Search Results (1 - 25 of 151 Results)

Sort By  
Sort Dir
 
Results per page  

Ghods, MasoudEffect of Convection Associated with Cross-section Change during Directional Solidification of Binary Alloys on Dendritic Array Morphology and Macrosegregation
Doctor of Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
This dissertation explores the role of different types of convection on macrosegregation and on dendritic array morphology of two aluminum alloys directionally solidified through cylindrical graphite molds having both cross-section decrease and increase. Al- 19 wt. % Cu and Al-7 wt. % Si alloys were directionally solidified at two growth speed of 10 and 29.1 µm s-1 and examined for longitudinal and radial macrosegregation, and for primary dendrite spacing and dendrite trunk diameter. Directional solidification of these alloys through constant cross-section showed clustering of primary dendrites and parabolic-shaped radial macrosegregation profile, indicative of “steepling convection” in the mushy-zone. The degree of radial macrosegregation increased with decreased growth speed. The Al- 19 wt. % Cu samples, grown under similar conditions as Al-7 wt. % Si, showed more radial macrosegregation because of more intense “stepling convection” caused by their one order of magnitude larger coefficient of solutal expansion. Positive macrosegregation right before, followed by negative macrosegregation right after an abrupt cross-section decrease (from 9.5 mm diameter to 3.2 mm diameter), were observed in both alloys; this is because of the combined effect of thermosolutal convection and area-change-driven shrinkage flow in the contraction region. The degree of macrosegregation was found to be higher in the Al- 19 wt. % Cu samples. Strong area-change-driven shrinkage flow changes the parabolic-shape radial macrosegregation in the larger diameter section before contraction to “S-shaped” profile. But in the smaller diameter section after the contraction very low degree of radial macrosegregation was found. The samples solidified through an abrupt cross-section increase (from 3.2 mm diameter to 9.5 mm diameter) showed negative macrosegregation right after the cross-section increase on the expansion platform. During the transition to steady-state after the expansion, radial macrosegregation profile in locations close to the expansion was found to be “S-shaped”. This is attributed to the redistribution of solute-rich liquid ahead of the mushy-zone as it transitions from the narrow portion below into the large diameter portion above. Solutal remelting and fragmentation of dendrite branches, and floating of these fragmented pieces appear to be responsible for spurious grains formation in Al- 19 wt. % Cu samples after the cross-section expansion. New grain formation was not observed in Al-7 wt. % Si in similar locations; it is believed that this is due to the sinking of the fragmented dendrite branches in this alloy. Experimentally observed radial and axial macrosegregations agree well with the results obtained from the numerical simulations carried out by Dr. Mark Lauer and Prof. David R. Poirier at the University of Arizona. Trunk Diameter (TD) of dendritic array appears to respond more readily to the changing growth conditions as compared to the Nearest Neighbor Spacing (NNS) of primary dendrites.

Committee:

Surendra Tewari, Ph.D. (Advisor); Jorge Gatica, Ph.D. (Committee Member); Orhan Talu, Ph.D. (Committee Member); Rolf Lustig, Ph.D. (Committee Member); Kiril Streletzky, Ph.D. (Committee Member)

Subjects:

Aerospace Materials; Automotive Materials; Chemical Engineering; Condensed Matter Physics; Engineering; Fluid Dynamics; High Temperature Physics; Materials Science; Metallurgy

Keywords:

Directional Solidification; Natural Convection; Fluid Flow; Binary Alloys; Macrosegregation; Dendritic Array; Dendrite Morphology; Solutal Remelting; Thermosolutal Convection; Aluminum Alloy; Cross section Change

Camardo, Andrew TC-JUN N-TERMINAL KINASE INHIBITORY NANOTHERAPEUTICS FOR REGENERATIVE ELASTIC MATRIX REPAIR IN ABDOMINAL AORTIC ANEURYSMS
Master of Science in Biomedical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Abdominal aortic aneurysms (AAA) are localized expansions of the aorta wall that continue to grow until they reach a critical size and fatally rupture. This growth is driven by the chronic disruption, degradation, and subsequent loss of aortal wall elastic fibers by matrix metalloproteinases (MMPs) secreted by inflammatory cells recruited to the aorta wall following an injury stimulus, and the inherent inability of vascular smooth muscle cells (SMCs) to naturally repair or regenerate elastic fibers. This leads to a net loss of elastic matrix and the continuing weakening of the aortal wall until eventual rupture. Current treatments seek to reinforce the vessel wall with grafts or stents, but do not arrest or reverse AAA growth. Therefore, inhibiting the proteolytic degradation of the elastic matrix while also stimulating elastic matrix neoassembly is needed to stop AAA growth and regenerate the vessel wall. We have previously shown utility of doxycycline (DOX), an MMP inhibitor drug, to stimulate elastic matrix neoassembly and crosslinking at low µg/ml doses in addition to inhibiting MMPs. We currently show in aneurysmal SMC cultures, that effects of exogenous DOX in this dose range are linked to its upregulation of transforming growth factor beta (TGF-ß1) via its inhibition of the regulatory protein c-Jun-N-terminal kinase isoform 2 (JNK 2). We have identified a DOX dose range that stimulates elastogenesis and crosslinking without adversely impacting cell viability. Using JNK 2 inhibition as a metric for pro-regenerative matrix effects of DOX, we further demonstrate that sustained, steady state release of DOX at the useful dose, from poly(ethylene glycol)-poly(lactic glycolic acid) nanoparticles (NPs) provides pro-elastogenic and anti-proteolytic effects that could potentially be more pronounced than that of exogenous DOX. We attribute these outcomes to previously determined synergistic effects provided by cationic amphiphile groups functionalizing the polymer NP surface. Released DOX inhibited expression and phosphorylation of JNK to likely increase expression of TGF-ß1, which is known to increase elastogenesis and lysyl oxidase-mediated crosslinking of elastic matrix. Our results suggest that JNK inhibition is a useful metric to assess pro-elastic matrix regenerative effects and point to the combinatorial regenerative benefits provided by DOX and cationic-functionalized NPs.

