Doctor of Philosophy, The Ohio State University, 2008, Food Agricultural and Biological Engineering

In microbial fuel cells (MFCs), bacteria generate electricity by mediating the oxidation of organic compounds and transferring the resulting electrons to an anode electrode. The objectives of this study were to: 1) test the possibility of generating electricity in an MFC with rumen microorganisms as biocatalysts and cellulose as the electron donor, 2) analyze the composition of bacterial communities enriched in cellulose-fed MFCs, 3) determine the effect of various external resistances on power output and coulombic efficiency of cellulose-fed MFCs, 4) evaluate bacterial diversity and cellulose metabolism under different circuit loads, 5) assess the influence of methane formation on the performance of cellulose-fed MFCs under long-term operation, and 6) characterize the diversity of methanogens in cellulose-fed MFCs. The results demonstrate that electricity can be generated from cellulose by exploiting rumen microorganisms as biocatalysts. Cloning and analysis of 16S rRNA gene sequences indicated that the most predominant bacteria in the anode-attached consortia were related to Clostridium spp., while Comamonas spp. abounded in the suspended consortia. Results suggest that oxidation of metabolites with the anode as an electron sink was a rate limiting step in the conversion of cellulose to electricity in MFCs. This study also shows that the size of external resistance significantly affects the bacterial diversity and power output of MFCs. A maximum power density of 66 mW/m2 was achieved by the 20-ohm MFCs, while MFCs with 249, 480 and1000 ohms external resistances produced 57.5, 53 and 47 mW/m2, respectively. Thus the external resistance may be a useful tool to control microbial communities and consequently enhance performance of MFCs. Furthermore, this study demonstrates that methanogenesis competes with electricity generation at the early stages of MFC operation but operating conditions suppress methanogenic activity over time. The suppression of methanoge (open full item for complete abstract)

Committee: Ann Christy PhD (Advisor); Burk Dehority PhD (Committee Member); Olli Tuovinen PhD (Committee Member); Alfred Soboyejo PhD (Committee Member); Zhongtang Yu PhD (Committee Member) Subjects: Agricultural Engineering; Chemical Engineering; Energy; Environmental Engineering; Environmental Science; Microbiology

Doctor of Philosophy, The Ohio State University, 2016, Industrial and Systems Engineering

The literature was reviewed to identify inflammatory markers found in the blood of subjects suffering from LBP. This information was then used to design an experiment intended to determine the contribution of repetitive lifting, mental load and subject personality to inflammatory responses after exposure. Twenty male subjects were exposed to repetitive lifting combined with a high or low mental workload task for two hours. Plasma, WBC counts, IL-1ß, TNF-a, IL-6, IL-8, IL-10, Substance P, Creatine Kinase, and salivary cortisol were sampled before, immediately post, 2 hours post and 20 hours post exposure. A well-regulated inflammatory response was observed following exposure. There was an initial elevation of IL-6, TNF-a, IL-8 and CK while the composition of plasma WBCs shifted in favor of granulocytes. 20 hours post exposure, CK concentrations have peaked and circulating granulocytes returned to normal. However, granulocytes are expected to live longer than 20 hours and therefore may still be active at sites of tissue trauma. In an industrial setting, 20 hours post lifting exposure would correspond to a worker returning to work the next day and creates conditions for cumulative lifting and inflammatory exposures. Interactions were noted between subject personality, mental load and inflammatory responses. Interactions were also noted between mental load, personality and spinal loading. However, these changes in spinal load did not correspond to changes in inflammatory responses.

Committee: William Marras Ph.D. (Advisor); Thomas Best MD, Ph.D. (Committee Member); Devina Purmessur Ph.D. (Committee Member); Safdar Khan MD (Committee Member) Subjects: Biochemistry; Engineering; Industrial Engineering

Master of Science (M.S.), University of Dayton, 2015, Aerospace Engineering

This thesis describes the design, setup, and testing of a unique mounting fixture built for the Variable Camber Compliant Wing developed by the U.S. Air Force Research Laboratory. The intent of the Variable Camber Compliant Wing is to demonstrate an active 2D section camber change under aerodynamic load. Mounting possibilities were limited in the Vertical Wind Tunnel due to the dimensions and weight of the wing which necessitated a custom design to obtain aerodynamic force measurements. ATI Industrial Automation offers a promising solution with their wide range of multi-axis force/torque sensors which are becoming widely adopted in aerodynamic testing of small unmanned aircraft. These sensors can provide accurate results when loaded in close proximity to the balance center. However, it has been reported in literature that measurement error increases dramatically when the balance is loaded off balance center. In this case, a load cell is mounted on each end of the unique fixture, forming a direct interaction between the two load cells. An extensive calibration loading procedure was performed prior to the test to develop a calibration matrix sensitive to the test setup. The intent of this thesis is to present development of a correction method for this unique mounting fixture which could provide a new flexible wing testing capability in the Vertical Wind Tunnel Facility at the Air Force Research Laboratory.

Committee: Aaron Altman (Advisor); James Joo (Committee Member); Ray Kolonay (Committee Member) Subjects: Aerospace Engineering; Engineering

Master of Science, The Ohio State University, 2013, Mechanical Engineering

Force measurement platforms play an important role in the field of biomechanics by allowing for accurate measurement of the ground reaction forces during studies. Several varieties of forces measurement platforms are available on the market, although strain gage based force platform are most prevalent. This thesis details the design of a 6-component load cell consisting of a machined aluminum cylinder with attached strain gages for use in force platforms. The load cell design is intended to improve accuracy, increase the natural frequency, and improve the calibration process for strain gage based force measurement platforms. The performance of different load cell geometries were tested using finite element analysis to determine strain levels. Once optimal load cell geometries were determined, two sets of load cells were manufactured and implemented in a full force platform assembly. While one of the prototype load cell designs proved to be ineffective in final installation, the other design slightly improved the natural frequency, maintained the accuracy, and allowed for a simplified calibration process.

Committee: Necip Berme Dr. (Advisor); Manoj Srinivasan Dr. (Committee Member) Subjects: Biomechanics; Mechanical Engineering

MS, University of Cincinnati, 2004, Engineering : Mechanical Engineering

Although DIM has proven to provide accurate estimates for a structure's inertia properties in a finite frequency band, the results are not always consistent throughout the measured band nor are the properties always accurate for all structures. Critical aspects in obtaining accurate and consistent inertia properties are examined. These include a method of determining direction cosines for transducers utilizing sonic digitization, supplementation of estimated values with known parameters, scaling FRF matrices to force known parameter solutions, selection of consistent perimeter excitations, and weighting the approximated input and response rotations against the measured translations. Experimental examples are presented illustrating these critical aspects.

Committee: Dr. Randall Allemang (Advisor) Subjects:

Master of Science, The Ohio State University, 2010, Mechanical Engineering

A planar solid oxide fuel cell is characterized by a thin ceramic electrolyte sandwiched between porous electrodes, along with seals and current collectors. To perform as a good oxide ion conductor, the electrolyte needs to be very thin. However, a thin electrolyte is highly prone to damage during production, assembly, and subsequent operation. To be both electrochemically efficient and mechanically robust, NexTech Materials Ltd has developed an innovative electrolyte, the FlexCellTM, for use in electrolyte-supported SOFCs. This electrolyte design has a honeycomb structure that supports thin, “active areas” thus providing good electro-chemical efficiency as well as mechanical robustness. To optimize the FlexCell and understand its mechanical limits, a combination of experiments and finite element modeling are performed. The out-of-plane dimensions are much smaller than the in-plane dimensions, and hence a two-scale approach is required for optimizing the geometrical design of the FlexCell. At the large-scale, the whole electrolytic membrane is modeled with equivalent properties, whereas at the small-scale, the repeating pattern of the honeycomb structure is studied. Nextech's goal to commercially produce ultra large FlexCells of the order of 700 to 1200 cm2 depends largely on its mechanical performance. The aim of this work is to suggest ways to geometrically alter the design so that the mechanical membrane performs well under mechanical and thermal loading. By performing finite element simulations on the large area FlexCell, design parameters which influence its mechanical robustness are identified. Results of this analyses show the areas of high stresses. The stresses can be mapped to the small-scale to study small-scale failure. Since it is not known if optimal geometries scale with membrane size, a more methodical approach is undertaken to ensure that the thin active areas have adequate support in thermally varying environments.

Committee: Mark Walter PhD (Advisor); Sandip Mazumder PhD (Committee Member) Subjects: Mechanical Engineering

Master of Environmental Science, Miami University, 2006, Environmental Sciences

This study investigated the impact of high-stage events on riverbed scour and hydraulic conductivity (Kv). Seepage-meter measured riverbed Kv averaged 0.092 m/d. Slug-test measured Kv of the underlying sediment averaged 9.6 m/d. The low riverbed Kv is probably due to a gravel and cobble layer clogged with fine sediment (colmation layer). Kv of cores of transient material overlying the cobble layer averaged 5.3 m/d. Event-driven scour, measured with cross-sectional profiles, scour chains, and a load-cell pressure sensor, never exceeded 0.06 m, indicating that the colmation layer remained intact, despite even a 60-year event. A riverbed conceptual model of three distinct layers –transient sediment, an armor/colmation layer and a transitional bottom – had an overall Kv of 4.6 m/d. Sensitivity analysis of layer thicknesses indicated that a) the transient layer has negligible impact on the overall Kv and b) loss of the colmation layer, while not observed, could double the overall Kv.

Committee: Jonathan Levy (Advisor) Subjects: