Engineering Commons^™

Controlling Biofilm And Persister Cells By Targeting Cell Membranes, Ali Adem Bahar

Dissertations - ALL

The rapid increase in antibiotic resistant infections and the slowing pace of antibiotic development emphasize the need for alternative therapeutic agents to cure infectious diseases especially those caused by multidrug-resistant (MDR) strains. Bacteria obtain resistance to antibiotics through multiple mechanisms. One of intrinsic mechanisms of drug resistance is persister formation, by which bacterial cells enter a metabolically inactive stage and become highly tolerant to essentially all antibiotics, even at the concentrations that are hundreds of times higher than the lethal dose required to kill normal planktonic cells of the same strain. Persister cells in biofilms are even more difficult to …

Power-Aware Planning And Design For Next Generation Wireless Networks, Chenfei Gao

Dissertations - ALL

Mobile network operators have witnessed a transition from being voice dominated to video/data domination, which leads to a dramatic traffic growth over the past decade. With the 4G wireless communication systems being deployed in the world most recently, the fifth generation (5G) mobile and wireless communica- tion technologies are emerging into research fields. The fast growing data traffic volume and dramatic expansion of network infrastructures will inevitably trigger tremendous escalation of energy consumption in wireless networks, which will re- sult in the increase of greenhouse gas emission and pose ever increasing urgency on the environmental protection and sustainable network development. …

Characterization And Chemical Kinetic Analysis Of The Ignition Of Representative Conventional And Bio-Derived Fuels, Mazen Eldeeb

Dissertations - ALL

Fossil fuels are the main energy source in the world. However, they are responsible for negative environmental impacts, such as global climate change and rising sea levels. Biofuels are an environmentally friendly alternative which can substitute fossil fuels without major engine modications, especially in the transportation sector. Furans, a class of biofuels, are considered as possible alternative fuels for SI engines. They can be produced from sugars, derived from non-food biomass sources. This thesis is a contribution to fundamental characterization of their combustion properties.

Reactivity trends in furan combustion are established through ignition delay measurements of selected furans; 2,5-dimethyl furan …

Indoor Environmental Quality (Ieq) And Building Energy Optimization Through Model Predictive Control (Mpc), Korbaga Fantu Woldekidan

Dissertations - ALL

This dissertation aims at developing a novel and systematic approach to apply Model Predictive Control (MPC) to improve energy efficiency and indoor environmental quality in office buildings. Model predictive control is one of the advanced optimal control approaches that use models to predict the behavior of the process beyond the current time to optimize the system operation at the present time. In building system, MPC helps to exploit buildings’ thermal storage capacity and to use the information on future disturbances like weather and internal heat gains to estimate optimal control inputs ahead of time.

In this research the major challenges …

Heterogeneous Sensor Signal Processing For Inference With Nonlinear Dependence, Hao He

Dissertations - ALL

Inferring events of interest by fusing data from multiple heterogeneous sources has been an interesting and important topic in recent years. Several issues related to inference using heterogeneous data with complex and nonlinear dependence are investigated in this dissertation. We apply copula theory to characterize the dependence among heterogeneous data.

In centralized detection, where sensor observations are available at the fusion center (FC), we study copula-based fusion. We design detection algorithms based on sample-wise copula selection and mixture of copulas model in different scenarios of the true dependence. The proposed approaches are theoretically justified and perform well when applied to …

Study Of Homogeneous Mineral Acid Dehydration Of Monosaccharides In A Cstr, Siddharth Sharad Bhat

Dissertations - ALL

Simple sugars (Aldohexoses/pentoses), (Ketohexoses/pentose) when subjected to a dehydration reaction, produce various compounds. An example of one such compound is 5-hydroxymethyl furfural. Such chemical products may be used in subsequent processing steps (hydrolysis, aldol condensation, hydrogenation and dehydration) to produce similarly structured condensed compounds that form the basis of complex molecules used in various industries such as production of fuels, chemical reagents and fertilizers. Most studies focus on heterogeneous packed beds and batch reactors to carry out dehydration reactions. This study illustrates use of a Continuous Stirred-Tank reactor to carry out such dehydration reactions. In order to maintain the homogenous …

Shape Memory Polymers As 2d Substrates And 3d Scaffolds For The Study Of Cell Mechanobiology And Tissue Engineering, Richard Mcclary Baker

