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Wroblewski, Adam C.Model Identification, Updating, and Validation of an Active Magnetic Bearing High-Speed Machining Spindle for Precision Machining Operation
Doctor of Engineering, Cleveland State University, 2011, Fenn College of Engineering
High-Speed Machining (HSM) spindles equipped with Active Magnetic Bearings (AMBs) are envisioned to be capable of autonomous self-identification and performance self-optimization for stable high-speed and high quality machining operation. High-speed machining requires carefully selected parameters for reliable and optimal machining performance. For this reason, the accuracy of the spindle model in terms of physical and dynamic properties is essential to substantiate confidence in its predictive aptitude for subsequent analyses. This dissertation addresses system identification, open-loop model development and updating, and closed-loop model validation. System identification was performed in situ utilizing the existing AMB hardware. A simplified, nominal open-loop rotor model was developed based on available geometrical and material information. The nominal rotor model demonstrated poor correlation when compared with open-loop system identification data. Since considerable model error was realized, the nominal rotor model was corrected by employing optimization methodology to minimize the error of resonance and antiresonance frequencies between the modeled and experimental data. Validity of the updated open-loop model was demonstrated through successful implementation of a MIMO µ-controller. Since the µ-controller is generated based on the spindle model, robust levitation of the real machining spindle is achieved only when the model is of high fidelity. Spindle performance characterization was carried out at the tool location through evaluations of the dynamic stiffness as well as orbits at various rotational speeds. Updated model simulations exhibited high fidelity correspondence to experimental data confirming the predictive aptitude of the updated model. Further, a case study is presented which illustrates the improved performance of the µ-controller when designed with lower uncertainty of the model’s accuracy.

Committee:

Jerzy T. Sawicki, PhD (Advisor); Stephen F. Duffy, PhD (Committee Member); James A. Lock, PhD (Committee Member); Taysir H. Nayfeh, PhD (Committee Member); Ana V. Stankovic, PhD (Committee Member)

Subjects:

Electromagnetism; Engineering; Industrial Engineering; Mechanical Engineering

Keywords:

rotordynamics; modeling; spindle; high speed; active magnetic bearing; AMB; machining; high speed machining; system identification; open loop model; model updating; optimization; robust control; mu-synthesis; mu-control;

Stovboun, AlexeiA tool for creating high-speed, memory efficient derivative codes for large scale applications
Master of Science (MS), Ohio University, 2000, Electrical Engineering & Computer Science (Engineering and Technology)

A tool for creating high-speed, memory efficient derivative codes for large scale applications

Committee:

David Juedes (Advisor)

Keywords:

high-speed codes; derivative codes; memory efficiency; large scale applications

Windholtz, Timothy NolanPlane-Strain Formability of Sheet Metal at High Velocity
Master of Science, The Ohio State University, 2012, Materials Science and Engineering
Electromagnetic forming via die impact has shown results beyond normal forming limits but there is little experimental research presenting the potential of kinetic type presses. This thesis introduces a suite of sheet metal forming methods to assess forming velocity’s affect on plane-strain formability using ten different materials within three different categories of sample dimensions. In addition to strain rate effects from each technique, lubricant is varied on self-similar forming dies to investigate impact geometry and frictional conditions. Three very different ‘press’ types are used to apply a large uniform pressure over flat sheet materials into a single sided die that is accompanied by no draw-in of the material. These presses include a traditional quasi-static press, QS; an electromagnetically driven high speed press, HSP; an electromagnetically driven uniform pressure actuator, UPA; and an electromagnetically exploded foil, EF. Experimental energy requirements for electromagnetic forming, EMF, limits are reported along with characterization of the HSP peak current and velocity through the use of a Photon-Doppler Velocimeter, PDV. Cross-sectional photographs and thickness strain measurements are presented to see the strain rate effects on the samples. The resulting methodologies allow for predictions of shearing conditions and forming limits of nominally flat grooved structures.

Committee:

Glenn Daehn, PhD (Advisor); Peter Anderson, PhD (Committee Member)

Subjects:

Materials Science

Keywords:

electromagnetically high speed press, HSP; electromagnetically uniform pressure actuator, UPA; electromagnetically exploded foil, EF; Photon-Doppler Velocimeter, PDV

Leque, NicholasDevelopment of an Experimental Methodology for Evaluation of Gear Contact Fatigue under High-Power and High-Temperature Conditions
Master of Science, The Ohio State University, 2011, Mechanical Engineering
Contact fatigue failures in the form of pitting or micro-pitting have been a perennial problem in power transmission applications. These failures are dictated by a large number of parameters including loading conditions, gear geometry and tooth modifications, kinematics (rolling and sliding velocities), lubricant parameters (viscosity, pressure-viscosity behavior), and material parameters (material type, hardness, case depth, residual stresses). As such, theoretical treatment of contact fatigue failures has been rather challenging, directing the focus to the experimental investigation of the problem. Most of the experimental gear pitting studies to date were limited to low-speed and low-temperature operating conditions. This study aims at developing a methodology for evaluating the contact fatigue lives of gears under high-speed (pitch-line velocities up to 50 m/s), high-stress (contact stresses up to 2 GPa) and high-temperature (oil inlet temperatures up to 150C). Specifications of a test machine concept that meets these requirements are defined and two test machines are designed and procured for this purpose. Gear test specimens that result in pits consistently are developed with the other competing failures (wear, scuffing, tooth breakage), as well as the high vibration conditions, avoided. Preliminary high-speed tests are presented at the end, representing both automotive and aerospace conditions to show that pitting and micro-pitting failures can be produced with the proposed methodology.

