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Rathi, Ajay KumarDevelopment of a microscopic simulation model for freeway lane closures /
Doctor of Philosophy, The Ohio State University, 1983, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Express highways;Roads--Design and construction;Traffic flow;Computer simulation

Lee, Wha-JoonA computer simulation study of omnidirectional supervisory control for rough-terrain locomotion by a multilegged robot vehicle/
Doctor of Philosophy, The Ohio State University, 1984, Graduate School

Committee:

Not Provided (Other)

Subjects:

Computer Science

Keywords:

Robots;Locomotion;Computer simulation

Zhao, PengyangMesoscale modeling of mechanical deformation of metallic glasses
Doctor of Philosophy, The Ohio State University, 2015, Materials Science and Engineering
Plastic deformation of metallic glasses (MGs) has been studied by both atomistic modeling such as molecular dynamics (MD) simulations and continuum modeling. However, heterogeneities above the atomic scale but below the micrometer scale are essential in understanding issues such as shear bands, which usually form at a time scale of 10^{-5} - 10^{-3} s with a characteristic thickness of 10 - 100 nm. To bridge over the length scale from atomistic to continuum simulations, a physics-based heterogeneously randomized shear transformation zone (STZ) model is developed by incorporating several key features, i.e., spatial heterogeneities, local order, and strain-induced softening that are missing from previous mesoscale models but are crucial to the understanding of the shear band formation in MGs. The model adopts STZ as the smallest unit of inelastic deformation and treats the macroscopic mechanical behavior of MGs as a stochastic sequence of discrete, spatially heterogeneously randomized STZ transformations, which can be then simulated using the kinetic Monte Carlo (kMC) method. Applications of the model to simulating the bulk MG samples under uniaxial tension tests find that the incorporation of softening plays a key role in localizing plastic shear, while the stress redistribution due to STZ transformation alone cannot lead to the shear band formation. The softening-induced shear instability inside the shear band is found responsible for a “runaway” feature of a local temperature rise, which falls in the same range of the experimental estimate. The simulated shear band thickness agrees with the theoretical predication and experimental measurements. Extreme statistics and self-organized criticality analysis further reveal some statistical features of the plasticity in MGs. The model is then applied to the simulation of nanometer-scale finite-sized samples with different pre-existing damage populations, which are inspired from experimental scenarios. It is found that experimentally observed “smaller is stronger” phenomena on the strength of MG may be attributed to the pre-existing damage population, which depends on the sample size when subject to the same processing history. The simulated size-dependent strengths, which explore a sample size range that has not been accessed by experiments, fit well to a previously proposed universal model that has been obeyed by many published experimental data. To further provide a quantitative representation of the initial microstructure (defects or damages) of MGs, a newly-proposed “connected atomistic free volume” (CAFV) theory is used to analyze the simulation results. The free-volume percolation process is quantitatively determined to confirm an explosive growth of free-volume accompanying the shear band formation. The calculated free-volume evolution during deformation can be directly examined using the existing experimental techniques, suggesting a linkage between the CAFV theory and experiments. These results have demonstrated the model’s capacity of reproducing shear banding and macroscopic stress-strain relationships, starting from the physically abstracted heterogeneity at the STZ scale (~1 nm). The connection between our STZ-level simulations and atomistic simulations can be further strengthened by incorporating MD simulation results on the residual stresses in MGs. The STZ picture may be further generalized to crystalline metals, in which the well-defined slip systems (close-packing crystallography planes) would fix the allowed shear modes for crystalline STZs that behave like dislocations. Within this unified STZ description of plasticity for both amorphous and crystalline metals, it is convenient to study the plasticity of BMG- matrix composites and may provide some insight of the underlying slip transmissions across the glass/crystal interfaces.

