Engineering Commons^™

Water Quality Sensor Placement Guidance For Small Water Distribution Systems, Stacey L. Schal

Theses and Dissertations--Civil Engineering

Water distribution systems are vulnerable to intentional, along with accidental, contamination of the water supply. Contamination warning systems (CWS) are strategies to lessen the effects of contamination by delivering early indication of an event. Online quality monitoring, a network of sensors that can assess water quality and alert an operator of contamination, is a critical component of CWS, but utilities are faced with the decision of what locations are optimal for deployment of sensors. A sensor placement algorithm was developed and implemented in a commercial network distribution model (i.e. KYPIPE) to aid small utilities in sensor placement. The developed sensor …

Kentrack 4.0: A Railway Trackbed Structural Design Program, Shushu Liu

Theses and Dissertations--Civil Engineering

The KENTRACK program is a finite element based railway trackbed structural design program that can be utilized to analyze trackbeds having various combinations of all-granular and asphalt-bound layered support. It is applicable for calculating compressive stresses at the top of subgrade, indicative of potential long-term trackbed settlement failure. Furthermore, for trackbeds containing asphalt layer, it is applicable for calculating tensile strains at the bottom of the asphalt layer, indicative of potential fatigue cracking. The program was recently expanded to include both English and international units. A procedure has been incorporated to provide a path to save results in a text …

Pressure Measurement At The Ballast-Tie Interface Of Railroad Track Using Matrix Based Tactile Surface Sensors, Michael T. Mchenry

Theses and Dissertations--Civil Engineering

The pressure distribution at the ballast-tie interface of railroad track plays a key role in overall track support. Failure of the ballast or tie can result from excessive loads that were not designed for, requiring increased maintenance and reducing railroad operating efficiency. Understanding the forces acting on the ballast and tie are required to design higher performance and longer lasting track. To further this understanding, the use of Matrix Based Tactile Surface Sensors (MBTSS) is employed to measure the actual pressure distribution at the ballast-tie interface, characterized by individual ballast particle contact points and non-uniform pressures. The research explores this …

Development Of A Constitutive Model Of Compacted Shales And Determination Of The Effect Of Weathering On Its Parameters, Isabel Cristina Gomez-Gutierrez

Theses and Dissertations--Civil Engineering

Compacted shales cause problems because they tend to degrade with time due to weathering. Degradation results in the shale deteriorating from a hard rock-like material to a soft fine-grained soil mass with lower shear strength and high deformability. Consequently, common problems that occur in embankments constructed with compacted shales include settlement and instabilities. Therefore, accelerating weathering prior to compaction by wetting and breaking down the shales before placement can reduce the deterioration during the service life of the construction. Extensive laboratory testing was performed in order to characterize the mechanical behavior of compacted shales.

Critical State theory is a clever …

A Three-Dimensional Quantitative Understanding Of Short Fatigue Crack Growth In High Strength Aluminum Alloys, Wei Wen

Theses and Dissertations--Chemical and Materials Engineering

The behaviors of short fatigue crack (SFC) propagation through grain boundaries (GBs) were monitored during high cycle fatigue in an Al-Li alloy AA8090. The growth behaviors of SFCs were found to be mainly controlled by the twist components (α) of crack plane deflection across each of up to first 20 GBs along the crack path. The crack plane twist at the GB can result in a resistance against SFC growth; therefore SFC propagation preferred to follow a path with minimum α at each GB. In addition to the grain orientation, the tilting of GB could also affect α.

An experiment …

Development Of A Design Based Intersection Safety Performance Evaluation Tool, Adam J. Kirk

Theses and Dissertations--Civil Engineering

The purpose of this research is to develop an intersection safety evaluation tool that is capable of assisting designers and planners in the assessment of alternative intersection designs. A conflict exposure model utilizing design hour volumes, intersection configuration and traffic control measures is proposed to achieve this goal. This approach makes use of data typically available for preliminary intersection design. The research goes beyond existing safety performance models which only examine non-directional average daily traffic (ADT) or practices which only account for the geometric and lane configuration of an intersection, such as conflict point analysis.

Conflict prediction models are developed …

Investigation Of Media Ingredients And Water Sources For Algae Co2 Capture At Different Scales To Demonstrate The Correlations Between Lab-Scale And Large-Scale Growth, Tabitha Graham

Theses and Dissertations--Biosystems and Agricultural Engineering

As energy use increases globally the environmental burdens increase alike. Many accusations have been made that carbon dioxide is a culprit of climate change. The University of Kentucky and Duke Energy Power have partnered to test carbon capture technology in a large scale project. To this end, the objective of this thesis is to investigate potential water media sources and nutrient sources at different volume scales for algae cultivation to help create a more environmentally viable and economically feasible solution. This work will conduct a life cycle assessment of water media sources and the effects of the inputs and outputs …

Alkaline Hydrogen Peroxide Pretreatment For Its Use In An On-Farm Bioprocessing Facility, Mary Kathryn Gray

Theses and Dissertations--Biosystems and Agricultural Engineering

Pretreatment is an essential step in biofuel production from lignocellulose. Disruption of the lignin structure gives enzymes and fermentation organisms access to long chains of cellulose and hemicellulose. For this project’s purposes, the pretreatment must work within the framework of an on-farm butanol bioprocessing facility. Alkaline hydrogen peroxide (AHP) is a delignification method that potentially provides several advantages. At the alkaline pH, powerful hydroxyl radicals are formed; which attack lignin. The objectives of this study were to determine if AHP removes substantial lignin for the feedstocks, corn stover, wheat straw, switchgrass and miscanthus, and to determine if AHP acts as …

Sodium Hydroxide Pretreatment Of Corn Stover And Subsequent Enzymatic Hydrolysis: An Investigation Of Yields, Kinetic Modeling And Glucose Recovery, Alicia Modenbach

Theses and Dissertations--Biosystems and Agricultural Engineering

Many aspects associated with conversion of lignocellulose to biofuels and other valuable products have been investigated to develop the most effective processes for biorefineries. The goal of this research was to improve the efficiency and effectiveness of the lignocellulose conversion process by achieving a more basic understanding of pretreatment and enzymatic hydrolysis at high solids, including kinetic modeling and separation and recovery of glucose.

Effects of NaOH pretreatment conditions on saccharide yields from enzymatic hydrolysis were characterized in low- and high-solids systems. Factors associated with pretreatment and hydrolysis were investigated, including duration of pretreatment at different temperatures and NaOH loadings, …

Hydrologic Characterization Of A Rain Garden Mitigating Stormwater Runoff From A Commercial Area, John T. Mcmaine

Theses and Dissertations--Biosystems and Agricultural Engineering

Impervious surfaces such as roads, sidewalks, and roofs increase the volume of runoff generated in a watershed. Traditional stormwater management techniques emphasize conveyance of runoff away from impervious surfaces in order to reduce flooding. Rain gardens are becoming popular as a different means to manage stormwater in such a way that runoff is captured and infiltrated onsite rather than conveyed offsite. A stormwater management system consisting of a rainwater harvest system, rain garden, and infiltration chamber was built at the Coca-Cola Refreshments USA, Inc. distribution center in Lexington, Kentucky during the fall of 2011. Precipitation, inflow, and water level were …

Nutrients Recycling Strategy For Microalgae-Based Co2 Mitigation System, Xinyi E

Theses and Dissertations--Biosystems and Agricultural Engineering

Coal-fired electricity production is the major emitter of CO₂ and other greenhouse gases including NO_x and SO_x. Microalgae-based CO₂ mitigation systems have been proposed to reduce the net CO₂ emission from coal-fired power plants. This study focused on developing an optimum culture media and exploring the possibilities for recycling nutrients, which were added as commercial mineralized chemicals at the beginning of cultivation.

In order to release the nutrients embedded in the cells so that they can be used as a nutrient source for new cells, Scenedesmus biomass was digested by anaerobic bacteria. Results showed …

A Framework For Understanding The Public's Perspectives Of Mining Applied To The Kentucky Coal Industry, Joshua M. Hoffman

Theses and Dissertations--Mining Engineering

People’s perceptions of mining are heavily based on the media they consume and the messages therein. News outlets ordinarily report on mining only when there is an accident or environmental concern. When messages that the public is exposed to are negative, it is no wonder that there are negative perceptions about mining.

Current public relations campaigns on the behalf of specific companies or select sectors do exist; however, this is often a reactionary move in response to recent shifts in the socio-political environment. The details of these campaigns are often tied up in proprietary information or withheld by public relations …

Characterizing The Variability In Respirable Dust Exposure Using Johnson Transformation And Re-Examining 2010 Proposed Changes To The U.S. Underground Coal Mine Dust Standard, Al I. Khan

Theses and Dissertations--Mining Engineering

Coal workers’ pneumoconiosis (CWP), commonly referred to as black lung, is a chronic lung disease that results from the inhalation and deposition of coal dust in the lungs. While this disease continues to afflict coal miners, its prevalence has steadily declined over three decades since 1970. Based on a voluntary X-ray surveillance program, conducted by the National Institute for Occupational Safety and Health (NIOSH), this downward trend, however, ended in 2000 and has actually begun to rise. The Mine Safety and Health Administration (MSHA) instituted a Comprehensive Initiative to “End Black Lung” to combat the reported upturn in black …

Cavitation Nanobubble Enhanced Flotation Process For More Efficient Coal Recovery, Ahmed S. Sayed Ahmed

Theses and Dissertations--Mining Engineering

Froth flotation is a widely used, cost effective particle separation process. However, its high performance is limited to a narrow particle size range, e.g., between 50 µm and 600 µm for coal and between 10 µm and 100 µm for minerals. Outside this range, the efficiency of froth flotation decreases significantly, especially for difficult-to-float particles of weak hydrophobicity (e.g., oxidized coal).

Nanobubbles integrated into a specially designed column flotation expanded the particle size range for efficient froth flotation as a result of increased probabilities of particle- bubble collision and attachment and reduced probability of detachment.

The major advantages of nanobubble …

Froth Flotation Performance Enhancement By Feed Cavitation And Magnetic Plastic Particle Addition, Mehmet Saracoglu

Theses and Dissertations--Mining Engineering

Froth flotation is the most commonly used process to recover and upgrade the portion of the coal preparation plant feed that has a particle size smaller than 150 microns. Problems that occur when employing froth flotation in the coal industry include i) coal surfaces that are weakly-to-moderately hydrophobic, and ii) flotation systems that are overloaded and limited by insufficient retention time.

Research was performed to evaluate techniques that could be implemented to improve flotation performance under the aforementioned scenarios. Pre-aeration of flotation feed using a cavitation system was extensively evaluated in laboratory and full-scale test programs. The benefits of adding …

Enhanced Phosphate Flotation Using Novel Depressants, Lingyu Zhang

Theses and Dissertations--Mining Engineering

Froth flotation is the most efficient method for phosphate separation, which is a physic-chemical separation process based on the difference of surface properties between the valuable minerals and unwanted gangue minerals. However, the presence of clay slimes in the slurry after grinding consumes a large amount of reagents, decreases the collision probability between bubbles and minerals, prevents phosphate particle attachment to air bubbles, and thus considerably reduces flotation recovery and concentrate grade. Georgia Pacific Chemical, LLC has recently developed novel depressants, i.e., clay binders, which are a series of low molecular weight specialty polymers to help improve phosphate flotation performance …

Assessing And Mitigating Airborne Noise From Power Generation Equipment, Limin Zhou

Theses and Dissertations--Mechanical and Aerospace Engineering

This dissertation examines the assessment and mitigation of airborne noise from power generation equipment.

The first half of the dissertation investigates the diagnosis and treatment of combustion oscillations in boilers. Sound is produced by the flame and is reflected downstream from the combustion chamber. The reflected sound waves perturb the mixture flow or equivalence ratio increasing the heat release pulsations and the accompanying sound produced by the flame. A feedback loop model for determining the likelihood of and diagnosing combustion oscillations was reviewed, enhanced, and then validated. The current work applies the feedback loop stability model to two boilers, which …

Decentralized Adaptive Control For Uncertain Linear Systems: Techniques With Local Full-State Feedback Or Local Relative-Degree-One Output Feedback, James D. Polston

Theses and Dissertations--Mechanical and Aerospace Engineering

This thesis presents decentralized model reference adaptive control techniques for systems with full-state feedback and systems with output feedback. The controllers are strictly decentralized, that is, each local controller uses feedback from only local subsystems and no information is shared between local controllers.

The full-state feedback decentralized controller is effective for multi-input systems, where the dynamics matrix and control-input matrix are unknown. The decentralized controller achieves asymptotic stabilization and command following in the presence of sinusoidal disturbances with known spectrum. We present a construction technique of the reference-model dynamics such that the decentralized controller is effective for systems with arbitrarily …

Kinetics Of Wedge-Tee Joint Formation During Brazing Of An Aluminum Alloy Under Controlled Atmosphere, Fangxiao Dong

Theses and Dissertations--Mechanical and Aerospace Engineering

This work involves investigation of the kinetics data of a joint formation during aluminum alloy brazing. Data was generated by several groups of experiments conducted under conditions of a controlled oxygen level of the background brazing atmosphere. Generated data are examined to identify the phases of the joint formation and the time frame of its evolution. Specifically, the triple line kinetics data are analyzed to verify whether a power law between (1) the triple line of the molten metal preceding joint formation and (2) the formation time can be established for each formation phase. In addition, both initial and residual …

Experimental Characterization Of Roughness And Flow Injection Effects In A High Reynolds Number Turbulent Channel, Mark A. Miller

Theses and Dissertations--Mechanical and Aerospace Engineering

A turbulent channel flow was used to study the scaling of the combined effects of roughness and flow injection on the mean flow and turbulence statistics of turbulent plane Poiseuille flow. It was found that the additional momentum injected through the rough surface acted primarily to enhance the roughness effects and, with respect to the mean flow, blowing produced similar mean flow effects as increasing the roughness height. This was not found to hold for the turbulence statistics, as a departure from Townsend’s hypothesis was seen. Instead, the resulting outer-scaled streamwise Reynolds stress for cases with roughness and blowing deviated …

Near Wall Shear Stress Modification Using An Active Piezoelectric Nanowire Surface, Christopher R. Guskey

Theses and Dissertations--Mechanical and Aerospace Engineering

An experimental study was conducted to explore the possible application of dynamically actuated nanowires to effectively disturb the wall layer in fully developed, turbulent channel flow. Actuated nanowires have the potential to be used for the mixing and filtering of chemicals, enhancing convective heat transfer and reducing drag. The first experimental evidence is presented suggesting it is possible to manipulate and subsequently control turbulent flow structures with active nanowires. An array of rigid, ultra-long (40 μm) TiO₂ nanowires was fabricated and installed in the bounding wall of turbulent channel flow then oscillated using an attached piezoelectric actuator. Flow velocity …

Numerical Modeling And Characterization Of Vertically Aligned Carbon Nanotube Arrays, Johnson Joseph

Theses and Dissertations--Mechanical and Aerospace Engineering

Since their discoveries, carbon nanotubes have been widely studied, but mostly in the forms of 1D individual carbon nanotube (CNT). From practical application point of view, it is highly desirable to produce carbon nanotubes in large scales. This has resulted in a new class of carbon nanotube material, called the vertically aligned carbon nanotube arrays (VA-CNTs). To date, our ability to design and model this complex material is still limited. The classical molecular mechanics methods used to model individual CNTs are not applicable to the modeling of VA-CNT structures due to the significant computational efforts required. This research is to …

Cerium Oxide (Ceo2) Promoted Oxygen Carrier Development And Scale Modeling Study For Chemical Looping Combustion, Fang Liu

Theses and Dissertations--Mechanical and Aerospace Engineering

According to IPCC reports, the greenhouse gas CO₂ is responsible for global climate change. Studies show that CO₂ concentration reached a level of 400 ppm in 2013, or 40 % above pre-industrial levels. The contribution of CO₂ from industrial activity to increasing global CO₂ concentrations is widely accepted and points to the need to reduce the emission of this greenhouse gas.One possible combustion technology that shows promise for reducing CO₂ emissions is chemical looping combustion (CLC). It is an oxy-fuel technology, but has the advantages of in situ oxygen separation, low NO_x emissions and …

Advanced Studies On Transfer Impedance With Application To After-Treatment Devices And Micro-Perforated Panel Absorbers, Xin Hua

Theses and Dissertations--Mechanical and Aerospace Engineering

This work is primarily comprised of five self-contained papers. Three papers are applications oriented. A common element in the first three papers is that micro-perforated panels (MPP), the permeable membranes in diesel particulate filters, and a source impedance are all modeled as a transfer impedance. The first paper deals with enhancing the performance of micro-perforated panels by partitioning the backing cavity. Several different backing schemes are considered which enhance the performance without increasing the total volume of the MPP and backing. In the second paper, a finite element modeling approach is used to model diesel particulate filters below and above …

Experimental Investigation To Inform Optimal Configurations For Dynamic Near-Field Passive Uhf Rfid Systems, Donnie E. Proffitt Ii

Theses and Dissertations--Mechanical and Aerospace Engineering

RFID has been characterized as a “disruptive technology” that has the potential to revolutionize numerous key sectors. A key advantage of passive RFID applications is the ability to wirelessly transmit automatic identification and related information using very little power. This paper presents an experimental investigation to inform the optimal configuration for programming passive ultra-high frequency (UHF) RFID media in dynamic applications. Dynamic programming solutions must be designed around the tag’s functionality, the physical programming configuration and environment. In this investigation, we present a methodology to determine an optimal configuration to maximize the systems programming efficiency for dynamic applications.

Process-Induced Surface Integrity In Machining Of Niti Shape Memory Alloys, Yusuf Kaynak

Theses and Dissertations--Mechanical and Aerospace Engineering

NiTi alloys have been the focus of Shape Memory Alloys (SMA) research and applications due their excellent ductility and shape memory properties, and these alloys have been extensively used in automotive, aerospace, and in biomedical applications.

The effects of machining on the surface integrity and the corresponding material and mechanical properties of alloys can be best studied by utilizing NiTi alloys as workpiece material since their physical and mechanical properties are highly microstructure dependent. However, due to very poor machining performance of NiTi shape memory alloys, no comprehensive or systematic investigation on this topic has been conducted by researchers as …

The Critical Role Of Mechanism-Based Models For Understanding And Predicting Liposomal Drug Loading, Binding And Release Kinetics, Sweta Modi

Theses and Dissertations--Pharmacy

Liposomal delivery systems hold considerable promise for improvement of cancer therapy provided that critical formulation design criteria can be met. The main objective of the current project was to enable quality by design in the formulation of liposomal delivery systems by developing comprehensive, mechanism-based mathematical models of drug loading, binding and release kinetics that take into account not only the therapeutic requirement but the physicochemical properties of the drug, the bilayer membrane, and the intraliposomal microenvironment.

Membrane binding of the drug affects both drug loading and release from liposomes. The influence of bilayer composition and phase structure on the partitioning …

Anchored Sheet Pile Wall Design In Expansive Soils, Ömer Bilgin, Eman Mansour

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

Expansive soils cause damage to civil engineering structures in various parts of the world, because they swell when absorb water and shrink when dry out. Due to swelling pressures, retaining walls can be subjected to additional lateral pressures causing increased wall deformations and bending moments. Anchor forces can also increase, if the walls are anchored. When expansive soils are present behind retaining walls, swell pressures should also be considered during design in addition to the traditional lateral earth pressures. This study proposes a method to predict potential swell pressures acting on retaining walls for use in design of these walls. …

Thermomechanical Fatigue Life Prediction Of Notched 304 Stainless Steel, Justin Karl

Electronic Theses and Dissertations

The behavior of materials as they are subjected to combined thermal and mechanical fatigue loads is an area of research that carries great significance in a number of engineering applications. Power generation, petrochemical, and aerospace industries operate machinery with expensive components that undergo repeated applications of force while simultaneously being exposed to variable temperature working fluids. A case of considerable importance is found in steam turbines, which subject blades to cyclic loads from rotation as well as the passing of heated gases. The complex strain and temperature histories from this type of operation, combined with the geometric profile of the …

Investigating The Relationship Between Adverse Events And Infrastructure Development In An Active War Theater Using Soft Computing Techniques, Erman Cakit

Electronic Theses and Dissertations

The military recently recognized the importance of taking sociocultural factors into consideration. Therefore, Human Social Culture Behavior (HSCB) modeling has been getting much attention in current and future operational requirements to successfully understand the effects of social and cultural factors on human behavior. There are different kinds of modeling approaches to the data that are being used in this field and so far none of them has been widely accepted. HSCB modeling needs the capability to represent complex, ill-defined, and imprecise concepts, and soft computing modeling can deal with these concepts. There is currently no study on the use of …