Committee:

Anand Ramamurthi, Ph.D. (Committee Chair); Chandrasekhar Kothapalli, Ph.D. (Committee Member); Nolan Holland, Ph.D. (Committee Member)

Subjects:

Biomedical Engineering

Mohammed, Alahmad SuleimanElectrochemical and Electroflotation Processes for Milk Waste Water Treatment
Doctor of Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
The dairy industry generates abundant milk waste waters characterized by high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations that can be very harmful to the environment, if left untreated. Electrocoagulation (EC) has been in use for waste water treatment. The treatment application uses aluminum electrodes and iron or the combined hybrid Al/Fe electrodes. Milk waste water contains high concentration organic pollutants and the main constituents of those organics are carbohydrates, proteins and fats, originating from the milk. The process of separating the flocculated sludge from waste water that has been treated using the electrocoagulation process can be accomplished by the flotation processes. The electroflotation technology is effective in removing colloidal particles, oil, grease, as well as organic pollutants from waste water. This study uses electrochemical and electroflotation treatment of milk waste water by means of an aluminum electrode with specific parameters including total organic carbon (TOC), pH, turbidity, transmittance, and temperature. Even though the electrochemical and electroflotation treatment processes have been around for some time, it has not been thoroughly studied. This study is going to highlight the importance of this technique as a pre-treatment method of milk waste water and its contribution to the reduction of pollutants in the milk processing industry. Furthermore, the process of electroflotation and electrochemical flotation continuously prove to be effective in remediation of varieties of pollutants of different chemical compositions and have the ability to achieve a very high treatment efficiency.

Committee:

Yung-Tse Hung, Ph.D. (Committee Chair); Walter Kocher , Ph.D. (Committee Member); Lili Dong, Ph.D. (Committee Member); Chung-Yi Suen, Ph.D. (Committee Member); Saili Shao, Ph.D. (Committee Member)

Subjects:

Civil Engineering; Engineering; Environmental Engineering

Keywords:

Electrochemical, electroflotation and electrocoagulation;Total organic carbon;Chemical oxygen demand; Biochemical oxygen demand ;Transmittance;Turbidity and pH

Bardhipur, SeemaModeling the Effect of Green Infrastructure on Direct Runoff Reduction in Residential Areas
Master of Science in Civil Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Urbanization causes a serious impact on storm water systems by expansion of impervious surfaces. Low Impact Development (LID) is a technique growing in popularity to solve the issue of storm water management. However, to evaluate the benefits of LIDs is a difficult task due to realistic parametrization of LIDs and subcatchments for modeling. The goals of this study are: a) to provide a practical guideline to parameterize and simulate LIDs (bio-retention and rain barrels) in residential areas; and b) to evaluate the resulting effect on the current drainage system under various design storms. U.S. Environmental Protection Agency’s Storm Water Management Model 5 (SWMM5) was used to simulate the hydrologic performance of LID controls and their effects on reducing direct runoff from a residential area, Klusner Avenue in Parma, Ohio. This study conceptualized the study site in reasonable detail, including house, garage, backyard, tree lawn, driveway, sidewalk, and street, so that the performance of LID controls could be identified easily. Specifically, a street catchment was carefully modeled using an open-conduit routing option, which simulated the street drainage systems more effectively. SWMM5 parameters were calibrated using the observed rainfall-runoff data which was collected before implementing LID practices at Klusner Avenue. The Nash-Sutcliffe efficiency (NSE) had a value of 0.69 for the calibrated model which indicates a strong fit between the output and observed data. Finally, the calibrated model was used to add LID controls to evaluate its effects under various design storms, 1-year, 2-year, 5-year, 10-year, 25-year, and 50-year return periods. The results show that two types of LID controls, bio-retention cell and rain barrel installed in the study site reduced the total runoff volume from 9 to 13% and the peak flow by from 11 to 15% depending on rainfall intensities. The analysis of results suggested that the performance of LID controls should be based on not only their capacity and treatment area but also target design storm and unit cost.

Committee:

Ung Tae Kim, Ph.D. (Committee Chair); Jacqueline Jenkins, Ph.D. (Committee Member); Yung Tse Hung, Ph.D. (Committee Member)

Subjects:

Civil Engineering

Keywords:

Low Impact Development; Storm Water Management Model; Bio-retention; Rain Barrels; Green Infrastructure; Modeling

Fox, Jonathan MCathepsin K Targeting Matrix Regenerative Nanoparticles for Small Abdominal Aortic Aneurysm Repair
Master of Science in Biomedical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Abdominal aortic aneurysms (AAAs) are characterized by the loss of elasticity in the aorta wall leading to a chronic increase in diameter and resulting in rupture. This is due to the lack of regeneration of elastic fibers and chronic proteolytic breakdown of elastic fibers within the aorta mediated by matrix metalloproteinases (MMPs), specifically MMP-2 and -9. Previous studies in our lab have shown cationic amphiphile-surface functionalized poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) loaded with doxycycline (DOX) to inhibit MMP activity and stimulate elastic matrix synthesis, effects we attributed to both low doses (< 10 mg/ml) of DOX released and independent effects of cationic amphiphile pendant groups on the NP surface. This promises application of these NPs to arrest or regress AAA growth since high oral DOX dosing inhibits new elastic matrix formation in the AAA wall and has undesirable side effects. In this study, we investigated feasibility of antibody-based active targeting of intravenously infused NPs to the AAA wall. Cathepsin K, a cysteine protease, is a biomarker for AAA and overexpressed in abdominal aortic aneurysm tissue making it an ideal target moiety. We have shown using a covalent conjugation method of modifying the surface of the NPs with a cathepsin K antibody resulted in a more robust antibody attachment which did not affect the DOX release profile. Cathepsin K expression was confirmed to be localized on the cell surface and utilizing cathepsin K Ab-conjugated NPs, we demonstrated an increased NP localization to the cathepsin K overexpressing cells in vitro and ex vivo. Importantly, the DOX-loaded NPs demonstrated pro-elastogenic and anti-proteolytic effects in aneurysmal smooth muscle cells supporting their use as regenerative therapies to arrest and regress AAA growth. Preliminary data has been collected indicating cathepsin K Ab-conjugated NP targeting to AAAs in elastase-injured rat models. The study outcomes support the feasibility of using cathepsin K Ab-conjugated NPs as a targeted therapy for elastic matrix regeneration in AAA tissue and will serve as a basis for already initiated follow up studies to assess NP biodistribution, in situ retention in the AAA wall, and safety as a function of time.

Committee:

Anand Ramamurthi, Ph.D. (Advisor); Nolan Holland, Ph.D. (Committee Member); Chandrasekhar Kothapalli, Ph.D. (Committee Member)

Subjects:

Biomedical Engineering

Barto, TaylorDesign and Control of Electronic Motor Drives for Regenerative Robotics
Master of Science in Electrical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Two regenerative motor drives, a voltage source converter and a bidirectional buck/boost converter, are studied for energy regeneration and joint trajectory tracking. The motor drives are applied to two different robotic systems—a PUMA560 robotic arm and a hip testing robot / prosthesis system. An artificial neural network controller is implemented with the two motor drives and provides joint trajectory tracking with an RMS error of 0.03 rad. The control signals produced by the artificial neural network contain a large amount of high frequency content which prevents practical implementation. A robust passivity-based motion controller is modified to include information about the motor drives to overcome the limitations of the artificial neural network controller. The modified robust passivity-based controller outperforms the artificial neural network controller by maintaining a 3 V RMS error between the voltage generated by the converter and the desired voltage while maintaining comparable trajectory tracking. The high frequency content of the robust passivity-based controller contains less high frequency content than the artificial neural network controller. The modified robust passivity-based controller is implemented inside the semiactive virtual control energy regeneration framework to demonstrate energy regeneration with one of the motor drives. The motor drive implemented with the energy regeneration framework shows that energy can be regenerated while using the bidirectional buck/boost converter.