Committee:

Yunzhi Wang (Advisor); Stephen Niezgoda (Committee Member); Wolfgang Windl (Committee Member)

Subjects:

Materials Science

Keywords:

Metallic glasses; shear band; free volume; computer simulation; mesoscale

Leuty, Gary MAdsorption and Surface Structure Characteristics Toward Polymeric Bottle-Brush Surfaces via Multiscale Simulation
Doctor of Philosophy, University of Akron, 2014, Polymer Science
For decades, device design has focused on decreasing length scales. In computer and electronic engineering, small feature sizes allow increasing computational power in ever-smaller packages; in medicine, nanoscale in vivo devices and sensors and coatings have myriad applications. These applications all focus strongly on material/component interfaces. While recent advances in experimental techniques probing interfaces at nanometer and sub-nanometer scales have improved dramatically, computational simulation remains vital to obtaining detailed information about structure and energetics in nanometer-scale interactions at interfaces and the physical properties arising from interactions at larger scales. We start with all-atom molecular dynamics simulations of methane and chloromethane adsorption on the (100) surface of molybdenum to understand adsorbate polarity/geometry and substrate interaction potential effects on interfacial structure, packing and energetics. For featureless substrates, adsorbate geometry and orientation do not influence packing and affinity. Substrates with explicit surface structure show cooperation between substrate and adsorbate geometry via adsorption-site preference. Methane prefers sites over unit cell faces, roughly commensurate with the Mo surface, whereas chloromethane invites disorder, orienting its long axis along ”bridges” between surface Mo atoms. In the second phase, we used a coarse-grained bead-spring model to perform simulations of bottle-brush homopolymers tethered to a wall substrate at long time/length scales. We studied the intra- and intermolecular accumulation of tension in tethered bottle-brush backbones vs. bottle-brush dimensions and surface grafting density. Variations in bond force and bottle-brush/component shape and size descriptors uncovered three tension ”regimes”: (i) an isolated-brush regime (low surface grafting density), where intramolecular interactions dominate and tension is minimal; (ii) a ”soft-contact” regime, where neighboring bottlebrushes’ side chains overlap, compressing side chains and transmitting moderate tension to backbones; and (iii) a ”hard-contact” regime, where increased side-chain overlap forces reorientation, accumulating significant backbone tension. We then performed a small number of simulations of tethered bottle-brushes with two different side chain types to illustrate the morphologies available as a result of microphase separation, varying the strength of the interactions between side chain types. Continuing this work in the future should help discover other possible applications arising from varying the chemical nature of the side chains.

Committee:

Mesfin Tsige, Dr. (Advisor); Mark Foster , Dr. (Committee Member); Shi-Qing Wang, Dr. (Committee Member); Gustavo Carri, Dr. (Committee Member); Jutta Luettmer-Strathmann, Dr. (Committee Member)

Subjects:

Condensed Matter Physics; Materials Science; Molecular Physics; Physical Chemistry; Physics; Polymers; Theoretical Physics

Keywords:

Molecular dynamics simulation; bottle-brush polymers; adsorption; computer simulation; coarse-grained bead-spring molecular dynamics; all-atom molecular dynamics; surfaces and interfaces

Wani, Tushar YeshwantComputer simulation of a fiber coating reactor
Master of Science (MS), Ohio University, 1991, Mechanical Engineering (Engineering)
Computer simulation of a fiber coating reactor

Committee:

Khairul Alam (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Computer Simulation; Fiber Coating Reactor

Puneet, VashisthaComputer simulation of hot wall fiber coating CVD reactor
Master of Science (MS), Ohio University, 1991, Mechanical Engineering (Engineering)
Computer simulation of hot wall fiber coating CVD reactor

Committee:

Khairul Alam (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Computer Simulation; Hot Wall Fiber Coating; CVD Reactor

BIDDELL, KEVIN MICHAELCREATION OF A BIOPHYSICAL MODEL OF A STRIATAL DORSAL LATERAL MEDIUM SPINY NEURON INCORPORATING DENDRITIC EXCITATION BY NMDA AND AMPA RECEPTOR MODELS
PhD, University of Cincinnati, 2007, Engineering : Biomedical Engineering
The medium spiny neurons of the ventral medial (VM) and dorsal-lateral (DL) striatum play different roles in the basal ganglia; these differences include NMDA receptor time characteristics and NMDA/AMPA receptor concentration ratio. To facilitate the advancement seen in other areas of computational modeling, a publicly available biophysical model that standardizes in NEURON the research of medium spiny neurons (MSN’s) of the dorsal lateral striatum is necessary. To assess the hypothesis that differences in VM and DL striatal MSN’s can be studied by measuring the individual and cumulative effects of NMDA and AMPA receptors, existing biophysical computational models of medium spiny neurons were translated, expanded, and integrated. Action potentials and individual currents of two model MSN’s were compared with simulated NMDA and AMPA receptors using parameters set at published nucleus accumbens values and values adapted to fit the dorsal lateral striatum. The combined effect of the time characteristics of the NMDA receptor and the NMDA/AMPA receptor ratio affected how the modeled behaved. Overall model excitation increased when NMDA and AMPA receptors were stimulated in distal dendrites compared to proximal excitation. Second, with significant decreases in time constants came an increase in action potential firing synchronicity. The dorsal lateral and ventral medial striatum of the sensory motor and limbic basal ganglia respectively are different, including the time constants, and the role these neuron types play in normal, abnormal and diseased process are independent. In building the model used to test this hypothesis, multiple theories of striatal behavior have been tied together in a comprehendible, consistent, and testable manner. This work now lends itself to generating and testing new hypotheses. The implications of the two hypotheses already generated are also discussed.

