Engineering Commons^™

Additive Manufacturing Techniques To Enhance The Performance Of Electronics Created On Flexible And Rigid Substrates, Aamir Hamed Hamad

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Different additive manufacturing (AM) methods including fused deposition modeling (FDM) and piezoelectrical drop on demand (DOD) inkjet printing have been used in printed electronics for easy production, easy integration, better performance, and low cost. These methods have been used in producing everyday smart printed electronics such as conformal antennas (planner and non-planar antennas), sensors, actuators, and solar cells created on flexible and rigid substrates. The performance of printed electronics strongly depends on printing techniques and printing resolution that enhance their electrical and mechanical properties. In this dissertation, 3D and surface printing techniques were used to enhance the performance of printed …

Adaptive Multi-Fidelity Modeling For Efficient Design Exploration Under Uncertainty, Atticus J. Beachy

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This thesis work introduces a novel multi-fidelity modeling framework, which is designed to address the practical challenges encountered in Aerospace vehicle design when 1) multiple low-fidelity models exist, 2) each low-fidelity model may only be correlated with the high-fidelity model in part of the design domain, and 3) models may contain noise or uncertainty. The proposed approach approximates a high-fidelity model by consolidating multiple low-fidelity models using the localized Galerkin formulation. Also, two adaptive sampling methods are developed to efficiently construct an accurate model. The first acquisition formulation, expected effectiveness, searches for the global optimum and is useful for modeling …

Correlating In-Situ Monitoring Data With Internal Defects In Laser Powder Bed Fusion Additive Manufacturing, Andrew J. Harvey

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The presence of defects within laser powder bed fusion (LPBF) parts can lead to reduced mechanical properties and life of components. Because of this, the ability to detect these defects within the parts is critical before the part is subject to its intended loading. Normally the parts are subjected to a quality analysis once they are completed however, this process is typically expensive and time consuming. A solution for these problems is to sense the creation of defects and pores in the parts in-situ, while the part is being fabricated. One proposed method of in-situ monitoring is visible spectroscopy to …

Analytical Approach To Multi-Objective Joint Inference Control For Fixed Wing Unmanned Aerial Vehicles, Julian L. Casey

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Fixed-wing Unmanned Aerial Vehicles (UAVs) have been found highly useful in various environments, including military and law enforcement. With the increased use of fixed-wing UAVs, there becomes an increased need to optimize the resources available. One approach to resource management is to create multi-objective flights. This thesis presents the design, analysis, and experimental implementation of multi-objective resource management for the resource of Range, distance available to the UAV, from the viewpoint of Intelligence Surveillance and Reconnaissance (ISR). First, a Simulation Environment is created capable of tracking multiple fixed-wing UAVs and to allow for the UAVs’ being controlled by an externally …

Processing And Properties Of Multifunctional Two Dimensional Nanocomposites Based On Graphene Nano-Flakes, Mohammed K. Mohammed

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The unique properties of graphene have directed researchers to study and characterize this new material. Graphene production and graphene based materials have been widely explored and developed in the past decade. Most research has aimed at developing scalable, environmentally friendly, and cheap procedures to produce defect-free graphene that can be used in various applications such as mechanical properties enhancement and multifunctional material. The challenge is processing such material on a scale suitable for engineering applications such as advanced photonics and advanced electronics. In this study, we investigate a new processing technique based on Langmuir-Blodgett (LB) Technique. We managed to produce …

Quantitative Susceptibility Mapping (Qsm) Reconstruction From Mri Phase Data, Sara Gharabaghi

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Quantitative susceptibility mapping (QSM) is a powerful technique that reveals changes in the underlying tissue susceptibility distribution. It can be used to measure the concentrations of iron and calcium in the brain both of which are linked with numerous neurodegenerative diseases. However, reconstructing the QSM image from the MRI phase data is an ill-posed inverse problem. Different methods have been proposed to overcome this difficulty. Still, the reconstructed QSM images suffer from streaking artifacts and underestimate the measured susceptibility of deep gray matter, veins, and other high susceptibility regions. This thesis proposes a structurally constrained Susceptibility Weighted Imaging and Mapping …

Stabilization Of Β-Cristobalite In The Sio2-Alpo4-Bpo4 System, Kathryn Doyle

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Fused silica (silica glass) is transparent in the optical and near-infrared and has a low dielectric constant, making it suitable as a window material for radio frequency radiation. However, at high temperatures (>1100C), fused silica will easily creep and lose dimensional stability. Crystallized silica is much more creep resistant than fused silica. Silica crystallizes to many different structures including quartz, tridymite, and α- and β cristobalite. The only cubic polymorph, which is suitable for both optical and radio frequency transmission in polycrystalline form, is β -cristobalite. Unfortunately, this polymorph transforms to α-cristobalite at ~300C, and the volume change during …

Hierarchical Structure, Properties And Bone Mechanics At Macro, Micro, And Nano Levels, Farah Mohammed Ridha Abdulateef Hamandi

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This research focuses on the hierarchical structure of bone and associated mechanical properties at different scales to assess damage accumulation leading to premature failure, with or without instrumentation. In this work, an attempt was made to develop a framework of macro, micro, and nano damage accumulation models and implementing them to derive mechanical behavior of the bone. At macrolevel, retrospective evaluation of 313 subjects was conducted, and the damage of bone tissue was investigated with respect to subject demography including age, gender, race, body mass index (BMI), height and weight, and their role in initiating fracture. Experimental data utilized 28 …

Developing Equivalent Solid Model For Lattice Cell Structure Using Numerical Approaches, Tahseen Abdulridha Ali Al-Wattar

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Lattice cell structures (LCS) are the engineered porous structures that are composed of periodic unit cells in three dimensions. Such structures have many scientific and engineering applications, such as in vessel gas technology, thermal systems, mechanical and aerospace structures, etc. for which lightweight, high strength, and energy absorption capabilities are essential properties. To have an optimized design, finite element analysis (FEA) based computational approach can be used for detailed analysis of such structures, sometime in full scale. However, developing a large-scale model for a lattice-based structure is computationally expensive. If an equivalent solid FE model can be developed using the …

Online Clustering With Bayesian Nonparametrics, Matthew D. Scherreik

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Clustering algorithms, such as Gaussian mixture models and K-means, often require the number of clusters to be specified a priori. Bayesian nonparametric (BNP) methods avoid this problem by specifying a prior distribution over the cluster assignments that allows the number of clusters to be inferred from the data. This can be especially useful for online clustering tasks, where data arrives in a continuous stream and the number of clusters may dynamically change over time. Classical BNP priors often overestimate the number of clusters, however, leading researchers to develop new priors with more control over this tendency. To date, BNP algorithms …

Development Of Real-Time Systems For Supporting Collaborations In Distributed Human And Machine Teams, Aishwarya Bositty

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Real-time distributed systems constitute computing nodes that are connected by a network and coordinate with one another to accomplish a cooperative task, combining the responsiveness, fault-tolerance and geographic independence to support time-constrained collaborative applications, including distributed Human-Machine Teaming. In this thesis research the viability of real-time distributed collaborative technologies is demonstrated through the design, development and validation of prototype systems that support two human-machine teaming scenarios namely, ACE-IMS (Affirmation Cue based Interruption Management Systems) and ReadMI (Real-time Assessment of Dialogue in Motivational Interview). ACE-IMS demonstrates how a combination of AI capabilities and the cloud and mobile computing infrastructure can be …

Mitigating Atmospheric Phase Errors In Sal Data, Randy S. Depoy Jr.

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Synthetic aperture ladar (SAL) is an emerging remote sensing technology capable of providing high-resolution, interpretable, and timely imagery. SAL and synthetic aperture radar (SAR) are similar in that they provide high-resolution imagery suitable for a wide-variety of applications beyond the diffraction limit of the real aperture. Several advantages of SAL are; realistic imagery resulting from diffuse scattering of optically-rough objects, fine directionality of laser beam making the technology inherently low probability-of-detect, and shorter synthetic aperture collection times, all of which result from operating at optical as opposed to RF wavelengths. With the dramatic decrease in wavelength, SAL systems become more …

Understanding Visual Representation Of Imputed Data For Aiding Human Decision-Making, Ryan M. Thompson

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The effectiveness of representing higher dimensional data on a two-dimensional visualization was required to be studied in the development of a novel data imputation method, Continuous Imputation With Association Rules (CIWAR). When the CIWAR method is used to impute missing data, the method generates additional metadata that increases each imputed data point's dimensionality. Potential use cases for CIWAR include situations where imputed data would be analyzed by individuals with little or no data analytic experience or situations where imputed data would be used to aid high-stress time-critical human decision processes. A study was conducted to assess the effect of the …

Turbine Passage Vortex Response To Upstream Periodic Disturbances, Mitchell Lee Scott

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Flow through the turbine section of gas turbine engines is inherently unsteady due to a variety of factors, such as the relative motion of rotors and stators. In low pressure turbines, periodic wake passing has been shown to impact boundary layer separation, blade surface pressure distribution, and loss generation. The effect of periodic disturbances on the endwall flow is less understood. Endwall flow in a low-pressure turbine occurs in the boundary layer region of the flow through the blade passage where the blade attaches to the hub in the turbine. The response of an endwall vortical structure, the passage vortex, …

Ultraviolet-B Radiation Induces Release Of Bioactive Microvesicle Particles In Keratinocytes Via Platelet-Activating Factor And Acid Sphingomyelinase, Langni Liu

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Ultraviolet-B (UV-B) radiation is one of the most common environmental factors and is known to induce the production of bioactive agents that cause several diseases including skin cancer. UVB exposure stimulates the production of a phospholipid activator, platelet-activating factor (PAF), and its analogs in keratinocytes that activate the PAF receptor (PAF-R) resulting in acute inflammatory and delayed systematic immunosuppressive effects. However, as UVB only penetrates into the skin epidermal layer, the detailed mechanisms of how UVB exerts systematic effects remains unclear. Previously we found that UVB induces keratinocytes to release large numbers of microvesicle particles (MVPs). These small membrane-bound particles …

Stream Clustering And Visualization Of Geotagged Text Data For Crisis Management, Nathaniel C. Crossman

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In the last decade, the advent of social media and microblogging services have inevitably changed our world. These services produce vast amounts of streaming data, and one of the most important ways of analyzing and discovering interesting trends in the streaming data is through clustering. In clustering streaming data, it is desirable to perform a single pass over incoming data, such that we do not need to process old data again, and the clustering model should evolve over time not to lose any important feature statistics of the data. In this research, we have developed a new clustering system that …

Small-Signal Analysis Of Non-Isolated Ćuk Dc-Dc Converter, Lokesh Kathi

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In the future, renewable energy sources will be the primary energy sources due to non-renewable energy resources depletion. Having a sustainable energy source as an input voltage source for the electrical system is essential. Its applications can be widely used in hybrid solar-wind energy systems, electric vehicles, etc. This converter is invented and named after by Slobodan Cuk. An analysis describing a detailed steady-state operation of the non-isolated Cuk converter operating in continuous-conduction mode (CCM) is provided. The expected steady-state current and voltage waveforms across different components of the converter are analytically derived. Design equations for the converter are provided. …

Global Identification Of Human Modifier Genes Of Alpha-Synuclein Toxicity, Ishita Haider

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Alpha-synuclein is a small lipid binding protein abundantly expressed in the brain. Lewy body or Lewy-like pathology, primarily composed of misfolded alpha-synuclein, is a pathological feature shared by several neurodegenerative disorders, including Parkinson's disease (PD). Both missense mutations and increased copy numbers of the SNCA gene, encoding the alpha-synuclein protein, have been genetically linked to autosome dominant PD. Other genetic variations affecting the expression of the SNCA gene have been associated with sporadic PD. Although the physiological function of alpha-synuclein is not well understood, its localization to plasma and vesicular membranes at the presynaptic terminals suggests a role in neurotransmission. …

Kv2.1 Channel Clustering In The Sod1-G93a Mouse Model Of Als, Joshua Christopher Harris

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Kv2.1 channels mediate slow-activating K+ rectifier current within the membrane of spinal motoneurons (MNs), and they are known to co-localize with other synapses and ion channels. Although Kv2.1 channels are suggested to regulate MN excitability, little research has gone into investigating its potential contribution to MN-altered excitability in Amyotrophic Lateral Sclerosis (ALS). Using the male SOD1-G93A mouse model of ALS, we examined Kv2.1 cluster area and density in lumbar MNs at four key stages of disease progression. In our experiments, MNs were separated by type via SK3 immunoreactivity in order to isolate and compare the responses of disease-resistant (slow; SK3+) …

In Vivo Data Capture Using Hssr For Calibration Of Computational Models, Thor Erik Andreassen

Electronic Theses and Dissertations

Computational modeling is a vital tool for understanding and evaluating healthy and unhealthy function of the musculoskeletal aspects of the human body. However, the accuracy of the musculoskeletal models depends significantly on the accuracy of the input data used to calibrate various behavioral parameters of the model. To date, most computational models have been built using generic in vitro data, mostly because of a lack of accurate and meaningful datasets from in vivo testing. The next major step in computational modeling is to create subject-specific computational models using calibration data taken from in vivo testing. The overall goal was to …

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Building Services Engineering

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Identification Of Heat Release Shapes And Combustion Control Of An Ltc Engine, Radhika Sitaraman

Dissertations, Master's Theses and Master's Reports

Low Temperature Combustion (LTC) regimes have gained attention in internal combustion engines since they deliver low nitrogen oxides (NOx) and soot emissions with higher thermal efficiency and better combustion efficiency, compared to conventional combustion regimes. However, the operating region of these high-efficiency combustion regimes is limited as it is prone to knocking and high in-cylinder pressure rise rate outside the engine safe zone. By allowing multi-regime operation, high-efficiency region of the engine is extended. To control these complex engines, understanding and identification of heat release rate shapes is essential. Experimental data collected from a 2 liter 4 cylinder LTC engine …

Role Of Flocculation And Dispersion In Pelletization Of Iron Ore, Victor J. Claremboux

Dissertations, Master's Theses and Master's Reports

Traditional modeling of iron ore pellet strength utilizes micromechanical models such as Rumpf’s equation, which correlate attractive forces and pellet properties into an average expected pellet strength. These models combine with repulsive forces within pellets to predict that pellet strength decreases with the introduction of these forces. However, naïvely applying Rumpf’s equation readily leads to incorrect predictions about the resulting behavior. Pellets created with strong repulsive forces arising from dispersion conditions are observed to be significantly stronger overall than pellets formed in the absence of dispersants. A new model is required to understand and predict the effects of these additives …

Efficient Enhancement Of Micro-Nucleation Rates In Flow-Boiling - By Concurrent Micro-Structuring Of The Boiling-Surface And Its Judicious Energization By Piezoelectric-Transducer Induced Acoustic Vibrations., Atharva Rahane

Dissertations, Master's Theses and Master's Reports

The report describes the science and technology backgrounds and uses for the technology breakthrough reported for enhanced flow-boiling based cooling of high-power density electronics (chips, memory etc.). A controlled but explosive growth in micro-scale nucleation rates during flow-boiling of HFE-7100 (electronics and environment friendly liquid from 3M, Inc) is enabled by the uses of inexpensive meshed-copper for micro-structuring of the boiling surface and a pair of Piezoelectric-transducers for active imposition of suitable acoustic vibrations. The pair of piezo transducers mounted just outside the mini-channel impose “in plane” acoustic vibrations of controllable amplitudes and frequencies, and they are used to induce …

Multiphysics Phase Field Modeling Of Electromigration, Zachary Morgan

Dissertations, Master's Theses and Master's Reports

With the miniaturization of microelectronic devices, the reliability of solder interconnects is a significant concern. As size is reduced, the current density flowing through an interconnect becomes larger and exacerbates electromigration leading to microstructural changes and failure. Since most solder alloys are required to be lead-free over toxicity concerns, there are additional challenges to interconnect performance. Nearly all solder alloys are comprised with its majority component being tin due to its low melting temperature and economical cost. The typical metallic white tin phase has a body-centered tetragonal crystal structure which exhibits strong anisotropy in its physical properties. In particular, the …

Innovative Sustainable Wood Preservatives From Pulp And Paper Industry Byproduct, Raisa Carmen Andeme Ela

Dissertations, Master's Theses and Master's Reports

In the modern forest industry, the need for bio-based, renewable, and environmentally-benign wood preservatives is increasing. Preservatives are used to prevent or limit decay and there has been an increasing interest in developing wood preservatives from renewable materials. To support the need for bio-based, environmentally-friendly preservatives, this work employed kraft lignin as a raw material to produce a novel bio-based wood preservative.

For the first project, a statistical design of experiments approach in Minitab® was used to study how fractionation process variables during acid precipitation of lignin influence the lignin mass yield and characteristics. After precipitating lignin from black liquor, …

Developing Innovative Spectral And Machine Learning Methods For Mineral And Lithological Classification Using Multi-Sensor Datasets, Chandan Kumar

Dissertations, Master's Theses and Master's Reports

The sustainable exploration of mineral resources plays a significant role in the economic development of any nation. The lithological maps and surface mineral distribution can be vital baseline data to narrow down the geochemical and geophysical analysis potential areas. This study developed innovative spectral and Machine Learning (ML) methods for mineral and lithological classification. Multi-sensor datasets such as Airborne Visible/Infrared Imaging Spectrometer-Next Generation (AVIRIS-NG), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Observing (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR), Sentinel-1, and Digital Elevation Model (DEM) were utilized. The study mapped the hydrothermal alteration minerals derived …

The Overexploitation Of The Valle De Querétaro Aquifer And Its Impact In Small Peri-Urban Communities, Querétaro, México, Kelsey Kirkland

Dissertations, Master's Theses and Master's Reports

The Valle de Querétaro Aquifer is the only viable local water source satisfying the domestic, agricultural, and industrial water needs of the Querétaro Valley. Severe depletion of the groundwater source has had significant consequences throughout the region, especially in the peri-urban communities of Santo Niño de Praga, Tlacote el Bajo, and La Palma. Historically, residents depended on aquifer-fed freshwater springs (known as Los Tajos) to meet their basic and productive needs. Spring production ceased between 10 and 15 ago and investigating the causes formed the basis of this research.

Analysis of available qualitative and quantitative data was used to identify …

High-Performance Spectral Methods For Computer-Aided Design Of Integrated Circuits, Zhiqiang Zhao

Dissertations, Master's Theses and Master's Reports

Recent research shows that by leveraging the key spectral properties of eigenvalues and eigenvectors of graph Laplacians, more efficient algorithms can be developed for tackling many graph-related computing tasks. In this dissertation, spectral methods are utilized for achieving faster algorithms in the applications of very-large-scale integration (VLSI) computer-aided design (CAD)

First, a scalable algorithmic framework is proposed for effective-resistance preserving spectral reduction of large undirected graphs. The proposed method allows computing much smaller graphs while preserving the key spectral (structural) properties of the original graph. Our framework is built upon the following three key components: a spectrum-preserving node aggregation and …

Rain Generated Lahars Prior To The 2018 Catastrophic Eruption Of Fuego Volcano, Guatemala, Claudia Buondonno

Dissertations, Master's Theses and Master's Reports

Fuego volcano is one of the most active and hazardous volcanoes in the world. It is located in the northern part of the Central American Volcanic Arc in Guatemala and its activity can be characterized by long term, low-level background activity, and sporadic larger explosive eruptions. Its historical observations of eruptions date back to 1531, but it has been erupting vigorously since 2002 with major activity throughout 2018, producing three main eruptions in February, June and November. Its almost persistent activity generates major ashfalls, pyroclastic flows, lava flows; when heavy rains mobilize its deposits, they can form damaging lahars. Phenomena, …