Committee:

Dan Simon, Ph.D. (Committee Chair); Hanz Richter, Ph.D. (Committee Member); Zhiqiang Gao, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Lacdao, ClaudineInfluence Of Cross-Section Change During Directional Solidification On Dendrite Morphology, Macrosegregation And Defect Formation In Pb-6 wt Sb Alloy
Master of Science in Chemical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
The purpose of this research is to examine the dendrite array morphology, macrosegregation, and defect formation caused by the fluid flow at the abrupt cross-section changes during directional solidification of Pb-6% Sb alloy. Four 24-cm long cylindrical alloy samples were directionally solidified in graphite crucibles: two having a constant diameter (9-mm) grown at 10.4 and 63.1 μm s-1 , one having an abrupt cross-section decrease (from 12.7 to 6.35 mm) and one having an abrupt increase (from 6.35 to 12.7 mm) by pulling down the alloy containing cylindrical graphite crucibles from the upper hot-zone of a stationary vertical furnace into its cold-zone below. Microstructures were examined on transverse slices cut along the length of the directionally solidified samples. Dendrite spacing and distribution were characterized on these transverse sections. The Pb-6% Sb alloy was selected as a low melting point analog for commercially used multicomponent nickel-base superalloys, because its thermophysical properties are well characterized. Also, a density inversion occurs in the inter-dendritic melt in the “mushy-zone” during directional solidification of this alloy, because the density of the melt decreases as Sb content increases from the array tips at the top of the mushy zone to the eutectic at their bottom. In constant cross-section crucibles, the formation of dendrite-trees in the mushy zone will be subject only to this “plume type” convection as solidification proceeds from the bottom end of the crucible to its top. Whereas in crucibles with abrupt cross-section change, the solidifying mushy-zone will be subject to additional “cross-section change induced” solidification shrinkage flow, when the speed of the liquid flowing downwards to feed the solidification shrinkage occurring below, will either suddenly accelerate or decelerate, because of the abrupt area change. This sudden change in the incoming fluid speed may break slender side-branches of dendrite trees. These broken dendrite fragments may rotate, sink, and grow further to develop into misaligned “spurious” grains. The “plume type of flow” is different than the “steepling convection flow” which was recently examined during directional solidification of Al-19% Cu and Al-7% Si alloys by Dr. Masoud Ghods in our laboratory.

Committee:

Surendra Tewari, Ph.D. (Committee Chair); Orhan Talu, Ph.D. (Committee Member); Christopher Wirth, Ph.D. (Committee Member); Nolan Holland, Ph.D. (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Cross-Section Change; Directional Solidification; Dendrite Morphology; Macrosegregation And Defect Formation In Pb-6 wt Sb Alloy; Density Inversion; Dendrite Trunk Diameter; Nearest Neighbor Spacings; Lead Antimony Alloy; Binary Alloy

Dinca, DragosDevelopment of an Integrated High Energy Density Capture and Storage System for Ultrafast Supply/Extended Energy Consumption Applications
Doctor of Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
High Intensity Laser Power Beaming is a wireless power transmission technology developed at the Industrial Space Systems Laboratory from 2005 through 2010, in collaboration with the Air Force Research Laboratory to enable remote optical `refueling’ of airborne electric micro unmanned air vehicles. Continuous tracking of these air vehicles with high intensity lasers while in-flight for tens of minutes to recharge the on-board battery system is not operationally practical; hence the recharge time must be minimized. This dissertation presents the development and system design optimization of a hybrid electrical energy storage system as a solution to this practical limitation. The solution is based on the development of a high energy density integrated system to capture and store pulsed energy. The system makes use of ultracapacitors to capture the energy at rapid charge rates, while lithium-ion batteries provide the long-term energy density, in order to maximize the duration of operations and minimize the mass requirements. A design tool employing a genetic algorithm global optimizer was developed to select the front-end ultracapacitor elements. The simulation model and results demonstrate the feasibility of the solution. The hybrid energy storage system is also optimized at the system-level for maximum end-to-end power transfer efficiency. System response optimization results and corresponding sensitivity analysis results are presented. Lastly, the ultrafast supply/extended energy storage system is generalized for other applications such as high-power commercial, industrial, and aerospace applications.

Committee:

Hanz Richter, Ph.D. (Committee Chair); Taysir Nayfeh, Ph.D. (Committee Member); Lili Dong, Ph.D. (Committee Member); Majid Rashidi, Ph.D. (Committee Member); Petru Fodor, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Hybrid energy storage; ultracapacitor; battery; power system optimization; laser power beaming; vertical multi-junction solar cells; wireless power transmission; laser; photovoltaic; high intensity lasers; electric propulsion; unmanned air vehicles

HE, ZHUOHUI JOEEffects of digestate, magnesium sulfate, and dipotassium hydrogen phosphate/potassium dihydrogen phosphate on microalga, Scenedesmus dimorphus
Master of Science in Chemical Engineering, Cleveland State University, 2016, Washkewicz College of Engineering
Digestate (D), the remaining substance after anaerobic digestion of a biodegradable feedstock, is rich in inorganic contents, which makes it a good candidate for growing algae for biofuel production. Previous studies showed digestate at around 1.25% to 1.75% (v/v) dilution is suitable for algae growth. In this study, magnesium sulfate (MgSO4) and dipotassium hydrogen phosphate/potassium dihydrogen phosphate (K-P) were added to diluted digestate growth media. Two sets of experiments were conducted in batch reactor mode to identify the digestate (D), magnesium sulfate (MgSO4) and dipotassium hydrogen phosphate/potassium dihydrogen phosphate (K-P) concentrations that would optimize the algae growth. Algae growth parameters, such as maximum growth rate (r) and maximum algae concentration (Xmax) were estimated by using non-linear regression with a four-parameter logistic equation. Average biomass productivity (Pa), instantaneous biomass productivity (Pi), and specific growth rate (ug) were also calculated. This study used a central composite design. A surface response regression equation was generated for each of these algae growth parameters; the equation contained linear terms, quadratic terms, and the first order interaction terms of the three factors (D, MgSO4, and K-P). The resulting regression models showed both the maximum growth rate and the maximum algae concentrations were mainly dependent on digestate. The highest maximum growth rate was obtained at around 1% (v/v) digestate dilution. Within the tested digestate dilutions (0.184 to 1.817% (v/v)), maximum algae concentration increases with digestate concentration. In addition, the data and analysis showed that digestate concentration of 1.4% (v/v) dilution and low K-P and MgSO4 concentrations would be expected to result in high average biomass productivity and instantaneous biomass productivity. The digestate concentrations does not alter the effects of K-P and MgSO4 on algae growth, but an interaction was seen between K-P and MgSO4. At low concentrations of these two factors (MgSO4 < 0.61 mmol/L and K-P < 2.81 mmol/L), both experiments 1 and 2 showed that lower the K-P and MgSO4 concentrations would yield higher maximum growth rate. The cause might be that the additional K-P and MgSO4 might promote larger cell production rather than cell replication, or the replicated cells may stay attached, which would lead to slower perceived growth rate but higher maximum algae concentration at the end of the batch growth.