Committee:

Ahmet Kahraman, PhD (Advisor); Carlos Castro, PhD (Committee Member)

Subjects:

Engineering; Mechanical Engineering

Keywords:

Gears; fatigue life; pitting; micro-pitting; high-speed; high-temperature; aerospace; automotive

Milligan, Ryan TimothyDUAL MODE SCRAMJET: A COMPUTATIONAL INVESTIGATION ON COMBUSTOR DESIGN AND OPERATION
Master of Science in Engineering (MSEgr), Wright State University, 2009, Mechanical Engineering
Numerical analysis was performed on a Dual-Mode Scramjet isolator-combustor. Preliminary analysis was performed to form a baseline geometry. Another study validated the results of a 2D model compared to a 3D model. Stable combustion was shown at two different flight conditions, M=3.0 and M=2.5. A marginal 5% decrease in stream thrust was shown by introducing a 50/50 mix of methane and ethylene. Based on the results of the preliminary analysis, detailed geometry analysis was performed on the 3D baseline geometry. Adding a new set of cavity feeding injectors increased the overall stream thrust and the equivalence ratio in the cavity. Using less fuel than the baseline configuration, revealed a 6.4% increase in stream thrust and an 11% increase in combustion efficiency by placing the second stage injector further upstream. Future analysis includes combining the cavity feeding with closer injector placement, which is expected to yield even better results.

Committee:

J. Mitch Wolff, PhD (Advisor); J. Mitch Wolff, PhD (Committee Co-Chair); Dean Eklund, PhD (Committee Co-Chair); Chung-Jen Tam, PhD (Committee Member)

Subjects:

Chemical Engineering; Chemistry; Design; Engineering; Fluid Dynamics; Mechanical Engineering; Physics

Keywords:

dual mode combustion; scramjet combustion; high speed chemical kinetics; dual mode; combustion

Subramonian, SoumyaImprovement of Punch and Die Life and Part Quality in Blanking of Miniature Parts
Doctor of Philosophy, The Ohio State University, 2013, Mechanical Engineering
Blanking or piercing is one of the most commonly used sheet metal manufacturing processes in the industry. Having a good understanding of the fundamentals and science behind this high deformation shearing process can help to improve the tool life and blanked edge quality in various ways. Finite Element Modeling of the blanking process along with experimental testing is used in this study to study the influence of various process parameters on punch and die life and blanked edge quality. In high volume blanking and blanking of high strength materials, improving the tool life can save not only tool material but also change over time which can take up to a few hours for every change over. The interaction between punch, stripper plate and sheet material is first studied experimentally since a fundamental understanding of the behavior of these components at different blanking speeds is very essential to design robust tooling for high speeds. A methodology is developed using the experimentally obtained blanking load and FEM of blanking to obtain flow stress data of the sheet material at high strains and strain rates. This flow stress data is used to investigate the effects of various process parameters on tool stress and blanked edge quality. The influence of all these parameters on tool stress, blanking load and blanked edge quality are studied. Some factors are found to influence the tool stress and blanked edge quality more than others. Parameters like punch-die clearance, punch corner radius, application of stripper pressure and blanking velocity affect the blanked edge quality. As punches and dies wear, the punch-die clearance and punch corner radius increase, causing the blanked edge quality to deteriorate by increasing the rollover and burr. Punch-die clearance along with other factors like lubrication conditions, sheet material, tool material and coating also affects the rate of tool wear. The punch tip geometry significantly affects the blanking load. For a given sheet material, tool material and punch geometry, can selecting the right punch-die clearance minimize punch wear? Since small radii in the punch geometry wear or chip earlier and more often than the straight edges, there is also non-uniform wear pattern observed in the punch due to the non-uniform stress on the punch. The effect of punch geometry on punch wear is studied by conducting FE simulations of blanking and correlating the punch stress obtained from FEM and punch wear obtained via experiments. The effect of sheet material and thickness on punch stress is also studied. In addition, the effect of punch-die clearance for different geometries is investigated. After having a good understanding of the relation between punch geometry and punch wear for different sheet materials, a guideline for selecting the most suitable punch-die clearance for a given punch geometry to have more uniform wear on the punch is suggested. The performance of geometry dependent variable punch-die clearance and commonly used uniform punch-die clearance is compared by conducting blanking experiments and comparing the wear patterns for both cases. It was observed that the tooling with variable punch-die clearance could punch almost three times more parts (350,000 parts) with significantly less but more uniform wear on them than the tooling with uniform clearance (126,000 parts). Methods to improve part edge quality by using the optimum stripper pressure and to improve tool life using geometry-dependent variable punch-die clearance are suggested in this study.

Committee:

Taylan Altan, Dr. (Advisor); Blaine Lilly, Dr. (Advisor); Gary Kinzel, Dr. (Committee Member); Jerald Brevick, Dr. (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

High Speed Blanking; Punch; Die Life

Hosseininejad, JustinDesign and Implementation of a Custom Force Pole Assembly for the Measurement of Primate Locomotor Kinetics
Master of Science in Engineering, Youngstown State University, 2013, Department of Electrical and Computer Engineering
The purpose of this research is to design and implement a custom force transducer assembly for the measurement of primate locomotor kinetics. The measurement system incorporates various strain gauges, accelerometers, high-speed video cameras, and a data acquisition system to generate quantitative stability measurements during primate locomotion. The tasks for this research include: (1) designing and constructing Wheatstone bridge circuitry to read outputs from the constructed force transducers, (2) calibrating and verifying force transducer outputs, (3) constructing a compliant force pole base to simulate tree branch mobility, and (4) constructing, wiring, and testing of accelerometers to independently measure force pole movement during animal locomotion on the compliant substrate. This system is used to gather locomotor kinetics of squirrel monkeys (Saimiri boliviensis), common marmosets (Callithrix jacchus), long-tailed macaques (Macaca fascicularis), and pig-tailed macaques (Macaca nemestrina). The transducer assembly is applied in two experimental contexts: (1) animals moving over static force poles and (2) animals moving over force poles mounted on a compliant base to simulate tree branch mobility. The design surpasses other similar testing structures through the use of accelerometers to independently measure relative movement and acceleration on compliant substrates. Most importantly, the system allows for adaptation and scalability required for application in other species, such as reptiles and other mammals. Data gathered from this system can be applied to impaired mobility studies in disabled individuals and elderly people.

Committee:

Jalal Jalali, PhD (Advisor); Jesse Young, PhD (Committee Member); Faramarz Mossayebi, PhD (Committee Member)

Subjects:

Biomechanics; Electrical Engineering; Engineering

Keywords:

force transducer; Wheatstone bridge; accelerometer; strain gauge; high-speed video camera; data acquisition system; DAQ; primate locomotor kinetics; arboreal stability; biomechanics

Liu, KaiyiCharacterization and Control of an Electrospinning Process
Doctor of Philosophy, University of Akron, 2013, Polymer Science
Optical observations of jets provide information useful for control of electrospinning of polymer solutions. Combinations of videography, stereography, and methods for illumination of the multiple coils of an electrospinning jet path, that depend on bright glints of reflected light from the jet, recorded quantitative information about the location and vector velocity of selected segments of the jet. New bending coils were observed to form at rates of 200-1560 turns per second. This bending frequency decreased as the capillary number of the solutions increased. The motion of mergence of coils of a jet was discovered and characterized. This characterization, combined with bending frequency, provides information for control of parameters in fiber collection in nonwoven products. The polarization of light, in glints reflected at Brewster's angle, allows measurement of the index of refraction of the fluid jet, in flight. Birefringence of a coiled charged jet was observed for the first time, providing information about the extension and order of molecular chains in a jet. Asymmetric illumination of an electrospinning jet made both the handedness and changes in handedness of the electrical bending coils apparent to visual observation and in 2-dimensional images. Other reliable methods for handedness characterization of a coiled jet were also established and introduced. Evidence was found, in the form of polarized ribbon-like glint traces, for the occurrence of undulations on the surface of some jets. New strategies were established for external initiation of multiple electrospinning jets at lower voltages than usual without the formation of a Taylor cone.

Committee:

Darrell H. Reneker, Dr. (Advisor); Shi-Qing Wang, Dr. (Committee Chair); Gary R. Hamed, Dr. (Committee Member); Stephen Z.D. Cheng, Dr. (Committee Member); George G. Chase, Dr. (Committee Member)

Subjects:

Materials Science; Nanotechnology; Polymers

Keywords:

electrospinning; polymer liquid jet; illumination; high speed video; stereo pictures; bending frequency; handedness; coil mergence; Brewster's angle; polarized glint; glint trace; birefringence; multiple jet; Taylor cone; external initiation; jet motion

Cronin, Joseph M.Exploring Capabilities of Electrical Capacitance Tomography Sensor & Velocity Analysis of Two-Phase R-134a Flow Through a Sudden Expansion
Master of Science (M.S.), University of Dayton, 2017, Mechanical Engineering
Future high-performance aircraft will require advances in the understanding of two-phase heat transfer in order to manage the ever-increasing airframe and engine heat loads. Two-phase liquid-vapor refrigerant systems are one solution for the heat removal from these systems. However, they require more study before implementation. This study examines the velocities of two-phase liquid-vapor flows with the use of high speed visualization. In flow channels where high speed visualization cannot be used, there are other noninvasive techniques for analyzing flow the flow, such as electrical capacitance tomography (ECT). In this thesis, capabilities of ECT sensors such as the location in the sensor where there is a detected change in permittivity as well as the sensor’s ability of determining simple surfaces are explored to assist in future work. Four sensors were tested and static experiments were able to determine location along the length of the sensor where a change in permittivity was detected. Each sensor tested showed a detection of permittivity at a different location than expected when comparing with the physical location of the electrodes according to the dimensional drawings of the sensors. Experiments testing the sensor’s ability to detect a surface showed that with a welldefined surface there was a noticeable change when the surface was rotated to different orientations. In fluid flow tests, high speed video analysis showed the velocities of 71 tracked points at varying level of qualities. These velocities were analyzed and the data from these experiments were compared with pressure drop correlations.

Committee:

Jamie Ervin, Ph.D. (Committee Chair); Vinod Jain, Ph.D. (Committee Member); Larry Byrd, Ph.D. (Committee Member); Robert Wilkens, Ph.D., P.E. (Other); Eddy Rojas, Ph.D., M.A., P.E. (Other)

Subjects:

Mechanical Engineering

Keywords:

two-phase flow; high speed video analysis; electrical capacitance tomography; sudden expansion; velocity analysis; R-134a

Cole, David S.Arrival: New York Pennsylvania Station
MARCH, University of Cincinnati, 2014, Design, Architecture, Art and Planning: Architecture

As the consequences of automobile dependency have become increasingly apparent, national discourse has shifted toward rebuilding America’s once-famed passenger rail infrastructure and creating a national network of high-speed rail lines as well as improvements to existing commuter and regional rail services. In order for New York to retain its role as a leader in the global economy and harness the potential of high-speed rail, it must create a viable facility to serve as a gateway to the city and as a hub for multiple modes of transit. New York Penn Station, as it stands today, is woefully inadequate for that purpose.

This thesis project examines the possibility of creating a new and expanded Penn Station as a gateway to New York, while improving its connections to other transit modes and the surrounding context. The project proposes expanding the station structure one block to the south, and replacing its labyrinthine network of confusing passageways with an open, light-filled structure with simplified circulation patterns that provide for an appropriate sense of arrival in New York.

The outcomes of the research include historical research and an examination of the facility’s present-day uses in the form of a written document, as well as precedent research on other facilities that have undergone similar transformations. The design proposal consists of diagrams, drawings, and renderings. Together, these demonstrate the viability and potential rewards of rebuilding Penn Station as a gateway to the city and a hub of activity in West Midtown.

Committee:

Udo Greinacher, M.Arch. (Committee Chair); John Eliot Hancock, M.Arch. (Committee Member)

Subjects:

Architecture

Keywords:

New York; Penn Station; High-Speed Rail; Transit; Transportation; Phenomenoogy

Stolze-Rybczynski, Jessica L.Biomechanics of spore discharge in the Basidiomycota
Doctor of Philosophy, Miami University, 2009, Botany
The Basidiomycota are a group of morphologically diverse fungi. One characteristic that sets these fungi apart from the rest of the kingdom is the production of actively launched basidiospores called ballistospores. The ballistospore discharge mechanism is a process powered by the rapid movement of a drop of fluid, called Buller’s drop, over the spore surface. Using biochemical techniques and mathematical modeling, this dissertation presents results from experiments that were designed to investigate how the discharge mechanism has been adapted in these diverse fungi. This is the first known comprehensive study to capture and model spore discharge in Basidiomycota using high speed video. Small particles are subject to viscous drag when in flight that greatly affects their trajectory. Using Stokes’ law to model spore flight, we were able to estimate spore trajectory. The video data and estimates of energy usage during spore discharge reveal how the mechanism has been adapted to limit discharge distance in species with gilled and poroid fruiting bodies, and to maximize range in basidiomycetes that produce ballistospores on exposed surfaces. The limited discharge distance in mushroom-forming fungi may have evolved to prevent spores from being wasted by impaction on closely opposing surfaces (i.e., gills, tubes). In contrast, the farther range reached by fungi with exposed surfaces, allows the spores to be shot beyond the boundary layer of still air in which they develop. The 6-carbon sugar alcohol, D-mannitol, was the dominant hygroscopic compound found in Buller’s drops across a range of species (from mushroom-forming fungi to basidiomycete yeasts) which indicates that it is conserved among species. This compound is involved in the formation of the Buller’s drop, and therefore, a potentially necessary component of the discharge mechanism. Discharge distance is determined by both spore size and the size of Buller’s drop. The size of Buller’s drop is controlled by spore shape, which means that seemingly minor changes in spore morphology exert major effects upon discharge distance. Based on these observations, we hypothesize that evolutionary modifications to fruiting body architecture, including changes in gill separation and tube diameter, may be tightly linked to alterations in spore morphology.

Committee:

Nicholas Money, PhD (Advisor); M. H. Hank Stevens, PhD (Committee Member); Daniel Gladish, PhD (Committee Member); Qingshun Quinn Li, PhD (Committee Member); Michael Crowder, PhD (Committee Member)

Subjects:

Cellular Biology

Keywords:

ballistospore discharge; high speed video; modeling spore trajectory

Mehta, Urmish R.Optimal control of a high speed overhead crane including hoisting
Master of Science (MS), Ohio University, 1992, Mechanical Engineering (Engineering)

In this thesis we derive a dynamical nonlinear model of the two dimensional crane including hoisting. We study the behavior of the load displacement during the hoisting operation. When the load is disturbed from its equilibrium position during hoisting it swings about the origin. This condition is considered hazardous in the industry. In this thesis a control is derived for a crane such that it can dampen out this oscillation as quickly as possible. The optimal control theory is applied to formulate the control law. This control is simulated on the crane model. The results show that a crane can be transfered to a desired place in such a way that at the end of transfer the swing of the load decays in the minimum time.

Committee:

Brian Fabien (Advisor)

Subjects:

Engineering, Mechanical

Keywords:

optimal control; high speed overhead crane; hoisting; equilibrium position; crane model

Waddell, Daniel C.Environmentally friendly synthesis using high speed ball milling
PhD, University of Cincinnati, 2012, Arts and Sciences: Chemistry
Recently, there has been a focused effort towards the development of an environmentally friendly America. The field of green chemistry has been born of this ideology. Green chemistry is the reduction or elimination of environmentally hazardous chemicals and chemical processes. The Mack lab attempts to reduce some of these hazards by synthesizing molecules with a solvent free and environmentally benign method known as high speed ball milling (HSBM). In HSBM, reactants are shaken vigorously in a reaction vial and the subsequent mixing and impacts generated deliver enough energy to the system to facilitate a chemical reaction. Here, we present the succesful incorporation of HSBM into organic synthesis. Acid/base chemistry, the Tischenko reaction, and enolate chemistry will be described in detail. As we increase our knowledge about the solvent free method of HSBM, we are creating a unique and environmentally friendly toolbox for organic chemists which will cause a paradigm shift in the way we conduct organic reactions.

