Engineering Commons^™

Numerical Study Of Erosion Of The Internal Wall Of Sales Gas Piping By Black Powder Particles, Ahmed Saud Al-Haidari

Theses and Dissertations

Micro particles, primarily from iron, can wreak havoc on a Sales Gas System. For example, the transport of particles with the gas flow can cause erosion damage to the piping system, lead to the release of toxic gasses, and interrupt the operation. The objective of the current work is to examine the erosion rate (ER) in an existing Sales Gas Piping System by simulating different black powder particles sizes and considering variable operation conditions. An elbow-shaped pipe spool is used to determine the area of maximum destruction. It will help the designer, engineer and operation personnel to predict the ER …

Non-Invasive Real Time, Accurate And Affordable Monitoring Of Hemoglobin And Vital Parameters For Icu Patients, Harsh S. Modi

Theses and Dissertations

The measurement of hemoglobin concentration (Hb), oxygen consumption (mL and %), and partial pressure of oxygen inside the lungs are vital parameters in early prediction of respiratory diseases such as sepsis, septic shock, acute respiratory distress syndrome (ARDS) etc. The availability of these parameters in real time can play a crucial role in management of modes and parameters of the ventilators. The real time monitoring of patient’s vital signals in intensive care units can reduce the number of blood tests, time and cost spent inside the intensive care units. The medical conditions such as blood loss from surgery or an …

Flow Field Dynamics In A High-G Ultra-Compact Combustor, Andrew E. Cottle

Theses and Dissertations

The Ultra Compact Combustor (UCC) presents a novel solution to the advancement of aircraft gas turbine engine performance. A high-g UCC design operates by diverting a portion of the axial compressor flow into a circumferential combustion cavity positioned about the engine outer diameter. The circumferential cavity (CC) provides the necessary residence length and time for combustion within reduced axial lengths; furthermore, high rates of centrifugal acceleration termed high-g loading are imposed upon the swirling cavity flow. These high-g conditions are hypothesized to increase flame speed, reduce flame length, and improve lean blow-out performance. Work at AFIT was sponsored by the …

An Investigation Of The Effect Of Different Additives On The Compressive And Flexural Strength Of Rammed Earth, Aiham Alskif

Theses and Dissertations

The main objective of this research is to study the effect of using different additives on the compressive and flexural strength of rammed earth structures. Different ratios of fly ash, and/or cement were added to the soil to identify their influence on the compressive strength. Recycled fiber materials were used to wrap and reinforce the cement-soil specimens in order to enhance the flexural strength of beams and control the cracks and the mode of failure. The study finds that adding cement to soil has significant effect on the soil strength, and it causes a remarkable increase in the strength while …

Investigation Of Sparsifying Transforms In Compressed Sensing For Magnetic Resonance Imaging With Fasttestcs, Christopher Adams Baker

Theses and Dissertations

The goal of this contribution is to achieve higher reduction factors for faster Magnetic Resonance Imaging (MRI) scans with better Image Quality (IQ) by using Compressed Sensing (CS). This can be accomplished by adopting and understanding better sparsifying transforms for CS in MRI. There is a tremendous number of transforms and optional settings potentially available. Additionally, the amount of research in CS is growing, with possible duplication and difficult practical evaluation and comparison. However, no in-depth analysis of the effectiveness of different redundant sparsifying transforms on MRI images with CS has been undertaken until this work. New theoretical sparsity bounds …

Synthesis And Characterization Of Microporous And Mesoporous Zeolites From Flyash For Heavy Metal Removal From Wastewater, Saeed Golbad

Theses and Dissertations

Class F fly ash was hydrothermally modified in one- and two-step processes to prepare zeolites with enhanced adsorption characteristics. Highly crystalline X type zeolite and hydroxy sodalite were targeted as microporous and mesoporous zeolite and were successfully synthesized using fly ash precursor by adjusting Si/Al molar ratio in reaction mixture. The heavy metal removal performance of the obtained fly ash-based zeolites was investigated in batch Pb2+ adsorption experiments.

