Master of Science (M.S.), University of Dayton, 2023, Mechanical Engineering

Particle systems for concentrating solar applications present a non-trival challenge to adequately model with DEM software. A compiled modeling suite for radiative exchange, coined DEM+, is directly integrated into commercial software Aspherix®. A presentation of this modeling suite, advantages, and disadvantages is followed by an expanded look at the Distance Based Approximation (DBA) method for estimating particle-particle and particle-wall radiative exchange of more realistic particle size distributions and some simple binary mixtures. In addition, design, operation, and preliminary experimental results for a lab-scale multi-stage falling particle curtain are evaluated with particle image velocimetry (PIV) from two perspectives with discussion of the challenges therein. A room temperature DEM model of investigated particles is compared to experimental results with emphasis on future work for material calibration for DEM+.

Committee: Andrew Schrader (Committee Chair); Kevin Hallinan (Committee Member); Andrew Chiasson (Committee Member); Rydge Mulford (Committee Member) Subjects: Alternative Energy; Energy; Experiments; Mechanical Engineering; Sustainability

Doctor of Philosophy, The Ohio State University, 2023, Civil Engineering

Multidimensional (coupled one-dimensional (1D) and two-dimensional (2D)) hydrodynamic models are developed to achieve computational efficiency for study areas with small-scale channel networks. Fine-scale computational domains are required to adequately resolve geometry of such study areas with typical 2D hydrodynamic models, which results in high computational cost. Coupled 1D/2D hydrodynamic models, which use 1D models for small-scale areas (typically small-scale channels), allow preserving geometric features of the study area with moderate computational cost and have been applied in various numerical studies. In this dissertation, we present computational techniques that further enhance coupled 1D/2D hydrodynamic models. The first one is an automatic mesh generation tool for coupled 1D/2D hydrodynamic models. Meshes are a required input for hydrodynamic models, and automatic mesh generation tools for 2D hydrodynamic models are well developed. However, development of such tools becomes challenging when they are designed for coupled 1D/2D hydrodynamic models. The difficulty of mesh generation in this case comes from the fact that the resolutions of the 1D/2D domains are closely intertwined with each other; however, the desired mesh resolutions for each domain may be quite different. The proposed mesh generator provides features to automatically identify 1D domains from given input data and to generates collocated meshes with efficient sizing along 1D domains. The developed techniques are demonstrated on three test cases, including two inland watersheds and a coastal basin. Second, a new smoothing method for digital elevation models (DEMs) is developed to enhance the application of an existing coupled 1D/2D kinematic wave model based on discontinuous Galerkin (DG) methods. The model has shown great success in rainfall-runoff simulations; however, it is highly sensitive to the topography represented by the mesh. The proposed method is compared to straightforwar (open full item for complete abstract)

Committee: Ethan J. Kubatko Dr. (Advisor); James H. Stagge Dr. (Committee Member); Yulong Xing Dr. (Committee Member); Ryan Winston Dr. (Committee Member) Subjects: Civil Engineering; Environmental Engineering; Fluid Dynamics

Master of Science (MS), Bowling Green State University, 2023, Geology

This study evaluates the potential for mineral prospectivity mapping (MPM) within the Kerkesha area, southwestern Eritrea using remote sensing and geochemical data analysis. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing data was used for mapping zones of hydrothermal alteration, while assessment of geologic structures is based on automated extraction of lineaments from a digital elevation model. Integration of these alteration and structural dataset with surface geochemical data were used in identifying pathfinder elements associated with Au-Cu-Zn mineralization as well as evaluating and delineating anomalous mineralization regions in this relatively underexplored region of Arabia Nubia Shield (ANS). Specifically, the modeling approach for the extraction and the interpretation of mineralization-related spectral footprints uses selective principal component analysis (SPCA), while the lineament features, which were extracted from different digital terrain models, were integrated with the soil geochemical data and modeled by principal component analysis (PCA). The results reveal a northeast-southwest trend of lineaments, delineate zones of hydrothermal alteration which indicate presence of multi-deposit type mineralization, and identify pathfinder elements. In addition, Au-Cu-Zn anomalous zones are extracted by one class support vector machine (OCSVM) and performances of such classification is validated by Kruskal-Wallis and Pearson's Chi-square tests. The results show significance in differences between the anomalous and non-anomalous zones and existence of a relationship between known mineral deposits and predicted anomalies. The proposed MPM shows promising results for robust automated delineation and understanding of mineralization processes.

