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Full-Text Articles in Engineering

Impact Of Chain Architecture On The Thickness Dependence Of Physical Aging Rate Of Thin Polystyrene Films, Gregory Brown, Elizabeth Lewis, Bryan D. Vogt Jan 2020

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 (Tg) 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 ...


Development And Testing Of Additively Manufactured Aerospike Nozzles For Small Satellite Propulsion, Isaac W. Armstrong May 2019

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 May 2019

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 May 2019

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 May 2019

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 May 2019

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 ...


Sensor Intrusion Detection In Control Systems Using Estimation Theory, Jiayi Su Apr 2019

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 ...


Passive Compliance Control Of Redundant Serial Manipulators, Jacob J. Rice Apr 2019

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 Apr 2019

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 ...


Characterization, Source Apportionment And Health Analysis Of Air Pollutants In India, Hao Guo Feb 2019

Characterization, Source Apportionment And Health Analysis Of Air Pollutants In India, Hao Guo

LSU Doctoral Dissertations

In recent years, severe pollution events occurred frequently in India, which are of significant concern of the public. However, limited studies have been conducted to understand the formation, sources and health effects of high pollution levels and the information for design of effective control strategies is urgently needed. First, criteria air pollutants data at 10 sites for 2017 in Delhi were analyzed to understand the current pollution status. The results show that annual fine particulate matter (PM2.5) concentrations exceeded the National Ambient Air Quality Standards (NAAQS), India of 60 µg/m3 at all sites. Source-oriented versions of ...


An Experimental Study Of Fractional Wettability Effects On Gas Assisted Gravity Drainage (Gagd), Abdullah Abdulrahman A. Al-Tameemi Jan 2019

An Experimental Study Of Fractional Wettability Effects On Gas Assisted Gravity Drainage (Gagd), Abdullah Abdulrahman A. Al-Tameemi

LSU Master's Theses

Utilizing the power of nature to solve engineering problems has been a time-honored tradition, for example, using the sunlight as a heat and light source. From this principle, the visionary idea of Gas Assisted Gravity Drainage (GAGD) came. The GAGD process utilizes the natural segregation phenomenon of fluids with different densities in order to produce oil efficiently and economically. Waterflooding processes typically do not recover more than 40% of the original oil in place (OOIP), leaving a vast amount of oil behind. A practical and well-planned enhanced oil recovery (EOR) method is needed. However, to plan a successful project, the ...


Low-Density Static Granular Media Filter Bed Turbidity Removal Model, Matthew Louque Jan 2019

Low-Density Static Granular Media Filter Bed Turbidity Removal Model, Matthew Louque

LSU Master's Theses

The scattering of light within a fluid, referred to as its turbidity, was investigated against the presence of suspended solids. A linear regression analysis was conduced against turbidity and the total count, combined surface area, and combined volume of the suspended particles for various surface water sources (lakes, rivers, indoor aquaculture systems). It was found that the total combined surface area of suspended particles had the best linear correlation to turbidity, with an adjusted R2 of 81.79%. This correlation was integrated with a current theoretical model for predicting solids removal across a granular bed to yield an Integrated ...


Bouncing Dynamics Of A Class Of Mem/Nem Switching Systems, Mohamed Bognash Jan 2019

Bouncing Dynamics Of A Class Of Mem/Nem Switching Systems, Mohamed Bognash

Electronic Thesis and Dissertation Repository

The aim of the present research is to understand the bouncing dynamic behavior of NEM/MEM switches in order to improve the switch performance and reliability. It is well known that the bouncing can dramatically degrade the switch performance and life; hence, in the present study, bouncing dynamics of a cantilever-based NME/MEM switch has been studied in detail. To this end, a model of a MEM switch that incorporates electrostatic force, squeeze film air damping force as well as asperity-based contact force has been proposed for an electrostatically actuated switch. An actuation force due to piezoelectric effects is further ...


A Study Of Catalytic Microcombustion For A Portable Power Supply Device, Bhanuprakash Reddy Guggilla Jan 2019

A Study Of Catalytic Microcombustion For A Portable Power Supply Device, Bhanuprakash Reddy Guggilla

Theses and Dissertations

The essential need for portable and dense power sources has been greatly increased with the prevalence of portable electronic devices in the past decade. Catalytic combustion of hydrocarbon and oxygenated fuels has the potential to provide an alternative power source for portable electronic devices by replacing relatively today's heavy battery technology. A successful self-ignition and sustainable catalyst combustion for a variety of fuels using Platinum (Pt)-impregnated substrate was demonstrated in our previous work.

