Engineering Commons^™

Novel Shape Memory And Multi-Shape Memory Polymers For Biomaterial Applications, Shelby Lois Buffington

Dissertations - ALL

Biomaterial platforms have been used to probe how cells respond to chemical, topographical or mechanical changes in their environments. However, these traditionally static biomaterial platforms have not enabled the study of how cells respond to dynamic changes in their environment. Driven by a need to better understand cell behavior and its role it disease, development and tissue regeneration recent efforts have focused on designing dynamic biomaterial platforms to better mimic a cell’s natural environment. In this work, advanced shape memory polymers (SMPs) that respond to non-thermal triggers and multi-shape memory materials capable of multiple topographical transitions were developed for advanced …

Copula-Based Multimodal Data Fusion For Inference With Dependent Observations, Shan Zhang

Dissertations - ALL

Fusing heterogeneous data from multiple modalities for inference problems has been an attractive and important topic in recent years. There are several challenges in multi-modal fusion, such as data heterogeneity and data correlation. In this dissertation, we investigate inference problems with heterogeneous modalities by taking into account nonlinear cross-modal dependence. We apply copula based methodology to characterize this dependence.

In distributed detection, the goal often is to minimize the probability of detection error at the fusion center (FC) based on a fixed number of observations collected by the sensors. We design optimal detection algorithms at the FC using a regular …

Widening Of Reinforced Concrete Bridges – Extension Of Pier Cap Beams With Cfrp Composites, Cheng Tan

Dissertations - ALL

Increase in traffic load dictates widening highway bridges rather than construction of new bridges, as it offers an economical solution. Highway bridge widening is usually accomplished by the construction of additional new bridge piers, however, large amount of construction work and extensive use of heavy plant and machinery could result in very high cost. For limited widening of bridges, e.g. addition of one driving/emergency lane, extension of the pier cap beam offers an attractive solution. Due to additional load resulting from the widened bridge, strengthening of extended cap beams may be needed. In addition, depending on the strength of the …

Homeostatic Elastic States And The Stability Of Elastic Arteries, Xinyu Zhang

Dissertations - ALL

Vascular mechanics has undergone significant growth within the last 50 years owing to the rapid development of nonlinear continuum mechanics occurring roughly within the same period and motivated primarily by rubber materials. However, one important distinction of blood vessels, in contrast to typical engineering materials is that, through a variety of physiological mechanisms, they seek to maintain constant a preferred mechanical state (mechanical homeostasis) thereby exhibiting a remarkable mechanical stability in response to temporal evolution and alterations in blood pressure, vessel tethering forces and geometry and material properties. The mechanical state experienced by blood vessels plays a critical role in …

Numerical Investigation Of Laser-Induced Ignition Phenomena, Deshawn Coombs

Dissertations - ALL

This thesis investigates various aspects of laser-ignition. Laser ignition is a form of combustion initiation by means of a focused laser pulse in a combustible mixture. The ignition process consists of a chain of processes with varying degrees of importance to the prediction of a successful flame propagation. Some of these processes include plasma formation, induced shock wave, emergence of a flame kernel, and successful transition to a self-sustained flame or flame quenching. This thesis will explore various aspects of this process using computational fluid dynamics and model analysis with the aim of identifying the controlling processes and simplified ways …

Sequential Methods For Non-Parametric Hypothesis Testing, Prashant Khanduri

Dissertations - ALL

In today’s world, many applications are characterized by the availability of large amounts of complex-structured data. It is not always possible to fit the data to predefined models or distributions. Model dependent signal processing approaches are often susceptible to mismatches between the data and the assumed model. In cases where the data does not conform to the assumed model, providing sufficient performance guarantees becomes a challenging task. Therefore, it is important to devise methods that are model-independent, robust, provide sufficient performance guarantees for the task at hand and, at the same time, are simple to implement. The goal of this …

Network Sampling Through Crawling, Katchaguy Areekijseree

Dissertations - ALL

In recent years, researchers have increasingly used OSN data to study human behavior. Before such a study can begin, one must first obtain appropriate data. A platform, e.g, Facebook or Twitter, may provide an API for accessing data, but such APIs are often ratelimited, restricting the amount of data that an individual collects in a given amount of time. In order for the data collector to efficiently collect data, she needs to make intelligent use of her limited budget. Therefore, when collecting data, efficiency is extremely important. We consider the problem of network sampling through crawling, in which the data …

Sampling And Characterizing Evolving Communities In Social Networks, Humphrey Appiah Mensah

Dissertations - ALL

One of the most important structures in social networks is communities. Understanding communities is useful in many applications, such as suggesting a friend for a user in an online friendship network, recommending a product for a user in an e-commerce network, etc. However, before studying anything about communities, researchers first need to collect appropriate data. Getting complete access to the data for community studies is unrealistic in most cases. In this work, we address the problem of crawling networks to identify community structure. Firstly, we present a network sampling technique to crawl the community structure of dynamic networks when there …

Status And Remediation Of Mercury In Fish And Aquatic Ecosystems, Geoffrey Dean Millard

Dissertations - ALL

Mercury is a known neurotoxin which can bioaccumulate and biomagnify as methylmercury, causing significant human and ecological impacts. New York State and the surrounding region is impacted by mercury in complex ways as some areas are recovering from the effects of acidic deposition while the entire region is increasingly influenced by climate change. In order to better understand the drivers and trends of mercury dynamics in New York State, my research was conducted in three phases: 1) the impact of lime (calcium carbonate) additions on mercury cycling in small acid-sensitive headwater streams of the Adirondack State Park; 2) applied advanced …

Locating People Of Interest In Social Networks, Pivithuru Wijegunawardana

Dissertations - ALL

By representing relationships between social entities as a network, researchers can analyze them using a variety of powerful techniques. One key problem in social network analysis literature is identifying certain individuals (key players, most influential nodes) in a network. We consider the same problem in this dissertation, with the constraint that the individuals we are interested in identifying (People of Interest) are not necessarily the most important nodes in terms of the network structure. We propose an algorithm to find POIs, algorithms to collect data to find POIs, a framework to model POI behavior and an algorithm to predict POIs …

Modeling The Interactions Of Forest Cutting And Climate Change On The Hydrology, Biomass And Biogeochemistry Of A Northeastern Forest, Mahnaz Valipour

Dissertations - ALL

Global and regional environmental disturbances, including harvesting and climate change, can lead to integrated and interactive effects on forest ecosystems, altering their structure and function, and therefore long-term sustainability. Understanding both short- and long-term impacts of harvesting practices (e.g., cutting rotation length, intensity) on forest dynamics is a key factor in developing criteria and guidelines for sustainable forest management practices. Process ecosystem models are useful tools to improve predictive understanding of complex, interacting ecological process and their response to disturbance. Few studies have rigorously tested model simulations against field measurements which would provide more confidence in efforts to quantify logging …

Intrusion Detection For Cyber-Physical Attacks In Cyber-Manufacturing System, Mingtao Wu

Dissertations - ALL

In the vision of Cyber-Manufacturing System (CMS) , the physical components such as products, machines, and tools are connected, identifiable and can communicate via the industrial network and the Internet. This integration of connectivity enables manufacturing systems access to computational resources, such as cloud computing, digital twin, and blockchain. The connected manufacturing systems are expected to be more efficient, sustainable and cost-effective.

However, the extensive connectivity also increases the vulnerability of physical components. The attack surface of a connected manufacturing environment is greatly enlarged. Machines, products and tools could be targeted by cyber-physical attacks via the network. Among many emerging …

Inferences From Interactions With Smart Devices: Security Leaks And Defenses, Diksha Shukla

Dissertations - ALL

We unlock our smart devices such as smartphone several times every day using a pin, password, or graphical pattern if the device is secured by one. The scope and usage of smart devices' are expanding day by day in our everyday life and hence the need to make them more secure. In the near future, we may need to authenticate ourselves on emerging smart devices such as electronic doors, exercise equipment, power tools, medical devices, and smart TV remote control. While recent research focuses on developing new behavior-based methods to authenticate these smart devices, pin and password still remain primary …

Performance Analysis For 5g Cellular Networks: Millimeter Wave And Uav Assisted Communications, Esma Turgut

Dissertations - ALL

Recent years have witnessed exponential growth in mobile data and traffic. Limited available spectrum in microwave ($\mu$Wave) bands does not seem to be capable of meeting this demand in the near future, motivating the move to new frequency bands. Therefore, operating with large available bandwidth at millimeter wave (mmWave) frequency bands, between 30 and 300 GHz, has become an appealing choice for the fifth generation (5G) cellular networks. In addition to mmWave cellular networks, the deployment of unmanned aerial vehicle (UAV) base stations (BSs), also known as drone BSs, has attracted considerable attention recently as a possible solution to meet …

Carboxylic Acid Hydrodeoxygenation Over Supported Noble Metal Catalysts, Joshua Gopeesingh

Dissertations - ALL

Carboxylic acid hydrodeoxygenation (HDO) over supported noble metal catalysts was carried out in order identify the main challenges associated with supported monometallic catalysts and identifying solutions that may increase the practicality of these high activity metals. Using propionic acid as a probe molecule, it was found that supported platinum (Pt) and ruthenium (Ru) catalysts have two main issues: selectivity and stability. Both metals are quite unselective towards HDO products, multiple chemistries occur over the catalysts that lead to a myriad of undesired products. Decarbonylation (DCN) is the most selective pathway over Pt catalysts, while both DCN and methanation chemistries are …

Modeling And Simulation Of High-Density Spray Combustion, Chenwei Zheng

Dissertations - ALL

High-efficiencies and low-emissions can be realized in combustion engines that operate at high-pressures and low-temperatures conditions (high densities). The design of such engines relies on accurate models of the physical processes involved. Three areas of concern are multi-phase phenomena, the equation of state for the gas phase and cost-effective chemical kinetic modeling. Fuel injected as liquid must break up into droplets, evaporate, and mix with air before combusting. Models for these processes have been developed and need to be tested against experiments. As for the gas phases, the ideal gas model fails to capture thermodynamic relations at high-density combustion. A …

Impacts Of Urban Development Pattern On Runoff Peak Flows And Streamflow Flashiness Of Peri-Urban Catchments: Assessing The Performance Of Physical And Data-Driven Models For Real-Time Ensemble Flood Forecasting, Babak Kasaee Roodsari

Dissertations - ALL

Urban growth is a global phenomenon, and the associated impacts on hydrology from land development are expected to increase, especially in peri-urban catchments, which are newly developing catchments in proximity of growing cities. In northern climates, hydrologic response of peri-urban catchments change with the water budget and climatic conditions. As a result, runoff response of northern peri-urban catchments can vary immensely across seasons. During warm seasons, the evapotranspiration (ET) and infiltration rates are high, so urban floods are expected to occur during high intensity, low duration storm events. During cold seasons and below freezing temperatures, surficial soils are typically frozen …

A Web-Based Collaborative Multimedia Presentation Document System, Chunxu Tang

Dissertations - ALL

With the distributed and rapidly increasing volume of data and expeditious development of modern web browsers, web browsers have become a possible legitimate vehicle for remote interactive multimedia presentation and collaboration, especially for geographically dispersed teams. To our knowledge, although there are a large number of applications developed for these purposes, there are some drawbacks in prior work including the lack of interactive controls of presentation flows, general-purpose collaboration support on multimedia, and efficient and precise replay of presentations.

To fill the research gaps in prior work, in this dissertation, we propose a web-based multimedia collaborative presentation document system, which …

Residual Flexural Strength Of Corroded Aashto Type Ii Pretensioned Concrete Girder-Deck System, Bo Yan

Dissertations - ALL

Precast-prestressed concrete (PC) girders are among the most cost-effective type of girders used on highway bridges. Unfortunately, in corrosive environments, corrosion of strands may result in cracking or spalling of concrete, cross-section loss of strands and degradation of material properties, which in turn reduces the load-carrying capacity of PC bridges.

This research presents an in-depth analysis of residual flexural strength of corroded AASHTO Type II pretensioned PC girders with a cast-in-place (CIP) concrete deck. The investigation involved development of a detailed Finite Element Analysis (FEA) model of the pretensioned girder-deck system subjected to corrosion. The FEA model developed for this …

Use Of Computational Electromagnetics To Enhance The Accuracy And Efficiency Of Antenna Pattern Measurements, Heng Chen

Dissertations - ALL

The objective of this dissertation is to illustrate that computational electromagnetics can be used to improve the accuracy and efficiency of antenna pattern measurements.

This can be accomplished in many different ways, such as moving a single probe over the measurement plane to generate accurate planar near field to far field transformation methodology over the classical Fourier based modal expansion methods. Also, one can use an array of probes instead of moving a single probe over the measurement plane to eliminate the inaccuracy of a mechanical movement of the probe antenna over a large planar surface and make the measurement …

Composite Right-Left Handed Stripline Structures For Antenna Array Feed Networks, Michael Douglas Enders

Dissertations - ALL

In this dissertation composite right/left-handed striplines are proposed as viable key structures in antenna array applications, enabling reduction of the overall feed network sizes as well as allowing integration opportunities and possible reduction of radiating beam pattern distortions.

A via-less composite right/left-handed stripline unit cell is introduced as an option to attain right/left-handed performance in stripline with a via-less fabrication process that is not sensitive to drill positioning errors and is amenable to academic settings. An analysis of the passbands of this structure based on the distributed transmission line circuit theory is provided as well as a description of the …

Wireless Electrostimulation To Eradicate Bacterial Biofilms, Hao Wang

Dissertations - ALL

Bacterial biofilms can form on medical implants and cause serious device-associated infections that are incurable by conventional antibiotics because of high-level tolerance to antimicrobials. Common strategies for controlling device-associated infections, such as coating with antimicrobials and modification of surface properties, can reduce or delay biofilm formation, but the inhibitory effect can be overcome by bacteria over time, and eradicating mature biofilms remains challenging. Direct currents (DCs) have been shown to have bactericidal effects and synergy with conventional antibiotics in concurrent treatment has been demonstrated for killing biofilm cells. However, these systems require a direct connection between electrodes and a power …

Synthesis Of Polymer Structures For Increasing Energy Conversion In Solar Cells, Fu-Hao Chen

Dissertations - ALL

Solar cells are the mainstream of renewable energy, since solar energy is abundant and accessible to most places on Earth. However, it has drawbacks, such as low energy conversion commonly less than 20 %, the power supply is intermittent and not stable. In industry, the energy conversion efficiency versus cost is the first priority to promote. Thus, implementing low cost but effective technique is attractive to industry. Based on geometric and wave optics, two simple-integrated and scalable techniques to improve the energy conversion of solar cells are developed. The first method is to make a v-groove structure on the encapsulant, …

Modern Methods In Machine Learning As Applied To The Study Of A Complex Supersonic Jet Flow, Andrew Steven Tenney

Dissertations - ALL

The desire for aircraft to fly higher, farther, and faster has led to the use of more complex nozzle geometries over the last several decades. These nozzles often take advantage of multiple high-velocity streams issuing from non-axisymmetric exit areas and can be optimized for airframe integration and stealth performance. The associated turbulent jet physics and the aeroacoustic phenomena have been studied thoroughly over the past 80 years; however, the complex non-linear interactions between multiple merging canonical flows are not well understood. In this study, we seek to gain a better understanding of the flow physics in the near-field of a …

Processing And Properties Of New Anisotropic And Mechanically Active Polymeric Composites, Matthew M. Ali

Dissertations - ALL

Electrospinning is a versatile and inexpensive method to fabricate micron-sized polymer fibers, and it has been employed in this work to develop highly anisotropic fibrous composites. Previous work has detailed the properties of using electrospinning to fabricate fibrous anisotropic composites that was achieved by embedding stiff fibers in an elastomeric matrix. The goal of this work is to achieve anisotropic composites through creating a layering of rigid and elastic fibers in a laminate structure using primarily electrospinning in the fabrication. The composite produced has a unique deformation pattern when strained perpendicularly. The rigid fibers experienced no entanglement with each other …

Computational Modeling Of Bacterial Outer Membranes And Development Of High-Throughput Screening Platform For Antibiotics, Huilin Ma

Dissertations - ALL

Antibiotic resistance is a major health challenge because it limits the treatment options for common infectious diseases and will cause 10 million deaths each year after 2050. There is an urgent need to reduce the misuse of antibiotics and seek new classes of antibiotics that induce less or no resistance. Despite the push for new therapeutics, there has been a precipitous decline in the number of newly approved antibacterial drugs due to a limited understanding of how bacteria adapt to the chemical stress stimuli. The development of antimicrobial resistance is especially true for Gram-negative bacteria that develop resistance to antibiotics …

Integrating Trustzone Protection With Communication Paths For Mobile Operating System, Kailiang Ying

Dissertations - ALL

Nowadays, users perform various essential activities through their smartphones, including mobile payment and financial transaction. Therefore, users’ sensitive data processed by smartphones will be at risk if underlying mobile OSes are compromised. A technology called Trusted Execution Environment (TEE) has been introduced to protect sensitive data in the event of compromised OS and hypervisor.

This dissertation points out the limitations of the current design model of mobile TEE, which has a low adoption rate among application developers and has a large size of Trusted Computing Base (TCB). It proposes a new design model for mobile TEE to increase the TEE …

Dynamics Of Water, Carbon, And Nitrogen In Forest And Alpine Tundra Ecosystems In The Pacific Northwest And The Rocky Mountains Of The U.S. Under Future Climate Change, Zheng Dong

Dissertations - ALL

Projection of ecosystem functions and biogeochemical cycling of elements under future climate change requires a quantitative understanding of both ecosystem processes and site-specific climate change scenarios. Biogeochemical and ecological studies over the last decades have provided the intellectual basis for these projections, especially at the small watershed scale. Recent developments in biophysical sciences and computationally based meteorology coupled with advanced downscaling techniques have made it possible to project future climate change scenarios at the small watershed scale. Using a biogeochemical model, PnET-BGC, which has been extensively applied to the forest ecosystems in the northeastern United States, the interactive effects of …