Committee:

Dr. Jeffery Johnson (Advisor)

Keywords:

computer simulation,; computational neuroscience,; biopyhsics

Huelskamp, Lisa MaryTHE IMPACT OF PROBLEM-BASED LEARNING WITH COMPUTER SIMULATION ON MIDDLE LEVEL EDUCATORS' INSTRUCTIONAL PRACTICES AND UNDERSTANDING OF THE NATURE OF MIDDLE LEVEL LEARNERS
Doctor of Philosophy, The Ohio State University, 2009, ED Teaching and Learning (Columbus campus)

The need for effective teachers is growing while national and state standards are putting ever-increasing demands on teachers and raising expectations for student achievement. Low science and mathematics standardized test scores, particularly in the middle grades, reflect unprepared adolescents, perhaps because of ineffective teaching strategies which result in fewer students seeking STEM (science, technology, engineering, mathematics) careers.

The researcher examined the use of problem-based learning, or PBL, with computer simulation, an example of which is the National Engineers Week Future City Competition. A model is to investigate the impact of PBL with computer simulation on a generalized use of inquiry-based instruction, use of technology in instruction, integration of science disciplines, and understanding of the nature of middle level learners. Following a review by a panel of experts and a field test, a questionnaire was given to all Ohio teachers who had enrolled and competed in the program on the state level during the 2008-2009 academic year, as well as those teachers competing at the national level.

In addition to demographics and background questions, the teachers were asked to self report on the impact of problem-based learning with computer simulation on frequency of inquiry-based teaching strategies and agreement on technology education,integration of science disciplines, and their understanding of their middle level students. Via sampling of the participants, 15 interviews were conducted after the questionnaire.

Significant areas were found regarding the teachers' Internet access at home and science agreement, number of technology college courses and inquiry frequency, technology professional development and both technology agreement and understanding of middle level learner agreement, past use of problem-based learning with computer simulation and inquiry frequency, gender and inquiry frequency, the teachers' Internet access in the classroom and technology agreement, and, finally, the amount of education and science agreement. High reliability and validity were demonstrated.

Conclusions were drawn to determine the impact on promising instructional practices with inservice teachers and teacher preparation programs, particularly those who teach STEM education. Findings support the proposed model and showed that experience with problem-based learning with computer simulation has a general positive effect on the teachers' instructional patters.

Committee:

David Haury, PhD (Advisor); Karen Zuga, PhD (Committee Member); Robert Hite, PhD (Committee Member)

Subjects:

Science Education

Keywords:

problem-based learning; inquiry; science education; technology education; educational technology; science discipline integration; STEM education; middle level learners; middle school; teacher education; preservice preparation; computer simulation; instruc

Zhou, NingSimulation Study Of Directional Coarsening (Rafting) Of γ' In Single Crystal Ni-Al
Doctor of Philosophy, The Ohio State University, 2008, Materials Science and Engineering

Dislocation propagation in and work hardening of γ channels and directional coarsening (rafting) of γ' precipitates are the major microscopic processes taking place during high temperature deformation of single crystal Ni-base superalloys. Understanding of those processes is crucial for developing improved models of creep and fatigue of turbine blades in aircraft engines. Recent investigations of rafting in superalloys demonstrate clearly the importance of elastic modulus difference between the γ and γ' phases and dislocation-level activities in the γ-channels in determining the kinetic pathway of the processes. The elastic modulus difference can lead to the non-uniform distribution of stresses through the interaction with the lattice misfit and external load. While work hardening in the γ channels has a direct effect on differentiation of the stress state in the vertical and horizontal channels and on γ/γ' interface coherency and energy, and hence influences the diffusive flow and morphological changes of the γ/γ' microstructure. In turn, changes in particle shape and coherency of the interface alter the local stress state and thereby the Peach-Koehler force on dislocations. Although existing models treating these processes separately can offer a qualitative explanation about the direction of rafting for typical superalloys, a complete quantitative understanding of rafting phenomena requires these processes to be treated simultaneously in a common framework because of their intimate coupling.

The objective of this thesis is to develop an integrated computational approach in simulating simultaneous evolution of both γ/γ' microstructure and dislocations in an elastically anisotropic and inhomogeneous system by using a single, consistent phase field methodology. In particular, the phase field dislocation model is used to simulate the initial dislocation γ channel filling process and calculate stress distribution associated with complex three-dimensional (3D) dislocation configurations in the γ-channels. The relative contributions from elastic modulus inhomogeneity and γ-channel plasticity are quantified by the dislocation-level simulations through the analysis of the spatial variation of solute atoms' chemical potential, which show that γ-channel plasticity plays the dominant role in controlling the rafting process (rafting type and kinetics). Micrometer-scale simulations are carried out that takes into account plastic deformation in γ-channels described by local channel dislocation densities from individual active slip systems. The rafting kinetics and the corresponding creep deformation are characterized at different values of applied stress, lattice misfit and precipitate volume fraction. The simulation predictions agree well with experimental observations and the models developed can be utilized in design of new superalloys and optimization of existing ones.

Committee:

Yunzhi Wang, PhD (Committee Chair); Michael Mills, PhD (Committee Member); Suliman Dregia, PhD (Committee Member); Sudhir Sastry, PhD (Committee Member)

Subjects:

Materials Science

Keywords:

Ni-base superalloys; Rafting; Computer simulation; Plastic deformation; Creep

Heikal, Aly SalemSimulation of midblock traffic flow along an arterial with and without a two-way left-turn lane /
Doctor of Philosophy, The Ohio State University, 1983, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Traffic flow;Digital computer simulation;Traffic engineering

Manhire, BrianA new probabilistic simulation technique for multiple energy storage devices for electric utility generation system expansion planning models /
Doctor of Philosophy, The Ohio State University, 1980, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Digital computer simulation;Energy storage

Park, Jin WonSimulation optimization with discrete decision variables and a single linear constraint /
Doctor of Philosophy, The Ohio State University, 1987, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Decision making;Computer simulation;Mathematical optimization

Thompson, Julie AnnThe Biomechanical Effects of Variability in Femoral and Tibial Component Rotational Alignment in TKA using a Simulated Oxford Rig
Master of Science, The Ohio State University, 2009, Mechanical Engineering

The success of total knee arthroplasty (TKA) depends on many factors, but malrotation of the prosthetic components, in particular, is a major cause of patellofemoral complications and can lead to revision surgery. Significant variability can be associated with femoral and tibial component rotational alignment, but how this variability translates into functional outcome remains unknown. The purpose of this thesis was to determine the biomechanical effects of variability in femoral and tibial component rotational alignment in TKA using a forward-dynamic computer model of an Oxford Rig, which simulates flexed-knee stance, such as occurs when riding a bicycle, rising from a chair, or climbing stairs.

To become familiar with the computer modeling environment, we performed a study of hip kinematics in OpenSim, an open-source software package that was developed for the purpose of creating and analyzing musculoskeletal models and dynamic simulations of movement. The simulations commonly use motion capture data as input, but frequently parameters such as the degrees of freedom (DOF) of certain joints is chosen by the user and may not match the same DOF used by the motion-capture software. OpenSim computes kinematics using a least squares approach to minimize the difference between experimental marker location and virtual markers on the model while maintaining joint constraints. We used a simple model, looking only at the motion of the hip, to investigate how marker weights and choice of model degrees of freedom affect kinematics and to compare the simulated kinematics with the same results from a common motion capture analysis technique. We found that high pelvis marker weights and a 6 degree-of-freedom hip model resulted in kinematics that most closely matched the results from motion capture, but large translations of the femoral head were present.

We then used a forward-dynamic model of an Oxford Rig to perform a parametric study on the effects of variations in component rotational alignment in TKA. The femoral component rotational alignment was varied from 15° internal rotation to 15° external rotation in 5° increments and the tibial component rotational alignment was varied from 20° internal rotation to 20° external rotation in 5° increments. The effects of component rotational alignment on knee kinematics, quadriceps muscle force, ligament forces, and contact forces were analyzed for the cruciate-retaining and posterior-substituting versions of the Scorpio implant from Stryker Orthopaedics. We found that femoral component alignment, in general, had a much greater effect on our variables of interest than tibial component alignment or choice of implant design. Internal rotation of the femoral component led to a reversal of the natural screw-home motion of the knee (internal rotation of the tibia with respect to the femur during flexion) as well as high MCL force, quadriceps muscle force, and contact forces between the femoral and tibial components.

Our findings suggest variability in component rotational alignment, especially internal femoral component alignment, may impact post-operative performance and further emphasize the need to accurately establish rotational alignment.

Committee:

Robert Siston, PhD (Advisor); Ajit Chaudhari, PhD (Committee Member)

Subjects:

Engineering; Mechanical Engineering

Keywords:

Total Knee Arthroplasty; Computer Simulation; Alignment

Park, Joon BooComputer simulation of the hammer forging process
Master of Science (MS), Ohio University, 1986, Mechanical Engineering (Engineering)
The A.L.P.I.D. 1.41 (Analysis of Large Plastic Increment Deformation) version based on rigid-viscoplaticity and finite element method has been modified for the simulation of hammer forging. As a theoretical background for this modification, three methodologies have been suggested and among them, energy balance method based on the force exerted on dies has been adopted. Also preprocessor program called 'HMINP' for the easy preparation of the input file to run A.L.P.I.D.H. has been developed and a command file to run A.L.P.I.D.H. has been developed.

Committee:

Jay Gunasekera (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

Analysis of Large Plastic Increment Deformation; Computer Simulation; Hammer Forging Process

Amankwah, KofiTHE IMPACT OF LOWER EXTREMITY PASSIVE JOINT PROPERTIES ON STANDING FUNCTION
Doctor of Philosophy, Case Western Reserve University, 2004, Biomedical Engineering
The impact of passive elastic and viscous joint properties during functional electrical stimulation (FES) standing was investigated with a musculoskeletal model of the human body adapted for spinal cord injury (SCI). Initially passive joint properties were measured from individuals with and without SCI to determine whether any differences existed. Then a mathematical model was developed to describe the passive joint moments and was integrated into the musculoskeletal model. Static computer simulations were performed with the musculoskeletal model to determine the impact that passive joint property changes had on the muscle effort required to stand. Dynamic computer simulations were also performed to understand the impact that passive property changes had on postural stability during a disturbance. The passive moment measurements showed that the passive moments at every joint except the knee were significantly higher in the subjects with SCI. The 11 static simulation results revealed that an increase in joint stiffness can increase or decrease the required energy during stance depending upon the location of the center of mass (COM) within the workspace. From the dynamic simulations, it was concluded that increases in joint stiffness and viscosity do aid individuals in their ability to resist external disturbances. Through this better understanding of passive properties, methods to exploit them to reduce muscle effort and increase stability can be found and improved musculoskeletal models can be built to develop improved FES control systems.

Committee:

Ronald Triolo (Advisor)

Keywords:

Passive Properties; Stiffness; Viscosity; Musculoskeletal modeling; Nonlinear modeling; Spinal cord injury; Biomechanics; Computer simulation

McNemar, Robert EdwinUse of microcomputer simulations of science activities to study the relationship between sequencing and nature of learning activities and concept development /
Doctor of Philosophy, The Ohio State University, 1985, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Sequency theory;Concepts;Science;Computer simulation

Ceranowicz, Andrew ZbigniewPlanar biped dynamics and control /
Doctor of Philosophy, The Ohio State University, 1979, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Computer simulation;Human locomotion

Hughes, William RodneyA study of the use of computer simulated experiments in the physics classroom /
Doctor of Philosophy, The Ohio State University, 1973, Graduate School

Committee:

Not Provided (Other)

Subjects:

Education

Keywords:

Physics;Physics;Digital computer simulation

Pigott, Jeffrey ScottExploration of Earth's Deep Interior by Merging Nanotechnology, Diamond-Anvil Cell Experiments, and Computational Crystal Chemistry
Doctor of Philosophy, The Ohio State University, 2015, Geological Sciences
The structure, dynamics, and composition of Earth’s deep interior have direct control on plate tectonics and surface-to-interior exchange of material, including water and carbon. To properly interpret geophysical data of the Earth’s interior, accurate and precise measurements of the material properties of the constituent mineral phases are required. Additionally, experimentally derived data need to be augmented by computational chemistry and modeling of physical properties to elucidate the effect of compositional variations and deep storage of volatile components (e.g. H2O and CO2) within the crystalline phases. This dissertation uses in situ high pressure, high-temperature experiments in the laser-heated diamond anvil cell (LHDAC) coupled with synchrotron-based x-ray diffraction. The thermal expansion and bulk modulus of Ni and SiO2 are measured to P = ~110 GPa and T = ~3000 K. Nickel is a significant component of the Earth’s core and SiO2 is the fundamental building block of the Earth’s mantle and crust. We have designed the first controlled-geometry samples of Ni and SiO2, manufactured using nanofabrication techniques, and specifically tuned to reduce systematic errors in the measurement. Knowledge of the thermoelastic properties of Ni and SiO2 has implications for subduction rates, plume buoyancy, dynamics of the Earth’s convective heat engine, and planetary formation. Complimentary to the Ni/SiO2 experiments, the energetics of different hydrogen defect mechanisms in garnet (MgSiO3-Mg3Al2Si3O12) and associated geophysical properties (P- and S-wave velocities) are calculated using atomistic simulations and first-principles calculations to a depth of 700 km. Garnet accounts for as much as 40 percent of the rock volume at 500 km. By calculating and comparing the defect energies associated with charge-balanced substitutions of hydrogen for magnesium or silicon, the hydrogarnet defect has the lowest energy and is therefore predicted to be the most favorable in the garnet structure. The fundamental question of the planet’s water budget has implications for the formation history of the planet and the cycling of volatile compounds between the surface and the interior.

Committee:

Wendy Panero (Advisor); Berry Lyons (Committee Member); Michael Barton (Committee Member); David Cole (Committee Member)

Subjects:

Earth; Geological

Keywords:

X-ray Diffraction, Focused Ion Beam, Nanofabrication, Diamond-Anvil Cell, High Pressure, Equation of State, Nickel, Stishovite, Hydrous Majorite, Defect Mechanisms, Force Field, Computer Simulation, Density Functional Theory

Yamazaki, KasumiLearning to Communicate in a Virtual World: The Case of a JFL Classroom
Doctor of Philosophy, University of Toledo, 2015, Curriculum and Instruction
The proliferation of online simulation games across the globe in many different languages offers Computer Assisted Language Learning (CALL) researchers an opportunity to examine how language learning occurs in such virtual environments. While there has recently been an increase in the number of exploratory studies involving learning experiences of predominantly English as a Second or Foreign Language (ESL/EFL) participants in these environments, the context of a Japanese as a Foreign Language (JFL) classrooms has rarely been examined. To address this, this study investigates a Second Language Acquisition-theory driven instantiation of CALL within the context of a JFL classroom. Through a mixed-method case study approach, participants' natural acquisition of Japanese in a 3D virtual environment was examined. Data detailing participants' communicative capacities in several modalities were collected, as were their attitudes toward participation in a massively multiplayer online (MMO)-based virtual world of Tokyo. In the present study, eight sources of data from eleven university-level JFL students (n=11) were collected and analyzed to evaluate the learning outcomes from an integrative CALL framework (Warschauer, 2004; Yamazaki, 2014). Based on both interpretative and statistical analyses of data, the major finding of the present study was that the participants, when immersed in the 3D virtual world of Tokyo, acquired contextualized communicative competence. More specifically, quantitative analyses revealed statistically significant improvement in the participants' acquisition of incidentally encountered vocabulary, in particular, kanji pronunciation and vocabulary interpretation. Qualitative analyses revealed participants' acquisition of various communicative competencies specific to the context, including persuasive talk, concept of audience, collaborative communication, and colloquial expressions. Data from a post-hoc reflection survey provided strong evidence that most students found the course to be effective, as it made them use Japanese more than in a regular class, and thereby developed more necessary communicative skills to function in Japan.

