Engineering Commons^™

Stability And Minimum Cost Analysis Of A Discrete-Time Disturbance Accommodation Controller, Katrina H. Barhouse

Master's Theses (2009 -)

Disturbance accommodation control (DAC) is a method for designing a controller that minimizes the effects of disturbances of known waveform type, but with unknown arrival time, duration or magnitude. Systems that do not have a control term in the measurement equation pose a particular challenge for DAC design. A disturbance accommodation controller for these types of systems was previously developed by defining a pseudo-output consisting of the current output and previous control input terms with weighting coefficients.

The objective of the present work is to analyze the stability and performance of the discrete- time disturbance accommodation controller for systems without …

Comparison Of An Ankle-Foot-Orthosis And Neuroprosthesis During Level And Non-Level Walking For Individuals Post-Stroke, Michelle Beverly Gallagher

Master's Theses (2009 -)

This study used gait analysis to compare the efficacy of the two foot drop treatments (ankle-foot-orthosis and neuroprosthesis) and to contrast the stimulation control of the two different neuroprosthesis sensors during level and non-level ambulation of post-stroke individuals.

Eight subjects completed two gait analysis sessions, once while using a study-provided articulated AFO and the other while using a WalkAide. After four weeks of acclimation to the device, each subject performed two minute walking trials on a level, inclined and declined treadmill. Kinematic and heart rate data were collected for all sessions. Plantar pressure and WalkAide tilt, heel loading, and stimulation …

Improving Cardiovascular Stent Design Using Patient-Specific Models And Shape Optimization, Timothy J. Gundert

Master's Theses (2009 -)

Stent geometry influences local hemodynamic alterations (i.e. the forces moving blood through the cardiovascular system) associated with adverse clinical outcomes. Computational fluid dynamics (CFD) is frequently used to quantify stent-induced hemodynamic disturbances, but previous CFD studies have relied on simplified device or vascular representations. Additionally, efforts to minimize stent-induced hemodynamic disturbances using CFD models often only compare a small number of possible stent geometries. This thesis describes methods for modeling commercial stents in patient-specific vessels along with computational techniques for determining optimal stent geometries that address the limitations of previous studies.

An efficient and robust method was developed for virtually …

Analysis Of An Air-Spaced Patch Antenna Near 1800 Mhz, Hermine Nathalie Akouemo Kengmo Kenfack

Master's Theses (2009 -)

Microstrip antennas are a type of printed antenna which consists of a patch on top of a grounded substrate. A major limitation for the performance of the patch antenna is the dielectric substrate. The idea of using air as dielectric was therefore considered to overcome that limitation because air has the lowest permittivity and no loss. The goal of this work is to build an air-spaced patch antenna, with the minimum resonant frequency at 1800 MHz and with a return loss of at least 10 dB.

This work is novel because the air-spaced patch antenna has not been extensively studied. …

Investigation Of Aluminum Equation Of State Generation, Aaron Ward

Master's Theses (2009 -)

There are many forms and methods to construct equations of state, EOSs. These methods are usually tailored for the particular problem of interest. Here, the EOSs of interest are those used in modeling shock responses. These EOSs cover a wide range of physical characteristics such as detonation and explosions, armor and anti-armor materials, and space structures protection. Aluminum will be the primary focus of this work. Aluminum was chosen because it has been studied in great length in the shock regime and is a common component in shock experiments and space type vehicles.

Droplet Behavior In Dense, Low Velocity Aerosols, Alexander Polley

Master's Theses (2009 -)

Rapid compression machines (RCM) are laboratory devices used to measure gas-phase fuel reactivity at conditions relevant to combustion engines. Test mixtures are generally prepared by rapidly compressing a gas phase fuel+oxidizer+diluent mixture to high pressure and temperature (e.g., 10-50 bar, 650-1000 K). It is extremely challenging to utilize diesel-relevant liquid fuels in these devices due to their involatility. One proposed method involves the delivery of an aerosol of suspended fuel droplets (∼ 0.1 mL_fuel/L_gas at stoichiometric fuel loading) to the machine. The compression stroke of the RCM subsequently heats the gas phase of the aerosol thereby achieving …

Adaptive Real-Time Decoding Of Brain Signals For Long-Term Control Of A Neuro-Prosthetic Device, Tushar Ashok Dharampal

Master's Theses (2009 -)

Changes in the statistical properties of neural signals recorded at the brain machine interface (BMI) pose significant challenges for accurate long-term control of prostheses interfaced directly with the brain by continuously altering the relationship between neural responses and desired action. In this thesis, we develop and test an adaptive decoding algorithm that can recover from changes in the statistical properties of neural signals within minutes. The adaptive decoding algorithm uses a Kalman filter as part of a dual-filter design to continuously optimize the relationship between the observed neural responses and the desired action of the prosthesis. Performance of the algorithm …

Modeling And Computational Framework For The Specification And Simulation Of Large-Scale Spiking Neural Networks, David James Herzfeld

Master's Theses (2009 -)

Recurrently connected neural networks, in which synaptic connections between neurons can form directed cycles, have been used extensively in the literature to describe various neurophysiological phenomena, such as coordinate transformations during sensorimotor integration. Due to the directed cycles that can exist in recurrent networks, there is no well-known way to a priori specify synaptic weights to elicit neuron spiking responses to stimuli based on available neurophysiology. Using a common mean field assumption, that synaptic inputs are uncorrelated for sufficiently large populations of neurons, we show that the connection topology and a neuron's response characteristics can be decoupled. This assumption allows …

Methods For Detecting High-Frequency Oscillations In Ongoing Brain Signals: Application To The Determination Of Epileptic Seizure Onset Zones, Chiran Dilip Doshi

Master's Theses (2009 -)

Epilepsy is a neurological disorder with varied expression. Patients with focal onset seizures that are resistant to medications can benefit from ablative surgery. However, localization of the seizure onset zone (SOZ) and characterization of propagation to secondary areas can be challenging. The present study aimed at developing the appropriate signal processing methodology to detect bursts of interictal high-frequency oscillations (HFOs), as a possible signature of the SOZ, in patients with drug-resistant partial epilepsy. Additionally, invasive interictal and ictal intracranial electroencephalography (iEEG) data and non-invasive electromagnetic source imaging with magnetoencephalography (MEG) data from three subjects were analyzed. We developed a novel …

Development Of An Experimental Model To Quantify Lumbar Spine Kinematics During Military Seat Ejection, Steven George Storvik

Master's Theses (2009 -)

The initial phase of a military ejection sequence exerts substantial axial loads on the spinal column. Eccentric inertial loading on the thoracolumbar spine can lead to injury. Most serious injuries due to ejection are in the form of a vertebral fracture, most commonly occurring at the thoracolumbar junction. The objective of the current study was to understand characteristics of a military seat ejection by employing an experimental model designed to simulate the boost or in-rail phase. The model incorporates realistic boundary conditions and is capable of quantifying metrics associated with injury tolerance such as applied accelerations and resultant loads and …

Surface Preparation Of Naval Ship Construction Steel (Abs-A And Ah-36) Via Bristle Blasting Process, Jorge Andres Martinez

Master's Theses (2009 -)

Bristle blasting is a new and unique corrosion-removal process that is rapidly gaining widespread acceptance among engineers and practitioners in the corrosion/ surface preparation community. Engineers from the ship construction and repair industries face a constant corrosive threat to ships' steel infrastructure and welded joints. To this end, great care is exercised in protecting the vessels' structural integrity and longevity, while maintenance engineers in the ship-building industry seek new methods to improve surface preparation that will not compromise the surface cleanliness and anchor profile required for proper adhesion of paints and coatings.

In this study, the cleanliness and texture of …

Asymmetric Transfer Of Task Dependent Perceptual Learning In Visual Motion Processing, Sampada Charudatta Wakde

Master's Theses (2009 -)

The effects of perceptual learning (PL) on the sensory representation are not fully understood, especially for higher–level visual mechanisms more directly relevant to behavior. The objective of this research is to elucidate the mechanisms that mediate task dependent learning by determining where and how task dependent learning occurs in the later stages of visual motion processing.

Eighteen subjects were trained to perform a dual–2TAFC visual discrimination task in which they were required to simultaneously detect changes in the direction of moving dots (task–1) and the proportion of red dots (task–2) shown in two stimulus apertures presented in either the left …

Role Of Tendon Vibration In Multijoint Reflex Coupling In The Hemiparetic Arm Post Stroke, Bani Gadhoke

Master's Theses (2009 -)

Post stroke hemiparesis causes reflex coupling in multiple muscles of the arm, leading to atypical movements that hamper motor control. In particular, people post-stroke can become unstable while holding the arm at the end of a planar motion. Recently, we have found that tendon vibration of the wrist flexors improves the stability of the arm during a hold task. The objective of the current study was to identify the effects of vibration applied to the wrist flexors on the biceps and triceps stretch reflexes, generated using a tendon tapper. In people post-stroke, tendon tap perturbations of the biceps and triceps …

Heat And Mass Transfer Correlations For Steam Methane Reforming In Non-Adiabatic, Process-Intensified Catalytic Reactors, Adam Stephen Kimmel

Master's Theses (2009 -)

Because of its high energy density, hydrogen is a desirable energy source for the achievement of a renewable energy landscape. Though production methods like thermolysis, electrolysis and biomass conversion, among others, are thought to be long term renewable solutions, catalytic steam methane reforming (SMR) is currently the predominant mechanism to produce hydrogen on an industrial scale. The highly endothermic, transport-limited reforming process has also been scaled down through process intensification to create efficient small-scale hydrogen-generating systems. One proposed geometry utilizes a catalytic finned cylinder that provides a manufacturable solution to enable high-efficiency heat exchange and SMR reaction. An accurate representation …

Examining The Relationships Among Injury Outcomes, Velocity And Grip Strength During Dynamic Platform Perturbation, Braden Cripe

Master's Theses (2009 -)

Studies examining the relationship between inputs and outputs for simulated models of dynamically perturbed horizontal platforms are scarce. Most of these scenarios include a standing operator with upper extremity grip, oftentimes subjected to lateral impulses, which may lead to occupant injury. While the detailed study of these collision scenarios is sparse, the prevalence of their application is great.

This thesis aims to identify how two input parameters, velocity change (ÄV) and grip strength, affect injury assessment reference values (IARVs). This is accomplished by using Mathematical Dynamic Modeling (MADYMO) software to simulate the scenarios defined by those inputs. In the simulation, …

Tools For Creating Wide-Field Views Of The Human Retina Using Optical Coherence Tomography, Ashavini M. Pavaskar

Master's Theses (2009 -)

Optical Coherence Tomography (OCT) has allowed in-vivo viewing of details of retinal layers like never before. With the development of spectral domain OCT (SD-OCT) details of nearly 2µm axial resolution and higher imaging speed have been reported. Nevertheless, a single volume scan of the retina is typically restricted to 6mm x 6mm in size. Having a larger field of view of the retina will definitely enhance the clinical utility of the OCT.

A tool was developed for creating wide-field thickness maps of the retina by combining the use of already available tools like i2k Retina (DualAlign, LLC, Clifton Park, NY) …

Applying Bayesian Forecasting To Predict New Customers' Heating Oil Demand, Tsuginosuke Sakauchi

Master's Theses (2009 -)

This thesis presents a new forecasting technique that estimates energy demand by applying a Bayesian approach to forecasting. We introduce our Bayesian Heating Oil Forecaster (BHOF), which forecasts daily heating oil demand for individual customers who are enrolled in an automatic delivery service provided by a heating oil sales and distribution company. The existing forecasting method is based on linear regression, and its performance diminishes for new customers who lack historical delivery data. Bayesian methods, on the other hand, respond effectively in the start-up situation where no prior data history is available.

Our Bayesian Heating Oil Forecaster uses forecasters' past …

Propagation Of Plate Acoustic Waves In Contact With Fluid Medium, Nagaraj Ghatadi Suraji

Master's Theses (2009 -)

The characteristics of acoustic waves propagating in thin piezoelectric plates in the presence of a fluid medium contacting one or both of the plate surfaces are investigated. If the velocity of plate wave in the substrate is greater than velocity of bulk wave in the fluid, then a plate acoustic wave (PAW) traveling in the substrate will radiate a bulk acoustic wave (BAW) in the fluid. It is found that, under proper conditions, efficient conversion of energy from plate acoustic waves to bulk acoustic waves and vice versa can be obtained. For example, using the fundamental anti symmetric plate wave …

Modeling And Validation Of A Fault Mitigation Method In Induction Motor-Drive Systems Using Magnetic Equivalent Circuits, Shaohua Suo

Master's Theses (2009 -)

In this thesis, a fault mitigation method for delta-connected induction motor-drive systems under a two-phase open-delta faulty operating condition is analyzed and verified. More specifically, this fault mitigation technique can provide a set of almost balanced motor line currents, and significantly reduce torque ripples, even when the machine runs under the aforementioned two-phase open-delta faulty operating condition. This condition is analyzed using a Magnetic Equivalent Circuit (MEC) model. This model is developed for a delta-connected induction motor which is coupled to its drive system, including the fault mitigation controller. That is, the MEC model is linked to its associated PWM …

Optimal Mobile It Location Based On Ergonomics, Kyle Saginus

Master's Theses (2009 -)

U.S. and Canadian electric utility companies are in the process of integrating mobile computers into their fleet vehicle cabs. The placement of the mobile computer in the vehicle cab could have a significant effect on biomechanical loading, performance, and subjective assessment. The objective of this research is to determine the best location to place a mobile computer in a truck cab.

In this experiment, four locations of mobile computers in a truck cab were selected and tested in a laboratory study to determine how location affected muscle activity of the lower back and shoulders; joint angles of the shoulders, elbows, …

Instrumentation Of Buildings To Enhance Student Learning - A Case Study At Marquette University's Discovery Learning Compex, Meredith Claeys

Master's Theses (2009 -)

The new engineering building at Marquette University, the Discovery Learning Complex, has been designed to change the way engineering education is delivered by using the building itself as a teaching tool for the next generation of engineers. The structural system for the building has been instrumented to allow students access to structural system data, wind speed data, and foundation pressures enabling this data from the building to be integrated into the teaching environment. The building also will display aspects of the building management system for public viewing. An array of weather stations will be installed on the roof, allowing the …

Method Of Tolerance Allocation To Maintain Rotary Balance Of Multi-Component Bodies, Lindsay Louise Rogers

Master's Theses (2009 -)

Vibration of rotating machinery caused by mass imbalance is the most frequent source of unwanted disturbing forces and also the most preventable. In the case of a CT scanner, unwanted vibration in the equipment causes artifacts to the X-ray image, and therefore all measures are taken to eliminate imbalance. The CT scanner is a multi-component rotating body, therefore making it a challenge to account for many discrete components, each with unique variation. This research developed the equations for static and dynamic balance including considerations for inertia. The variation of the components was studied using two models: a sensitivity analysis and …

One-Dimensional Strain Initiated By Rapid Compaction Of A Heterogenous Granular Mixture Consisting Of Cu, Fe, Sio2, C, Mos2, And Sn, Cullen Braun

Master's Theses (2009 -)

The dynamic compaction of metal powders is of great interest to the metallurgical and military communities. The compaction of a heterogeneous granular mixture consisting of copper, iron, silica, graphite, molybdenum-disulde, and tin predominately used in aviation break-pad creation is presented. The initial density of the material was on average 2.756 g/cm3 . The research also required developing a working projectile velocity measurement system and a proper target assembly for pressure measurements. Manganin gages were used to record the shock wave transit time and the pressure of the transmitted waveform into the powder mixture. An impedance matching technique was utilized to …

A Novel Approach To The Part Orientation Problem For Robotic Assembly Applications, Brian James Slaboch

Master's Theses (2009 -)

SCARA (Selective Compliant Assembly Robot Arm) type robots are the most common type of assembly robots. These robots have four degrees of freedom (three rotational and one translational). Typically these robots are used for assembly tasks that take place along a vertical axis. Many times, however, assembly tasks take place along a non-vertical axis. To account for non- vertical axis assembly, parts must be fed in a proper orientation to allow for correct assembly. Parts feeders and specialized end-effectors are typically used to feed parts in their proper orientation. This thesis investigates a novel end-effector that can be used to …

Fitting Model Parameters To Patient Data Automatically Through Evolutionary Computation, Michael Wesley Sagan

Master's Theses (2009 -)

The Orthopaedic and Rehabilitation Engineering Center (O.R.E.C) has been studying two conditions which can wreak havoc on the human body's balance control system. The conditions being studied are cerebral palsy (CP) and adolescent idiopathic scoliosis (AIS)[1, 2, 3, 4, 5, 6]. A greater understanding of postural deficits in children with these conditions and the causes for these conditions may help researchers achieve better interventions and treatments [3]. A tool used to characterize postural stability is a bi-planar postural stability model. This model is designed where 10 parameter values have to be adjusted until the simulated data is statistically the same …

Micromachined Differential Scanning Calorimeter For Cellular Differentiation And Metabolism Monitoring, Robert Blise

Master's Theses (2009 -)

This thesis presents a micromachined differential scanning calorimeter (DSC) for cellular differentiation and metabolism monitoring. The misregulation of cell physiology due to disease increases the metabolic rate of the cell and therefore its heat output. Observing or monitoring the cell's heat output will lead to a method to detect diseased cells and distinguish them from normal cells.

The calorimetric chambers of the DSC were fabricated on a silicon nitride thin film, which allows for rapid thermal equilibrium and insulation. The temperature sensing element was a resistive temperature detector fabricated from nickel. The DSC incorporated integrated nickel resistive heaters to apply …