Present work explores the performance of a microcombustion thermoelectric coupled (MTC) device with improved reactor configuration design. Chemically synthesized platinum nanoparticles with particle diameters of ...


Heat Of Hydration Thermal Performance And Flexural Capacity Of Stainless-Steel Reinforced Concrete Sections, Mokhtar Khalifa Jan 2019

Heat Of Hydration Thermal Performance And Flexural Capacity Of Stainless-Steel Reinforced Concrete Sections, Mokhtar Khalifa

Electronic Thesis and Dissertation Repository

Stainless steel (SS) is increasingly used in the construction field due to its high strength and corrosion resistance. However, its coefficient of thermal expansion is different from that of concrete. This difference raises concerns about the potential for concrete cracking during the hydration process. To address this concern, a thermal-structural finite element model was developed to predict the stresses in SS reinforced concrete (RC) sections during the hydration process. Different curing regimes were taken into consideration. The analysis was performed in two stages. First, a transient thermal analysis was performed to determine the temperature distribution within the concrete section as ...


From Drought To Food-Energy-Water-Security Nexus: An Assessment Of Food Insecurity In The Middle East, Maysoun Ayad Hameed Jan 2019

From Drought To Food-Energy-Water-Security Nexus: An Assessment Of Food Insecurity In The Middle East, Maysoun Ayad Hameed

Dissertations and Theses

Drought is an extreme climate phenomenon that happens slowly and periodically threatens the environmental and socio-economic sectors. Developing countries have experienced crucial conditions in meeting the needs for food, energy, and water security. Natural disasters contribute as risky sources of food insecurity and vulnerability in the Middle East. This dissertation presents a country-level review and quantitative assessment of the current issues associated with the Food-Energy-Water-Security (FEWS) Nexus in the Middle East. In this study, sixteen countries in the Middle East are chosen, namely, Arabian Peninsula, Iran, Syria, Lebanon, Israel, Palestine, Egypt, and Turkey. The most recent datasets are used to ...


Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma Jan 2019

Ignition And Extinction Behavior Of Fuels In A Microcombustor, Pawan Sharma

LSU Doctoral Dissertations

Conventional fuel testing device-CFR engine requires large quantities of fuels, which makes it unsuitable for research of small samples of fuels. This current study seeks to address this limitation by using an externally heated microcombustor as an alternative fuel testing device. Mainly three combustion behaviors have been observed inside a microcombustor: strong flames at higher flow rates, Flames with Repetitive Extinction and Ignition (FREI) at intermediate flow rates, and weak flames at marginal flow rates. In previous studies, weak combustion behavior has been proven suitable to study fuel properties from small samples of fuels. Microcombustor experiments typically rely on flame ...


An Airlifted Tidal Mesocosm For Oil Degradation Studies, Daniel Christopher Alt Jan 2019

An Airlifted Tidal Mesocosm For Oil Degradation Studies, Daniel Christopher Alt

LSU Doctoral Dissertations

Mesocosms were constructed to allow scientists to isolate variables in a microtidal marsh environment, mimicking the natural conditions found in Terrebonne Bay. The control offered by these mesocosms is given by a process control system that takes user inputs and automates water movement. Twelve mesocosms were constructed, each holding 4.02 m3 (142 ft3) of marsh soil and 3.88 m3 (137 ft3) of water to give 3 experimental levels and a control, all in triplicate.

Each mesocosms that was constructed contained marsh plants in soil plugs 9 feet in diameter and 3 feet deep. These ...


Optimizing 3d Printed Prosthetic Hand And Simulator, Stephen Estelle Jan 2019

Optimizing 3d Printed Prosthetic Hand And Simulator, Stephen Estelle

LMU/LLS Theses and Dissertations

The purpose of this study is to examine the position and use of an upper extremity prosthetic simulator on non-amputees. To see how a 3D printed prosthetic simulator can be optimized to serve the user correctly and accurately. In addition, this study examines the improvement of the Hosmer 5X Prosthetic Hook with the addition of newly designed trusses on to the prosthetic, as well as utilizing a new manufacturing method known as 3D printing. These topics are important because there is no standardized prosthetic simulator for schools and research facilities to use. Off the shelf prosthetic simulator cost upwards of ...


Hybrid Optical Integrator Based On Silicon-On-Insulator Platform, Taewon Huh Jan 2019

Hybrid Optical Integrator Based On Silicon-On-Insulator Platform, Taewon Huh

Graduate Theses - Physics and Optical Engineering

A hybrid optical integrator is a recirculating loop that performs oversampling typically for analog input, using the cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). The modulated input signal changes the gain of the loop through XGM and thus modifies the loop accumulation. This thesis presents hybrid optical integrator for an all-optical analog-to-digital converter based on a silicon photonics platform. The device consists of silicon waveguides of dimension 220 × 500 nm (thick × width) and approximately 5 m optical loop length including fiber length, input and output grating couplers for 1550 nm signal, directional couplers, and external components (SOA, optical ...


Design And Optimization Of An Ionizing-Radiation-Free Dental Imaging Scheme By Near Infrared Fluorescence, Thomas Hartzler Jan 2019

Design And Optimization Of An Ionizing-Radiation-Free Dental Imaging Scheme By Near Infrared Fluorescence, Thomas Hartzler

LSU Master's Theses

There is a global need for access to oral health care. Proper oral health care is necessary for physiological and psychological health, as well as social and economic issues. Major oral diseases that must be screened include caries, cracked teeth, and impacted molars. These diseases are screened and diagnosed using a variety of medical imaging methods, computed tomography (CT) X-ray being the most popular and efficient method. The challenges in screening with X-ray technology include financial and time cost as well as health risk, including radiation exposure induced cancer (REIC). This thesis summarizes research to explore the possibility of overcoming ...


Rc Baja: Drivetrain, Nick Paulay Jan 2019

Rc Baja: Drivetrain, Nick Paulay

All Undergraduate Projects

The American Society of Mechanical Engineers (ASME) annually hosts an RC Baja challenge, testing a RC car in three events: slalom, acceleration and Baja. Although ASME will not be holding an event this year, CWU will be holding an event with three RC Baja car teams from CWU as well as other teams from local colleges. The RC car that is tested in these events is designed and manufactured typically in teams of two. The RC car that each team submits must be able to complete these events to score points. One part of great importance for the RC car ...


Self-Leadership To Servant Leadership: A Metatheoretical Antecedent To Positive Social, Allen Lloyd Carn Jan 2019

Self-Leadership To Servant Leadership: A Metatheoretical Antecedent To Positive Social, Allen Lloyd Carn

Walden Dissertations and Doctoral Studies

A majority of current leadership programs are failing to deliver a comprehensive approach to leadership development by not providing middle and frontline managers the skills to enhance their potential to develop others. In failing to generate a comprehensive system, animosity towards all types of leadership has been festering for over 40 years as first identified by Greenleaf in 1977. The purpose of the study was to establish a link between the theoretical paradigms of servant leadership and self-leadership using the lens of emotional intelligence to generate an integral leadership development framework. The conceptual framework used Goleman et al.'s version ...


Perceptions Of Vulnerability To Flooding, Hurricanes, And Climate Change On Grand Isle, Louisiana’S Only Inhabited Barrier Island, Lauren Miller Jan 2019

Perceptions Of Vulnerability To Flooding, Hurricanes, And Climate Change On Grand Isle, Louisiana’S Only Inhabited Barrier Island, Lauren Miller

Graduate Student Theses, Dissertations, & Professional Papers

This study used in-depth interviews of permanent residents on Grand Isle, Louisiana, a remote barrier island, to better understand their perceptions of structural flood measures, non-structural responses to flooding and hurricanes, and perceptions of vulnerability to flooding, hurricanes, and climate change on a remote barrier island-Grand Isle, Louisiana. Residents' perceptions regarding the various structural measures implemented by the federal, state, and local government appeared mixed. Non-structural responses to flooding risks implemented at the household, community, state, and federal level continue to strengthen resiliency on Grand Isle. According to interviewees, aspects of environmental, rural, and economic vulnerability on Grand Isle impact ...


Weld Penetration Identification Based On Convolutional Neural Network, Chao Li Jan 2019

Weld Penetration Identification Based On Convolutional Neural Network, Chao Li

Theses and Dissertations--Electrical and Computer Engineering

Weld joint penetration determination is the key factor in welding process control area. Not only has it directly affected the weld joint mechanical properties, like fatigue for example. It also requires much of human intelligence, which either complex modeling or rich of welding experience. Therefore, weld penetration status identification has become the obstacle for intelligent welding system. In this dissertation, an innovative method has been proposed to detect the weld joint penetration status using machine-learning algorithms.

A GTAW welding system is firstly built. Project a dot-structured laser pattern onto the weld pool surface during welding process, the reflected laser pattern ...


Optimal Distribution Feeder Reconfiguration With Distributed Generation Using Intelligent Techniques, Ahmad Ghaweta Jan 2019

Optimal Distribution Feeder Reconfiguration With Distributed Generation Using Intelligent Techniques, Ahmad Ghaweta

Theses and Dissertations--Electrical and Computer Engineering

Feeder reconfiguration is performed by changing the open/close status of two types of switches: normally open tie switches and normally closed sectionalizing switches. A whole feeder or part of a feeder may be served from another feeder by closing a tie switch linking the two while an appropriate sectionalizing switch must be opened to maintain the radial structure of the system. Feeder reconfiguration is mainly aiming to reduce the system overall power losses and improve voltage profile. In this dissertation, several approaches have been proposed to reconfigure the radial distribution networks including the potential impact of integrating Distributed Energy ...


A Possible Link Between R-Wave Amplitude Alternans And T-Wave Alternans In Ecgs, Sahar Alaei Jan 2019

A Possible Link Between R-Wave Amplitude Alternans And T-Wave Alternans In Ecgs, Sahar Alaei

Theses and Dissertations--Biomedical Engineering

Sudden Cardiac Death (SCD) is the largest cause of natural deaths in the USA, accounting for over 300,000 deaths annually. The major reason for SCD is Ventricular Arrhythmia (VA). Therefore, there is need for exploration of approaches to predict increased risk for VA. Alternans of the T wave in the ECG (TWA) is widely investigated as a potential predictor of VA, however, clinical trials show that TWA has high negative predictive value but poor positive predictive value. A possible reason that TWA has a large number of false positives is that a pattern of alternans known as concordant alternans ...


Vhf Transmitter Development For Wildlife Tracking, Bryan Westra Jan 2019

Vhf Transmitter Development For Wildlife Tracking, Bryan Westra

Masters Theses

Wildlife biologists often use collars with VHF transmitters to gather wildlife data. The purpose of this project is to determine the best approach to designing a wildlife tracking VHF transmitter on a Printed Circuit Board (PCB). A variety of frequency generation methods were considered for the transmitter, including transistor-based crystal oscillators and chip based solutions from the chip manufacturers Analog Devices and Silicon Labs. Prototypes of the feasible options were built and evaluated for cost, power consumption, efficiency, size, frequency range, signal bandwidth, and frequency stability. It was found that the Silicon Labs Si4010 chip was the best solution based ...


Investigating The Feasibility Of Using Mesoporous Silica Particles To Deliver Glucose During Anaerobic Fermentation, Megan E. Walz Jan 2019

Investigating The Feasibility Of Using Mesoporous Silica Particles To Deliver Glucose During Anaerobic Fermentation, Megan E. Walz

Theses and Dissertations--Biosystems and Agricultural Engineering

The study presented herein investigated a potential low-energy method to separate and concentrate glucose from a lignocellulosic hydrolysate. The motivation for this method was twofold: 1) to provide the fermentation microorganism an optimal glucose concentration and 2) to supply a fermentation media free of inhibitory compounds. Two sizes of porous silica particles (with 7 nm and 2.3 nm pores) were synthesized and their ability to adsorb glucose from solution confirmed. Next, the ability of two different microorganisms, Saccharomyces cerevisiae and Streptococcus bovis, to utilize sugars adsorbed to the porous silica particles was investigated.

Both the 7 nm and 2 ...


Coating Component Migration In Paper Coatings, Emilia Purington Dec 2018

Coating Component Migration In Paper Coatings, Emilia Purington

Electronic Theses and Dissertations

In many applications such as in paints and coatings, pigments are mixed with polymeric binders to generate the final product. In the coating of paper, properties like strength, durability, and print quality are affected not only by the binder type, but the final location of the binder relative to the pigments and the fibers. During the application and drying of a paper coating, binder is known to migrate. A number of methods are available to measure the migration of latex or starch. However, all of these methods have some limitations, especially when starch, latex and kaolin are components of the ...