Committee:

James Mack, PhD (Committee Chair); Michael Baldwin, PhD (Committee Member); Anna Gudmundsdottir, PhD (Committee Member)

Subjects:

Chemistry

Keywords:

Green Chemistry;High Speed Ball Milling;Mechanochemistry;;;;

Zhang, DuoDYNAMIC CMOS MIMO CIRCUITS WITH FEEDBACK INVERTER LOOP AND PULL-DOWN BRIDGE
Master of Science in Engineering (MSEgr), Wright State University, 2013, Electrical Engineering
Two novel techniques, feedback inverter loop and pull-down bridge, adopted for multiple-input multiple-output (MIMO) dynamic CMOS circuits have been proposed in this thesis. The pull-down bridge technique optimizes the area and power of a single stage MIMO dynamic CMOS circuits, and the feedback inverter loop (FIL) technique improves the speed of multiple-stage dynamic CMOS circuits. Applying the pull-down bridge to the MIMO dynamic CMOS seven segment decoder, it is shown that common paths of different outputs are shared and optimized, which accounts for 12% speed improvement, 48% power reduction, and 73% area saving, as compared to the conventional logic design. Next, an optimized 64-bit binary comparator implemented by mixed-static-dynamic CMOS with FILs is presented. After partitioning the conventional dynamic CMOS into a mixed-static-dynamic CMOS, optimizing transistor sizes and using the FILs on the critical paths, the proposed design achieves 60% speed improvement and 42% power reduction, as compared to the conventional 64-bit dynamic CMOS comparator.

Committee:

Henry Chen, Ph.D. (Advisor); Marian K. Kazimierczuk, Ph.D. (Committee Member); Yan Zhuang, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Multiple Input Multiple Output, dynamic CMOS, high-speed, low power

Hopgood, Heather MSubstitution Reactions in the High Speed Ball Mill
PhD, University of Cincinnati, 2016, Arts and Sciences: Chemistry
As environmental concerns are becoming more prominent in today’s society through a modern environmental movement, Green Chemistry has evolved with the effort to reduce the harmful impact of chemical waste. Ideally, Green Chemists would be able to eliminate all hazardous and wasteful components of their experiments. With that lofty goal, a series of principles have been outlined which guide chemists in synthetic design and implementation towards safety and waste reduction. Following this approach, the Mack group has adapted a solventless method which uses high speed ball milling. Since the role of the solvent is to break-down the reagents and disperse the molecules so that a reaction can occur, the ball mill replicates this process through shaking and mixing. Although this process has been applied to a wide range of chemical reactions, the fundamental principles are still not fully understood in the context of a solvent-free system. In order for these new Green Chemistry methodologies to be adopted, these knowledge gaps must be filled. Substitution reactions encompass one of the largest categories of organic chemistry and this work seeks to elucidate the similarities and differences with known solution reactivity.

Committee:

James Mack, Ph.D. (Committee Chair); Anna Gudmundsdottir, Ph.D. (Committee Member); Patrick Limbach, Ph.D. (Committee Member); David Smithrud, Ph.D. (Committee Member)

Subjects:

Chemistry

Keywords:

Green Chemistry;High Speed Ball Milling;Substitution;Enolates;Solvent-free

Bontupalli, VenkatarameshIntrusion Detection and High-Speed Packet Classification Using Memristor Crossbars
Master of Science (M.S.), University of Dayton, 2015, Electrical Engineering
Intrusion Detection Systems (IDS) are intelligent specialized systems designed to interpret intrusion attempts from incoming network traffic. IDSs aim at minimizing the risk of accessing unauthorized data and potential vulnerabilities in critical systems by examining every packet entering a system. Packet inspection and Pattern matchings are often computationally intensive processes and that are the most power hungry functionalities in network intrusion detection systems. This thesis presents a high throughput, low latency and low power memristor crossbar architecture for packet header and payload matching that could be used for high-speed packet classification and malware detection. The memristor crossbar systems can perform intrusion detection through a brute force approach for static contents/signatures and a state machine approach for regular expressions. A large portion of the work completed in this thesis has been published in [1-2].

Committee:

Tarek Taha, Dr (Advisor); Eric Balster, Dr (Committee Member); Vamsy Chodavarapu, Dr (Committee Member)

Subjects:

Computer Engineering; Electrical Engineering

Keywords:

Intrusion Detection; Memristor Crossbars; High Speed Packet Classification; Low Power; Network Security; SNORT; String Matching; Regular Expression Matching

Sattler, Andrew MAn Analysis of Strain and Displacement within Elastically Averaged Electromagnetic Formed Joints
Master of Science, The Ohio State University, 2015, Mechanical Engineering
Within the automotive industry, a growing interest in lightweight vehicles has led to a need for novel methods of multi-material joining. Development of methods for joining various materials, with aluminum in particular, has become an increasing focus for many vehicle manufacturers. Electromagnetic forming (EMF) provides a method for creation of tubular joints, which have great potential for use within space-frame structures. This thesis attempts to more comprehensively understand the behavior of multi-groove electromagnetically formed joints under axial tension loading, and suggests an overall methodology for analyzing mechanical joints based on micro-displacement under load. This thesis focused on forming aluminum tubes to steel mandrels. Three different mandrel geometries, each with a different basic groove geometry; rectangular, curved, and trapezoidal, were designed and tested. These each utilized elastic averaging, and incorporated three grooves of varying depths, in order to distribute the load evenly across all grooves. A set of fixtures was designed in order to facilitate the creation of consistent electromagnetically formed joints using each of these geometries. These joints were loaded under various axial tension tests, and ezz strains in the grooves were monitored, primarily using a digital image correlation (DIC) optical strain tracking system. This was intended to compare strain distribution between the three grooves and observe micro-movement within the joints. The three different geometry joints were tested under quasi-static loading until failure, and all joints exceeded the full tensile strength of the undeformed aluminum tube. Significantly lower strains were found in the trapezoidal and rectangular geometry joints, as well as higher stiffnesses, than in the curved geometry joint. The trapezoidal joints were then progressively loaded to 20%, 40%, 60%, and 80% of the tube's ultimate tensile strength. Movement of the mandrel within the joint was observed; however, complications prevented further conclusions from this testing. The rectangular joint was then tested under low cycle testing at 20%, 40%, and 75% of ultimate tensile strength. Initial movement of the joints was observed during the first few cycles, but nearly all samples showed signs of global joint shakedown. Finally, a thermoplastic heat-shrink layer was applied to the joints as a method of galvanic insulation, and the resulting joint was quasi-statically loaded. The insulated joint maintained full tube strength, but showed greater strains than those seen within non-insulated joints.

Committee:

Anthony Luscher, Dr. (Advisor); Glenn Daehn, Dr. (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

electromagnetic forming; high speed joining; electromagnetic compression; elastic averaging; mechanical fastening

Srinivasan, ShekharA Simulation Perspective on Dimensional Control and Formability in Impact Forming
Master of Science, The Ohio State University, 2010, Materials Science and Engineering

Traditional stamping technologies that sandwich sheet metal between a die and punch have several inherent limitations such as the use of heavy tools, localized deformation that damage the parts and inhibit consistency. High speed forming is a light weight tooling assembly that forms the part without using any punch. Electromagnetic forming (EMF) is one among the gamut of high speed forming technologies that is used for embossing fine surface features onto sheet metals. This work investigates the dynamics of sheet metal impact through a simulation study. The primary objective of this work is to develop a modelling facility that guides experimental design of flat ridged parts. Critical factors that influence the product quality are investigated. The high impact energy translates into an appreciable rebound that affects the product shape. Interface conditions play a critical role in influencing the shape of the final part. Contrary to intuition, friction is beneficial in high speed forming unlike traditional stamping where friction leads to tearing of sheet metal. Shape fidelity is investigated through a prototypical study of the expansion of a round tube into a square hole.

Traditional modelling techniques solve a coupled system of equations with spatially varying electromagnetic fluxes controlling the dynamics of the plastic deformation. Because the magnetic pressure is spatially uniform, the flux equations are obviated from the coupled system rendering them computationally efficient. The calibration of contact mechanics that influence the rebound behaviour of the sheet metal remains as a difficult issue. The interfaces between various sheet metals and the metal die play a critical role in controlling the shape of the final product. The characterization of such an interface using appropriate calibrated friction coefficients is assessed. The role of magnetic pressure in reducing the sheet metal rebound is demonstrated via a comparison between results from mechanical and electromagnetic simulations. The influence of the channel geometry on final shape is illustrated through simulations and experiments.

Committee:

Shekhar Daehn (Advisor); Suresh Babu (Committee Member)

Subjects:

Materials Science; Mechanical Engineering; Mechanics

Keywords:

Electromagnetic forming; sheet metal impact; high speed; numerical simulation

Balaji, PavanHigh performance communication support for sockets-based applications over high-speed setworks
Doctor of Philosophy, The Ohio State University, 2006, Computer and Information Science
In the past decade several high-speed networks have been introduced, each superseding the others with respect to raw performance, communication features and capabilities. However, such aggressive initiative is accompanied by an increasing divergence in the communication interface or "language" used by each network. Accordingly, portability for applications across these various network languages has recently been a topic of extensive research. Programming models such as the Sockets Interface, Message Passing Interface (MPI), Shared memory models, etc., have been widely accepted as the primary means for achieving such portability. This dissertation investigates the different design choices for implementing one such programming model, i.e., Sockets, in various high-speed network environments (e.g., InfiniBand and 10-Gigabit Ethernet). Specifically, the dissertation targets three important sub-problems: (a) designing efficient sockets implementations to allow existing applications to be directly and transparently deployed on to clusters connected with high-speed networks; (b) analyzing the limitations of the sockets interface in various domains and extending it with features that applications need but are currently missing; and (c) designing a communication substrate to allow compatibility between various kinds of protocol stacks belonging to a common network family (e.g., Ethernet). The proposed stack comprising of the above mentioned three components, allows development of applications and other upper layers in an efficient, seamless and globally compatible manner.

Committee:

Dhabaleswar Panda (Advisor)

Keywords:

Sockets; High-speed Networks; Programming Models

Ren, SaiyuBROAD BANDWIDTH HIGH RESOLUTION ANALOG TO DIGITAL CONVERTERS: THEORY, ARCHITECTURE AND IMPLEMENTATION
Doctor of Philosophy (PhD), Wright State University, 2008, Engineering PhD
Analog to digital converters (ADCs) translate analog quantities, which are characteristic of most phenomena in the "real world" to digital language for a variety of applications including information processing, computing, communication and control systems. The performance of the digital signal processing and communication systems is generally limited by the speed and precision of the digital input signal which is achieved at the interface between analog and digital information. The analog to digital converter (ADC) has become a critical component for advanced telecommunication systems. The desire to move the analog to digital interface closer to the sensor has resulted in more stringent performance requirements for high speed, and high resolution ADCs. High speed ADCs have become the bottle neck for achieving high performance signal processing systems. This has motivated many researchers and scientists to continuously work on the development of innovative ADC architectures and new techniques.The dissertation is going to present 1) The design, fabrication and testing for a CMOS ADC architecture which has up to 62.5 MHz base bandwidth and 1 GHz sample frequency with 12 bits resolution. This work is done by using a unique patented architecture, "Pipelined Delta Sigma Modulator Analog to Digital Converter". 2) A CMOS band pass ADC which includes M single channel sub-sampling delta sigma modulators having N-bit quantizer outputs arranged in a time interleaved configuration. This unique patented architecture facilitates a flexible RF/IF Band Pass ADC. MATLAB SIMULINK simulation results show that more than 8 bits of resolution are obtained for center frequencies in the 1.8 GHz to 3.0 GHz region with a bandwidth of 70 MHz using time interleaved first order delta sigma modulators operating with sampling frequencies of 600 MHz to 1.0 GHz. 3) The design, fabrication and testing for CMOS Phase Lock Loop synthesizer architectures which will be able to generate In phase and Quadrature clock signals up to 7.8GHz frequency which may be used as the ADCs and receivers on chip clock source.

Committee:

Raymond Siferd, PhD (Advisor); Henry Chen, PhD (Committee Member); Marian Kazimierczuk, PhD (Committee Member); Marty Emmert, PhD (Committee Member); Frank Scarpino, PhD (Committee Member)

Subjects:

Electrical Engineering

Keywords:

CMOS ADC High Speed Broad Bandwidth Clock Generator

Taesopapong, SomboomA VLSI-nMOS hardware implementation of a high speed parallel adder
Master of Science (MS), Ohio University, 1986, Electrical Engineering & Computer Science (Engineering and Technology)

A VLSI-nMOS hardware implementation of a high speed parallel adder

Committee:

Janusz Starzyk (Advisor)

Keywords:

A VLSI-nMOS Hardware Implementation; High Speed Parallel Adder

Bhupatiraju, Raja D.V.A comparative study of high speed adders
Master of Science (MS), Ohio University, 1999, Electrical Engineering & Computer Science (Engineering and Technology)

A comparative study of high speed adders

Committee:

Janusz Starzyk (Advisor)

Keywords:

high speed adders; boolean equations; Brent-Kung structure

Liu, ZhenReconstruction and Control of Tip Position and Dynamic Sensing of Interaction Force for Micro-Cantilever to Enable High Speed and High Resolution Dynamic Atomic Force Microscopy
Doctor of Philosophy, The Ohio State University, 2017, Mechanical Engineering

In the last three decades, atomic force microscopy (AFM) has evolved to be one of the most powerful and versatile tools enabling nanoscale analysis and exploration in many areas such as material science, physics, chemistry, tribology and nanomanufacturing. Especially, there has been intensively increasing interest in applying AFM in biological researches due to its unmatched capability of studying biological samples like protein, DNA molecule and live cell in their native physiological environment with high resolution. Dynamic AFM is a widely used AFM mode because it greatly reduces the lateral force between tip and sample through intermittent tip-sample contact during scanning and it is insensitive to thermal drift of cantilever. However, there is a major drawback in conventional dynamic AFM which inhibits further innovation and full development of its potentials: its capability of high speed scanning with high spatial resolution retained is limited by several fundamental issues involving the tapping dynamics of cantilever, the instrument hardware and the amplitude modulation principle of dynamic AFM operation.

In this dissertation, the fundamental aspects in modeling, actuation, sensing and control of AFM are investigated. Accurate multi-mode tip position reconstruction, high speed and high precision active tip motion control, precise sensing and direct control of dynamic interaction force are realized to overcome the limitations in conventional dynamic AFM and to enable the potential of high speed and high resolution dynamic AFM imaging.

As scanning speed increases, cantilever’s responses of high dynamic modes can be excited noticeably by tip-sample interaction force. These responses are distorted in the optical lever measurement system due to measurement sensitivity difference among distinct dynamic modes, which leads to tip position measurement error and therefore compromises image resolution. In this research work, cantilever dynamics of multiple dynamic modes is modeled and multi-mode measurement sensitivity calibration is realized. Based on the multi-mode cantilever model and the calibrated measurement sensitivities, two approaches, i.e., the modal projection filtering method and the multi-mode state estimation method, are developed to reconstruct actual tip position from the distorted optical lever measurement signal with sub-Angstrom level accuracy to help retain image resolution during high speed scanning.

AFM system relies on adjustment of cantilever’s z position/tip position to track sample topography. Therefore, speed and accuracy of tip position control are of paramount importance to the scanning speed and image resolution. In conventional dynamic AFM, tip positioning speed is severely limited by the low-bandwidth piezo actuator used as z-positioner and tip positioning accuracy is compromised by the thermal fluctuation of cantilever. In this research work, a novel active tip motion control system is developed to realize high speed and high precision tip positioning. In this system, a collocated electromagnetic actuation mechanism, used as a high-bandwidth z-positioner, and a model-based controller, designed according to the multi-mode cantilever model, are employed to extend the bandwidth of tip motion control over cantilever’s fundamental dynamic mode to enable rapid tip stepping in each tapping cycle. Cantilever’s thermal fluctuation is also actively suppressed through high-bandwidth feedback control so that tip positioning accuracy of sub-Angstrom level can be achieved even in liquid.

Amplitude modulation is commonly used for tip-sample interaction regulation in conventional dynamic AFM, whereas its regulation bandwidth is limited by the transient response of cantilever as well as the oscillation amplitude measurement delay. In this research work, dynamic sensing and direct regulation of the tip-sample interaction force are realized, which avoid the bandwidth limitation of conventional amplitude modulation method and enable the potential of high speed dynamic AFM imaging. By introducing the physical interaction process between tip and sample into a Kalman-filter-based state estimator and by estimating and compensating cantilever dynamic parameter variation, dynamic interaction force is precisely estimated with estimation resolution reaching the physical thermal force limit. Peak of the estimated interaction force in each tapping cycle is thus detected and directly regulated with a feedback controller through adjustment of tip-sample distance with the high speed and high precision active tip motion control system.

The enabling technologies developed in this research work are integrated to deliver a one-of-a-kind AFM probing system. A high-performance digital controller based on field programmable gate array (FPGA) is built, wherein various sensing, estimation and control algorithms are implemented for real-time computation and control with 1 MHz update rate. A standard calibration grid composed of circular hole array with 20 nm depth and 5 um pitch is imaged to prove the scanning speed advantage of developed AFM probing system over conventional dynamic AFM. Its scan rate is shown to be only limited by cantilever bandwidth. The image resolution is illustrated by simulated scanning of a sample of repeated spherical structure with 0.5 nm height and 6.2 nm pitch. Topography imaging and mechanical property mapping of live MCF7 human breast cancer cell in its native physiological environment are realized to demonstrate this system’s potential of biological applications.

Committee:

Chia-Hsiang Menq (Advisor); Junmin Wang (Committee Member); Noriko Katsube (Committee Member); Vadim Utkin (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

atomic force microscopy; multi-mode cantilever dynamics; tip position reconstruction; high bandwidth tip motion control; thermal fluctuation suppression; dynamic interaction force estimation and control; high speed and high resolution dynamic AFM imaging

Liu, JiuxingDesigning high performance and scalable MPI over InfiniBand
Doctor of Philosophy, The Ohio State University, 2004, Computer and Information Science

Rapid technological advances in recent years have made powerful yet inexpensive commodity PCs a reality. New interconnecting technologies that deliver very low latency and very high bandwidth are also becoming available. These developments lead to the trend of cluster computing , which combines the computational power of commodity PCs and the communication performance of high speed interconnects to provide cost-effective solutions for computational intensive applications, especially for those grand challenge applications such as weather forecasting, air flow analysis, protein searching, and ocean simulation.

InfiniBand was proposed recently as the next generation interconnect for I/O and inter-process communication. Due to its open standard and high performance, InfiniBand is becoming increasingly popular as an interconnect for building clusters. However, since it is not designed specifically for high performance computing, there exists a semantic gap between its functionalities and those required by high performance computing software such as Message Passing Interface (MPI). In this dissertation, we take on this challenge and address research issues in designing efficient and scalable communication subsystems to bridge this gap. We focus on how to take advantage of the novel features offered by InfiniBand to design different components in the communication subsystems such as protocol design, flow control, buffer management, communication progress, connection management, collective communication, and multirail network support.

Our research has already made notable contributions in the areas of cluster computing and InfiniBand. A large part of our research has been integrated into our MVAPICH software, which is a high performance and scalable MPI implementation over InfiniBand. Our software is currently used by more than 120 organizations world-wide to build InfiniBand clusters, including both research testbeds and production systems. Some of the fastest supercomputers in the world, including the 3rd ranked Virginia Tech Apple G5 cluster, are currently powered by MVAPICH. Research in this dissertation will also have impact on designing communication subsystems for systems other than high performance computing and for other high speed interconnects.

Committee:

Dhabaleswar Panda (Advisor)

Subjects:

Computer Science

Keywords:

Cluster Computing; InfiniBand; MPI; High Performance Computing; High Speed Interconnect; Performance; Scalability

Wormald, DavidEvaluation of Cincinnati Union Terminal for Intercity Rail Passenger Service
MCP, University of Cincinnati, 2010, Design, Architecture, Art and Planning : Community Planning

The American Recovery and Reinvestment Act of 2009 (ARRA) allocated approximately $8 billion to the Federal Railroad Administration (FRA) for distribution to individual states on a competitive basis for the planning design and implementation of high-speed intercity passenger rail service. This represents the most significant expenditure by the federal government for the development of new passenger rail service in the post World War II period.

The FRA has designated several corridors to receive prioritization for funding towards implementation of high-speed passenger rail service. Two of these corridors terminate in Cincinnati. One corridor links Cincinnati to Chicago via Indianapolis, while the second links Cincinnati to Cleveland via Columbus (3-C Corridor). The exact route, service parameters, station locations, as well as capital and operational costs have not been finalized for either corridor.

In February 2010, the FRA awarded the Ohio Rail Development Commission (ORDC) $400 million for the implementation of “Quickstart” passenger service within the 3-C Corridor. The proposed “Quickstart” service would operate on a combination of existing fright railroads at a maximum speed of 79 mph starting in 2012. At the same time, planning and engineering would commence with the goal of establishing “high-speed” rail service which would operate at speeds up to 110 mph in the future.

The ORDC application to the FRA designates a preferred location for the Cincinnati terminal station near Lunken Airport for “Quickstart” service and at the Cincinnati Union Terminal (CUT) for future high-speed rail service. Regional political leadership, print and electronic media, as well as many in the public at large, have stated that the Lunken station location should be discarded and that all efforts should be directed at the utilization of the CUT as the City of Cincinnati’s rail terminal. To date, there have been few, if any, efforts evaluating the suitability of the CUT as a terminal station for both high-speed rail corridors as well as potential future upgrades to the existing Amtrak Cardinal linking Cincinnati to Washington, DC and New York City.

The parameters for evaluating intercity rail passenger station facilities and related land use planning are complex. Prior to making a long term commitment to the future of intercity passenger rail service and investing significant sums of money for the development of a terminal station serving the region, significant study should be undertaken to verify that the CUT (although serving the region during the peak of rail travel in the mid 20th century) is a desirable facility for a terminal passenger rail station to serve Cincinnati during the 21st century.

This project seeks to answer the following questions: • Is the use of the CUT as a rail passenger station serving both designated high-speed rail corridors feasible, given the physical constraints of the location, existing building configuration and adjacent railroad operations?

• If it is physically feasible to use the CUT, what is the likelihood that the CUT will spur economic development and provide a favorable location for a railroad terminal station serving Cincinnati?

Committee:

Menelaos Triantafillou, MLA (Committee Chair); John Niehaus, MA (Committee Member)

Subjects:

Transportation

Keywords:

High-Speed Rail;Cincinnati Union Terminal;Railroads;Cincinnati Museum Center;Station Planning;3-C Corridor

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