Lead (Pb2+) is a positively charged toxic pollutant that can be present in surface water and industrial wastewater and may cause harmful physiological effects to human. As a result, standards for water …

A Fuzzy Inference System Approach For Evaluating The Feasibility Of Product Remanufacture, Thomas Aming'a. Omwando

Theses and Dissertations

In the recent past, efforts have been made in enhancing sustainable manufacturing aimed at protecting the environment and saving natural resources. Among the efforts that have been explored include strategies to ensure responsible end-of-life product management so as reduce the impact on the environment and achieve effective use of resources. Towards this end, reduce, reuse and recycle product disposal strategies have found a lot of consideration in manufacturing. Of the product reuse strategies, remanufacturing has been widely applied owing to its unique feature of rendering the remanufactured product as good as new. For remanufacturers, this strategy leads to provision of …

In-Situ Optical Microscopic Investigation Of The Dendrite Formation On Lithium Anode Under Different Electrolyte Conditions In Li-S Battery, Tianyao Ding

Theses and Dissertations

By utilizing a high-resolution optical microscope, the dendrite formation on a lithium electrode with different electrolytes suitable for Li-S battery was investigated. It is found that the anions of lithium, the solvents, and the deposition current density have significant effects on the dendrite formation and surface morphology of lithium electrodes in electrolytes without polysulfides. On the contrary, in electrolytes with 25 mM concentration of polysulfides, the dendrite formation and surface morphology tend to be similar regardless of the other conditions. The dendrite-suppression effect of polysulfides, inorganic additive (CsNO3), and electrode modifier (TEOS) are not significant in the electrolytes with polysulfides …

Sensitivity Analysis Of Geometry Changes In The Simulation Of Basilar Aneurysms, Paul Eserkaln

Theses and Dissertations

Computer simulation is a useful tool in the research and treatment of basilar aneurysms. Current technology allows researchers to create 3D models from cerebral vasculature in-vivo, allowing for the investigation of surgical options with minimal risk to the patient. The method used to construct these models overlooks smaller lateral arterial branches which are difficult to discern due to resolution limits of the imaging process. These lateral branches have minimal impact on the overall blood flow through the basilar artery, but they play a significant role in the health of the patient, so it is important to ensure sufficient blood will …

Quantitative Optical Studies Of Oxidative Stress In Rodent Models Of Eye And Lung Injuries, Zahra Ghanian

Theses and Dissertations

Optical imaging techniques have emerged as essential tools for reliable assessment of organ structure, biochemistry, and metabolic function. The recognition of metabolic markers for disease diagnosis has rekindled significant interest in the development of optical methods to measure the metabolism of the organ.

The objective of my research was to employ optical imaging tools and to implement signal and image processing techniques capable of quantifying cellular metabolism for the diagnosis of diseases in human organs such as eyes and lungs. To accomplish this goal, three different tools, cryoimager, fluorescent microscope, and optical coherence tomography system were utilized to study the …

Corrosion Of Aluminum Current Collector In Cost Effective Rechargeable Lithium-Ion Batteries, Shengyi Li

Theses and Dissertations

Rechargeable lithium ion batteries (LIB) have been widely used as commercial energy storage systems for portable equipment, electronic devices and high power applications (e.g. electronic vehicles). One issue with the commercialized LIB is that expensive, highly toxic and flammable organic solvents are used in the electrolyte and the fabrication process of electrodes. The toxic organic based solvents increase the production cost and lead to significant safety concerns in the event of a battery overcharge or short circuit. The recent development of “green manufacturing” technology allows manufacturers to replace the organic solvents used in the cathode coating process by aqueous based …

Computational Modeling Of Transient Processes During Run-In For Tribological Systems, Rob Morien

Theses and Dissertations

Understanding the frictional behavior of machine elements in mutual rolling or sliding contact is important for many engineering applications. When frictional sliding is initiated, the tribological system passes through several stages with each stage possessing its own unique frictional property. The initial transition process preceding stationary sliding is usually called “run-in”. During the run-in time interval, surface topographies of frictional contacts as well as lubricant distribution and surface tribofilms reorganize and adjust through asperity deformation and wear processes before reaching the steady state. This surface stability formed during run-in leads to an improvement in frictional performance during steady state operation, …

Durability Of Mechanically Loaded, Freeze Thawed Concrete Determined By Water Absorption, Brian Daniel Mitchell

Theses and Dissertations

The design of concrete bridges is primarily focused on strength characteristics. However, it is often the case that durability characteristics, specifically early deterioration of the bridge deck, requires expensive repairs before the designed service life of the bridge can come to term. Lin et al. (2012) identified the development of microcracks as a possible source of this early deterioration. He proposed that these microcracks propagated due to high local compressive stress induced by overweight trucks. The resulting permeability increase caused by the propagation of these microcracks is not significant enough to cause the kind of early deterioration of bridge deck …

High Temperature Oxidation Of Alumina Forming Cast Austenitic Stainless Steels Within An Environment Of Pure Steam, Elmer A. Prenzlow

Theses and Dissertations

Steam cracking of hydrocarbons in the petrochemical industry is a multibillion dollar industry. The processes performed in these plants create byproducts that negatively affect the integrity of stainless steel piping through high temperature corrosion. Alloys used presently in industry rely on the formation of chromium oxide (chromia) as a protective layer between the bulk metal pipe and chemical byproducts. However, chromia can become susceptible to attack from aggressive species such as carbon, water vapor, and sulfur compounds, thus creating a need for a better protection method.

A new series of austenitic stainless steels have been developed in recent years that, …

Travel Time Estimation On Urban Arterials - A Real Time Aspect, Jingcheng Wu

Theses and Dissertations

This dissertation attempts to develop simple and direct approaches to estimate the vehicle queue length and travel time along signalized arterial links for real-time traffic operations. This dissertation is the first to demonstrate a process using vehicle trajectory data to generate detector volume, speed and time occupancy data, along with the generalized flow rate, density and space mean speed data. This approach minimizes detector over-counting and miss-counting issues. The detection zone can be of any shape or size and at any location along the trajectory. The relationships among detector volume, speed and time occupancy along signalized arterials are analyzed theoretically …

An Ion Detection Scheme Employing Solid State Devices For Use In Portable Mass Spectrometers, Sanjiv Nath Pant

Theses and Dissertations

This thesis presents a solid state approach to the ion detection system used in the back-end of modern mass spectrometers. Although various techniques already exist to detect ions – even with the sensitivity of a single particle, the existing techniques require high voltage or lower operation temperature to counteract the noise inherent in the system. The suggested design presents an alternative to the more popular detection system whereby the requirement of high operation voltage or low operation temperature can be precluded. This is made possible through the gate capacitance of a Metal Oxide Semiconductor Field Effect Transistor (MOSFET). This thesis …

How A Systematic Approach To Uncertainty Quantification Renders Molecular Simulation A Quantitative Tool In Predicting The Critical Constants For Large N-Alkanes, Richard Alma Messerly

Theses and Dissertations

Accurate thermophysical property data are crucial for designing efficient chemical processes. For this reason, the Design Institute for Physical Properties (DIPPR 801) provides evaluated experimental data and prediction of various thermophysical properties. The critical temperature (T_c), critical density (ρ_c), critical pressure (P_c), critical compressibility factor (Z_c), and normal boiling point (T_b) are important constants to check for thermodynamic consistency and to estimate other properties. The n-alkane family is of primary interest because it is generally assumed that other families of compounds behave similarly to …

Life-Cycle Benefit-Cost Analysis Of Safety Related Improvements On Roadways, Jordan Browne Frustaci

Theses and Dissertations

The Highway Safety Manual (HSM) lists four different methods for determining the change in crash frequency in order of reliability. Currently, the Utah Department of Transportation (UDOT) uses the fourth reliable method. The goal of this research was to develop a tool that the most reliable method mentioned in the HSM could be used to perform life-cycle benefit-cost analyses. A spreadsheet program was built that performs the HSM's Part C Predictive Method for 11 different roadway segment types mentioned in HSM using Excel macros and Visual Basic for Applications (VBA) programming. Intersections were not included in this spreadsheet program as …

Submerged Jump Remediation At Low-Head Dams: The Multiple Staggered Deflector Design, Ronald Francis Mcghin

Theses and Dissertations

Low-head dams are capable of creating dangerous counter-currents just downstream from the structure. These dangerous counter-currents are known as submerged hydraulic jumps and are responsible for hundreds of fatalities at numerous low-head dams across the United States. The counter-current creates high upstream-directed surface velocities across the width of the channel, making it nearly impossible for an individual to escape. This submerged jump can occur during a range of upstream and downstream conditions. Effective, safe and low-cost remediation options must be explored in order to prevent further fatalities at these structures. This document explores such a remediation option: the Multiple Staggered …

Voltage Measurement Using Slab-Coupled Optical Sensors With Polarization-Maintaining And Absorption-Reduction Fiber, Rex Lavell King

Theses and Dissertations

This research presents the first use of side-polished Panda fiber in the fabrication of slab-coupled optical sensors (SCOS). It is determined that the Panda SCOS provides a sensor that is comparable to the D-fiber SCOS in cases of electric field sensing. It exhibits greater power transfer and higher bandwidth than a typical D-SCOS. The Panda SCOS is also less costly and easier to splice than the D-fiber alternative. This comes at a cost of slightly decreased sensitivity and a more fragile fabrication process. This research also demonstrates the use of the Panda-SCOS as means of voltage characterization across both the …

Selecting Cloud Platform Services Based On Application Requirements, Bridger Ronald Larson

Theses and Dissertations

As virtualization platforms or cloud computing have become more of a commodity, many more organizations have been utilizing them. Many organizations and technologies have emerged to fulfill those cloud needs. Cloud vendors provide similar services, but the differences can have significant impact on specific applications. Selecting the right provider is difficult and confusing because of the number of options. It can be difficult to determine which application characteristics will impact the choice of implementation. There has not been a concise process to select which cloud vendor and characteristics are best suited for the application requirements and organization requirements. This thesis …

A Comparison Of Gestures For Virtual Object Rotation, Brandon Michael Garner

Theses and Dissertations

The fields of virtual reality and gesture-based input devices are growing and becoming more popular. In order for the two technologies to be implemented together, an understanding of gestures in relation to virtual objects and users' expectations of those gestures needs to be understood. Specifically, this thesis focuses on arm gestures for the rotation of virtual objects. Participants in the study were first asked to freely perform an arm gesture they felt should execute a task. Next, participants were asked to perform specific rotation tasks with pre- configured arm gestures on four objects. There were two types of objects: those …

Extending Time Until Failure During Leaking In Inflatable, Pneumatically Actuated Soft Robots, Joshua Parker Wilson

Theses and Dissertations

Soft robots and particularly inflatable robots are of interest because they are lightweight, compact, robust to impact, and can interact with humans and their environment relatively safely compared to rigid and heavy traditional robots. Improved safety is due to their low mass that results in low-energy collisions and their compliant, soft construction. Inflatable robots (which are a type of soft robot) are also robust to impact and have a high torque to weight ratio. As a result inflatable robots may be used for many applications such as space exploration, search and rescue, and human-robot interaction. One of the potential problems …

Simulation Of Aircraft Sortie Generation Under An Autonomic Logistics System, Gunduz Bingol

Theses and Dissertations

Parallel to the developments in diagnostic and prognostic technology, autonomic logistics systems (ALS) have been a potential improvement for the aircraft sortie generation process. Currently, Lockheed Martin and the Joint Program Office are developing a new autonomic logistics system for the multibillion F-35 Lightning Joint Strike Fighter project, which is named the Autonomic Logistics Information System (ALIS). Generally, researchers make an analogy between the ALS and the human bodys autonomic nervous system since both of them monitor, control, and adjust autonomic responses to external stimuli. Based on this perspective, ALS aims to switch the Air Force logistics mentality from a …

Router Security Effect On Performance Of A Network, David L. Leal

Theses and Dissertations

Recently many of the devices that create a computer network offer security to help protect networks from hackers, such as computers, servers, firewalls and even routers. In most cases when protecting a network from hackers having more security is not always the best, because the more resources of the device is used by the security in inspecting connections, and it can compromise performance of the network.

This thesis investigates performance benefit of having security on a router and its impact on the connection rate of the network when it is under security attacks. In this thesis, different security features and …

Multivariate Calibration Of A Load Sensor For Dynamic And Static Freight Railcar Applications, Dylan Michael Blackwell

Theses and Dissertations

Determination of the load carried by each bearing in a railcar system is crucial to the integrity of the railroad industry. With accurate load measurement, the process of filling a railcar with its specified cargo can be optimized to provide the maximum amount of cargo without exceeding the upper weight limits imposed by the Associations of American Railroads (AAR). An accurate load measurement will additionally make it possible to identify any load imbalance that occurs during periods of travel which result in having a detrimental effect on the health of the bearing. Previous work conducted with a strain-gauge load sensor …

Low Temperature Flexible Perovskite Solar Cell With Mesoporous Tio2 Electron Transport Layer In High Humidity Environment, Felipe De La Torre

Theses and Dissertations

Perovskite solar cells are the fastest advancing solar technology to date with efficiencies increasing from 3.9% to more than 21% within a few years. They have emerged as a possible alternative to silicon photovoltaics due to their exceptional photovoltaic performance, light absorbing properties, and low-cost fabrication with methylammonium lead iodide (CH3NH 3PbI3) getting considerable interest in research and development. However, there are still many challenges that must be addressed for perovskite solar cells to replace contemporary solar cells, such as improving their stability, making them nonhazardous, further increasing their efficiency, and developing better techniques for large scale fabrication. In this …

Forcespinning®: An Alternative Method To Fabricate Metal Oxide/Carbon Composite Nanofiber Anodes For Li-Ion Batteries, Luis Zuniga

Theses and Dissertations

Metals and their respective oxides have been highly regarded as next generation anode materials for lithium-ion batteries (LIBs). In this research work the electrochemical performance of Sn, SnO2, and TiO2. With the advantages of nanotechnology and the Forcespinning® method of fabricating micro and nanofibers, binder-free anodes are produced from metal or metal oxide/carbon composite microfibers. Through these microfibers the electrochemical performance of the above mentioned materials are significantly improved due to the increased surface area per volume providing a large number of reaction sites for the anode materials. Further performance enhancement was achieved by also modifying the fiber microstructure to …

Optimizing Border Security With Stochastic And Deterministic Strategies, Gabriel A. Rueda

Theses and Dissertations

International trade and border security have always been linked together, and so has the need to find ways to improve security decisions. The United States and bordering countries benefit from the North American Free Trade Agreement (NAFTA), but amongst the positive effects of NAFTA there is a looming drug threat that effects the bi-national supply chains. In 2015 Customs and Border Protections (CBP) processed over 72,000 trucks, rail, and sea containers a day. CBP also seized 3.4 million pounds of narcotics, the majority of them at the ports of entry. With unknown threats using commercial vehicles to transport their illicit …

Knee Joint Internal Forces During Squat Jump Exercise, Ricardo Moreno

Theses and Dissertations

The purpose of this research is to investigate muscular ligament and joint contact forces produced during squat jump exercise. An inverse dynamics, two dimensional, leg model is used to describe the motion in the sagittal plane. The lower extremity model includes two bones, tibia and femur, tibio-femoral ligaments, and muscles such as quadriceps, hamstrings, and gastrocnemius. The ligaments are anatomically modeled as nonlinear strings, but the femoral condyle is modeled as a circle and the tibial plateau as a straight line. Experimental squat jump exercises are conducted to obtain the ground reaction forces, the angular accelerations, and centroid linear acceleration …