Committee: Peter Gorsevski Ph. D. (Committee Chair); Kurt Panter Ph. D. (Committee Member); John Farver Ph. D. (Committee Member) Subjects: Geochemistry; Geographic Information Science; Geology

MS, University of Cincinnati, 2022, Engineering and Applied Science: Mechanical Engineering

Additive manufacturing (AM) is a fabrication technique that allows for complicated geometries to be manufactured that might otherwise be challenging using more traditional methods. AM is often seen paired with topology optimization to reduce weight while maximizing the strength of the part. Another benefit of AM is the ability to reduce the part count of components by integrating multiple parts into one single piece, lowering both cost and weight. However, integrating multiple parts into one single piece eliminates the jointing interfaces which are typically a dominant source of damping due to friction in the joints. This source of damping from jointing interfaces is beneficial to the fatigue life of a component and without it, other sources of damping features are required. One such method that has seen increasing interest is embedding damping features such as particle dampers within a component. This is done by leaving a small pocket of powder within strategic areas of an AM part during the printing process. In general, particle dampers are known to reduce the vibration in a system, though they are rather intricate and difficult to qualify their behavior. As a statement to their complexity, the literature covering particle dampers have mixed results on what type of particle damper structures work best and their overall effectiveness. Additionally, many works focus on particle dampers that utilize particles orders of magnitude larger than AM feedstock powder, which are typically 5-50 μm in diameter. As a result, many of the conclusions made based on current design particle dampers might not be applicable to the design of one that is additively manufactured. This thesis looks to develop some guidelines and analysis towards AM particle dampers using a simulation model and experimental data. A Discrete Element method (DEM) simulation model is used to capture and model the behavior and explicit motion of particles and their interactions. Reported experi (open full item for complete abstract)

Committee: Daniel Kiracofe Ph.D. (Committee Member); Yongfeng Xu Ph.D. (Committee Member); Michael Mains M.S. (Committee Member) Subjects: Mechanical Engineering

Doctor of Philosophy, The Ohio State University, 2020, Chemical Engineering

The advancements of hydraulic fracturing techniques ensure the improved fracture surface areas that are open to fluids flow. The induced microcracks accelerate the fluid communications between fractures and the fracture adjacent rock matrix at fracture surface. In brittle rocks, the generated fracture network puzzles engineers since the induced hydraulic fractures and activated pre-existing fractures challenge the stimulated reservoir volume (SRV) characterizations. Furthermore, the necessary engineered justifications of each stage due to lateral heterogeneity of the reservoir and the stress shadow effect (in-situ stress increase along the wellbore) even introduce another level of complexity of the effective fracture drainage complexity. Simultaneous fracture growth becomes difficult, resulting in variations of fracture half lengths, within a stage, and among stages. The failure planes of the rock, from mode I, mode II and the combination of them, are not smooth and parallel; instead, they are usually associated with certain surface roughness and non-planar morphology, which in turn inhibit the ideal Poiseuille flow in the fracture. As a result, the fundamental studies of non-planar and rough complex fracture paths to the proppant transport are essentially inevitable. To gain better understanding of the fracture network and the geomechanical aspects that form the complex fracture network, the objective of this work is firstly to quantitatively measure the rock damage from the induced microcracks at the adjacent matrix of the hydraulic fracture; we will then investigate the rock geomechanical properties which essentially dominant the fracture generation using machine learning approaches with cross-disciplinary data sources, including well logs, petrophysical properties, and rock microstructures information. Lastly, we will probe proppant transport characteristics in bifurcated fracture system. To achieve the aforementioned adjectives, this dissertation is structu (open full item for complete abstract)

Committee: Ilham El-Monier (Advisor); David Tomasko (Committee Co-Chair); Liang-Shih Fan (Committee Member); Yang Shang-Tian (Committee Member) Subjects: Chemical Engineering; Petroleum Engineering

Doctor of Philosophy (PhD), Ohio University, 2020, Mass Communication (Communication)

