Engineering Commons^™

Modeling The Collagen Fibril Network Of Biological Tissues As A Nonlinearly Elastic Material Using A Continuous Volume Fraction Distribution Function, Reza Shirazi, Pasquale Vena, Robert L. Sah, Stephen M. Klisch

Mechanical Engineering

Despite distinct mechanical functions, biological soft tissues have a common microstructure in which a ground matrix is reinforced by a collagen fibril network. The microstructural properties of the collagen network contribute to continuum mechanical tissue properties that are strongly anisotropic with tensile-compressive asymmetry. In this study, a novel approach based on a continuous distribution of collagen fibril volume fractions is developed to model fibril reinforced soft tissues as nonlinearly elastic and anisotropic material. Compared with other approaches that use a normalized number of fibrils for the definition of the distribution function, this representation is based on a distribution parameter (i.e. …

Hyperspectral-Based Adaptive Matched Filter Detector Error As A Function Of Atmospheric Profile Estimation, Allan W. Yarbrough

Theses and Dissertations

Hyperspectral imagery is collected as radiance data. This data is a function of multiple variables: the radiation profile of the light source, the reflectance of the target, and the absorption and scattering profile of the medium through which the radiation travels as it reflects off the target and reaches the imager. Accurate target detection requires that the collected image matches as closely as possible the known "true" target in the classification database. Therefore, the effect of the radiation source and the atmosphere must be removed before detection is attempted. While the spectrum of solar light is relatively stable, the effect …

Optimizing The Use Of Ultrasound To Deliver Chemotherapeutic Agents To Cancer Cells From Polymeric Micelles, Ghaleb A. Husseini, Nabil M. Abdel-Jabbar, Farouq S. Mjalli, William G. Pitt, Ala'a Al-Mousa

Faculty Publications

In this study, we present an artificial neural network (ANN) model that attempts to predict the dynamic release of doxorubicin (Dox) from P105 micelles under different ultrasonic power densities at 20 kHz. The goal is to utilize the developed ANN model in optimizing the ultrasound application to achieve a target drug release at the tumor site by controlling power density and ultrasound duration via an ANN-based model predictive control. The parameters of the controller are then tuned to achieve good reference signal tracking.

Utilizing An Improved Rotorcraft Dynamic Model In State Estimation, Timothy Mclain, Randal W. Beard, Robert C. Leishman, John Macdonald, Jeffrey L. Ferrin, Stephen C. Quebe

Faculty Publications

Multirotor aircraft have become a popular platform for indoor flight. To navigate these vehicles indoors through an unknown environment requires the use of a SLAM algorithm, which can be processing intensive. However, their size, weight, and power capacity limit the processing capabilities available onboard. In this paper, we describe an approach to state estimation that helps to alleviate this problem. By using an improved dynamic model we show how to more accurately estimate the aircraft states than can be done with the traditional approach of integrating IMU measurements. The estimation is done with relatively infrequent corrections from accelerometers (40Hz) and …

Analysis Of Migration Models Of Biogeography-Based Optimization Using Markov Theory, Haiping Ma, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Biogeography-based optimization (BBO) is a new evolutionary algorithm inspired by biogeography, which involves the study of the migration of biological species between habitats. Previous work has shown that various migration models of BBO result in significant changes in performance. Sinusoidal migration models have been shown to provide the best performance so far. Motivated by biogeography theory and previous results, in this paper a generalized sinusoidal migration model curve is proposed. A previously derived BBO Markov model is used to analyze the effect of migration models on optimization performance, and new theoretical results which are confirmed with simulation results are obtained. …

The Eigenvalues Of A Tridiagonal Matrix In Biogeography, Boris Igelnik, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

We derive the eigenvalues of a tridiagonal matrix with a special structure. A conjecture about the eigenvalues was presented in a previous paper, and here we prove the conjecture. The matrix structure that we consider has applications in biogeography theory.

Nonholonomic Feedback Control Among Moving Obstacles, Stephen Gregory Armstrong

Doctoral Dissertations and Master's Theses

A feedback controller is developed for navigating a nonholonomic vehicle in an area with multiple stationary and possibly moving obstacles. Among other applications the developed algorithms can be used for automatic parking of a passenger car in a parking lot with complex configuration or a ground robot in cluttered environment. Several approaches are explored which combine nonholonomic systems control based on sliding modes and potential field methods.

Development And Implementation Of A Fault Mitigating Control System For A Biodiesel Plug-In Hybrid Electric Vehicle For The Ecocar: The Next Challenge Competition, Sean Christopher Carter

Doctoral Dissertations and Master's Theses

The automotive industry is continuously developing, and with it hybrid vehicle technology is a growing field of interest. The design of the electric vehicle is a pressing matter and grows in complexity with new powertrain components such as power inverters and transmission systems that use electric motors. As a control system develops, the architecture always comes back to systems engineering documentation to find safety protocols, solutions to problems through fault testing, and validating and verifying the control architecture throughout the whole process. Testing and evaluation plans are required more than ever and are constantly being updated and implemented in today's …

Novel Approaches To The Analysis Of Localised Stress Concentrations In Deformed Elastomers, John Mcnamara

Doctoral

The research described here is concerned with improving finite element analysis (FEA) of rubber components subjected to dynamic loading, particularly in respect of accurate modelling of stress softening using standard software codes and phenomenological material models. The research required the design and implementation of a user subroutine capable of inclusion in standard highly nonlinear codes. Experimental methods were employed to corroborate the FEA simulations and so validate the subroutine. This was also achieved using 3D image correlation photogrammetry (ICP) and other novel experimental procedures. From this experimentation and modelling, the results for different rubber specimens and load cases were presented. …

Spatial And Temporal Variation Of Rod Photoreceptor Reflectance In The Human Retina, Robert F. Cooper, Adam M. Dubis, Ashavini M. Pavaskar, Jungtae Rha, Alfredo Dubra, Joseph Carroll

Biomedical Engineering Faculty Research and Publications

Using adaptive optics imaging tools to image the living retina, numerous investigators have reported temporal fluctuation in the reflectivity of individual cone photoreceptors. In addition, there is cone-to-cone (spatial) variation in reflectivity. As it has only recently become possible to image the complete rod photoreceptor mosaic in the living human retina, we sought to characterize the reflectivity of individual rods and compare their behavior to that of foveal/parafoveal cones. Across two subjects, we were able to successfully track the reflectance behavior of 1,690 rods and 1,980 cones over 12 hours. Rod and cone photoreceptors showed similar regional and temporal variability …

Improved Manufacturing Methods Of Bovine Femur Samples For Ultrasonic Testing And Assessment Of Materials Through Contract Angle Measurement, Kevin Mathew Lopez Galang

Biomedical Engineering

At California Polytechnic State University of San Luis Obispo (Cal Poly), the Biomedical Engineering department (BMED) requires its students to take the course listed as “BMED 420: Principles of Biomaterial Designs.” BMED 420 has a required laboratory section every week throughout the duration of the course that is meant to be a supplemental tool for learning. During the lab sections, students perform experiments and exercises that are currently being implemented in the industry. Despite accuracy of the methods and experiments relative to their use in the industry, there is always room for improvement. The objective of this project will illustrate …

Impaired Resistance Artery Reactivity Following Arteriogenesis, Michael (Mike) Machado

Biomedical Engineering

No abstract provided.

Robust And Resilient Finite-Time Control Of A Class Of Discrete-Time Nonlinear Systems, Mohammad N. Elbsat, Edwin E. Yaz

Electrical and Computer Engineering Faculty Research and Publications

In this paper, we address the finite-time state-feedback stabilization of a class of discrete-time nonlinear systems with conic type nonlinearities, bounded feedback control gain perturbations, and additive disturbances. Sufficient conditions for the existence of a robust and resilient linear state feedback controller for this class of systems are derived. Then, using linear matrix inequality techniques, a solution for the controller gain is obtained. The developed controller is robust for all unknown nonlinearities lying in a hyper-sphere and all admissible disturbances. Moreover, it is resilient against any bounded perturbations that may alter the controller’s gain by at most a prescribed amount. …

Computational Simulations For Aortic Coarctation: Representative Results From A Sampling Of Patients, John F. Ladisa, Alberto Figueroa, Irene E. Vignon-Clementel, Hyun Jin Kim, Nan Xiao, Laura M. Ellwein, Frandics P. Chan, Jeffrey A. Feinstein, Charles A. Taylor

Biomedical Engineering Faculty Research and Publications

Treatments for coarctation of the aorta (CoA) can alleviate blood pressure (BP) gradients(D), but long-term morbidity still exists that can be explained by altered indices of hemodynamics and biomechanics. We introduce a technique to increase our understanding of these indices for CoA under resting and nonresting conditions, quantify their contribution to morbidity, and evaluate treatment options. Patient-specific computational fluid dynamics (CFD) models were created from imaging and BP data for one normal and four CoA patients (moderate native CoA: D12 mmHg, severe native CoA: D25 mmHg and postoperative end-to-end and end-to-side patients: D0 mmHg). Simulations incorporated vessel deformation, downstream vascular …

Differential Flatness Based Control Of A Rotorcraft For Aggressive Maneuvers, Timothy Mclain, Randal W. Beard, Robert C. Leishman, Jeffrey L. Ferrin

Faculty Publications

We propose a new method to control a multi-rotor aerial vehicle. We show that the system dynamics are differentially flat. We utilize the differential flatness of the system to provide a feed forward input. The system model derived allows for arbitrary changes in yaw and is not limited to small roll and pitch angles. We demonstrate in hardware the ability to follow a highly maneuverable path while tracking a time-varying heading command.

Robust And Resilient State Dependent Control Of Discrete-Time Nonlinear Systems With General Performance Criteria, Xin Wang, Edwin E. Yaz, Yvonne I. Yaz

Electrical and Computer Engineering Faculty Research and Publications

A novel state dependent control approach for discrete-time nonlinear systems with general performance criteria is presented. This controller is robust for unstructured model uncertainties, resilient against bounded feedback control gain perturbations in achieving optimality for general performance criteria to secure quadratic optimality with inherent asymptotic stability property together with quadratic dissipative type of disturbance reduction. For the system model, unstructured uncertainty description is assumed, which incorporates commonly used types of uncertainties, such as norm-bounded and positive real uncertainties as special cases. By solving a state dependent linear matrix inequality at each time step, sufficient condition for the control solution can …

Vibration-Based Health Monitoring Of Multiple-Stage Gear Train And Differential Planetary Transmission Involving Teeth Damage And Backlash Nonlinearity, Andrew Patrick Sommer

Master's Theses

The objective of this thesis is to develop vibration-based fault detection strategies for on-line condition monitoring of gear transmission systems. The study divides the thesis into three sections. First of all, the local stresses created by a root fatigue crack on a pinion spur gear are analyzed using a quasi-static finite element model and non-linear contact mechanics simulation. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. The second section is dedicated to fixed axis power trains. Torsional vibration …

Protective Effects Of Milk Phospholipids Against Uv Photodamage In Human Skin Equivalents, Zyra Achay

Master's Theses

The ultraviolet (UV) spectrum has been known to cause damage to skin in varying degrees. UVB radiation (290-320 nm) in particular, has been proven to be highly mutagenic and carcinogenic in many animal experiments compared to either UVA or UVC. The alarming rate of increase in skin cancer incidence has prompted many investigators to pursue other alternatives to sunscreens including changes in lifestyle habits and dietary consumption in order to boost our efforts in tackling this widespread disease. Previous studies employing confocal reflectance, MTT assay and histology suggest that milk phospholipids may possess protective properties against UVB-mediated damage but the …

Effects Of Wrist Tendon Vibration On Arm Tracking In People Poststroke, Megan O. Conrad, Robert A. Scheidt, Brian D. Schmit

Biomedical Engineering Faculty Research and Publications

The goal of this study was to evaluate the influence of wrist tendon vibration on a multijoint elbow/shoulder tracking task. We hypothesized that tendon vibration applied at the wrist musculature would improve upper arm tracking performance in chronic stroke survivors through increased, Ia-afferent feedback to the central nervous system (CNS). To test this hypothesis, 10 chronic stroke and 5 neurologically intact subjects grasped the handle of a planar robot as they tracked a target through a horizontal figure-8 pattern. A total of 36 trials were completed by each subject. During the middle trials, 70-Hz tendon vibration was applied at the …

Two-Scale Microstructure Dynamics, Arkadi Berezovski, Mihhail Berezovski, Juri Engelbrecht

Publications

Wave propagation in materials with embedded two different microstructures is considered. Each microstructure is characterized by its own length scale. The dual internal variables approach is adopted yielding in a Mindlin-type model including both microstructures. Equations of motion for microstructures are coupled with the balance of linear momentum for the macromotion, but not coupled with each other. Corresponding dispersion curves are provided and scale separation is pointed out.

Toward GemeinschaftsgefüHl: Exploring Subordinate And Manager Perceptions Of Trust And Perceptions Regarding Behavioral Change Potential, Bobby G. Martin

Publications

In this qualitative, phenomenological study, Maslow‘s Eupsychian theory was used as the guiding framework for exploring the perceptions of trust and the behavioral change potential of subordinates (includes frontline supervisors) and managers (excludes frontline supervisors) within selected aviation maintenance organizations in Arizona. The problem addressed in the study was the growing concern that managers willfully mistreated subordinates, which led to decreased trust, motivation, and productivity. A combined representative sample of 10 maintenance technicians and frontline supervisors was purposively selected from the production lines of a large commercial aviation repair and overhaul station located in Arizona. An additional combined representative sample …

Self-Adaptive Application For Indoor Wayfinding For Individuals With Cognitive Impairments, Basel Magableh, Stephen Barrett

Articles

This article focuses on describing a Model Driven Archi- tecture (COCA-MDA) approach that facilitates the develop- ment of self-adaptive application for indoor wayfinding for individuals with cognitive impairments. COCA-MDA pro- vides the following benefits: 1) It enables the architecture to anticipate several behavioural variations based on the context and the specific needs of the individuals with cog- nitive impairments. 2) It enables the application to proac- tively anticipate or reactively address unforeseen changes through support by a dynamic-decision making and policy framework. The policy framework is based on a stable de- scription of software models and proprieties. 3) It can …

Theoretical Prediction Of Drug Release In Gi Tract From Spherical Matrix Systems, Naga Lakshmi Ramana Susarla

Dissertations

The significance of controlled release drug delivery systems (CRDDS) lies in their ability to deliver the drug at a steady rate thus reducing the dosage interval and providing a prolonged pharmacodynamic effect. But despite the steadily increasing practical importance of these devices, little is known regarding their underlying drug release mechanisms. Mathematical modeling of these drug delivery systems could help us understand the underlying mass transport mechanisms involved in the control of drug release. Mathematical modeling also plays an important role in providing us with valuable information such as the amount of drug released during a certain period of time …

Dispersion Of Particles On Liquid Surfaces, Sathishkumar Gurupatham

Dissertations

When small particles (e.g., flour, pollen, etc.) come in contact with a liquid surface, they immediately disperse. The dispersion can occur so quickly that it appears explosive, especially for small particles on the surface of mobile liquids like water. This explosive dispersion is the consequence of capillary force pulling particles into the interface causing them to accelerate to a relatively large velocity. The maximum velocity increases with decreasing particle size; for nanometer-sized particles (e.g., viruses and proteins), the velocity on an air-water interface can be as large as 47 m/s. They also oscillate at a relatively high frequency about their …

The Impact Of Dynamic And Passive Standing On Bone Mineral Density And Appositional Growth In Immobilized Children, Megan Diane Damcott

Dissertations

The first discovery of the potential role that mechanical loading has on determining the strength of bone occurred in 1892. However, for almost a century after this discovery, the specific mechanisms influenced by mechanical loading remained locked in a mysterious 'black box'. Then in the 1960s, the 'black box' was opened and continued work has now unlocked the basic mechanisms involved in mechanical loading and whole-bone strength. This increased knowledge has spurred clinicians and researchers to investigate the impact of weight-bearing interventions on individuals with an increased risk of osteoporosis. The most common weight-bearing clinical intervention used in non-ambulant populations …

Effects Of Operating And Geometric Variables On Hydrodynamics And Tablet Dissolution In Standard And Modified Dissolution Testing Apparatuses 2, Yimin Wang

Dissertations

Dissolution testing is routinely conducted in the pharmaceutical industry to provide critical in vitro drug release information for quality control purposes, and especially to assess batch-to-batch consistency of solid oral dosage forms such as tablets. Among the different types of apparatuses listed in the United States Pharmacopoeia (USP), the most commonly used dissolution system for solid dosage forms is the USP Dissolution Testing Apparatus 2, consisting of an unbaffled, hemispherical-bottomed vessel equipped with a 2-blade radial impeller.

Despite its extensive use in industry and a large body of work, some key aspects of the hydrodynamics of Apparatus 2 have received …

Synthesis And Development Of Boron Nanotubes And Metal/Ceramic-Carbon Nanotube Composites, Jinwen Liu

Dissertations

The first part of this thesis will be focused on developing a facile and scalable solid — solid chemical vapor deposition (CVD) process using a solid boron precursor to synthesize crystalline boron nanotubes (BNTs) mixed with small amounts of boron nanofibers (BNFs). The synthesis involves the use of solid boron precursors - magnesium boride and magnesium borohydride, magnesium and nickel boride as co-catalysts, and porous MCM-41 zeolite as the growth template. Experimental parameters, such as temperature, grinding of constituents and starting precursor-catalyst-template compositions, were studied and optimized. Detailed characterization have been carried out using field-emission scanning electron microscopy (FE-SEM), transmission …

Multifunctional Reactive Nanocomposite Materials, Demitrios Stamatis

Dissertations

Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al•MoO₃ and 2B•Ti nanocomposite powders enhances the reaction rate with little change …

Development Of A Vibration-Powered Impact Recorder, William Contreras

Theses

Currently, the U.S. Army stores a great deal of equipment for long periods of time. Often, this equipment is subjected to damaging vibrations. Given this, the army wants to be able to monitor the vibrations that are undergone by this equipment. Here, a battery-powered monitoring device would be undesirable because its batteries would need to be replaced. To solve this problem, an energy harvesting, vibration monitoring device has been developed. The device, which is known as a vibration-powered impact recorder (VPIR for short), uses a piezoelectric transducer to power a microcontroller, which uses the power to count the number of …

Influence Of Rear Wheel Tire Type On Wheelchair Propulsion Biomechanics, Mathew Yarossi

Theses

The objective of this study was to determine how rear wheel tire type affects wheelchair propulsion mechanics. Four persons with paraplegia and four persons with tetraplegia propelled their own wheelchairs on a roller system at self-selected speed using five different pairs of tires. Upper limb and trunk kinematics, perceived exertion, stroke pattern and the temporal characteristics of propulsion were measured. When using pneumatic (air filled) tires, with lower rolling resistance, participants had lower push frequency (p < .05), higher self selected speed (p < .05), less perceived exertion, less shoulder internal rotation, and a longer push stroke than when using solid, high rolling resistance tires. As rolling resistance increased, participants experienced negative changes in propulsion characteristic that contradicted current clinical practice guidelines for upper limb preservation following spinal cord injury. In addition, kinematics with solid, high rolling resistance tires were similar to those described during uphill or over carpet propulsion. In order to avoid unnecessary strain on the upper limbs and unwanted changes in propulsion biomechanics, wheelchair users, clinicians, and researchers should consider the use of lower rolling resistance, pneumatic rear tires.