Engineering Commons^™

Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt

Williams Honors College, Honors Research Projects

The dynamics of polymer thin films have been demonstrated to be significantly altered from the bulk, but the origins of such differences are not well defined. In this work, we seek to understand the differences in the structural dynamics (or physical aging) of polystyrene (PS) through branching and other well defined architectures (comb and centipede). The aging dynamics of ultrathin films (< 30 nm) differ from relatively thick films (100-150nm) with linear PS thin films aging more rapidly than the relatively “bulk-like” thick films. Ellipsometric measurements are used to characterize the physical aging rate of the films. The change in film thickness and refractive index as the films are held below the glass transition temperature (T_g) provides a simple measure of the physical aging. In this study, four different architectures (linear, comb, 4 arm star, and centipede) will be investigated. For each PS architecture, the aging rate will be determined for film thickness ranging ...

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the ...

Development And Testing Of Additively Manufactured Aerospike Nozzles For Small Satellite Propulsion, Isaac W. Armstrong

All Graduate Theses and Dissertations

Automatic altitude compensation has been a holy grail of rocket propulsion for decades. Current state-of-the-art bell nozzles see large performance decreases at low altitudes, limiting rocket designs, shrinking payloads, and overall increasing costs. Aerospike nozzles are an old idea from the 1960’s that provide superior altitude-compensating performance and enhanced performance in vacuum, but have survivability issues that have stopped their application in satellite propulsion systems. A growing need for CubeSat propulsion systems provides the impetus to study aerospike nozzles in this application. This study built two aerospike nozzles using modern 3D metal printing techniques to test aerospikes at a ...

Comparison Of Induced And Parasitic Drag On Wings With Minimum Induced Drag, Sarah A. Abdel-Motaleb

All Graduate Plan B and other Reports

Minimizing the induced drag for steady level flight is a variational problem that requires solving for the optimum lift distribution given a set of design constraints. From lifting-line theory, minimizing the induced drag is, in part, achieved by varying the Fourier coefficients used to describe the section lift. The elliptic lift distribution minimizes the induced drag for a wing with fixed weight and wingspan by setting all but the first coefficient to zero. If wingspan is allowed to vary, a negative third Fourier coefficient is utilized to reach an optimum lift distribution that further reduces the induced drag for stress-limited ...

Investigation Of Thermoplastic Polymers And Their Blends For Use In Hybrid Rocket Combustion, Spencer D. Mathias

All Graduate Theses and Dissertations

This thesis set out to find a blend of thermoplastics that had better combustion properties than the current ABS (acrylonitrile butadiene styrene) plastic or “Lego ^TM plastic” used by Utah State University. The current work is in an effort to eliminate toxic propellants from small space applications. High and low density polyethylene plastics were used because they are common plastic waste items. In this way rocket fuel can be made from these items to reduce the waste found in landfills. Three plastics were considered for replacement and as mixture components with the ABS plastic, namely low and high density polyethylene ...

Hydrodeoxygenation Of Pinyon-Juniper Catalytic Pyrolysis Oil, Hossein Jahromi

All Graduate Theses and Dissertations

Catalytic hydrodeoxygenation (HDO), is an effective process to convert oxygenated compounds to hydrocarbons. This process is widely used for improving the negative properties of biomass-derived pyrolysis oils (bio-oils) such as high acidity, poor stability, and low heating value. During this process oxygen is removed from the bio-oil in the form of water, thus the liquid product of HDO process consists of aqueous phase and hydrocarbon phase that can be easily separated. Synthesis of efficient HDO catalyst has been a major challenge in the field of bio-oil upgrading. Red mud, which is an alkaline waste from alumina industry was used to ...

Pressure Loss Coefficients For Large Mitered Elbows With Diameters Ranging From 36-Inches To 144-Inches, Hayden J. Coombs

All Graduate Theses and Dissertations

When designing a pipeline system, it is important to understand the pressure losses that will occur within the system. One common source of pressure loss is from elbow pipe fittings. There is extensive research available for pressure loss coefficients of elbow pipe fittings, but the research is derived from elbows with relatively smaller pipe diameters. The purpose of this research is to investigate pressure losses associated with larger diameter mitered elbows (36-inches to 144-inches). The dimensions for all mitered elbows considered in this research follow ANSI/AWWA C208-17 recommendations (AWWA 2017).

Due to the large size of the mitered elbows ...

Influence Of Mechanical Properties Of Paper Coating On The Crack At The Fold Problem, Seyyed Mohammad Hashemi Najafi

Electronic Theses and Dissertations

Paper coating layers are subject to various stresses and deformations in many converting processes such as calendering, printing, slitting, and folding of the paper. In some cases, products may crack during folding to generate a defect called cracking at the fold (CAF). The parameters that influence these defects are not well understood. The overall goal of this thesis is to better understand the CAF behavior as related to material properties of the coating layer.

A method was developed to produce free-standing pigmented coating layers thick enough to be tested in bending as well as tension. The mechanical properties of these ...

Measuring Nitrogen Transformation In Wastewater Impacted Streams Using In-Situ Benthic Chambers, Makenzi Beltran

All Graduate Theses and Dissertations

Acrylic chambers and metal frames were installed at the sediment-water interface of streams impacted by the effluent from wastewater reclamation facilities in order to determine nitrogen rates for nitrification, denitrification, assimilation, ANAMMOX, and DNRA. Each chamber was dosed with an isotopic form of nitrate (¹⁵NO₃ ^- ), and both isotopic (¹⁵N) and non-isotopic (¹⁴N) samples were collected. The project locations included East Canyon Creek near the East Canyon Wastewater Reclamation Facility in Park City, Utah and Box Elder Creek near the Brigham City Wastewater Treatment Plant in Brigham City, Utah. Separate chamber measurements were conducted upstream and downstream ...

Sensor Intrusion Detection In Control Systems Using Estimation Theory, Jiayi Su

Master's Theses (2009 -)

In this thesis, two different approaches to sensor intrusion detection are presented. In the first approach, an estimation algorithm using a bank of Kalman Filters is designed that is capable of estimating the intrusion signal when sensors are affected in control systems. The mathematical models of the control system will be estabilished and the system measurement will be shown and after that, various false signals, such as constant-type and ramp-type signal, will be selected as the intrusion signal to affect the system output mentioned above. The system measurement will be tested based on a bank of Kalman Filters. The probabilities ...

Synopsis Of Engineers Without Borders (Ewb) Trip, Guatemala January 5 To January 12, 2019, Willis Weight

Engineers Without Borders

The Carroll Guatemala Engineers Without Borders (EWB) team assembled at a variety of locations from around the western USA before traveling together as a group into Guatemala City from a flight from Los Angeles. The flight from Los Angeles on Saturday morning departed about 11:00 AM local time. Two of us departed about 6:00 am from the Missoula airport (Willis Weight and Kennedy Bahm) and the following students: Ian Kirby, Josiah Groux, Amelia Schuver, Ericka Seehafer, Mary Van Dyke (health and safety officer), and Amber Pickering (project leader) came in from Portland, Seattle, and SLC). Professional mentor Ryan ...

Passive Compliance Control Of Redundant Serial Manipulators, Jacob J. Rice

Dissertations (2009 -)

Current industrial robotic manipulators, and even state of the art robotic manipulators, are slower and less reliable than humans at executing constrained manipulation tasks, tasks where motion is constrained in some direction (e.g., opening a door, turning a crank, polishing a surface, or assembling parts). Many constrained manipulation tasks are still performed by people because robots do not have the manipulation ability to reliably interact with a stiff environment, for which even small commanded position error yields very high contact forces in the constrained directions. Contact forces can be regulated using compliance control, in which the multi-directional elastic behavior ...

Detection And Characterization Of Actuator Attacks Using Kalman Filter Estimation, Yuqin Weng

Master's Theses (2009 -)

In this thesis, two discrete-time control systems subject to noise, are modeled, analyzed and estimated. These systems are then subjected to attack by false signals such as constant and ramp signals. In order to find out how and when the control systems are being attacked by the false signals, several detection algorithms are applied to the systems. This work focuses on actuator attack detection. To detect the presence of false actuator signals, a bank of Kalman filters is set up which uses adaptive estimation and conditional probability density functions for detecting the false signals. The individual Kalman filters are each ...

Determining The Relationship Between Walking Activity And Inter-Day Patterns In Stroke Survivors, Sydney Andreasen

Student Research and Creative Activity Fair

Populations that have suffered from stroke are generally less active than people of otherwise similar demographics and are more susceptible to further health problems, such as another stroke. This study seeks to assess the validity of a treatment that encourages stroke survivors to walk more steps each day, in order to improve their active abilities and become less idle by establishing motivation for activity and therefore, also establishing patterns in the distribution of that activity throughout a stroke survivor’s day. 172 subjects (6 months post-stroke) have participated in a step activity monitoring program to record steps taken using wearable ...

Collision Work Performed By Patients With Peripheral Artery Disease, Alex Dzewaltowski, Sara A. Myers, Jason M. Johanning, Iraklis I. Pipinos

Student Research and Creative Activity Fair

The goal of this study was to assess the differences in collision work performed by healthy, aged-matched controls compared to patients with peripheral artery disease (PAD) to provide foundations for an eventual exoskeleton design. Collision work is energy dissipated into the surrounding environment from impact, in this study’s case, upon heel strike. When designing an exoskeleton for patients with PAD, harvesting energy lost to collision work could be a valuable mechanism to improve walking performance. Devices designed to utilize the normally dissipated energy for assisting propulsion to improve walking performance are under-explored [1, 2]. The purpose of this study ...

The Time Of Slip Onset During Stance Influences The Characteristics Of The Unconstrained Perturbation, Corbin Rasmussen, Nathaniel Hunt

Student Research and Creative Activity Fair

Falls pose a significant health hazard, resulting in devastating injuries like broken wrists, fractured hips, and traumatic brain injuries that exceed $50 billion in U.S. medical costs. To address these risks, biomechanists have subjected individuals to simulated slips in order to study the factors that lead to falls. These studies have focused on slips that happen immediately after heel-strike and are unnaturally restricted by the methods used to cause the slip. Therefore, the effects of unconstrained slips that occur throughout stance phase are unknown. To address this knowledge gap, we examined the relationship between the timing of slip onset ...

A Radio Frequency Identification (Rfid) Prosthetic Control System, Andrew Butler

Student Research and Creative Activity Fair

Item classification and tagging in embedded systems has become ubiquitous in our society due to radio frequency identification (RFID) and the cost has dropped significantly for hardware that can interact with these devices. Due to this, possibilities in the realm of prosthetic control systems opens up for dynamic grip selection without user intervention. This study focuses on the development of a device capable of this functionality that is compatible with the prosthetics designed by Dr. Zuniga and his research team.

The printed circuit board (PCB) was designed using the EAGLE EDA package and incorporates a lithium polymer battery with a ...

Automotive Intrusion Detection Based On Constant Can Message Frequencies Across Vehicle Driving Modes, Clinton Young, Habeeb Olufowobi, Gedare Bloom, Joseph Zambreno

Electrical and Computer Engineering Conference Papers, Posters and Presentations

The modern automobile relies on numerous electronic control units communicating over the de facto standard of the controller area network (CAN) bus. This communication network was not developed with cybersecurity in mind. Many methods based on constant time intervals between messages have been proposed to address this lack of security issue with the CAN bus. However, these existing methods may struggle to handle variable time intervals between messages during transitions of vehicle driving modes. This paper proposes a simple and cost-effective method to ensure the security of the CAN bus that is based on constant message frequencies across vehicle driving ...

Anomaly Detection Approach Using Adaptive Cumulative Sum Algorithm For Controller Area Network, Habeeb Olufowobi, Uchenna Ezeobi, Eric Muhati, Gaylon Robinson, Clinton Young, Joseph Zambreno, Gedare Bloom

Electrical and Computer Engineering Conference Papers, Posters and Presentations

The modern vehicle has transformed from a purely mechanical system to a system that embeds several electronic devices. These devices communicate through the in-vehicle network for enhanced safety and comfort but are vulnerable to cyber-physical risks and attacks. A well-known technique of detecting these attacks and unusual events is by using intrusion detection systems. Anomalies in the network occur at unknown points and produce abrupt changes in the statistical features of the message stream. In this paper, we propose an anomaly-based intrusion detection approach using the cumulative sum (CUSUM) change-point detection algorithm to detect data injection attacks on the controller ...

Emerging Need For A European Approach To Space Traffic Management, Tomas Hrozensky

Space Traffic Management Conference

The intensification of space activities worldwide, together with the emergence of new actors and disruptive concepts (e.g. miniaturized satellites, mega-constellations, in-orbit operations), create new challenges to ensure the safety and security of space systems and operations as well as the long-term sustainability of space activities. Among policy responses to these challenges, the development of a new approach to space traffic management was recently brought to the forefront by the adoption of a policy directive in this domain by the United States.

A comparable STM policy has not yet been developed in Europe even though considerations for the safety, security ...