The arrival of the internet and its related platforms have created feminist communities in the virtual world in western countries and these phenomena have extended to the African continent. This study investigates the Ghanaian-based feminist movement, Pepper Dem Ministries (PDM), the group's activities on social media, and how it is utilizing the platform to propagate its feminist agenda. Specifically, this research focuses on Pepper Dem Ministries' cyberfeminists' articulations on Facebook platform and the group's contribution to the politics of feminism in Ghana. The study is premised on three grounds: first, the perceived democratic nature of digital media platforms has afforded minority groups, particularly women, space to engage their feminists' politics and contribute to global feminist discourse; second: that scholarly work on cyberfeminists practice is heavily skewed towards Western cyberfeminist groups thereby alienating African cyberfeminist groups; and third, that consequent upon the latter, there is the urgent need to draw attention to African cyberfeminist practices, show how they negotiate their space within the digital space and eventually mainstream their feminist voices into the global feminism discourse. The study is anchored on Black cyberfeminist theory which draws on intersectional studies and Black feminists thought to interrogate how black cyberfeminists construct their identity on digital media platforms. The study is further positioned on post-colonial feminists' articulations and African feminists theories that provide a lens of interpretations for Pepper Dem Ministries' feminist positionality and practice. Utilizing feminist cyberethnography as a methodological standpoint, the study found that social media has provided new spaces for African feminist movements such as the PDM to openly articulate their otherwise muted voices leading to initiation of fresh discourses on hitherto uncontested masculinecentered spaces and issues. Members of P (open full item for complete abstract)

Committee: Steve Howard (Advisor) Subjects: African Studies; Gender; Mass Media; Womens Studies

Master of Science (MS), Bowling Green State University, 2020, Geology

The purpose of this study is determining a potential correlation between soil moisture and burn severity as well as examining potential correlations between slope, elevation, wind speed, wind direction and Normalized Difference Vegetation Index (NDVI) value and burn severity within the Mendocino Complex Fire, California, which occurred in 2018. A time-series of the difference Normalized Burn Ratio (dNBR), the difference between pre- and intra-fire NBR values, was calculated via Sentinel-2, soil moisture was mapped using SMAP, and the Digital Elevation Model (DEM) from ASTER was used to derive elevation and slope values. The imagery was obtained from USGS and USDA websites. Images were processed and reprojected to the same spatial resolution (60 m) and projection (UTM Zone 10N, WGS-87). dNBR imagery was subdivided in newly burned areas for each consecutive day for ten days from 29 July 2018 to 31 August 2018. The findings suggested that there was no strong correlation trend consistently found over the proposed period of time between dNBR values and soil moisture content (R ≈ -0.20 to 0.39), slope (R ≈ -0.35 to 0.46), elevation (R ≈ -0.24 to 0.56), wind speed (R ≈ -0.15 to 0.36), and wind direction (R ≈ -0.42 to 0.24). However, a positive correlation between NDVI values and dNBR values was found to be strong and consistent (R ≈ -0.48 to 0.57). This implies that burn severity increased more significantly and frequently with NDVI, a surrogate for vegetation biomass and leaf area index. It can be surmised that soil moisture must reach some higher values before having a possible impact upon burn severity. Considering that the summer of 2018 was one of the warmest and driest summers in the study area's recent history, soil moisture content was relatively low while, simultaneously, vegetation was dry and more prone to burning.

Committee: Anita Simic Milas Ph.D. (Advisor); Yuning Fu Ph.D. (Committee Member); Ganming Liu Ph.D. (Committee Member) Subjects: Environmental Geology; Geography; Geology; Remote Sensing; Statistics

PhD, University of Cincinnati, 2018, Engineering and Applied Science: Mechanical Engineering

Fluid-solid multiphase interactions are prevalent in many industrial processes. Food processing, pharmaceuticals, petroleum refining, and chemical processing are some of the industries which rely on high-efficiency multiphase processes. While many multiphase processing systems have been developed through prototyping and experimental analysis, recent developments have shown that numerical simulations are effective for design and analysis of multiphase systems. Numerical simulations are able to capture the multi-scale phenomena in fluid-solid interactions, and provide detailed information across a large range of scales. Coupled Computational Fluid Dynamics - Discrete Element Method (CFD-DEM) is a common numerical approach for fluid-solid flows, as CFD-DEM can provide information at the particle scale, while remaining computationally efficient enough to model large experimental systems. However, CFD-DEM simulation results reported in the literature occasionally display large unexplained errors. I theorize that numerical error produced in the coupling procedure between CFD and DEM is responsible for the unexplained error. To evaluate this theory, I question how, and to what extent, the computational mesh cell size affects results from CFD-DEM simulations. My question of `how' contains two parts, (a) how are results quantitatively affected as the cell size is modified, and (b) what is the relationship, fundamentally, between the cell size and the results. For Part (a), I investigate to what extent results are affected by the computational cell size, by systematically modifying cell size for simulations of several common applications of CFD-DEM. Part (b) requires tracing the changes due to cell size through the full CFD-DEM calculation to determine the lattice of effects. I quantify the change in simulation results with computational grid refinement for mono-size particle fixed beds, binary-size particle fixed beds, and binary-size particle fluidized (open full item for complete abstract)

Committee: Urmila Ghia Ph.D. (Committee Chair); Milind Jog Ph.D. (Committee Member); Gui-Rong Liu Ph.D. (Committee Member); Christopher Stoltz Ph.D. (Committee Member) Subjects: Mechanical Engineering

Master of Arts, The Ohio State University, 2018, Germanic Languages and Literatures

In this MA thesis, I argue that the deal with the devil, as it manifests in 19th century German literary texts like Johann Wolfgang Goethe's Faust: Eine Tragodie, Gottfried Keller's Romeo und Julia auf dem Dorfe, and Theodor Storm's Der Schimmelreiter, negotiates the experience of modernity and mediates the experience thereof through offering moments of forgetting. Upon approaching modernity with help from Jurgen Habermas, Friedrich Nietzsche and Karl Marx, the thesis explores the existential importance of Gluck and forgetting according to Nietzsche's second Untimely Meditation, Vom Nutzen und Nachteil der Historie furs Leben. Subsequently, I posit that the deal with the devil, as an explicit component and, later on, implicit undercurrent of 19th century German texts, takes on the role of facilitator of moments of such forgetting. Goethe's masterpiece Faust lays the foundation for this conflux of developments, motifs, and experiences in the wager its protagonists strikes with the devil Mephistopheles and in the various escapades that take Faust out of the Gothic halls of the university to the changing feudal world, where he encounters his lover Gretchen. The experience of Gluck that he significantly does not seal with her drives him, first, away into the classical spheres of Greek Antiquity, where he cannot rest to be with Helen of Troy, and, second, into a proto-capitalist dam project through which he intends to atone for his failings with Gretchen and congeal the otherwise insubstantial forgetting. In Keller's Romeo und Julia auf dem Dorfe, the devilish Black Fiddler offers Sali and Vrenchen, the two losers of an unfolding modernity, the chance for a tainted forgetting, an offer they do not take. In Der Schimmelreiter, the deal with the devil materializes from the winning, bourgeois end to Hauke Haien, who builds a dam for purposes palpably similar to Faust's.

Committee: Robert Holub (Advisor); John Davidson (Committee Member) Subjects: Germanic Literature

Doctor of Philosophy, University of Akron, 2018, Civil Engineering

Bridge local scour has long been identified as the most critical cause to bridge failures. Countermeasures that are commonly used nowadays still have disadvantages to some extent. This work is among one of the ongoing efforts to explore reliable alternatives. Inspired by the streamlined body of boxfish and blue shark, this study introduced streamlining features to the bridge piers in order to reduce the erosive forces locally. Based on the excess shear stress criteria, the Reynolds-Averaged Navier Stokes (RANS) numerical model was employed to optimize the streamlined features through parametric studies. The maximum bed shear stress around the optimal streamlined pier was shown to be reduced by ~34% as compared to that around a non-streamlined pier. Further simulation using the advanced Detached Eddy Simulation (DES) model revealed that the streamlined pier also helped reduce the locally turbulence dynamics, which played a significant role in local scour. A set of small-scale flume tests were then conducted in the laboratory to characterize the flow physics and scour behavior of uniform Ottawa sand around piers with various streamlined extents. The experimental results further confirmed the effectiveness of pier streamlining in scour reduction. The maximum scour depth around the streamlined pier was reduced by ~66% as compared to that around a non-streamlined pier. Through monitoring the pore pressure response within sand, the role of vortex-induced excess pore pressure that plays in the scour mechanism was discussed. The vortex-induced excess pore pressure also helped to partially account for an interestingly counterintuitive observation from an independent experiment: the local scour resistance was a slightly decreasing function of the granular bulk density. Finally, a CFD-DEM (Discrete Element Model) two-way coupled model was established to simulate the scour behavior of uniform spherical particles around an oblong pier. The two-phase model successfully captured t (open full item for complete abstract)

Committee: Junliang Tao Dr. (Advisor); Kevin Kreider Dr. (Committee Member); Qindan Huang Dr. (Committee Member); Yalin Dong Dr. (Committee Member); Zhe Luo Dr. (Committee Member) Subjects: Civil Engineering

MS, University of Cincinnati, 2015, Engineering and Applied Science: Mechanical Engineering

Detailed description of flow through stationary particle beds is crucial for the design and implementation of municipal water filtration, material extraction systems for nuclear waste and industrial water purification systems. Knowledge of fluid-particle interactions and fluid flow properties through the bed is essential to design, but difficult to determine from experimental investigations. Combined granular-fluid simulation methods such as coupled Computational Fluid Dynamics and Discrete Element Method (CFD-DEM) have been used to bridge this gap in fundamental knowledge. Able to capture details of the small-scale and large-scale interactions that are difficult to study in physical beds, simulation findings have added great understanding to this field. Unfortunately, the reported results are occasionally flawed by a lack of understanding, specifically regarding the magnitude of numerical and modeling errors. Uniform reporting of error, investigations of simulation trend, and proof of mesh-independence have not been performed for granular-fluid simulations. A standard method of open-source granular-fluid flow simulation known as CFDEM is applied to the simulation of flow through a fixed bed. The Ergun equation is a validated empirical expression used to predict the drag force in fixed bed flow and this prediction is compared directly to simulation results. A grid-refinement procedure, standard for publication of CFD simulation results, is applied to the CFD-DEM simulations. The solution trend over the refinement range is investigated using the frequency of convergence, convergence types, and the proposed `offset' method; a comparison of the expected numerical error and actual extrapolated solution error. An optimal grid size resulting in the least amount of error is investigated by solution trend, drag profile comparison, and the grid-refinement study results. Error is seen to increase in the simulations at both large cell sizes and as the cell siz (open full item for complete abstract)

Committee: Urmila Ghia Ph.D. (Committee Chair); Christopher G. Stoltz Ph.D. (Committee Member); John Hecht Ph.D. (Committee Member); Kirti Ghia Ph.D. (Committee Member) Subjects: Mechanical Engineering; Textile Research; Theater

Master of Science, The Ohio State University, 2015, Earth Sciences

Cinder cones in the Erebus Volcanic Province provide important markers of climate, erosion, and stress in the Ross Sea region of Antarctica, but they have not previously been systematically studied. Cinder cones provide ideal subjects for morphological analysis because they consistently form as radially symmetric landforms with approximately constant slopes. DEMs are used in tandem with satellite images and parameterization algorithms in this study to characterize landforms and surface properties of glaciated and non-glaciated Erebus Volcanic Province cinder cones. Cone dimensions are similar to those in other intraplate environments and generally smaller than cones in subduction- and rift-related settings. Average height/width ratios are more characteristic of volcano cone fields than platform cone fields, but the volcanic terrain of the Erebus Volcanic Province is likely a complex combination of both field types. Elongation of cinder cones in the Erebus Volcanic Province is common and most elongated cones have long axes oriented parallel or subparallel to the slope direction of terrain underlying them, indicating topographic control of cone asymmetry. Some cones with orientations independent of terrain controls suggest that regional stresses exert control on cone elongation, as suggested by previous research. Shape modification by wind and overriding glaciers may also play a role in producing cone asymmetry. Erosion rates on cinder cones in the Erebus Volcanic Province are generally slower and more linear than in other, more temperate regions. This is most likely due to a decreased influence of the role of liquid water, as evidenced by lack of increasing surface irregularity with time. Previous research has shown that wind has significant abrading power when persistent, and that volcanic terrain has increased shear strength because of surface roughness and angularity. Both of these factors likely contribute to the relatively slow rate of erosion in the EVP (open full item for complete abstract)