Committee:

Susanna Hapgood (Committee Chair); Leigh Chiarelott (Committee Member); Douglas Coleman (Committee Member); Florian Feucht (Committee Member)

Subjects:

Curricula; Curriculum Development; Educational Technology; Instructional Design; Language

Keywords:

CALL; computer assisted language learning; virtual world; JFL; Japanese as a Foreign Language; computer simulation; digital gaming; computer mediated communication; CMC; SLA; interaction; computer games; MMO

Zhang, ShuoAnalysis of Phase Transitions and Crystal Structures of Novel Benzothiophene Derivatives
Doctor of Philosophy, University of Akron, 2015, Polymer Science
Although single crystal X-ray diffraction remains the most important technique for analyzing periodically ordered structures at atomic resolution, single crystal X-ray diffraction of organic macromolecules is challenged by difficulty in growing single crystals of desired size and quality. Electron crystallography of organic macromolecules, on the other hand, is limited by image resolution due to radiation damage and highly dependent on high-resolution instrumentation. Novel alkylated benzothiophene derivatives synthesized previously can be readily fabricated into semiconductor devices for various applications (photodetectors, explosive sensors, field-effect transistors, light-emitting diodes, etc.) via solution process. The object of this research is to identify phase transitions of organic macromolecules of this kind via differential scanning calorimetry and temperature-resolved wide angle X-ray diffraction, and to determine their lattice parameters and space groups by reconstruction of their reciprocal space via transmission electron microscopy / selected area electron diffraction followed by refinement with X-ray diffraction, supplemented by polarized light microscopy. Computer simulation was performed to rationalize the molecular packing schemes, so as to understand the origin of their electronic performance from crystallographic perspective.

Committee:

Stephen Z. D. Cheng, Dr. (Advisor); Yu Zhu, Dr. (Committee Chair); Toshikazu Miyoshi, Dr. (Committee Member); Tianbo Liu, Dr. (Committee Member); Xiong Gong, Dr. (Committee Member)

Subjects:

Chemistry; Condensed Matter Physics; Materials Science; Organic Chemistry; Physical Chemistry; Physics; Polymers; Solid State Physics

Keywords:

phase transition; crystal structure; thermal analysis; electron diffraction; X-ray diffraction; organic electronics; OFETs; benzothiophene; computer simulation

Lemke, Sean PaulBiomechanical Effects of Component Alignment Variability in Total Knee Arthroplasty: A Computer Simulation Study of an Oxford Rig
Master of Science, The Ohio State University, 2012, Mechanical Engineering

Success in total knee arthroplasty (TKA) depends on several factors including the patient’s pre-operative condition, sex, and proper post-operative rehabilitation, but perhaps the most crucial factor is proper component alignment. Alignment of the femoral and tibial components in TKA is highly variable due to difficulty in identifying anatomical landmarks and debate on how the components should be aligned. The purpose of this thesis was to examine the biomechanical effects of the variability in femoral and tibial component alignment in the three anatomical planes. This was done using a forward-dynamic computer model of an Oxford Rig device with a cruciate-retaining version of the Scorpio implant from Stryker Orthopaedics digitally implanted. The Oxford Rig has 6 degrees of freedom at the knee and simulates flexed knee stance, which is similar to what occurs during functional activities such as riding a bicycle or climbing stairs.

In order to examine the relationship between femoral and tibial component alignment and knee biomechanics, we ran three rounds of simulations: changing the alignment of one component in one plane, changing alignment of both components in one plane, and changing the alignment of one component in multiple planes. The effects of component alignment were examined on patellofemoral kinematics and contact force, tibiofemoral kinematics and contact force, ligament forces, and quadriceps force. The alignment of the femoral component in the transverse plane had the greatest effect on a majority of the variables of interest including patellofemoral and tibiofemoral kinematics, contact forces, and MCL force. Frontal plane alignment of the femoral and tibial component impacts the forces in both collateral ligaments in early flexion. Sagittal plane alignment of the tibial component has the greatest effect on the PCL. Alignment of the femoral component in the sagittal plane has the greatest effect on quadriceps force.

The results of the simulations were used to develop mathematical models that can be used to describe effects of changing component alignment at a given knee flexion angle. In order to develop these equations, best fit polynomials were found for the curves of the variable of interest with respect to knee flexion angle. The polynomial coefficients were then regressed against component alignments. These mathematical models were developed to make the information found using the Oxford Rig simulation more accessible.

Our findings suggest that variability in component alignment, especially transverse plane alignment of the femoral component and frontal plane alignment of both components, can impact post-operative performance. This thesis highlights the importance for properly establishing the rotational alignment of the femoral and tibial components in TKA.

Committee:

Robert A. Siston, PhD (Advisor); Ajit M.W. Chaudhari, PhD (Committee Member); Matthew D. Beal, MD (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

orthopedics; total knee arthroplasty; TKA; computer simulation

Wang, ShihuComputer Simulation and Mathematical Modeling of Reversibly Associated Polymers
Doctor of Philosophy, Case Western Reserve University, 2010, Macromolecular Science and Engineering
Reversible and specific interactions have been employed extensively for the preparation of smart materials and biomaterials. Using computer simulation and mathematical modeling, we studied the equilibrium properties of different polymeric systems that utilize these interactions, including metal-ligand and ligand-receptor interactions. The equilibrium properties of metallo-supramolecular micelles formed by core- and corona- blocks connected via 2:1 ligand-metal complexes were studied by analyzing the competition of 2:1 and 1:1 metal-ligand complexation in the bulk and on the core surface as well as steric interactions between neighboring corona blocks attached to the surface. We found that increasing association energy for the second metal-ligand bond or decreasing corona block length can enhance the micelle core surface coverage. 3:1 ligand-metal complexation leads to the self-assembly of linear end-functionalized oligomers in solution and formation of a metallo-supramolecular network in a limited range of metal-to-oligomer ratios and at a sufficiently large oligomer concentration. We studied the conditions of network formation and investigated the properties of metallo-supramolecular networks, such as elastic plateau modulus, mesh-size and molecular weight between effective crosslinks. The obtained results were in qualitative agreement with experimental data. We showed that cis-trans isomerization of 2:1 ligand-metal complexes being in equilibrium with 3:1 ligand-metal complexes significantly affects self-assembly and network formation of metallo-supramolecular polymers. We predicted conditions when trans-cis isomerization can trigger sol-network transition and cause a significant change in materials properties. The molecular mechanisms of network transformation upon cis-trans isomerization were discussed. Ligand-receptor interactions have been employed to enhance the targeting efficiency of nanoparticles. We systematically studied the influence of different design parameters of a spherical nanoparticle tethered with monovalent ligands on its targeting efficiency to planar cell surfaces containing mobile receptors. Predictions were made regarding the preferable nanoparticle design to achieve high affinity of a nanoparticle to cell surface. We also discussed the selectivity of nanoparticle targeting to cells with a high receptor density and made recommendations for the desirable nanoparticle design to improve targeting selectivity.

Committee:

Elena E. Dormidontova, PhD (Advisor); Ica Manas-Zloczower, PhD (Committee Member); Alexander M. Jamieson, PhD (Committee Member); Philip L. Taylor, PhD (Committee Member)

Subjects:

Biomedical Research; Biophysics; Engineering; Materials Science; Physics; Polymers

Keywords:

Computer Simulation; Monte Carlo; Bond Fluctuation Model; Metal-Ligand Interaction; Metallo-Supramolecular Micelles; Metallo-Supramolecular Gels; cis-trans Isomerization; Ligand-Receptor Interaction; Nanoparticle Targeting; Targeting Efficiency

Kwak, Se-HungA computer simulation study of a free gait motion coordination algorithm for rough-terrain locomotion by a hexapod walking machine /
Doctor of Philosophy, The Ohio State University, 1986, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Robots;Locomotion;Computer simulation

Koenig, David M.OSUSIM : a modular approach to dynamic simulation /
Doctor of Philosophy, The Ohio State University, 1972, Graduate School

Committee:

Not Provided (Other)

Subjects:

Engineering

Keywords:

Digital computer simulation;Mathematical models;O S U I S M

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