene propylene rubber (SEPDM) by common carbonate-based electrolytes is probed using quartz crystal microbalance with dissipation (QCM-D). The swelling of the PVDF was significantly greater than the other polymers, while addition of Li salt only marginally deceased the swelling. The composition of ethylene and propylene carbonate in the electrolyte more significantly impacts the swelling with the 50:50 mixture exhibiting the greatest swelling. The shear modulus of the PVDF remains on the order of 10 MPa for all conditions examined. This mechanical invariance is attributed to the semi-crystalline structure of PVDF that provides a robust network. These measurements provide insight into the electrolyte-binder interactions and can be used to help select pairs for emerging high-performance electrodes from the aspect of swelling of binder by carbonate electrolyte and interaction between binder and active material. As QCM-D is a very sensitive and accurate method for in-situ real time analysis on thin film swelling and mechanical properties, it can also be used to measure salts effect on the swelling of physical crosslink hydrogel. In this study, the Hofmeister series effect on swelling of 2-(N-ethylperfluorooctane sulfonamido)ethyl acrylate (FOSA)/N,N-dimethylacrylamide (DMA) physical crosslink hydrogel which containing 9.7 mol% FOSA (DF10) is introduced. The influence of temperature and different salts species (Na2SO4 and NaClO4) are investigated. The DF10 swollen in aqueous solution dissipates significant energy to enable determine of the mechanical properties. The swelling of DF10 is reversible with temperature increases and salts concentration. Na2SO4 decreases the swelling of DF10 and increases elastic modulus. Conversely, NaClO4 increases the swelling ratio, softens the DF10 hydrogel and increases viscosity in low concentration NaClO4 solutions (from 0.003M to 0.1M). At higher NaClO4 concentration (3M), the swelling decreases slightly when compared with the swelling at 0.3M. This study demonstrated that salts have dramatic effect on swelling of DF10 in aqueous solution, resulting in the change on swelling ratio and mechanical properties of DF10 hydrogel. The efficiency of the anions in increasing swelling was found to be consistent with the Hofmeister anion sequence with the ability of destabilize the hydrophobic aggregates.

Committee:

Bryan Vogt (Advisor); Erol Sancaktar (Committee Chair); Yu Zhu (Committee Member)

Subjects:

Polymers

Hardy-Butler, Kayla AGendered Expressions of the “Passing” Narrative: An Intersectional African-American and Post-Colonial Study
Master of Arts, University of Akron, 2017, English-Literature
The intention of this thesis is to look at several African American passing narratives through the critical lens of a combination of post colonial research and African American criticism in the following texts: Kate Chopin’s “Desiree’s Baby” (1893); Langston Hughes’ “Passing”(1934); Nella Larsen’s Passing (1929); William Faulkner’s Light in August (1932); Written predominantly within the Harlem Renaissance, these narratives most often relay the experiences of black or “Negro” characters who would, in certain contexts, pass themselves off as white if their skin or other phenotypic features were white enough. This study’s goal is to explore the cultural environment of the black experience post colonization in which those who are considered black are forced to grapple with the racially charged doctrine of the colonizer—the Jim Crow rhetoric of a Eurocentric America. Of course, given the specificity of each category of criticism and of the historically sensitive nature of racism, this study’s goal is to use postcolonial research as an entry point to further springboard into a conversation of viewing African-Americans or those who are considered black in a racially hostile environment. In short, the research question is, how to view race with racialized dichotomies set in place by colonial or imperialist rule within U.S literature? More so, this study intends to show the instability of classifications of race and what passing narratives seek to trouble these societal hierarchies.

Committee:

Philathia Bolton (Advisor)

Subjects:

African American Studies; Literature

Keywords:

passing narratives; post-colonialism;double consciousness;gender

Zhu, HaidongSynthesis of Biodegradable Silicon Functionalized Polyester Scaffolds for Bone Tissue Engineering
Master of Science, University of Akron, 2017, Polymer Science
Tissue engineering technology uses the combination of cells, materials and engineering methods, and suitable biochemical and physicochemical factors to improve or replace biological functions. Scaffolds are frequently involved in tissue engineering. Scaffolds are biodegradable materials that have been modified to form new functional tissues for medical purposes. Many studies indicated that silicon is an essential element in bone and connective tissue formation. By functionalizing the biodegradable poly(lactic acid) with silicon, its’ application in tissue engineering is available. The silicon-functionalized copolymer used in this study was synthesized by grafting methyl methacrylate and a silicon-containing methacrylate by atom transfer radical polymerization (ATRP) from a brominated poly(lactic acid) (PLB) used as a macroinitiator. The PLB macroinitiator (GPCPSt Mn = 1.6 ×104 Da; Ð = 2.25) was prepared by incorporating 2-bromo-3-hydroxypropionic acid (BrH) as a co-monomer with lactic acid (LA). This polymerization was well controlled using CuBr as the catalyst and bipyridine as the ligand in toluene at 90 °C. The resulting graft copolymer contains PLA, PMMA and 3-(triethoxysilyl)propyl methacrylate (TESPMA). The final scaffolds prepared by compression method showed good integrity in cell culture media.

Committee:

Coleen Pugh (Advisor); Abraham Joy (Committee Member)

Subjects:

Polymer Chemistry; Polymers

Keywords:

Tissue engineering; scaffold; PLA; TESPMA; ATRP

Quasem, TanvirDevelopment of a Pavement Marking Striping Strategy for ODOT District 11.
Master of Science in Engineering, University of Akron, 2016, Civil Engineering
This research work evaluated four pavement marking materials installed on pavements at 11 test sites located at ODOT District 11. Fast dry traffic paint, polyester, epoxy and thermoplastic were the four marking materials installed at the sites across the district on two-lane and four-lane highways having a variety of pavement types, pavement geometries, and traffic volumes. The main focus was to evaluate fast dry traffic paint and polyester as a restriping material, while epoxy and thermoplastic were evaluated for a purpose of comparison. Most of the sites were located on two-lane roads in rural locations, with an average daily traffic (ADT) of less than 5,000 vehicles per day and an average daily truck traffic (ADTT) of less than 1,000 trucks per day. Only two four-lane sites (located along US 22 in Jefferson County) were included because of their high traffic levels and to facilitate the comparison between two-lane and four-lane roads. Marking materials were installed on a 2 mile road section. The test section was divided into 4 segments each with a 0.5 mile length. In order to evaluate the performance of polyester and fast-dry traffic paint as restriping materials, a 0.1-mile portion of the right edge line in the middle of Sections 1 and 4 was left intact so that both materials could be installed over the existing markings. For the remaining portion of the sections, polyester and fast-dry traffic paint were installed on bare pavement surfaces after the removal of the existing pavement markings. Epoxy and thermoplastic was installed after removing existing marking material. Centerlines were restriped with polyester at section 1 and paint at other sections. During a two year period, the pavement markings were evaluated in terms of dry retroreflectivity, daytime color and durability. A handheld Delta LTL-X retroreflectometer was used to measures pavement marking retroreflectivity in accordance with CEN and ASTM standards using a 30-m geometry to simulate the roadway being illuminated by the headlights of a car. A MiniScan XE Plus (Model 4500L) spectrocolorimeter was used to measure the daytime color of the markings. Durability was evaluated using a subjective rating as an integer on a scale of 0 (the material is completely missing) to 10 (where 100% of the material remains).Photographs were taken to document the condition of the markings for future reference. Laboratory testing was also conducted to examine the quality of the glass beads used during the marking installation. Finally, statistical analysis was performed on the initial and two-year field evaluation data using Minitab 17. Effect of various factors (such as the pavement type, line type, marking material and color, etc.) on the retroreflectivity performance of the pavement markings were determined. The service life of all marking materials was estimated using the linear and the power models for each line at all test sites using a minimum retroreflectivity value of 100 mcd/m2/lux. A Microsoft Excel macro was developed to handle the large amount of data involved in the analysis. Based on the analysis result different restriping strategies were proposed along with the cost analysis for the whole district. Material selection matrices were presented for the two-lane and multi-lane roadways which will help the district office in strategy development and decision making.

Committee:

Ala R Abbas, Dr. (Advisor); Junliang Tao, Dr. (Committee Member); Zhe Luo, Dr. (Committee Member)

Subjects:

Civil Engineering; Transportation

Keywords:

Retroreflectivity, Marking material selection matrix, Restriping strategy, Fast dry traffic paint, Polyester

Gabor, Kelly MComputational Investigations of Polymer Devolatilization Processes in Steam Contactors
Master of Science in Engineering, University of Akron, 2016, Mechanical Engineering
The process of polymer devolatilization is a critical step in manufacturing high quality polymers. Polymer devolatilization is a technique that involves removing unwanted substances, such as unreacted monomers, volatile by-products, solvents, or any other unwanted materials, with the use of superheated steam. The polymer mixture considered here, initially consists of polymer and an excess hydrocarbon solvent like cyclohexane. This polymer mixture is referred to as "cement". To remove the cyclohexane, superheated steam is mixed with the cement, and the steam causes the cyclohexane to evaporate, leaving behind a cement mixture with less solvent and a higher concentration of polymer. As the cement dries out and forms into particles, or "crumb", it is carried away and further processed while the steam and solvent vapor are vented out of the contactor. This process is modeled using computational fluid dynamics (CFD), specifically employing the commercial code, ANSYS FLUENT, to gain insights into the complex phenomena occurring and accounts for several aspects of this multiphase flow problem. The model shows the initial breakup of the cement and the heat transfer and phase change as the solvent evaporates, in addition to tracking the droplet’s size, temperature, solvent content, and other important parameters used to monitor the droplet’s evolution within the contactor. After completion of the simulation, the cement particle sizes are compared to average values from the field for the actual final product to verify this model. This thesis focuses on modeling two separate contactors, referred to as Contactor A and Contactor B, which differ in shape, but involve the same processes. For each contactor, once a final model is constructed, a parametric study is performed to test for several modifications involving lower levels of steam usage, which can in turn potential reduce the manufacturing cost. Contactor A tested the effects of different initial polymer temperature on the final polymer product. Increasing the cement operating temperature reduced the solvent concentration in the cement crumb significantly, and the final cement crumb sizes showed a slight decrease as well, which indicated a better production performance. For Contactor B, several simulations were carried to determine the effects of changing the operating steam pressure and also several geometric parameters. Simulations were carried out using steam as the only phase to test how the flow rate and residence time were affected with the changes in such operating parameters. After determining an improved geometry modification, a full simulation was carried out with steam and cement particles and compared to the original case. The modified case performed better compared to the original case by providing reduced particle sizes, residence times, and cyclohexane content, all indicating better performance.

Committee:

Abhilash Chandy (Advisor)

Subjects:

Mechanical Engineering

Keywords:

Computational Fluid Dynamics, Multi-phase flows

Herbert, JosephThermal Analysis of a Permanent Magnet Assisted Synchronous Reluctance Motor Using Lumped Parameter Thermal Modeling
Master of Science, University of Akron, 2017, Electrical Engineering
With the advent of high power density motors in applications such as electric vehicles, the need for an effective thermal analysis of motors is further warranted to ensure their efficient and reliable operation. While existing Lumped Parameter Thermal Models (LPTMs) provide a convenient method for the thermal evaluation of motor designs, they provide a single, average temperature of the various regions of the motor without data on the temperature variation in the axial direction. LPTMs are a convenient reduced finite-element method to analyze the thermal performance of electric motors based on their design parameters and operating conditions. In this thesis the thermal analysis of a Permanent Magnet Assisted Synchronous Reluctance Motor (PMa-SynRM) is conducted by proposing two LPTMs: 1. Radial Lumped Parameter Thermal Model (R-LPTM). 2. Axial Lumped Parameter Thermal Model (A-LPTM). The R-LPTM adopts an existing approach considered for the thermal modeling of interior rotor configurations with the key contribution being the modeling of the unique rotor con figuration of the PMa-SynRM under study. In this approach, the individual geometries of the motor are modeled as single nodes, the voltages of which correspond to the average temperature for the respective machine part. The A-LPTM introduces a novel thermal model by employing the Finite Volume Method (FVM). While the R-LPTM models heat flow only in the radial direction due to the lamination structure of the stator and the rotor regions, the extension of this approach to the axially thermally shorted conductor coil sides, the magnets and the shaft results in a relative oversimpli cation of the heat transfer in these regions. While equivalent lumped thermal resistances model axial heat flow in these regions in the R-LPTM, by employing the FVM in the A-LPTM a higher resolution of axial temperature data is determined by providing a more accurate method of radial and axial heat flow modeling in these regions. In this model, the conductors, magnet and shaft nodes are evaluated as a function of the position along the axial length of the machine to determine their corresponding axial temperature variation. The results of both the thermal models formed in this thesis have been evaluated and the results were compared with both experimental and Finite Element Analysis (FEA) data. The experimental data was determined using temperature sensors mounted at various points in the machine. For the temperature measurement of the magnet an innovative Printed Circuit Board (PCB) integrated with sensors and wireless data transmission capabilities was mounted on the rotor for real time axial temperature measurement of the magnets. An analysis comparing the data from the R-LPTM and the A-LPTM shows the advantages of the A-LPTM. Additionally, plots of the accuracy of data obtained from both the models clearly highlights their respective accuracy when compared to the experimentally measured values. Lastly, a sensitivity analysis of both models was determined as a function of the thermal resistance values to establish the dependency of the accuracy of the thermal resistance determination on system.

Committee:

Seungdeog Choi (Advisor); Guo-Xiang Wang (Committee Member); Malik Elbuluk (Committee Member); Jin Kocsis (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Lumped Parameter Thermal Model; PMa-SynRM; Permanent Magnet Assisted Synchronous Reluctance Motor

Handagala, Suranga MSpecial Relativistic Array Multi-Port Circuits with Spacetime Noise-Shaping
Master of Science in Engineering, University of Akron, 2017, Electrical Engineering
The dramatic growth in mobile data services and increased demand of subscribers will pose tremendous challenges for the design of future communication systems. The ever increasing need for communication bandwidth and multiple access has made current 4G technologies approach their limits. Extensive research is currently underway to develop communication systems to achieve both capacity and multiple access for an exponentially increasing number of connections. The future of wireless communication will employ millimeter wave (mmW) technologies that have a broad underutilized spectrum. Design of such devices and networks will bring challenges in terms of metrics such as chip area, complexity and power consumption. Inspired by recent trends in mmW technologies, this thesis introduces novel architectures for improving power efficiency, linearity and fabrication cost for receiver-end electronics used in array processing radio receivers. We introduce the concept of delta-sigma noise shaping in the spatial dimension, an approach that pushes undesirable noise and non-linearities of receiver-end devices towards higher spatial frequencies. This method will enable the design of highly compact, fast, power efficient devices which will make future communication systems achieve exponential performance gains.

Committee:

Arjuna Madanayake (Advisor); Ryan Toonen (Committee Member); Kye-Shin Lee (Committee Member); Joan Carletta (Committee Member)

Subjects:

Electrical Engineering

Miller, William HAnalog Implementation of DVM and Farrow Filter Based Beamforming Algorithms for Audio Frequencies
Master of Science in Engineering, University of Akron, 2018, Electrical Engineering
Beamforming is a signal processing technique that is utilized in many communications and signal processing applications. Beamformers help to improve signal quality and enhance the performance of sensor networks and communications arrays. Current digital design methods may require the use of an FPGA or ASIC to perform signal processing. These implementations can be very expensive in terms of design cost and production cost. For this reason, it is worth investigating analog design approaches which can be implemented efficiently and inexpensively using analog design techniques. This thesis explores the recent developments in method and algorithm, and demonstrates applicability to analog beamforming. Two algorithms are investigated and tested: the Delay Vandermonde Matrix (DVM) and a novel analog implementation of the Farrow filter. The DVM design implements a five-beam multi-beam beamformer while the analog Farrow filter implements a single beam which is steerable in the range of 0º to 60º. These two algorithms are analyzed in the analog domain and prototype designs were developed, built, and tested in the laboratory. The prototype designs implemented audio beam-forming using analog electronic components for a four-element array of miniature speaker drivers. A 64-element array of miniature speaker drivers was also analyzed and tested using the same prototype designs. The results from these prototype designs were analyzed and show that a 10dB to 15dB beam intensity can be achieved with the speaker arrays. The results demonstrate that the analog design approach can be a viable and cost effective alternative to typical digital design approaches. This research may have specific applications to teleconference, home theater, virtual reality, and other audio applications.

Committee:

Arjuna Madanayake, PhD (Advisor); Hamid Bahrami, PhD (Committee Member); Kye-Shin Lee, PhD (Committee Member)

Subjects:

Acoustics; Computer Engineering; Electrical Engineering; Engineering

Keywords:

beamformer; delay vandermonde matrix; farrow filter; all-pass filter; audio beamformer; directional loudspeaker; analog audio; audio beamforming; array loudspeaker; array speaker; directional speaker array; multi-beam beamforming

Wang, HaoranPreparation of Titanium Oxide/Epoxy Hybrid Anticorrossive Coating
Master of Science, University of Akron, 2016, Polymer Engineering
ABSTRACT Using organic coating is one of the most effective methods to prevent material from the corrosion which acts as barriers to air, ions and water. The organic/inorganic hybrid material not only combines the inorganic and organic characteristic, but also may own some unique properties. Generally speaking, the organic/inorganic hybrid coating can own the specific property from inorganic part such as: thermal stability, hardness and scratch resistance, and the specific property form organic phase such as: flexibility, toughness, impact resistance and adhesion. Also, the inorganic phase can improve the anticorrosive property of organic coating. In this dissertation, six kinds of the titanium alkoxide/epoxy hybrid coating have been prepared and characterized. The standard liquid BPA epoxy resin was modified by the 3-isocyanatopropyltrietoxysilane (IPTES). The structures were confirmed by Fourier transform infrared spectroscopy (FTIR) liquid state 29Si NMR and mass spectrometry (MS).The viscoelastic properties of coating films were tested by DMTA and DSC. General coating properties including pencil hardness, cross-hatch adhesion, pull-off adhesion, reverse impact resistance and MEK resistance were tested in aluminum panel according ASTM standards. Most importantly, the anticorrosion performance was evaluated by electrical impedence spectroscopy (EIS), 240h salt spray test in steel panel and acid undercutting test.

Committee:

Mark D Soucek (Advisor)

Subjects:

Polymers

Keywords:

Tianium Oxide; Epoxy; Hybrid; Anticorrosive coating

Houser, Shelley AKey Steps to Reading Success: Measuring the Impact of Participation in a Family/School Literacy Partnership Program on the Foundational Literacy Skills of Kindergarteners
Doctor of Philosophy, University of Akron, 2017, Elementary Education-Literacy
Substantial research has revealed several early literacy skills are predictive of later reading achievement. The current quasi-experimental study considered a ten-week family/school literacy partnership program designed to assist families in helping their children with early literacy skills at home. The researcher was interested in determining if participation status in this literacy program made a significant contribution to learning of early literacy skills as revealed in outcomes on winter reading Rasch Unit (RIT) scores on the Measures of Academic Progress for Primary Grades (MPG) for kindergarten students who were placed on a Reading Improvement and Monitoring Plan (RIMP). One hundred and seventy-seven families were invited to participate in the partnership program. Of those, 112 participated. The remainder, 65, made up the control group. Data were analyzed using multiple linear regressions. Findings from the data indicated that scores of kindergarten students whose families participated in the program were .7 of a point higher for each week of participation in comparison to scores of those students whose families did not participate. Gender was not found to be a significant factor on overall reading RIT scores for students in the control group, but girls had significantly higher outcomes over boys in the experimental group. Minority status was not found to be a significant factor on outcomes for kindergarten students in the experimental group, but minority students scored significantly lower according to outcomes for the control group.

Committee:

Lisa Lenhart, PhD (Committee Chair)

Subjects:

Education; Families and Family Life; Literacy

Keywords:

early literacy, reading achievement, kindergarten students, family-school literacy partnership, Measures of Academic Progress for Primary Grades, Reading Improvement and Monitoring Plan, families, quasi-experimental

Ganji, TaherehTHE INFLUENCE OF NANOPARTICLES ON THE KERR EFFECT AT THE NEMATIC-ISOTROPIC PHASE TRANSITION
Master of Science, University of Akron, 2016, Physics
Nanoparticles can affect some physical properties of liquid crystals. We investigate the influence that nanoparticles have on the Kerr coefficient by measuring the electric field Kerr effect (induced birefringence proportional to the square of the applied electric field), above the nematic-isotropic transition temperature by using various concentrations of cerium dioxide nanoparticles in 4-octyl-4’-cyanobiphenyl (8CB) liquid crystal. On cooling toward the nematic-isotropic transition temperature the nematic correlation length increases (but does not diverge because the transition is first order). When the correlation length is of the same order as the characteristic distance between the nanoparticles, the nematic fluctuations are disrupted and the Kerr coefficient will no longer increase as rapidly with decreasing temperature as predicted by Landau-DeGennes theory.

Committee:

Sasa V. Dordevic, Dr. (Advisor); Charles Rosenblatt, Dr. (Advisor); Jutta Luettmer-Strathmann, Dr. (Committee Member)

Subjects:

Physics

Keywords:

Liquid Crystals; Nanoparticles; Kerr Effect; Nematic-Isotropic Phase Transition; Nematic Correlation Length

Adams, Jennifer AnnInstitutions of Higher Education Emergency Management Grant Resiliency?
Master of Public Administration, University of Akron, 2017, Public Administration
Institutions of Higher Education as communities are susceptible to disasters and other dangers. The Department of Education provided a grant in 2008, 2009, and 2010 for emergency management programs to 61 IHE. Since this time, resilience has come to the forefront of emergency management. In determining if these grants increased the positive perception of the level of resilience at IHE that received these grants, a study was completed using Likert-type and open-ended questions. During the course of the literature review it became apparent there may be a confusion of the definitional understanding of resilience, so a qualitative study was included to determine the level of confusion between and among practitioners and scholars. Through a mixed-methods analysis: including correlational studies and qualitative analysis, the net result was more research needs to be completed and the level of confusion of the definitional understanding of resilience is high. By understanding how IHE perceive their levels of resilience and how they are understanding the definition of resilience, a plan can begin to be formulated on how to guide IHE toward being resilient.

Committee:

Raymond Cox, Dr. (Advisor)

Subjects:

Higher Education; Public Administration

Keywords:

IHE; Institutions of Higher Education; resilience; preparedness; recover; response; mitigation; disaster theory; resilience theory; EMHE grant; Higher Education Act 1965

Ji, YijieMetal Organic Frameworks Derived Nickel Sulfide/Graphene Composite for Lithium-Sulfur Batteries
Master of Science, University of Akron, 2018, Polymer Science
With the increasing demanding of energy density and power density in electric vehicles (EVs) and unarmed aerial vehicles, novel rechargeable battery technology with higher performance is required.1 Lithium-sulfur battery is considered as a promising second battery for replacing lithium ion battery (LIB), due to its high theoretical specific capacity and low cost. However, the stability and coulombic efficiency of current Li-S cells are still not satisfactory for many applications. One of the major issue is the cell degradation due to the shuttle effect of soluble polysulfide (PS).2 Here in this thesis, we introduce a metal organic frameworks (MOFs) derived NiS/Graphene composite as cathode host material for Li-S battery. MOFs were used as a precursor to prepare carbon framework with well-organized nanostructure.3 NiS was used to provide good affinity with lithium polysulfide, mitigating shuttle effect. In addition, graphene acted as substrate for anchoring MOFs nanoparticles and provided necessary electron transport passages. The Li-S cell with the designed cathode exhibited improved electrochemical performances. A reversible capacities of 1366 mA h g-1 at a current density of 0.05 C, 609 mA h g-1 at a 3 C were achieved (1 C = 1675 mA h g-1). In addition, a good stability (98 % capacity retention after 400 cycles) was observed at 0.75 C.

Committee:

Yu Zhu (Advisor); Steven Chuang (Committee Member)

Subjects:

Energy; Polymer Chemistry

Keywords:

metal organic frameworks; lithium-sulfur batteries

Gopagani, VikasPARAMETRIC STUDY OF SIX-STORY STRUCTURE WITH SELF-CENTERING CONCENTRICALLY BRACED FRAMES AND VARYING MASS PER FRAME
Master of Science in Engineering, University of Akron, 2016, Civil Engineering
Self-centering concentrically braced frames (SC-CBFs) have been developed to reduce the structural damage caused due to earthquakes. SC-CBF systems have better seismic performance than the conventional concentrically braced frame (CBF) system; SC-CBF systems exhibit less damage to structural and non-structural components under earthquake loading. Recent research has shown that low-rise or mid-rise building seismic performance is better compared to high-rise SC-CBF performance. This study includes the design procedure of the SC-CBF structural members, prototype building, and the analytical procedure considerations in analyses of the prototype structure. The engineering demand parameters (inter-story drift and the peak roof drift) are developed using the nonlinear time history analysis of the structure under a set of ground motions. Then the results are used to evaluate the performance of the structure. In this study, static pushover and dynamic analyses are performed on a 6 story SC-CBF with different numbers of frames in each direction for the same building dimensions (essentially varying the tributary mass per frame). This study proposes to investigate the performance of the structure with varying tributary mass per frame.

Committee:

David Roke (Advisor)

Subjects:

Civil Engineering

Bo, NiDesign, Synthesis and Self-assembly of Polyhedral Oligomeric Silsesquioxane (POSS) Based Hybrid Materials
Doctor of Philosophy, University of Akron, 2018, Polymer Science
The giant molecules systems exhibit very interesting behaviors in the supramolecular assemblies over the past several years compared to other macromolecular systems. As an old Chinese saying goes “good tools are prerequisites for a successful execution of a job”. This dissertation focuses on the synthetic possibilities based on the previous work and try to explore some progress in the first part. The second part of the dissertation encapsulates the self-assembly behaviors of the synthesized giant molecular systems. A pre-functionalization method was developed to achieve giant molecular families with more abundant functionalities. Fluorinated polyhedral oligomeric silsesquioxane (FPOSS), long alkyl chain functionalized POSS (C8POSS), and protected carboxylic acid group functionalized POSS (tAPOSS) were designed and prepared. These kinds of molecules are viewed as molecular nanoparticles (MNPs). The reactivities of the modules was proved by combining them with polymer systems like polystyrene via “click” chemistry. These precisely defined functionalized POSS-containing hybrids could serve as model molecules to investigate the self-assembly behaviors of giant molecules. The solution self-assembly of a giant surfactant consisting of a polystyrene-block-poly (ethylene oxide) (PS-b-PEO) diblock copolymer tail tethered onto a fluorinated polyhedral oligomeric silsesquioxane (FPOSS) cage in 1,4-dioxane/water was investigated. Abundant unconventional micellar structures including toroids, two-dimensional hexagonally patterned colloidal nanosheets, and laterally structured vesicles were observed.2 This study not only exhibits various unique morphologies, but also promotes the fundamental understanding on the pathways of the transformations between different morphologies in the solution self-assembly behavior of giant surfactants. In the MNPs and polymer hybrid systems, the MNPs were with precise molecular weights and chemical compositions. But the polymers used still have a molecular weight distribution which originates from the nature of the polymerization methods applied. To eliminate the polydispersity effect from the system, it is crucial to have molecular systems with precise molecular weights and chemical structures from the physical point of view. Upon this anticipation, we have designed a series of dendrons which are compositionally identical, but their linkers are in different chemical connection geometries. These sets of macromolecules are composed of hydroxyl group functionalized POSS (DPOSS) and isobutyl functionalized POSS (BPOSS). The final dendron structure consists of three parts, one DPOSS at the apex, four BPOSSs at the periphery and the flexible linkers. Note that this series of dendrons is topological isomers. Self-assembled structures of four dendron topological isomers were studied using SAXS and TEM. The results help us to understand the role of linkers in a amphiphiles system and give us some guidance on how to design a molecular system in the future.

Committee:

Stephen Z. D. Cheng (Advisor); Miyoshi Toshikazu (Committee Chair); Mesfin Tsige (Committee Member); Chrys Wesdemiotis (Committee Member); Yu Zhu (Committee Member)

Subjects:

Polymer Chemistry; Polymers

Keywords:

polymer, self-assembly, POSS, FPOSS, tAPOSS, hybrid material

Yu, JiayiTunable Biodegradable Polymers for Regenerative Medicine
Doctor of Philosophy, University of Akron, 2018, Polymer Science
Since the early 1960s, synthetic biodegradable polymers have been widely used in biomedical applications due to their large chemical diversity and the reproducible properties. However, the local acidification during degradation has shown to cause significant inflammation that can lead to device or implant failure. It is necessary to design new biodegradable polymer systems that do not cause local acidosis during degradation. To facilitate this requirement, Becker group has developed the amino acid-based poly(ester urea)s. These polymers are semi-crystalline. Their hydrolysis byproducts are non-toxic and can be self-buffered by the presence of the urea linkage at each repeat unit. In addition, there is a tremendous physical and chemical landscape that is available for exploration by using different natural amino acids with different pendant groups and different diols. This dissertation outlines our efforts to develop biodegradable polymers with tunable mechanical properties, degradation rates, and bioactivity. We varied the diol chain length (Chapter 3), branch density (Chapter 4), bioceramic contents (Chapter 5) in the poly(ester urea) system; cis/trans ratio (Chapter 6) in the biodegradable elastomer system and studied how these subtle structural differences would influence the mechanical properties and water uptake ability. Based on their tunable physical properties, these materials can be selected and used for various biomedical applications (Chapter 7).

Committee:

Matthew L. Becker, Ph.D. (Advisor); Bryan Vogt, Ph.D. (Committee Chair); Yu Zhu, Ph.D. (Committee Member); Amis J. Eric, Ph.D. (Committee Member); Chrys Wesdemiotis, Ph.D. (Committee Member)

Subjects:

Biomedical Engineering; Materials Science; Plastics; Polymer Chemistry; Polymers

Keywords:

biodegradable polymers; poly ester urea; diol chain length; branch density; composite; stereochemistry; mechanical property; biodegradation rate; application, processing; characterization; structure property relationship; amino acid; tunable property

Walker, Ruth VirginiaExpanding Our Conceptualization of Ageism: Moving Toward an Intersectional Lifespan Approach
Doctor of Philosophy, University of Akron, 2016, Psychology-Adult Development and Aging
Ageism is a form of age-based discrimination most frequently studied in terms of unequal treatment toward older adults (Butler, 1969; 2005). Ageism is unique from other forms of discrimination as anyone can experience it if they live long enough (Palmore, 2001); this presents concerns for aging women, by the virtue of their longer lifespan, and the potential intersection of experiences with ageism with experiences with sexism, racism, and other forms of inequality (Kochanek et al., 2011). A focus on attitudes and prejudice toward older adults in the literature has resulted in limited empirical understandings of experiences with ageism, with research on ageism lagging behind research on racism and sexism. Utilizing both lifespan development theory (Baltes, 1987) and intersectionality theory (McCall, 2005), the purpose of this study is to utilize phenomenological methods to describe experiences with ageism across adulthood and to answer the following research questions: (1) How, if at all, is ageism gendered?, (2) How, if at all, does the experience of ageism differ across the lifespan?, and (3) In what ways does understanding how experiences with ageism are shaped by gender and age add to our conceptualization of ageism? A total of 70 participants, 22-87 years old, participated in story circles and in-depth interviews exploring how they have been treated due to their age and gender. Using phenomenological methodology, participants' responses were analyzed and clustered into three broad thematic categories: (a) context matters, (b) short-term reactions to discrimination, and (c) long-term reactions to discrimination. The results suggest implications for theory and policy development as well as clinical interventions.

Committee:

Toni Bisconti (Advisor)

Subjects:

Gerontology; Psychology; Social Research; Sociology

Keywords:

Ageism; phenomenology; lifespan development; qualitative methodology; interviews; story circles; sexism; intersectionality; gender; aging; reverse ageism; ageing

Fathi, Ariya RezaBarium Solidification/Stabilization of Legacy Fly Ash
Master of Science in Engineering, University of Akron, 2018, Civil Engineering
A legacy fly ash pile in Ashtabula county has 20,000 – 30,000 cubic yards of material and contains barium and other various heavy metals. The concentrations of barium in the fly ash are below Regional Screening Levels (RSLs) for soil, but if the barium leached out it would pose a threat to human health. Solidification/Stabilization (S/S) of the ash was investigated with concrete and sulfate. After physical/chemical characterization, the fly ash was identified as class F fly ash, meaning it has no self-stabilizing/cementing characteristics, and had barium concentrations ranging from 0-1,500 mg/kg. Fly ash was used as a replacement for either cement or fine aggregate at 10-50%. Cement replacement did not achieve a compressive strength above 3,000 psi when using a 6,500 psi concrete mixture when cement to waste ratios exceeded 20% replacement. When fine aggregate replacement was investigated, fine aggregate to waste ratios up to 40% was effective at achieving above 3,000 psi concrete. X-ray diffraction (XRD) revealed the barium present was already in the insoluble barium sulfate form. Therefore, the Toxicity Characteristic Leaching Procedure (TCLP) and accelerated leaching procedure were used to access the potential for barium to leach form the ash and from the concrete mixtures. Barium concentrations never exceeded the U.S. EPA drinking water maximum contaminated level (MCL) for 2 mg/L. Concrete made with ash spiked with 1,500 mg/kg had increased barium leached but still below the primary drinking standard with the highest concentration being 1.79 ± 0.44 mg/L. Therefore, the ash can be handled as solid waste if no beneficial use can be identified.

Committee:

Stephen Duirk (Advisor); Christopher Miller (Committee Member); David Roke (Committee Member)

Subjects:

Environmental Engineering

Chu, YangRATIONAL CONTROLLED SELF-ASSEMBLY BEHAVIOR OF INORGANIC-ORGANIC HYBRIDS IN SOLUTION
Doctor of Philosophy, University of Akron, 2017, Polymer Science
In the past several decades, self-assembly of amphiphiles in solutions has attracted great interest of researchers due to their unique properties and applications. Besides the well-explored small-molecule surfactants and block-copolymers, giant surfactants also known as inorganic-organic amphiphilic hybrids have been regarded as a new attractive topic because they contain functional (e.g., catalytic, magnetic, oxidation-reduction redox or biologically active) inorganic nanoparticles/molecular clusters which simultaneously act as surfactant polar head groups. The self-assembly/disassembly can be triggered by different kinds of external stimuli like light, heat, magnetic field or solution polarity. Besides, the morphology and size of the assemblies are also tunable by the experimental conditions and molecular structures. In this dissertation, three representative kinds of hybrids, which include multi-headed giant surfactants based on polystyrene (PS)-polyhedral oligomeric silsesquioxane (POSS) conjugates with different number and topology of POSS heads, triangular shaped PS-POSS hybrids with different length of PS linkers and spiropyran (SP)-polyoxometalate (POM)-alkyl hybrids, are prepared to study the effect of hydrophilic head groups, hydrophobic linkers and change of hydrophobicity on the self-assembly behavior. Dynamic light scattering (DLS) and static light scattering (SLS) are used during the whole process of self-assembly to suggest the size and morphology of the assemblies and electron microscopy and atomic force microscopy confirm the results obtained by light scattering techniques. We found the rational control of the self-assembly behavior of inorganic-organic hybrids in solution can be successfully achieved due to their multiple-responsive property on light, solvent polarity, molecular structures and solution concentration.

Committee:

Tianbo Liu (Advisor); Stephen Cheng (Committee Chair); Toshikazu Miyoshi (Committee Member); Mesfin Tsige (Committee Member); Jie Zheng (Committee Member)

Subjects:

Chemistry; Polymer Chemistry; Polymers

Keywords:

Inorganic-organic hybrid; Self-assembly behavior; polyoxometalates;

Howard, Christopher AllenBlack Insurgency: The Black Convention Movement in the Antebellum United States, 1830-1865
Doctor of Philosophy, University of Akron, 2017, History
During the antebellum era, black activists organized themselves into insurgent networks, with the goal of achieving political and racial equality for all black inhabitants of the United States. The Negro Convention Movement, herein referred to as the Black Convention Movement, functioned on state and national levels, as the chief black insurgent network. As radical black rights groups continue to rise in the contemporary era, it is necessary to mine the historical origins that influence these bodies, and provide contexts for understanding their social critiques. This dissertation centers on the agency of the participants, and reveals a black insurgent network seeking its own narrative of liberation through tactics and rhetorical weapons. This study follows in the footing of Dr. Howard Holman Bell, who produced bodies of work detailing the antebellum Negro conventions published in the 1950s and 1960s. Additionally, this work inserts itself into the historiography of black radicals, protest movements, and racial debates of antebellum America, arguing for a successful interpretation of black insurgent action. Class, race, gender, religion, and politics, all combine within this study as potent framing devices. Together, the elements within this effort, illustrates the Black Convention Movement as the era’s premier activist organization that inadvertently pushed the American nation toward civil war, and the destruction of institutionalized slavery.

Committee:

Walter Hixson, Ph.D. (Advisor); Elizabeth Mancke, Ph.D. (Committee Member); Zachery Williams, Ph.D. (Committee Member); Kevin Kern, Ph.D. (Committee Member); Daniel Coffey, Ph.D. (Committee Member)

Subjects:

African American Studies; African Americans; American History; Black History; Black Studies; Gender; History; Journalism; Minority and Ethnic Groups; Religion

Keywords:

African American History; African Diaspora; Black History; Black Studies; Insurgency; Antebellum United States; Civil War; Resistance Studies; Gender; Newspapers; Ohio Compromise; Protest Movements; Black Church, Christianity; Canada; United States

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