Committee:

Joanne Belovich, Ph.D. (Advisor); Jorge Gatica, Ph.D. (Committee Member); Moo-Yeal Lee, Ph.D. (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Digestate; Scenedesmus dimorphus; magnesium sulfate; dipotassium hydrogen phosphate;potassium dihydrogen phosphate; algae;

Vodhanel, JulieCharacterization of Performance of a 3D Printed Stirling Engine Through Analysis and Test
Master of Science in Mechanical Engineering, Cleveland State University, 2016, Washkewicz College of Engineering
This thesis involves the fusion of two technologies, Stirling engines and additive manufacturing. The project began by building a Stirling engine primarily out of 3D printed parts. Methods to measure the power output were designed and built with a combination of 3D printed and off the shelf parts. The Stirling engine was tested to see if there was a correlation to analysis results, and a regenerator was installed to determine the effect on performance for this relatively low temperature engine. Finally, variations in test operation and the use of heat sinks were used to find a combination that will allow the unit to run more reliably. One challenge of the 3D printed parts was the durability when subjected to heat and assembly loads, especially over multiple rebuilds. However, the convenience of 3D printing made it possible to print replacement parts easily. New designs and assemblies were also created as a part of the effort to develop a power measurement system. Power output was measured and corresponded to analysis predictions. Testing was conducted with a hot plate temperature of 349K (168 F) and a cold plate temperature of 308K (94 F), which corresponds to a Temperature Ratio of 1.13. Rate of rotation was 150 RPM, or 2.5 Hz. The net power output was measured to be 3.1mW. Adding that to the losses attributed to engine friction resulted in a gross power output of 17mW, which was close to the analysis prediction of 15mW. Regenerator testing showed that using a regenerator, on average, doubled the speed of rotation at the same temperature ratio. However, the regenerator was detrimental to long term operation because without active cooling, the cold plate was unable to dissipate the heat efficiently enough. Increasing the cold side heat transfer to ambient would be essential in increasing reliability. The addition of heatsinks to the cold side was tested to determine the effectiveness, with positive results. The heatsinks that were used in testing were also analyzed, and it was determined that the spacing was too narrow for optimum performance. For future designs, custom heatsinks could be used that maximize the natural convection of the cold side, or a method developed to provide active cooling.

Committee:

Mounir Ibrahim, Ph.D. (Committee Chair); Asuquo Ebiana, Ph.D. (Committee Member); Majid Rashidi, Ph.D. (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Stirling Engine; 3D Printed; Additive Manufacturing

Zarei, MiladPredictive Simulation of Rowing Exercise
Master of Science in Mechanical Engineering, Cleveland State University, 2016, Washkewicz College of Engineering
Long term exposure to microgravity environment in spaceflight causes some health issues such as space motion sickness, shift in body fluids, muscle atrophy and bone demineralization. Studies have shown that aerobics, and resistive exercise could help astronauts to deal with the issues. Rowing exercise can provide both resistive and aerobic exercise. A rowing exercise machine has mechanical parameters which affect the user’s movement and the loads on the user’s tissues. If these effects can be predicted, exercise results can be improved. However, human testing is only possible on Earth during the development, and also the absence of gravity may affect the task execution in the space. Therefore, computational modeling is necessary. In this thesis, a computational model of an arm based on human musculoskeletal simulation and optimal control was used to investigate the effects of mechanical properties of the exercise machine on predicted human performance. Moreover, the other goal was to study the effects of the exercise on arm motion and tissue loads during the exercise. To explore this concept, we have modeled a scaled down rowing exercise machine and a biceps mus- cle. A system identification has been done on the Concept2 rowing machine to determine baseline machine parameters. In order to solve the problem, different methods in trajectory optimization were evaluated to choose the reliable one. Then, a linear muscle force generator was coupled to the rowing machine to examine how it performs the task. The design parameters were changed to investigate their effects on the movement. Finally, the simple muscle force generator was replaced by a brachii muscle model to study how it executes the exercise. Effects of the design elements were also studied.

Committee:

Antonie van den Bogert, Ph.D. (Advisor); Hanz Richter, Ph.D. (Committee Member); Jason Halloran, Ph.D. (Committee Member)

Subjects:

Biomechanics; Mechanical Engineering

Keywords:

Simulation, Predictive Simulation, Modeling, Exercise, Sports Science, Rowing

Vaidya, Prahar SPURE AND BINARY ADSORPTION OF METHANE AND NITROGEN ON SILICALITE
Master of Science in Chemical Engineering, Cleveland State University, 2016, Washkewicz College of Engineering
Separation processes comprise a large portion of the activity in the chemical and petrochemical industries. For the chemical, petroleum refining, and materials processing industries as a group, separation processes are considered to be critical. Almost all the applications of chemical industries involves mixtures, so innovation in separation technology not only enhances productivity and global competitiveness of U.S. industries, but is also critical for achieving the industrial energy and waste reduction goals. Traditionally, air separation to produce nitrogen and oxygen and to separate nitrogen from methane was practiced by cryogenic distillation, which involved expensive high pressure units and large requirement of energy. The separation of nitrogen from methane is becoming increasingly important for upgrading LGF (Landfill gas), coal gas, and natural gas. Natural gases contain significant amounts of nitrogen. From the environmental perspective, Methane is the most important non-CO2 greenhouse gas responsible for global warming with more than 10 % of total greenhouse gas emissions. Adsorption separation techniques are used widely among other separation processes as they tend to utilize fewer resources and are highly energy efficient. By considering the advantages of adsorption processes over other separation processes, it is of great interest to characterize the adsorption properties of microporous and nanoporous solid materials for their potential use as an alternative to the conventional catalytic separation process, and storage applications. Despite the advantages of using adsorption for methane upgrading, methane-nitrogen separation has been found particularly difficult because of the lack of satisfactory adsorbent. The equilibrium selectivity favors methane over nitrogen (or high methane/nitrogen selectivity) for all known adsorbents. Therefore, it is one of the objective of this study to check the potential application of silicalite adsorbent in natural gas upgrading. Plenty of data is available in the literature for pure component but not for the binary mixtures as it is very time consuming and involves tedious calculations for quantifying binary adsorption measurement. According to some statistics, there are more models to predict multicomponent adsorption than accurate data to test them. So the effort made here was to complete measurements of the binary adsorption isotherms, compare those with Ideal Adsorbed Solution Theory (IAST) predictions and the experimental data available in the literature. This study reviews one of the most commonly used technique (i.e. volumetric measurement) for pure and binary adsorption isotherm measurement for methane and nitrogen on silicalite adsorbent. This method involves measuring the pressure change in a known volume of gas subjected to adsorption. As the gas is adsorbed and allowed to reach equilibrium, the measured decrease in the system pressure yields the amount of gas adsorbed under the given conditions. Pure adsorption equilibria for the gases listed above was measured at three different temperatures (283.15 K, 308.15 K and 338.15 K). The virial equation of state was used to correlate the experimental data, to calculate the Henry’s law constants and the heats of adsorption at zero loading. Ideal separation factor (selectivity) was obtained from the experimental pure adsorption isotherms by using the virial isotherm model. Binary adsorption behavior for methane and nitrogen mixture, covering the whole concentration range at 308.15 °K and at 504 kPa was determined experimentally. The corresponding x-y diagrams and selectivity were obtained from these data. The experimental results were compared with the results predicted from a mixture adsorption model, IAST. It was found that IAST successfully predicted the total amount adsorbed throughout the concentration range. There is a considerable deviation in selectivity as well as partial amount adsorbed for both the species at higher pressure. The reason is attributable to the fact that selectivity is much more sensitive to uncertainties in the measurement.

Committee:

Orhan Talu, PhD (Committee Chair); Dhananjai Shah, PhD (Committee Member); Jorge Gatica, PhD (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Methane; Nitrogen; Adsorption; Silicalite; Henry law constant; Heat of adsorption; Binary adsorption Isotherm; Ideal adsorbed solution theory

Walia, PiyushThe Effect of Combined Bony Defects on the Anterior Stability of the Glenohumeral Joint and Implications for Surgical Repair
Doctor of Engineering, Cleveland State University, 2015, Washkewicz College of Engineering
The combined defects of the glenoid and humeral head defects are often associated with recurrent anterior instability. Past studies have only investigated the effects of isolated humeral head or glenoid defects. A cadaveric model was developed to investigate the effect of combined defects. Moreover, two different finite element models were developed to validate against the experimental data. It was hypothesized that combination of smaller sizes of the two defects would reduce the glenohumeral joint’s stability. Furthermore, it was hypothesized that the instability due to humeral head defect will be dependent on the arm position but this won’t be the case for the glenoid defect. Also, it was believed that both specimen-specific and population-based models will validate against the experimental data. Different sets of simulation were run with both isolated and combined defects to analyze the reaction forces and calculate distance to dislocation. The experiments were performed with displacement control under a 50N compressive load. The results from the study predicted a statistical model that explained the direct correlation between the anterior stability of glenohumeral joint and the size of the defect. It was found that with the increase in size of the defect, the distance to dislocation decreased. It was determined that a combination of 10% glenoid defect with a 19% humeral head defect resulted in lower stability (p<0.05) than that of an isolated 20% glenoid defect. Results from finite element analysis showed that both specimen-specific and population-based models were similar to cadaveric model.

Committee:

Stephen Fening, Ph.D. (Committee Chair); Antonie van den Bogert, Ph.D. (Advisor); Anthony Miniaci, M.D., F.R.C.S.C. (Committee Member); Morgan Jones, M.D., M.P.H (Committee Member); Ahmet Erdemir, Ph.D. (Committee Member); Brian Davis, Ph.D. (Committee Member)

Subjects:

Biomechanics; Biomedical Engineering; Biomedical Research; Design; Engineering; Experiments; Mathematics; Pathology; Sports Medicine

Keywords:

Shoulder, Glenohumeral Joint, Anterior Instability, Combined Bone Defects, Hill-Sachs Defect, Bony Bankart Lesion, Humeral Head Bone Loss, Bipolar Defects, Concavity Depth, Stability Ratio

Warner, Holly E.Optimal Design and Control of a Lower-Limb Prosthesis with Energy Regeneration
Master of Science in Mechanical Engineering, Cleveland State University, 2015, Washkewicz College of Engineering

The majority of amputations are of the lower limbs. This correlates to a particular need for lower-limb prostheses. Many common prosthesis designs are passive in nature, making them inefficient compared to the natural body. Recently as technology has progressed, interest in powered prostheses has expanded, seeking improved kinematics and kinetics for amputees. The current state of this art is described in this thesis, noting that most powered prosthesis designs do not consider integrating the knee and the ankle or energy exchange between these two joints. An energy regenerative, motorized prosthesis is proposed here to address this gap.

After preliminary data processing is discussed, three steps toward the realization of such a system are completed. First, the design, optimization, and evaluation of a knee joint actuator are presented. The final result is found to be consistently capable of energy regeneration across a single stride simulation. Secondly, because of the need for a prosthesis simulation structure mimicking the human system, a novel ground contact model in two dimensions is proposed. The contact model is validated against human reference data. Lastly, within simulation a control method combining two previously published prosthesis controllers is designed, optimized, and evaluated. Accurate tracking across all joints and ground reaction forces are generated, and the knee joint is shown to have human-like energy absorption characteristics. The successful completion of these three steps contributes toward the realization of an optimal combined knee-ankle prosthesis with energy regeneration.

Committee:

Daniel Simon, Ph.D. (Committee Chair); Hanz Richter, Ph.D. (Committee Member); Antonie van den Bogert, Ph.D. (Committee Member)

Subjects:

Biomedical Engineering; Engineering; Mechanical Engineering; Robotics

Bhave, RadhikaNanoparticle-Cell Lipid Membrane Biophysical Interaction and its Role in Developing Tumor Targeted Nanoparticles
Master of Science in Biomedical Engineering, Cleveland State University, 2015, Washkewicz College of Engineering
Tumor targeted nanoparticles could improve drug delivery of the encapsulated cancer therapeutics to the tumor while reducing their non-specific side effects. However, complex conjugation chemistry, weak antibody-nanoparticle binding, and finite number of receptors available for nanoparticle binding could limit the efficacy of tumor targeted nanoparticles. Therefore, there is need for a new approach to improve nanoparticle localization in tumors. Physical properties of nanoparticles particularly their surface properties have shown to influence in vitro cellular uptake, in vivo biodistribution and tumor localization of nanoparticles. Apart from physical characteristics of nanoparticles, their uptake has also been shown to depend on the cell type. Additionally, progression of disease such as cancer can cause changes in the cell membrane lipid composition, and thereby influence nanoparticle-cell membrane interactions and cellular uptake of nanoparticles. The research described in this thesis explores an interesting approach that explores the differences in the cell membrane lipid composition as well as modification in nanoparticle surface characteristics to design nanoparticles that would preferentially target tumors. In our study, biophysical interactions between nanoparticles and endothelial cell model membrane demonstrate the effect of surface chemistry of nanoparticles on such interactions. Nanoparticles with sulfate and amine surface chemistry show higher interactions with model membrane as compared to nanoparticles with carboxyl and amidine surface chemistry. Biophysical characteristics of cell membrane lipids extracted from normal endothelial and cancerous cells demonstrate the fluidic nature of cancerous cell membrane as compared to the rigid and condensed nature of normal endothelial cell membrane. Nanoparticle-cell membrane lipid interactions demonstrate more selective interactions between nanoparticles with sulfate surface chemistry and cancer cell membrane lipids than with normal cell membrane lipids. On the other hand, nanoparticles with amine surface chemistry demonstrate non-selective interactions with both cancerous and endothelial cell lipid membranes. Nanoparticles loaded with a hydrophobic near infrared dye were used to quantitatively determine biodistribution and tumor localization of nanoparticles in vivo, using an optical imaging technique. Surface chemistry of nanoparticles was shown to influence nanoparticles biodistribution and tumor localization. Nanoparticles with sulfate groups demonstrate higher tumor localization and retention as compared to nanoparticles with amine and carboxyl groups. The results demonstrate that selectivity of nanoparticle with sulfate surface chemistry towards cancerous cell lipid membrane translates in greater tumor localization in vivo. We further studied effect of surface of PLGA-based biodegradable nanoparticles and their interactions with model membranes. These biodegradable nanoparticles when formulated using emulsion-solvent evaporation method retains a fraction of emulsifier, polyvinyl alcohol (PVA) associated with the surface, commonly referred as residual PVA. In this study, nanoparticles were formulated with PVA of different molecular weight and degree of hydrolysis. Our findings illustrated that surface associated residual PVA significantly influences biophysical interactions of nanoparticles with endothelial cell model membrane. Biophysical interactions between nanoparticles and cell lipid membranes could potentially be explored to understand the effect of surface characteristics of nanoparticles on cellular uptake, biodistribution and targeting.

Committee:

Vinod Labhasetwar, PhD (Committee Chair); Nolan Holland, PhD (Committee Member); Mekki Bayachou, PhD (Committee Member); Kiril Streletzky, PhD (Committee Member); Xue-Long Sun, PhD (Committee Member); Maciej Zborowski, PhD (Committee Member)

Subjects:

Biomedical Engineering

Siyum, Samuel HUMAN HAIR KERATIN PROTEIN, HAIR FIBERS AND HYDROXYAPATITE (HA) COMPOSITE SCAFFOLD FOR BONE TISSUE REGENERATION
Master of Science in Biomedical Engineering, Cleveland State University, 2014, Washkewicz College of Engineering
The field of tissue engineering aims at promoting the regeneration of tissues or replacement of failing or malfunctioning tissue by means of combining a scaffold material, adequate cells and bioactive molecules. Different materials have been proposed for use as three-dimensional porous scaffolds for bone tissue engineering procedures. Among them, polymers of natural origin are one of the most attractive options mainly due to their similarities with the extracellular matrix (ECM), chemical versatility as well as typically good biological performance. In this study, two biocompatible composite scaffolds were developed from natural polymer by tissue engineering approach and tested in vitro. The first Scaffold (SCAF-1) that was developed was composed of human hair keratin protein and human hair fibers (cuticle-cortex). The second scaffold (SCAF-2) was composed of human hair keratin protein, human hair fibers (cuticle-cortex) and hydroxyapatite (HA) particles. SEM and EDX were used to analyze the three dimensional structure, surface chemistry and pore size of the scaffolds. Both scaffolds showed a three-dimensional structure with a pore size ranging from 40-500µm and porosity greater than 50%. Compressive tests were carried out under dry as well as wet conditions for both scaffolds. SCAF-1 showed compressive modulus of 0.009 MPa in wet condition and 0.90 MPa in a dry condition. Likewise, SCAF-2 had compressive modulus of 0.09 MPa in wet condition and 2.7 MPa in dry condition. Cell culture experiments with bone marrow stromal cells demonstrate that the composite scaffolds support cell attachment and proliferation. Overall, human hair keratin scaffolds have been shown to have a porous three-dimensional structure that induces proliferation of GFP- stromal cells for bone tissue regeneration. These preliminary results suggest that human hair keratin, cuticle-cortex fibers and HA composite scaffolds appear to be an interesting structure for potential studies in bone tissue engineering.

Committee:

Surendra N. Tewari, PhD (Committee Chair); Joanne M. Belovich, PhD (Committee Member); Chandra Kothapalli, PhD (Committee Member)

Subjects:

Biomedical Engineering

Keywords:

Tissue Engineering, Bone,Hair,Biomedical Engineering

Rollakanti, Kishore ReddyProtoporphyrin IX Fluorescence for Enhanced Photodynamic Diagnosis and Photodynamic Therapy in Murine Models of Skin and Breast Cancer
Doctor of Engineering, Cleveland State University, 2015, Washkewicz College of Engineering
Protoporphyrin IX (PpIX) is a photosensitizing agent derived from aminolevulinic acid. PpIX accumulates specifically within target cancer cells, where it fluoresces and produces cytotoxic reactive oxygen species. Our aims were to employ PpIX fluorescence to detect squamous cell carcinoma (SCC) of the skin (Photodynamic diagnosis, PDD), and to improve treatment efficacy (Photodynamic therapy, PDT) for basal cell carcinoma (BCC) and cutaneous breast cancer. Hyperspectral imaging and a spectrometer based dosimeter system were used to detect very early SCC in UVB-irradiated murine skin, using PpIX fluorescence. Regarding PDT, we showed that low non-toxic doses of vitamin D, given before ALA application, increase tumor specific PpIX accumulation and sensitize BCC and breast cancer cells to ALA-PDT. These optical imaging methods and the combination therapy regimen (vitamin D and ALA-PDT) are promising tools for effective management of skin and breast cancer.

Committee:

Edward Maytin, PhD (Committee Chair); Sridhar Ungarala, PhD (Committee Member); John Turner, PhD (Committee Member); Judith Drazba, PhD (Committee Member); Anand Ramamurthi, PhD (Committee Member)

Subjects:

Biomedical Engineering; Biomedical Research; Engineering; Medical Imaging; Optics

Keywords:

Aminolevulinic acid; Protoporphyrin IX; Photodynamic therapy; Photodynamic Diagnosis; IVIS, basal cell carcinoma; squamous cell carcinoma; breast cancer; vitamin D; differentiation

BHAYANI, RACHIT BCOLOR REMOVAL OF DYES WASTEWATER BY COAGULATION AND MICROFILTRATION PROCESSES
Master of Science in Civil Engineering, Cleveland State University, 2014, Washkewicz College of Engineering
Various Industries such as textiles, paper, clothing, food etc. uses significant amount of dyes and generates large volumes of effluents which are heavily loaded with pollutants, turbidity and are highly concentrated in salts and color. A significant improvement in effluent quality is required prior to discharging into the water bodies. In the present research work performances of combined process using chemical coagulation and microfiltration were investigated in treating dyes wastewater containing reactive dyes (Disperse Yellow 3,Congo Red, Methylene Blue, Crystal Violet & Pro Indigo). The main objective was the color removal from dye wastewater using stage 1 coagulation process combined with stage 2 microfiltration treatment. Also the objective was to choose appropriate coagulants with appropriate doses for each type of dye. Further objectives were to achieve reductions in the Total Organic Carbon (TOC) in the dye wastewater. Decolorization and TOC rates were highly dependent on the type of the dye, type of coagulant used and concentration of dye.

Committee:

Yung-Tse Hung, PhD (Committee Chair); Walter M. Kocher, PhD (Committee Member); Lili Dong, PhD (Committee Member); Chung-Yi Suen , PhD (Committee Member); Sailai Sally Shao, PhD (Committee Member)

Subjects:

Environmental Engineering

Hedges, LaurenDEVELOPING IMPROVED BRIDGE PARAPET DESIGNS
Master of Science in Civil Engineering, Cleveland State University, 2014, Washkewicz College of Engineering
The Ohio Department of Transportation has identified that premature parapet cracking is a significant problem in Northeast Ohio. Background research related to concrete cracking and parapet cracking was conducted to determine possible causes of the premature cracking that ODOT has discovered. To further look at possible causes of this cracking, current ODOT bridge parapet practices were reviewed. In addition to ODOT practices, ten other state DOTs were surveyed to identify the bridge parapet practices used. These practices include the parapet design characteristics, construction joint spacing and depth, and the class of concrete used for construction. Various differences among all of these characteristics were identified and discussed to determine an improved bridge parapet design. Many of the districts located within ODOT were also surveyed and asked to identify premature bridge parapet cracking repair or replacement projects. Four of the districts were able to present twelve separate bridge parapet cracking projects. From these projects, it was determined that ODOT spends on average $188,175 per bridge parapet replacement project, or $283 per linear foot ($86 per meter) of parapet. Based on the state DOTs that confirmed parapet cracking was not a problem for their state, parapet improvements were determined. These improvements include decreasing the maximum construction joint spacing, and increasing the joint cut depth.

Committee:

Norbert Delatte, PhD (Committee Chair); Lutful Khan, PhD (Committee Member); Mehdi Jalalpour, PhD (Committee Member)

Subjects:

Civil Engineering

Davis, Ronald JEVOLUTIONARY GROUND REACTION FORCE CONTROL OF A PROSTHETIC LEG TESTING ROBOT
Master of Science in Electrical Engineering, Cleveland State University, 2014, Washkewicz College of Engineering
Typical tests of prosthetic legs for transfemoral amputees prove to be cumbersome and tedious. These tests are burdened by acclimation time, lack of repeatability between subjects, and the use of complex gait analysis labs to collect data. To create a new method for prosthesis testing, we design and construct a robot that can simulate the motion of a human hip. We discuss the robot from concept to completion, including methods for modeling and control design. Two single-input-single-output (SISO) sliding mode controllers are developed using analytical and experimental methods. We use human gait data as reference inputs to the controller. When doing so we see the problems associated with the gait data that make it unfit for use as reference data. We apply a smoothing algorithm to correct the gait data. The robot is evaluated based on its ability to track the gait data. Despite proper tracking of the reference inputs, operating the robot with a passive prosthesis shows that the robot cannot adequately produce the ground reaction force (GRF) of an able bodied person. We devise a novel method to control GRF of the robot/prosthesis combination based on the way that human subjects walk with a prostheses. When walking with a prosthesis, users compensate for the deficiencies of the prosthesis by modifying their gait patterns. To simulate this we use an evolutionary algorithm called biogeography-based optimization (BBO). We use BBO to modify the reference inputs of the robot, minimizing the error between the able-bodied GRF data and that of the robot walking with the passive prosthesis. Experimental results show a 62% decrease in the GRF error, effectively showing the robot’s compensation for the prosthesis and improved control of GRF.

Committee:

Daniel Simon, Ph.D. (Committee Chair); Hanz Richter, Ph.D. (Committee Member); Antonie van den Bogert, Ph.D. (Committee Member); Eugenio Villaseca, Ph.D. (Committee Member)

Subjects:

Biomechanics; Biomedical Engineering; Electrical Engineering; Engineering; Robotics

Zhang, HanInformation Driven Control Design: A Case for PMSM Control
Doctor of Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
The key problem in control system design was the selection and processing of information. The first part was to collect some system dynamics offline or online in a cost-effective manner and use them in the controller design effectively. Next was to minimize the phase lag in the feedback loop to ensure best performance and stability. A systematic information-driven design strategy was discussed. A few key problems in permanent magnet synchronous motor control were taken in a case study: the current loop and decoupling, velocity loop with position feedback and position estimation at low speed. An active disturbance rejection based integrated current loop control solution was presented. Some implementation problems were also discussed: restructuring of active disturbance rejection control for implementation, scaling of extended state observer in fixed-point implementation and observer-based parameter estimation. The proposed methods were tested in simulation and hardware experiments.

Committee:

Zhiqiang Gao, Ph.D. (Advisor); Ana Stankovic, Ph.D. (Committee Member); Lili Dong, Ph.D. (Committee Member); Hanz Richter, Ph.D. (Committee Member); Sally Shao, Ph.D. (Committee Member); Hui Tan, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Systems Design

Keywords:

PMSM; ADRC

Pogul, Brinda BalchandCORTICAL REPRESENTATIONS AND MOTOR PERFORMANCE OF THE DIGITS IN PATIENTS WITH CARPAL TUNNEL SYNDROME
Master of Science in Biomedical Engineering, Cleveland State University, 2018, Washkewicz College of Engineering
Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy and is characterized by compression of the median nerve. Median nerve injury in CTS patients alters the afferent-efferent processing circuit within the central nervous system, affecting digits’ sensory and motor performance. Studies have reported that the disrupted afferent input in CTS reorganizes the digit cortical representation in the primary sensory cortex (S1) of median nerve innervated digits, with the exception of the thumb. However, the extent of altered digit representation in the primary motor cortex (M1) due to CTS remains to be determined. It is important to evaluate S1/M1 reorganization because alterations at the cortical level due to CTS may undermine digit performance, including the interdependency and stability of digit forces during manual tasks. Moreover, by providing augmented tactile information at the digit pad to compensate for patients diminished sensory capacity, it may be possible to reverse or rehabilitate impaired performance. Therefore, the objective of this thesis was to investigate CTS-induced alterations in digit cortical representations of the thumb and forefinger and to examine each individual digits’ motor performance with and without tactile stimulation. Firstly, CTS-induced alterations in the cortical representation of the thumb and forefinger were examined in the S1 and M1 cortices using high resolution functional magnetic resonance imaging (fMRI). Then digit’s interdependency and force stability of the thumb and forefinger were investigated with and without vibrotactile stimulation applied to the digit pad. The results from this study showed that CTS is associated with altered digit cortical representations with decreased activation strength and decreased distinctiveness in both S1 and M1 regions. We also observed that CTS patients demonstrated increased digit interdependency and force variability compared to controls. Forced variability, but not interdependency, improved through tactile stimulation. The results of this thesis helped to identify both alterations at the cortical level as well as digit motor performance of the thumb and forefinger in CTS patients as compared to healthy subjects. It also provided evidence in favor of vibrotactile therapy for motor rehabilitation. This approach may aid in the development of new strategies for diagnosis, rehabilitation, and treatment of this hand disorder.

Committee:

ZONG-MING LI (Committee Chair); MOO-YEAL LEE (Committee Member); ANN REINTHAL (Committee Member)

Subjects:

Biomechanics; Biomedical Engineering; Biomedical Research; Engineering; Neurobiology; Neurology; Neurosciences; Radiology; Rehabilitation; Science Education; Scientific Imaging

Keywords:

Digit Cortical Representations, fMRI, Digit Motor Performance, Carpal Tunnel Syndrome

Varghese, Selwin MWATCHING PAINT DRY WITH PASSIVE MICRORHEOLOGY
Master of Science in Chemical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Coatings are complex fluids that are present in every aspect of our lives, and are primarily used to protect and decorate materials, such as automobiles, houses, and industrial structures. The U.S automotive coating industry is expected to have revenues of $3.5 billion by 2025, according to a report by Global Market Insights1. The drying step in the coating application process is crucial to creating a well performing product. For paints used in automobiles, drying involves a “flash” stage after which the product is cured. During flash, solvent evaporation occurs in paints exposed to the atmosphere. Paint remains fluidic for a portion of the flash step and semi-solid for the remaining portion, thereby allowing defects to form and solidify during flash. The rheological properties, and how these properties relate to flows during drying, are crucial to controlling defect formation during flash and ultimate performance of the coating. This work studies the transient rheological behavior of a drying thin film of paint during flash. We used passive microrheology to probe both steady (non-drying) and unsteady (drying) conditions and determined how parameters such as film thickness affect the properties of the film. We found that microrheology can be conducted in both clear and cloudy coatings, using fluorescent micro particles. An algorithm was developed to account for convection while drying. Drying behavior could be observed from the decrease in logarithmic slopes of the mean squared displacement (MSD), which indicated an increase in viscosity over the course of the drying period. Using a confocal microscope, non-drying and drying measurements were conducted in 3D. And finally it was discovered that drying could be observed as a function of film thickness for 100 and 150µm wet films.

Committee:

Christopher Wirth, Ph.D. (Committee Chair); Nolan Holland, Ph.D. (Committee Member); Andrew Resnick, Ph.D. (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Microrheology

Eguagie, Alexander EkenatanseCombined coagulation-microfiltration process for dye and fruit drink wastewater treatment
Master of Science in Environmental Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
This study shows the treatment of a binary mixture of dye wastewater of varied concentrations and fruit drink wastewater at three different concentrations; low (10 ppm), medium (50 ppm) and high (100 ppm) concentrations. Synthetic dye wastewater prepared in the laboratory was used as a representation of textile wastewater while the fruit drink wastewater was purchased from the grocery store. Transmittance and Absorbance values were used as indices to measure the color removal efficiency of the combined coagulation and microfiltration process. Even though there are modern technologies for color removal till this date, coagulation is one of the most economical alternatives to all technologies present now. In this thesis, the performance of a combined coagulation-microfiltration process for the removal of dyes was studied. After the coagulation-microfiltration process, transmittance values as high as 99.8% were achieved. Color removal efficiency was also investigated for the three coagulants; ferric chloride, aluminum sulfate and ferrous sulfate. Ferric chloride gave the best results in terms of color removal efficiency. Ferrous sulfate gave the worst result in terms of color removal efficiency.

Committee:

Yung-Tse Hung, Ph.D. (Committee Chair); Walter Kocher, Ph.D. (Committee Member); Lili Dong, Ph.D. (Committee Member); Chung-Yi Suen, Ph.D. (Committee Member); Sailai Sally Shao, Ph.D. (Committee Member)

Subjects:

Environmental Engineering

Keywords:

dye; coagulation; microfiltration; water; color removal; transmittance; absorbance

Ivancic, William DanielEffect of Surface Oxidation on the Mechanics of Carbon Nanotube Laden Interfaces
Master of Science in Chemical Engineering, Cleveland State University, 2017, Washkewicz College of Engineering
Single and multi-walled carbon nanotubes (SWCNT & MWCNT) have been studied over the past three decades because of their excellent properties, including their mechanical strength and large electrical and thermal conductivities. Incorporating CNTs into phases necessary for use in consumer or industrial products has been challenging because of strong attractive interactions, heterogeneity, and lack of separation techniques for these nanomaterials. Moreover, there are further challenges incorporating CNTs into multiphase materials because of the many remaining open questions regarding the properties of an interface with CNTs adsorbed or nearby. In the present work, the mechanics and microstructure of a water/air interface laden with industrial grade MWCNTs was studied. Specifically, the properties of an interface laden with MWCNTs that were systematically modified via oxidation in nitric acid were measured. The duration of oxidation was varied, and the surface pressure of the nanotube laden interfaces was measured via a Langmuir-Blodgett trough and microbalance. The elasticity and film relaxation times for MWCNTs with varying extents of oxidation were measured and compared. Data suggests that film elasticity increased with increased surface oxidation. However, these measurements also revealed that elasticity increased with compression number, suggesting that surface oxidation may have had only an indirect effect on elasticity. Additionally, MWCNT films were observed with an optical microscope and SEM. Micrographs showed evidence of buckling in the films at low modification times. These data together suggest that the films densify at higher modification times, pulling together due to capillary interactions brought on by stronger adsorption to the interface.

Committee:

Christopher Wirth, PhD (Committee Chair); Holland Nolan, PhD (Committee Member); Jessica Bickel, PhD (Committee Member)

Subjects:

Chemical Engineering

Keywords:

Carbon Nanotubes, Interface, Modification, Oxidation

Next Page