Committee: Terry Wilson (Advisor); Ian Howat (Committee Member); Michael Durand (Committee Member) Subjects: Earth; Geological; Geology; Geomorphology

Doctor of Philosophy, The Ohio State University, 2015, Civil Engineering

Landslides are natural disasters that cause environmental and infrastructure damage worldwide. In order to reduce future risk posed by them, effective detection and monitoring methods are needed. Landslide susceptibility and hazard mapping is a method for identifying areas suspect to landslide activity. This task is typically performed in a manual, semi-automatic or automatic form, or a combination of these, and can be accomplished using different sensors and techniques. As landslide hazards continue to impact our environment and impede the lives of many, it is imperative to improve the tools and methods of effective and reliable detecting of such events. Recent developments in remote sensing have significantly improved topographic mapping capabilities, resulting in higher spatial resolution and more accurate surface representations. Dense 3D point clouds can be directly obtained by airborne Light Detection and Ranging (LiDAR) or created photogrammetrically, allowing for better exploitation of surface morphology. The potential of extracting spatial features typical to landslides, especially small scale failures, provides a unique opportunity to advance landslide detection, modeling, and prediction process. This dissertation topic selection was motivated by three primary reasons. First, 3D data structures, including data representation, surface morphology, feature extraction, spatial indexing, and classification, in particular, shape-based grouping, based on LiDAR data offer a unique opportunity for many 3D modeling applications. Second, massive 3D data, such as point clouds or surfaces obtained by the state-of-the-art remote sensing technologies, have not been fully exploited for landslide detection and monitoring. Third, unprecedented advances in LiDAR technology and availability to the broader mapping community should be explored at the appropriate level to assess the current and future advantages and limitations of LiDAR-based detection and modeling of land (open full item for complete abstract)

Committee: Dorota Grejner-Brzezinska (Advisor); Charles Toth (Advisor); Tien Wu (Committee Member) Subjects: Civil Engineering

Doctor of Philosophy, The Ohio State University, 2014, Geodetic Science and Surveying

Shoreline mapping has been a critical task for federal/state agencies and coastal communities. It supports important applications such as nautical charting, coastal zone management, and legal boundary determination. Current attempts to incorporate data from hyperspectral imagery to increase the efficiency and efficacy of shoreline mapping have been limited due to the complexity in processing its data as well as its inferior spatial resolution when compared to multispectral imagery or to sensors such as LiDAR. As advancements in remote-sensing technologies increase sensor capabilities, the ability to exploit the spectral formation carried in hyperspectral images becomes more imperative. This work employs a new approach to extracting shorelines from AVIRIS hyperspectral images by combination with a LiDAR-based DEM using a multiphase active contour segmentation technique. Several techniques, such as study of object spectra and knowledge-based segmentation for initial contour generation, have been employed in order to achieve a sub-pixel level of accuracy and maintain low computational expenses. Introducing a DEM into hyperspectral image segmentation proves to be a useful tool to eliminate misclassifications and improve shoreline positional accuracy. Experimental results show that mapping shorelines from hyperspectral imagery and a DEM can be a promising approach as many further applications can be developed to exploit the rich information found in hyperspectral imagery.

Committee: Alper Yilmaz Ph.D. (Advisor); Alan Saalfeld Ph.D. (Committee Member); von Frese Ralph Ph.D. (Committee Member) Subjects: Geographic Information Science; Remote Sensing

Master of Science, University of Toledo, 2014, Civil Engineering

Mechanisms of coupled hydro-bio-chemo-mechanical phenomena play an important role in many natural and engineered processes in granular soils. The present work studies two seemingly distinctly different processes which share a common thread in their need for addressing the effect of non-mechanical phenomena across scales. Firstly, desiccation shrinkage of drying soils is investigated via a hydro-geomechanical multi-scale model. This research aims to identify and quantitatively evaluate various critical mechanisms associated with the processes of desiccation shrinkage and cracking in drying silty soils. A previously developed 1D bundle-of-tubes model is refined to simulate the various stages of drying shrinkage in 2D, using the actual pore size distribution based on mercury intrusion porosimetry (MIP) data. It is revealed that the resulting shrinkage evolution is affected by air entry that may occur in two possible scenarios: air incursion at the external surface and formation of vapor nucleus in the interior. The analysis of mechanical deformation is coupled with the numerical simulation of the drying process which can be often characterized as a two-stage development, consisting of a constant rate period and a falling rate period. Numerical simulation of the drying rate evolution suggests that it may be closely associated with the onset of air entry and/or the progress of desaturation. Further transition of solid- water structural configuration into funicular and pendular states from initially capillary state is simulated. The second topic investigated is the coupled bio-chemo-geomechanical mechanisms through a discrete element modelling approach. Bio mediated soil improvement method based on microbial induced calcite precipitation (MICP), can be a sound technique for modifying soil properties such as strength, stiffness and permeability. This portion of work focuses on establishing the bio-chemo-mechanical coupling effects at the micro scale and explores the macr (open full item for complete abstract)

Committee: Liangbo Hu (Advisor); Brian Randolph (Committee Member); Youngwoo Seo (Committee Member) Subjects: Civil Engineering; Geotechnology

Doctor of Philosophy, The Ohio State University, 2007, Geodetic Science and Surveying

This study deals with the methods of forward gravity gradient modeling based on gravity data and densely sampled digital elevation data. In this study, we develop an improved modeling of the gravity gradient tensors and study the comprehensive process to determine gravity gradients and their errors from real data and various models (Stokes' integral, radial-basis spline and LSC). Usually, the gravity gradients are modeled using digital elevation model data under simple density assumptions. Finite element method, FFT and polyhedral methods are analyzed in the determination of DEM-derived gravitational gradients. Here, we develop a method to model gradients from a combination of gravity anomaly and DEM data. Through a solution on the boundary value problem of the potential field, the gravity anomaly data are combined consistently with the forward model of DEM to yield six components of the gravity gradient tensor. The second Helmert condensation principle and the remove-restore technique are used to connect DEM and gravity data in the determination of gravity gradients. Modeling of the gradients thus, particularly at some altitude above ground, from surface gravity anomalies is based on numerical implementations of solutions to boundary-value problems in potential theory, such as Stokes' integral, least-squares collocation, and some Fourier transform methods, or even with radial-basis splines. Modeling of this type would offer a complementary if not alternative type of support in the validation of airborne gradiometry systems. We compare these various modeling techniques using FTG (full tensor gradient) data by Bell Geospace and modeled gradients, thus demonstrating techniques and principles, as well limitations and advantages in each. The Stokes' integral and the least-squares collocation methods are more accurate (about 3 E at altitude of 1200 m) than radial-basis splines in the determination of gravity gradient using synthetic data. Furthermore, the comparison betw (open full item for complete abstract)

Committee: Christopher Jekeli (Advisor) Subjects: Geodesy

Doctor of Philosophy, The Ohio State University, 2005, German

Despite Bettina von Arnim's (1785-1859) interest and participation in the Vormarz political discourse of the 1830s and 40s in Berlin, scholarship has traditionally focused on the literary aspects of her earlier texts, largely ignoring her later, politically charged works. My project explores Bettina von Arnim's use of mythological and heroic imagery in her later writings, as it relates to her vision of an ideal governmental structure, which is based on the figure of the Volkskonig or “People's King.” One of the many new ideas on government discussed in intellectual circles during this period, von Arnim's Volkskonig model of government called for a strong and moral monarch, who would value the welfare and development of his subjects above all else. I bring attention to the discrepancies between von Arnim's call for a strong monarchy and her desire for progressive social reform, which demonstrate the tensions between the author's cultural background in Romantic thought and her involvement in Young German and Young Hegelian intellectual discourse. The presence of such tensions illustrates not only Bettina von Arnim's problematic role as an emerging female voice with her own formative concepts of nationhood, but the general complexity of nineteenth-century German debates on government.

Committee: Barbara Becker-Cantarino (Advisor) Subjects:

Doctor of Philosophy, The Ohio State University, 2003, Geodetic Science and Surveying

Establishing a rigorous model for non-frame dynamic imaging system requires incorporating the complex geometry of perspective center into the transformation function thatconnects image space to object space. This research addresses an appropriate transformation method by extending traditional collinearity equations for the sophisticated descriptions of the relationship between the panoramic image space and object space in order to achieve the robustness of reconstructing the object space. Generally, the crucial requirement of the rigorous model for the non-frame satellite sensor is to have the direct measurements of the GPS/INS for determining the satellite trajectory for the image acquisition periods. However, since there were no measurements of Global Positioning System (GPS) and Inertial Navigation System (INS) for the satellite trajectory of panoramic image data used in this research, we unavoidably applied the indirect method for recovering Exterior Orientation Parameters (EOPs) of the panoramic imagery. This indirect method is a suitable method because it is less sensitive to the errors, caused by the incorrect interior orientation parameters, for obtaining less uncertain results of the reconstructing 3D object space. This research proposes the a robust model for panoramic cameras. This model includes extended collinearity equations, space intersection algorithm based on the coplanarity condition, and object reconstructing modules for generating Digital Elevation Model (DEM) and ortho-rectified image. The proposed model is analyzed in terms of its capabilities for the recovery of the EOPs and the performance of the space intersection by inspecting the statistics of the output. The model is also tested for proving the validity by comparing it with the generic sensor models such as affine transformation, Direct Linear Transformation (DLT), and Rational Function Model (RFM). Experiments performed in this research show that the proposed model is a suitable represe (open full item for complete abstract)

Committee: Anton Schenk (Advisor) Subjects: Engineering, Civil

Master of Science (MS), Ohio University, 2012, Civil Engineering (Engineering and Technology)

The primary objective of this research was to study sedimentation and erosion in the Tappan Lake Watershed. A bathymetric survey performed in 1998 by the United States Army Corps of Engineers had identified the lake as having a sedimentation rate five times greater than other lakes located in the region. Erosion and sedimentation were studied by using data from a 2011 bathymetric survey, the Revised Universal Soil Loss Equation (RUSLE), and a Geographical Information System. The conclusion of the study was that Tappan Lake does not have a sedimentation or erosion problem. Secondary objectives of the study were to evaluate the effects of Digital Elevation Model (DEM) resolution on the terrain related variables of RUSLE, L and S factors. Comparisons of RUSLE results were made using 3-, 9-, and 27- meter DEMS which showed that estimated erosion potential decreases as DEM resolution increases. The results also demonstrated that DEMs with resolutions greater than nine meters are not appropriate for calculating terrain characteristics, as they are incapable of clearly defining areas where overland flow accumulates or where deposition should occur.

Committee: Tiao Chang (Advisor) Subjects: Engineering; Geography; Geology

Doctor of Philosophy, Case Western Reserve University, 2005, Chemical Engineering

The behavior of clusters of particles ranging from the nanometer scale to the micrometer scale impacts a number of important processes. Dispersion of particle clusters is seen in applications involving pharmaceutical tablets, detergent granules, agglomerates of biological cells, and clusters of pigments or fillers for advanced materials. As these clusters are subjected to shearing forces associated with the motion of their host fluid, they can be broken down into smaller fragments. Often, this is the desirable outcome, but in other cases dispersion may be undesirable. Previous research has analyzed and modeled dispersion in simplified and idealized situations: steady, simple flows and agglomerates of uniform structure. The current work aims to improve the level of sophistication for the understanding of dispersion processes by considering the effects of binders in particulate agglomerate systems and the impact of unsteady dispersion conditions, more representative of real dispersion scenarios. Through experimental trials, practical limitations of our testing protocols were clarified. Agglomerates made from compacted powders provided the most control and consistency in response. Multiple testing protocols were deemed key to clarifying the complex interactions that impact particulate agglomerate dispersion. Packing effectiveness and molecular weight were found to impact the characteristics of particulate agglomerates. The development of a flexible and detailed simulation allowed predictions of dispersion and enhanced understanding of the phenomenon. The discrete/distinct element method (DEM) was adopted to study the behavior of single nano-scale spherical agglomerates, immersed in a simple shear flow field, in response to shearing under steady or dynamic/oscillatory flow conditions. Results, in good agreement with reported experimental trends, were used to demonstrate the functionality of the three-dimensional simulation as a predictive and analytical tool. The curren (open full item for complete abstract)

Committee: Donald Feke (Advisor) Subjects: