Engineering Commons^™

Particle-In-Cell Simulations Examining Ak Gap Closure Mechanisms In The Pinch Reflex Diode, Elizabeth Madrid

Electrical and Computer Engineering ETDs

Gap closure mechanisms in the pinch reflex diode are studied using cylindrical, two-dimensional, fully kinetic, electromagnetic, particle-in-cell simulations. The key physical dimensions in the model are based on the Mercury accelerator at the Naval Research Laboratory in Washington, DC. Simulation results agree well with theoretically predicted currents and impedances as well as with experimental values. The effects of cathode plasma formation with various desorption rates are studied. Also examined are different cathode plasma species including H, H2, N2, H2O, and C. While the presence of heavier plasma species results in lower ion current production, total diode current and voltage are …

Water Condensation And Protein Adsorption On Hybrid Superhydrophobic-Hydrophilic Surfaces, Bikash Mondal

Dissertations, Theses, and Capstone Projects

This thesis describes the study of protein adsorption and water condensation on hybrid superhydrophobic-hydrophilic surfaces for various technological applications such as diagnostics, artificial organs and medical devices, water collection, and heat transfer.

In the chapter 1, a general introduction to wetting theories, superhydrophobic surface, and hybrid surfaces is given. In chapter 2, design and fabrication of a hybrid superhydrophobic surface for studying dropwise condensation and heat transfer is discussed. Effect of surface chemistry and wettability on protein adsorption is discussed in the chapter 3. Finally, in chapter 4, the protein adsorption study on hybrid superhydrophobic surfaces made by 3D-printing and …

Effect Of Temporal Onset Of Mechanical Loading On Tendon To Bone Healing, Determined With A Novel In-Vivo Device, Mark E. Stasiak

Dissertations, Theses, and Capstone Projects

Background: Exposure to tensile loading has been shown to maintain tendon/ligament homeostasis, with the tensile modulus of the tissue increasing in response to greater loading frequency, and even decreasing in the absence of load. However after injury or surgical repair the effect of tensile load is controversial, with many studies implicating mechanical loading with impaired healing. It is currently unknown when the tensile loading imparted during rehabilitation exercise, can be safely reintroduced after surgical tendon repair or ligament reconstruction, and at what time point it can most benefit the remodeling process. To investigate the effect of tensile loading protocols on …

Design And Development Of A High-Performance Quadrotor Control Architecture Based On Feedback Linearization, William Neeley

Electrical and Computer Engineering ETDs

The purpose of this thesis is to outline the development of a high-performance quadrotor control system for an AscTec Hummingbird quadrotor using direct motor speed control within a Vicon motion capture system environment. A Ground Control Station (GCS) acts as a user interface for selecting flight patterns and displaying sensor values. An on-board Intel Edison embedded Linux computer acts as the quadrotor's controller. The Vicon system measures the quadrotor's position and orientation, while the Hummingbird's stock AscTec Autopilot board provides inertial measurements and receives motor speed commands. Based on the flight pattern set by the GCS, smooth and di erentiable …

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose

Dissertations

Oil spills could have devastating effects on the shorelines, and for this reason, chemical dispersants are commonly used to disperse the oil slick in the water column, preventing it from reaching the shorelines. However, the long term fate of dispersed oil depends on its biodegradation by indigenous microorganisms, which in turn depends on the concentration of nutrients in water and on the droplet size distribution.

Using water from the shorelines of Atlantic City, we placed the water with oil and dispersant inside EPA Baffled Flasks and placed them on rotatory shakers. We selected two speeds: high (250 rpm) and low …

Verification Of Emotion Recognition From Facial Expression, Yanjia Sun

Dissertations

Analysis of facial expressions is an active topic of research with many potential applications, since the human face plays a significant role in conveying a person’s mental state. Due to the practical values it brings, scientists and researchers from different fields such as psychology, finance, marketing, and engineering have developed significant interest in this area. Hence, there are more of a need than ever for the intelligent tool to be employed in the emotional Human-Computer Interface (HCI) by analyzing facial expressions as a better alternative to the traditional devices such as the keyboard and mouse.

The face is a window …

Normal-Strength And High-Strength Concrete Columns Under Cyclic Axial Load And Biaxial Moment, Mehdi Zarei

Dissertations

The technique of using Carbon Fiber Reinforced Polymer (CFRP) materials to repair and strengthen various concrete members has become popular in the structural retrofitting field as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. In this study a method was introduced to study the behavior of concrete columns with and without CFRP jackets under constant axial load and variable lateral load. The lateral load was applied monotonically and cyclically. To predict the behavior of concrete columns under monotonic and cyclic compressive loadings, a computer code was developed to produce the …

Experimental And Theoretical Evaluation Of In-Depth Damage Distribution In Sawn Silicon Wafers, Srinivasamurthy Devayajanam

Dissertations

As-sawn silicon wafers have surface damage that needs to be removed before any further processing into solar cells. This damage distribution can vary with cutting parameters such as wire size, slurry particle/diamond grit size, and wire usage. To date, there is no simple way to measure the degree of damage, damage depth, and damage distribution. But, this information is needed by the wafer manufacturers as well as solar cell manufacturers.

A technique based on sequential etching of silicon wafers and minority carrier lifetime (τ_eff) measurements is used to determine damage depth. In this technique, samples are sequentially etched …

Reversing The Tide In Science, Engineering, Technology And Mathematics (Stem): Academically Gifted African American Students In Historically Black Colleges & Universities, Delores Rice, Fred Bonner, Chance Lewis, Mary Alfred, Felecia M. Nave, Sherri Frizell

Journal of Research Initiatives

What started off as a national concern has escalated to the point of crisis (Bonner, Alfred, Lewis, Nave & Frizell, 2009; Chubin & Malcolm, 2008; Hrabowski, Summers & Hrabowski, 2006). The current state of affairs regarding African American participation in STEM disciplines has become one of the thorniest issues of contemporary focus. This article highlights data collected for a NSF Education Research grant. The focus of this HBCU-UP project was to uncover factors contributing to the success of academically gifted (high-achieving) African American students enrolled in engineering programs at the 12 ABET accredited four-year institutions in the U.S. Specifically, this …

The Stem Pipeline: Recruiting And Retaining African American Female Engineers, Delores Rice

Journal of Research Initiatives

The purpose of the study was to examine the career experiences of African American female engineers and explore their challenges and support systems during their career development. This qualitative study utilized a life history approach and was designed using basic interpretive inquiry. There were nine African American female participants in the study who currently worked in an engineering field within an engineering industry. Using an ecological model to ground the study, the findings were categorized as macrosystem (environment) or microsystem (individual) factors. The highlight of this manuscript includes a focus on implications, which offer insight into recruiting and retaining African …

Understanding Bulk Behavior Of Particulate Materials From Particle Scale Simulations, Xiaoliang Deng

Dissertations

Particulate materials play an increasingly significant role in various industries, such as pharmaceutical manufacturing, food, mining, and civil engineering. The objective of this research is to better understand bulk behaviors of particulate materials from particle scale simulations.

Packing properties of assembly of particles are investigated first, focusing on the effects of particle size, surface energy, and aspect ratio on the coordination number, porosity, and packing structures. The simulation results show that particle sizes, surface energy, and aspect ratio all influence the porosity of packing to various degrees. The heterogeneous force networks within particle assembly under external compressive loading are investigated …

Plasticity Of The Cortical Representation Of Finger Extensors Induced By Paired Associative Stimulation, Ian Anthony Gerard Lafond

Dissertations

This dissertation first explored associative plasticity of the human motor cortical representation with the use of noninvasive transcranial magnetic stimulation (TMS) paired with peripheral electrical stimulation. Paired Associative Stimulation (PAS) has grown in popularity because of its potential clinical applications. PAS techniques are used in combination with electromyography (EMG) measurements to study cortical excitability and features of hand movement. This work focuses on a cohesive approach to answer central questions about: the ideal mechanism to facilitate cortical plasticity via PAS, the interaction between the behavior performed and type of stimulation delivered to the targeted cortical network and the effects of …

Generalized Dft: Extensions In Communications, Yuewen Wang

Dissertations

Discrete Fourier Transform (DFT) is a restricted version of Generalized DFT (GDFT) which offers a very limited number of sets to be used in a multicarrier communication system. In contrast, as an extension on Discrete Fourier Transform (DFT) from the linear phase to non-linear phase, the proposed GDFT provides many possible carrier sets of various lengths with comparable or better performance than DFT. The availability of the rich library of orthogonal constant amplitude transforms with good performance allows people to design adaptive systems where user code allocations are made dynamically to exploit the current channel conditions in order to deliver …

Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst

Theses

With the rapid depletion of non-renewable sourced materials, unpredictable fluctuations in the prices of fossil fuels, and increased environmental awareness the need to develop biobased materials grows ever more desperate. Furan derivatives sourced from hexoses provide a promising solution for replacing petrochemical based materials. One furan derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline properties of a totally renewable sourced thermotropic polyester based on FDCA. Fructose was …

An Fpga Implementation Of A Sleep Enabled Pon System, Zheyu Liu

Theses

Owing to the growing demand for bandwidth-hungry video-on-demand applications, Passive Optical Network (PON) has been widely considered as one of the most promising solutions for broadband access. Environmental concerns motivated network designers to lower energy consumption of optical access networks. A well-known approach to reduce energy consumption is to allow network elements to switch to the sleep mode.

In this framework, an improved Optical network Unit (ONU) architecture in TDM-PON is proposed to reduce the handover time of status switching. Energy-saving performances of current and improved architectures are compared in different scenarios. The simulation results show that by applying a …

A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri

Theses

Drug nanoparticles can achieve targeting capabilities, enhanced dissolution rates and improved bioavailability when injected intravenously. Sterile filtration of drug nanoparticle suspensions (nanosuspensions) is critically needed for administration by intravenous delivery route. Avoiding gamma irradiation and high temperatures, sterile filtration could be an effective process to sterilize drug nanosuspensions. On the other hand, two major challenges must be tackled: drug particles must at least be smaller than the filter pore size and minimum amount of non-toxic stabilizers must be used to prevent side effects like pain on the injection site. The aim of this study is to prepare naproxen (NPX) nanosuspensions …

Thermoelectric Properties Of Silicon-Germanium Alloys, Aniket Annasaheb Maske

Theses

Direct energy conversion from thermal to electrical energy, based on thermoelectric effects, is attractive for potential applications in waste heat recovery and environmentally friendly refrigeration. The energy conversion efficiency of thermoelectric devices is related to the thermoelectric figure of merit ZT, which is proportional to the electrical conductivity, the square of the Seebeck coefficient, and the inverse of the thermal conductivity. Currently, the low ZT values of available materials restrict the large scale applications of this technology. Recently, however, significant enhancements in ZT have been reported in nanostructured materials such as super-lattices mainly due to their low thermal conductivities. According …

A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye

Theses

Several studies such as the equilibrium point hypothesis (EPH) purport that the motor signals that descend from the brain instead of encoding muscle torques, influence an existing relationship between muscle torque and body configuration.

In the present study, the possibility of torque depending explicitly on position was tested using a task in which subjects (N=5) moved a simulated weightless frictionless mass through a small (<8 degree) elbow extension in order to move a cursor on a screen to a target location. Each subject completed 720 trials. On ~10% of trials the simulated mass was increased unknown to the subject. The relationship between the cursor’s position and the torque applied to the system was held constant even when the simulated mass was increased. Thus, any change in torque produced was neither due the subjects’ perception of the mass nor due to their perception of the cursor. The time at which the subjects torque changed direction was seen to be significantly different (p<0.005) during trials which the mass changed. This change in torque is concluded to be position-dependent. However the possibility of this being a merely mechanical effect could not be ruled out by due to poor EMG collection.

A post-hoc analysis of different position-dependent motor control models, was done. Particularly, an exponential spring model, a linear spring model, and a linear spring with relative damping model were each tested to see how well …

Shock Wave Interaction With A Fluid Filled Cylinder Experimental Methods, Praveen Kumar Baba Siddabattuni

Theses

In the recent wars of Iraq and Afghanistan, many soldiers sustained bTBI (blast-induced traumatic brain injury). The blasts are created by extensive use of improvised explosive devices (IED’s). Whether pure blast-shock waves cause TBI or what is the mechanism of injury are not fully known. Research efforts are underway to find answers to these questions.

The primary objective of this project is to understand how the shockwave interacts with a fluid-filled cylinder of different thicknesses. Here, the cylinder is idealized as head and the fluid filled inside it as the brain material. The primary interest here is, how the pure …

Comparison Of Muscle Synergies Elicited From Transcranial Meganetic Stimulation (Tms) And Voluntary Movements, Yifei Wei

Theses

A key question in motor control is the redundancy of musculoskeletal elements involved. This problem refers to as the degree of freedom problem. The Muscle Synergy Hypothesis is one of the hypotheses that aim to resolve the problem which defines that a muscle synergy is a combination of a small set of muscles activated at different levels, serving as a building block that constructs motor behaviors. A recent study (Overduin et al. 2012) demonstrated that muscle synergies decomposed by Nonnegative Matrix Factorization (NMF) from EMG patterns evoked by intra-cortical microsimulation (ICMS) in the monkey remarkably matched ones observed in naturalistic …

Rodent Testing Device Surrogate For Shockwave Blast Testing, Anthony C. Misistia

Theses

Many laboratories around the world are conduct shockwave blast injury tests on rodents to simulate blast traumatic brain injury (TBI). Each of these laboratories has different techniques for creating the shockwave blasts as well as positioning the rats. There is no device to determine whether or not the rodent animal models actually experiences a true blast wave in a given set up. This device was developed as a method for verifying rodents undergoing true shockwave blasts through biometrics, instrumentation and the basic biomechanical responses a rodent experiences during such tests. Since the goal of shockwave blast testing is to replicate …

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential flow, …

Investigating Neural Mechanisms Of Hand Movements In Virtual Reality, Chuang Mu

Theses

Mirror visual feedback (MVF), a technique by which movement of one limb is perceived as movement of the contralateral limb, has the capacity to relieve phantom limb pain or promote motor recovery of the upper limbs after stroke (Ramachandran et al., 1995). Functional MRI studies have demonstrated activation of the motor areas in the hemisphere ipsilateral to the moving hand in response to MVF. However, the neural mechanisms of MVF are still unclear. This Electroencephalography (EEG) study was designed to investigate the timing of neural responses to MVF presented in virtual reality. 16 right-handed, neurologically healthy subjects participated in a …

Realization Of Dynamixel Servo Plant Parameters To Improve Admittance Control For A Compliant Human-Robot Interaction, Ahmad Zahid Rao

Theses

In theory, admittance control offers a very effective method of implementing smooth human-robot interaction. It allows the user’s applied force to control the movement of a powerful robot as if the robot were a small, passive mass. However, the real-world application of admittance control faces limitation posed by the dynamics of servo motors, the accuracy of the force sensors, and the computation speed of processors.

This research investigates the limitations on achieving compliant passive behavior when using state-of-the-art actuators, sensors and processors. The work involves characterizing the dynamic behavior of the servo motors, development of improved differential equations representing admittance …

Key Management Scheme Based On Route Planning Of Mobile Sink In Wireless Sensor Networks, Ying Zhang, Jixing Liang, Bingxin Zheng, Shengming Jiang, Wei Chen

Computer Science Faculty Research

In many wireless sensor network application scenarios the key management scheme with a Mobile Sink (MS) should be fully investigated. This paper proposes a key management scheme based on dynamic clustering and optimal-routing choice of MS. The concept of Traveling Salesman Problem with Neighbor areas (TSPN) in dynamic clustering for data exchange is proposed, and the selection probability is used in MS route planning. The proposed scheme extends static key management to dynamic key management by considering the dynamic clustering and mobility of MSs, which can effectively balance the total energy consumption during the activities. Considering the different resources available …

Growth Control Of Oxygen Stoichiometry In Homoepitaxial Srtio3 Films By Pulsed Laser Epitaxy In High Vacuum, Ho Nyung Lee, Sung S. Ambrose Seo, Woo Seok Choi, Christopher M. Rouleau

Physics and Astronomy Faculty Publications

In many transition metal oxides, oxygen stoichiometry is one of the most critical parameters that plays a key role in determining the structural, physical, optical, and electrochemical properties of the material. However, controlling the growth to obtain high quality single crystal films having the right oxygen stoichiometry, especially in a high vacuum environment, has been viewed as a challenge. In this work, we show that, through proper control of the plume kinetic energy, stoichiometric crystalline films can be synthesized without generating oxygen defects even in high vacuum. We use a model homoepitaxial system of SrTiO₃ (STO) thin films on …

Dynamic Phase-Control Of A Rising Sun Magnetron Using Modulated And Continuous Current, Sulmer Fernandez-Gutierrez, Jim Browning, Ming-Chieh Lin, David N. Smithe, Jack Watrous

Electrical and Computer Engineering Faculty Publications and Presentations

Phase-control of a magnetron is studied via simulation using a combination of a continuous current source and a modulated current source. The addressable, modulated current source is turned ON and OFF at the magnetron operating frequency in order to control the electron injection and the spoke phase. Prior simulation work using a 2D model of a Rising Sun magnetron showed that the use of 100% modulated current controlled the magnetron phase and allowed for dynamic phase control. In this work, the minimum fraction of modulated current source needed to achieve a phase control is studied. The current fractions (modulated versus …

Human Igg1 Antibodies Suppress Angiogenesis In A Target-Independent Manner, Sasha Bogdanovich, Younghee Kim, Takeshi Mizutani, Reo Yasuma, Laura Tudisco, Valeria Cicatiello, Ana Bastos-Carvalho, Nagaraj Kerur, Yoshio Hirano, Judit Z. Baffi, Valeria Tarallo, Shengjian Li, Tetsuhiro Yasuma, Parthasarathy Arpitha, Benjamin James Fowler, Charles B. Wright, Ivana Apicella, Adelaide Greco, Arturo Brunetti, Menotti Ruvo, Annamaria Sandomenico, Miho Nozaki, Ryo Ijima, Hiroki Kaneko, Yuichiro Ogura, Hiroko Terasaki, Balamurali K. Ambati, Jeanette H. W. Leusen, Wallace Y. Langdon, Michael R. Clark, Bradley D. Gelfand, Jayakrishna Ambati

Ophthalmology and Visual Science Faculty Publications

Aberrant angiogenesis is implicated in diseases affecting nearly 10% of the world’s population. The most widely used anti-angiogenic drug is bevacizumab, a humanized IgG1 monoclonal antibody that targets human VEGFA. Although bevacizumab does not recognize mouse Vegfa, it inhibits angiogenesis in mice. Here we show bevacizumab suppressed angiogenesis in three mouse models not via Vegfa blockade but rather Fc-mediated signaling through FcγRI (CD64) and c-Cbl, impairing macrophage migration. Other approved humanized or human IgG1 antibodies without mouse targets (adalimumab, alemtuzumab, ofatumumab, omalizumab, palivizumab and tocilizumab), mouse IgG2a, and overexpression of human IgG1-Fc or mouse IgG2a-Fc, also inhibited angiogenesis in wild-type …

College Of Engineering Undergraduate Advisor Receives National Award | College Of Engineering, Usu College Of Engineering

College of Engineering News

Jan. 27, 2016 – An undergraduate advisor in the College of Engineering has been selected to receive a major award from the National Academic Advising Association, or NACADA.

Katherine Grover, who advises biological and mechanical engineering students in the College of Engineering, will receive the 2016 Region 10 Excellence in Advising – New Advisor Award at an upcoming conference in Santa Fe, N.M.

Finite Element Modeling Of Shallow Embedded Connection Stiffness, Trevor Jones, Dr. Paul Richards

Journal of Undergraduate Research

Shallowly embedded connections are a common and important connection of steel columns to reinforced concrete foundations, which can increase the building’s overall stiffness and strength. Until now, their contributions have been neglected because they are hard to quantify and study. Previous research at BYU (Barnwell 2015) has shown that the strength and stiffness available in these connections is greater than was previously assumed. A thorough understanding of these desirable properties would allow engineers to design buildings that are more cost-effective.