Engineering Commons^™

Campusbookshare, Aditya Varkhedi

Computer Science and Software Engineering

Every few months, students in the US and abroad face the expensive and time consuming task of buying textbooks for the classes they are enrolled in. Despite the advent of the internet and social networking websites the ability for peer to peer textbook exchange is still limited. There are few if any dedicated websites for general purpose peer to peer textbook transfer for every university and college.

The project I have created for my Senior Project is a peer to peer solution for buying and selling textbooks on US college campuses. The underlying idea is to create an authentication system …

Multiphase Ferrofluid Flows For Micro-Particle Focusing And Separation, R. Zhou, Cheng Wang

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Modeling The Effects Of Acid Deposition And Natural Organic Acids On Surface Waters, Habibollah Fakhraei

Dissertations - ALL

Atmospheric deposition of sulfuric and nitric acids has impacted surface waters in the eastern U.S. Controls on anthropogenic S and NOx emissions have resulted in a substantial decrease in acid deposition. Long-term measurements of surface water chemistry indicate contrasting responses of surface waters to this deposition reduction. Streams in Great Smoky Mountain National Park (GRSM), in Tennessee and North Carolina, generally show a delayed response in contrast to lakes in the Adirondacks in New York State which are responding relatively rapidly to decreases in acid deposition. In this dissertation, I used a biogeochemical model, PnET-BGC, as a tool to investigate …

High Speed Digital Sample Rate Conversion For A Real-Time Ground Station Receiver, Brian Joseph Carrick

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Small satellites are becoming a popular spacecraft option because of their low cost, and complexity. Past small satellites had simple communication systems with low data rates that rarely exceeded 38.4 kbps. Engineers, researchers, and students, from Space Dynamics Laboratory and Utah State University, have recently created and launched a pair of small satellites called the Dynamic Ionosphere CubeSat Experiment (DICE). This mission was revolutionary because of its high-speed data link, with data rates up to 1.5 Mbps.

Due to the high-speed data link, it was necessary to create a ground station capable of receiving and processing the received data. For …

Energy Transfer And Localization In Molecular Crystals, Mitchell A. Wood

Open Access Dissertations

With the aim of developing new technologies for the detection and defeat of energetic materials, this collection of work was focused on using simulations to characterize materials at extremes of temperature, pressure and radiation. Each branch of the work here is collected by which material response is potentially used as the detectable signal.

Where the chemical response is of interest, this work will explore the possibility of non-statistical chemical reactions in condensed-phase energetic materials via reactive molecular dynamics (MD) simulations. We characterize the response of three unique high energy density molecular crystals to different means of energy input: electric fields …

Three-Dimensional Simulation For Fast Forward Flight Of A Calliope Hummingbird, Jialei Song, Bret W. Tobalske, Don Powers, Tyson Hedrick, Haoxiang Luo

Faculty Publications - Department of Biological & Molecular Science

We present a computational study of flapping-wing aerodynamics of a calliope hummingbird (Selasphorus calliope) during fast forward flight. Three-dimensional wing kinematics were incorporated into the model by extracting time-dependent wing position from high-speed videos of the bird flying in a wind tunnel at 8.3 m s⁻¹. The advance ratio, i.e. the ratio between flight speed and average wingtip speed, is around one. An immersed-boundary method was used to simulate flow around the wings and bird body. The result shows that both downstroke and upstroke in a wingbeat cycle produce significant thrust for the bird to overcome …

Sustainable Reuse Of Fly Ash To Mitigate Landfill Methane, Sharon Priyadarshini

Civil Engineering Theses - Archive

According to US, EIA 2014 coal alone produces nearly 40% of electricity more than another source in US. Out of the 110 million tons of Coal combustion by-products (CCBs) generated per year as a result of coal combustion, 47% is reused whereas 53% is stored on-site or sent to landfills. There are a number of adverse economic and environmental impacts associated with storage and disposal of coal. Methane (CH4) is a powerful greenhouse gas (GHG), contributing 32% of current climate forcing (US EPA, 2015). Landfill gas comprises of 50-55% CH4 and 40-45% CO2. Global warming potential of CH4 is 28 …

Air Dispersion Modeling Of Multiple Natural Gas Well Pads At Different Terrain Conditions And Determination Of Inverse Distance Weighting Function Exponent, Fatemeh Khalaj

Civil Engineering Theses - Archive

Natural gas production and development has been widely spreading all over the United States. Texas has been leading the nation in natural gas production by holding approximately twenty three percent of the nation’s natural gas reserves. However, natural gas exploration, drilling, production and distribution process have impacts on air quality and human health. The emissions from natural gas processes could be categorized as volatile organic compounds (including Hazardous Air Pollutants), methane, carbon monoxide, nitrogen dioxides, particulate matter and some other minor emitted pollutants, which have the potential of causing serious health problems and also impact air quality from an environmental …

Safety Aspects Of Bicyclists In A Connected Vehicle Environment, Ajaykumar Patil

Civil Engineering Theses - Archive

The revival in the number of bicyclists, bike infrastructure investments and bike policies in the U.S. in the last two decades has escalated the importance of bicycling as a mode of transportation. With the proliferating role of the bicycle mode, bike fatalities continue to grow, too. In response to the increase in fatalities and crashes caused by human driven vehicles, the automobile industry and governments seek to develop autonomous vehicles that can address most of the human related crash causes. While increasing safety remains the primary goal of autonomous vehicles (AV) innovation, the difficulty of bicyclist and pedestrian detection using …

Improving Hydrologic Prediction For Large Urban Areas Through Stochastic Analysis Of Scale-Dependent Runoff Response, Advanced Sensing And High-Resolution Modeling, Amir Norouzi

Civil Engineering Dissertations - Archive

Due to urbanization and climate change, large urban areas such as the DallasFort Worth Metroplex (DFW) area is vulnerable not only to river flooding but also flash flooding. Due to the nonstationarities involved, projecting how the changes in land cover and climate may modify flood frequency in large urban areas is a challenge. Part I of this work develops a simple spatial stochastic model for rainfall-to-areal runoff in urban areas, evaluates climatological mean and variance of mean areal runoff (MAR) over a range of catchment scales, translates them into runoff frequency as a proxy for flood frequency, and assesses its …

Guided-Mode Resonant Filters And Reflectors: Principles, Design, And Fabrication, Manoj Niraula

Electrical Engineering Dissertations - Archive

Thin-film structures incorporating wavelength-scale gratings provide functionalities for applications in various optical systems. Previously, spectral filters, wideband reflectors, and polarizers have been identified as potential application areas. In this dissertation, we overview the operational principles of these resonant periodic structures, discuss the methods of their design and fabrication, and propose and demonstrate novel functionalities for spatial and spectral filtering, and unpolarized wideband reflection. Fashioned with materially sparse gratings, these optical devices are easy to fabricate and integration friendly compared to their traditional multi-layer counterparts making their research and development critical for practical applications. We study, theoretically, modal properties and parametric …

Power-Derived Thermal Characterization Of Sige Hbts And Design Of Timing Circuit Using A Phase Locked-Loop, Valay Dineshbhai Shah

Electrical Engineering Dissertations - Archive

Silicon Germanium (SiGe) hetero-junction bipolar transistors (HBTs) have been designed to cater the demand of high speed circuits having speed applications in wireless, optical communication and space electronics. Due to higher cut-off frequencies and high speed applications, self heating plays a significant role in the performance of SiGe HBTs. This dissertation paper does an extensive analysis on the effect of self heating and used DC measurement methods to extract the self heating parameter, thermal resistance (Rth). A non-linear thermal model is proposed to take into account the effects of the non-linearity in device parameters with increase in device temperature. The …

Sparse Decentralized Principal Components Analysis For Dimensionality Reduction, Nanruo Chen

Electrical Engineering Theses - Archive

Principal components analysis (PCA) is a data compression technology relying on dimensionality reduction. In a wireless sensor network, the acquired data may be spatially scattered and include many zero variables, for which a standard PCA approach cannot account for. To this end, a new algorithm is designed to solve both problems. We combine sparse principal components analysis (SPCA) and distributed principal components analysis (DPCA) together to obtain a sparse distributed principal components analysis (SDPCA) algorithm. Norm-one regularization along with the alternating direction method of multipliers (ADMM) is used for SPCA. ADMM is also employed to obtain a distributed compression algorithm …

Investigation Of Prefrontal Cognition Responses To Transcranial Laser Stimulation In Ptsd Using Functional Near Infrared Spectroscopy, Dev Rajanikant Patel

Bioengineering Theses - Archive

In recent years low level laser therapy (LLLT) has been of great research interest because of its therapeutic applications in psychiatry, neurology and ophthalmology. In-vivo transcranial delivery of LLLT has shown to induce beneficial metabolic effects and increase in cognitive functions and hence has been found to be useful in treating neurodegenerative disorders. The aim of this study was to evaluate effects of LLLT on prefrontal cognitive functions, namely attention and short term memory, over six sessions on veterans with Post-Traumatic Stress Disorder (PTSD), using near infrared spectroscopy (fNIRS). In this study the subjects were instructed to perform two neurocognitive …

Diffused Correlation Spectroscopy For Measurement Of Blood Perfusion During Low Level Laser Therapy (Lllt), Soni Sagar

Bioengineering Theses - Archive

Near infrared stimulation or Low Level Laser Therapy (LLLT) is an innovative technique shown to effect the microvasculature hemodynamics. The aim of this study is to use Diffused Correlation Spectroscopy (DCS) to evaluate the physiological effects of LLLT on blood perfusion. This study is divided into two parts: the fist part is the development of DCS system and the second part is investigating the effects of LLLT on biological tissue. DCS is an emerging non-invasive technique to probe deep tissue hemodynamics. DCS uses time-averaged intensity autocorrelation function for the fluctuations caused due to the moving scatterers (RBCs) in biological tissue. …

Mathematical Optimization Techniques For Managing Selective Catalytic Reduction For A Fleet Of Coal-Fired Power Plants, Antonio Alejandro Alanis Pena

Industrial, Manufacturing, and Systems Engineering Dissertations - Archive

Major commercial electricity generation is done by burning fossil fuels out of which coal-fired power plants produce a substantial quantity of electricity worldwide. The United States has large reserves of coal, and it is cheaply available, making it a good choice for the generation of electricity on a large scale. However, one major problem associated with using coal for combustion is that it produces a group of pollutants known as nitrogen oxides (NOx). NOx are strong oxidizers and contribute to ozone formation and respiratory illness. The Environmental Protection Agency (EPA) regulates the quantity of NOx emitted to the atmosphere in …

Analysis Of An Artificial Tailplane Icing Flight Test Of A High-Wing, Twin-Engine Aircraft, Shehzad Maksudahmad Shaikh

Mechanical and Aerospace Engineering Theses - Archive

The US Air Force Flight Test Center (AFFTC) conducted a civilian, Federal Aviation Administration (FAA) sponsored, evaluation of tailplane icing of a twin-turboprop business transport at Edwards Air Force Base. The flight test was conducted to evaluate ice shape growth and extent of ice on the tailplane for specific weather conditions of Liquid Water Content (LWC), droplet size, and ambient temperature. This work analyzes the flight test data comparing the drag for various tailplane icing conditions with respect to a flight test verified calibrated aircraft model. Although less than a third of the test aircraft was involved in the icing …

A Mesh Based Boom To Stop Oil Spread, Bharathram Visweswaran

Mechanical and Aerospace Engineering Theses - Archive

In this work, we develop a new boom to separate oil and water. In a commonly used boom, a membrane that has no pores is normally used to block oil spread. Since this membrane also blocks water flow, high pressure is easy to build on such a membrane to break or damage it. To solve this problem, in the new boom, the membrane is replaced with a hydrogel-coated mesh. The hydrogel-coated mesh has dual properties of superhydrophilicity and superoleophobicity. Accordingly, water can still go through the mesh, while oil cannot. Subsequently, liquid pressure on the mesh is reduced. In this …

Analysis Of Electric Double Layer Structure Formed During Corrosion Of Steel Pipes Carrying Potable Water, Tanmay Sanjeev Gupte

Mechanical and Aerospace Engineering Theses - Archive

Corrosion of steel pipes carrying drinking water is a universal issue. It affects human health as the corrosion sediments in these pipes can be toxic and unfit for consumption. Further, the amassing of the corrosion products can lead to operational difficulties. Drinking water consists of anions like carbonate, hydroxides and chloride ions which are responsible for the corrosion process. In such types of aqueous corrosion, there is an interfacial region formed between the corroding metal and the bulk of the aqueous environment. This interfacial region is called the Electrical Double Layer. In this article, we direct to study the effects …

Reliability Challenges In Airside Economization And Oil Immersion Cooling, Jimil Manojbhai Shah

Mechanical and Aerospace Engineering Theses - Archive

The Datacom facility which comprises rooms or closets used for communication, computers/servers or electronic equipment requires cooling unit which consumes 31% (23% HVAC cooling + 8% HVAC fans) of overall energy. The ASHRAE TC9.9 subcommittee, on Mission Critical Facilities, Data Centers, Technology Spaces, and Electronic Equipment, has suited the data center’s executives by permitting brief period outings of the environmental conditions outside the prescribed temperature-humidity range, into passable extents A1-A4. To comprehend the expanding server densities and the required cooling vitality costs, data center operators are falling back on cost cutting measures. For instance, they are not firmly controlling the …

Harvesting Of Water From Fog Using Sponges, Jae Jun Lee

Mechanical and Aerospace Engineering Theses - Archive

Supervising Professor: Cheng Luo A sponge has porous structures. It is capable of both storing and transmitting water. In this work, we explored the possibility of applying three different types of sponges to collect fog. We also compared their fog-collection efficiencies with that of a typical Raschel mesh that is widely used in the field to collect fog. We found that, for three different fog speeds, the fog-collection efficiencies of three tested sponges were 39% to 93% those of the typical Raschel mesh, indicating that the sponges could serve as alternative fog collectors when well-developed collectors were not available. Sponge …

Structural Retrofit Of Reinforced Concrete Circular Columns Using Cfrp, Ahmed Haider Mohiuddin

Civil Engineering Theses - Archive

Fiber reinforced polymer (FRP) composites have developed numerous applications in the field of Civil Engineering, mostly because of their beneficial properties like high strength-to=weight ratio and high corrosion resistance. This study presents an easy and expedient finite element (FE) able to accurately estimate the axial load carrying capacity of reinforced concrete (RC) circular columns confined with externally bonded carbon fiber reinforced polymer (CFRP) sheets. The element is able to model collapse due to concrete crushing. The FE generated in this study is used the load carrying capacity of CFRP confined RC columns subjected to concentric loading. Constitutive models for materials …

Discriminating Parkinson's Disease Using Functional Connectivity And Brain Network Analysis, Daniel Gellerup

Industrial, Manufacturing, and Systems Theses - Archive

In this study, we explored the use of functional connectivity patterns in fMRI data to classify subjects on the basis of Parkinson's disease. We explore various brain networks and features. We partition our fMRI data in 5 filtered frequency ranges. We use a proximal support vector machine paired with a minimum-redundancy and maximum-relevance feature selection method on each frequency range. We use a majority voting ensemble classification method on the results of the proximal support vector machine classification results. We use a double 5-fold cross validation scheme for model validation. We achieve 84% accuracy 74% sensitivity, and 93% specificity. Our …

A Radial Basis Function Method For Solving Optimal Control Problems., Hossein Mirinejad

Electronic Theses and Dissertations

This work presents two direct methods based on the radial basis function (RBF) interpolation and arbitrary discretization for solving continuous-time optimal control problems: RBF Collocation Method and RBF-Galerkin Method. Both methods take advantage of choosing any global RBF as the interpolant function and any arbitrary points (meshless or on a mesh) as the discretization points. The first approach is called the RBF collocation method, in which states and controls are parameterized using a global RBF, and constraints are satisfied at arbitrary discrete nodes (collocation points) to convert the continuous-time optimal control problem to a nonlinear programming (NLP) problem. The …

Mechanical Properties And Microstructure Evolution Of 17-4 Ph Stainless Steel Processed By Laser-Powered Bed Fusion., Harish Irrinki

Electronic Theses and Dissertations

Laser powder bed fusion (L-PBF) is a potential manufacturing route for the production of tooling using different steel materials. However, there is a limited understanding of how the mechanical properties and microstructures of the L-PBF produced parts vary with change in powder type and process conditions. The current research studied the influence of L-PBF process parameters on mechanical properties and microstructures of 17-4PH stainless steel using gas and water-atomized powders. The results demonstrate the feasibility of using water-atomized powders as starting raw materials instead of typically used gas-atomized powders to fabricate parts in the L-PBF process at high energy densities.

Model Validation And Transition To Turbulence In Orbiting Culture Dishes., Jonathan Michael D. Thomas

Electronic Theses and Dissertations

Wall shear stress (WSS) is commonly accepted as the primary influence affecting characteristics of anchored endothelial cells when subjected to fluid flow. Orbital shakers are commonly used to study cellular responses due to their ease of use, ability to run several experiments simultaneously, and since they exert physiologically relevant oscillatory shear. These studies require comprehensive resolution of WSS, however the fluid dynamics inside orbiting culture dishes has not yet been well described since the flow is complex and difficult to quantify analytically. A computational fluid dynamics (CFD) model of flow in an orbiting dish has been developed that yields detailed …

Synthesis, Characterization, And Electronic Properties Of Novel 2d Materials : Transition Metal Dichalcogenides And Phosphorene., George Anderson

Electronic Theses and Dissertations

Scaling electronic devices has become paramount. The current work builds upon scaling efforts by developing novel synthesis methods and next generation sensing devices based on 2D materials. A new combination method utilizing thermal evaporation and chemical vapor deposition was developed and analyzed to show the possibilities of Transition Metal Dichalcogenide monolayers and heterostructures. The materials produced from the above process showed high degrees of compositional control in both spatial dimensions and chemical structure. Characterization shows controlled fabrication of heterostructures, which may pave the way for future band gap engineering possibilities. In addition, Phosphorene based field effect transistors, photodetectors, and gas …

Effect Of Non-Uniform Air-Side Velocity Distribution On Heat Transfer Model Predictions For Microchannel Condenser., Zachary Chapin

Electronic Theses and Dissertations

This is a study of the effects on heat transfer capacity predictions of microchannel condensers when airflow is maldistributed due to the shape of the condenser. The three shapes investigated in this study are flat, U-shape and roll. Each coil was tested in a water calorimeter and those results were compared to the model prediction. The model prediction was calculated using CoilDesigner™ modeling software with standard correlations. Using the uniform airflow assumption, the model over predicted the heat capacity measured in the calorimeter by 5-11% depending on the coil and inlet conditions. The local airflow velocity was measured using a …

The Effects Of Ball Interactions On The Dynamic Behavior Of A Ball Balancer Rotating At Speeds Above The Translational Resonant Frequency Of The System., Gregory A. Dedow

Electronic Theses and Dissertations

Many applications are inherently rotational in nature. These applications range from industrial products to consumer products. As seen in a traditional frequency response plot, the motion of a rotating imbalance does not approach zero as the forcing frequency is increased. Unlike a traditional forced mass spring oscillator, the motion of the rotating imbalance approaches some non-zero value. To account for this residual motion, some systems utilize a balancing device to reduce this motion. These balancing devices can be passive or active, depending on the design considerations. This paper will focus on the traditional, passive ball-type balancer due to its simplicity …

An Adaptable Fuzzy-Based Model For Predicting Link Quality In Robot Networks., Christopher J. Lowrance

Electronic Theses and Dissertations

It is often essential for robots to maintain wireless connectivity with other systems so that commands, sensor data, and other situational information can be exchanged. Unfortunately, maintaining sufficient connection quality between these systems can be problematic. Robot mobility, combined with the attenuation and rapid dynamics associated with radio wave propagation, can cause frequent link quality (LQ) issues such as degraded throughput, temporary disconnects, or even link failure. In order to proactively mitigate such problems, robots must possess the capability, at the application layer, to gauge the quality of their wireless connections. However, many of the existing approaches lack adaptability or …