Dissertations - ALL

Tissue engineering is a promising, fast-growing field that combines cells, signals, and scaffolds to regenerate damaged tissues. To develop new, functional, engineered tissues, it is becoming increasingly important to understand how cell-material interactions affect the cell mechanobiological response. As a result, recent efforts have focused on developing complex synthetic materials that can mimic the dynamic in vivo cell environment. In this work, shape memory polymers (SMPs) were employed to develop dynamic 2D substrates and 3D scaffolds that undergo programmed changes in shape under cell compatible conditions. These substrates and scaffolds were applied in vitro and in vivo to demonstrate their …

An Experimental Study On Thermal Stability Of Faee Biodiesel Fuel With Ethanol, Yujie Shen

Dissertations - ALL

Biodiesel fuel is usually synthesized from vegetable oil and animal fat, and now it has been widely used in tractors, trucks, buses and ships. Unlike traditional fossil fuels, biodiesel is more environment-friendly and it is renewable, which can help people solve the energy crisis to some extent.

Nowadays, supercritical esterification has become a novel way to produce biodiesel, but high temperature may cause the decomposition of biodiesel. Researchers mainly focus on studying the properties of fatty acid methyl ester (FAME), however, fatty acid ethyl ester (FAEE) biodiesel has only been slightly explored. So in this study, ethanol was used to …

Design Of A High Capacity, Scalable, And Green Wireless Communication System Leveraging The Unlicensed Spectrum, Mohammad Riaz Khawer

Dissertations - ALL

The stunning demand for mobile wireless data that has been recently growing at an exponential rate requires a several fold increase in spectrum. The use of unlicensed spectrum is thus critically needed to aid the existing licensed spectrum to meet such a huge mobile wireless data traffic growth demand in a cost effective manner. The deployment of Long Term Evolution (LTE) in the unlicensed spectrum (LTE-U) has recently been gaining significant industry momentum. The lower transmit power regulation of the unlicensed spectrum makes LTE deployment in the unlicensed spectrum suitable only for a small cell. A small cell utilizing LTE-L …

Soft Reversible Actuator Based On Shape Memory Polymer, Che Tan

Dissertations - ALL

My research employs two shape memory polymer based approaches to develop thermally-triggered soft reversible actuators. Our approaches throughout this thesis aim at developing soft actuators with both simple and complex geometries that have the spatial control over actuation shapes, which makes them desirable for a broad range of applications.

In this thesis, we employed a porous poly (caprolactone) (PCL) shape memory polymer foam infiltrated with PDMS elastomeric matrix to fabricate the actuators. Thermal/mechanical characterizations were used to demonstrate good thermal properties and thermomechanical behavior of materials and composites. Scanning electron microscopy was conducted to illustrate the morphology of the composite …

Fundamentals Of Microlayer Evaporation And Its Role On Boiling Heat Transfer Enhancement, An Zou

Dissertations - ALL

Boiling, a dynamic and multiscale process, is widely used in industrial applications as it can transfer a large amount of heat over a small surface area. It has been studied for over five decades; however, a comprehensive understanding of the process is still lacking. The bubble ebullition cycle (nucleation, growth and departure) happens over a very short time-span (milliseconds) making it challenging to study the near-surface interfacial characteristics of a single bubble, which involves a microlayer. The microlayer is a thin film present at the bubble base and varies from nano-scale to micro-scale in thickness. The dynamics of the microlayer …

Structure, Dynamics And Rheology Of Polymer Solutions From Coarse-Grained Molecular Dynamics: Effects Of Polymer Concentration, Solvent Quality And Geometric Confinement, Yutian Yang

Dissertations - ALL

Understanding flow-microstructure interactions in macromolecular fluids is of great

importance in the design and optimization of ubiquitous polymer processing operations.

Further, such interactions are routinely encountered in separation of biopolymer mixtures

using gel electrophoresis and microfluidic technologies, manufacturing of polymer-based

functional nanocomposites and polymer-induced reduction in turbulent friction drag. To

date, the vast amount of theoretical/computational modeling efforts on flowmicrostructure

coupling has focused on continuum-level and stochastic descriptions.

Such approaches, while useful in qualitatively predicting polymer dynamics and rheology

in model systems, are incapable of describing the effects of polymer-solvent, polymerpolymer

and polymer-wall interactions. Further, in the context of polymer …

Integration Of Evs And Dgs Into The Electric Power System For Grid Modernization, Mohammad Nikkhah Mojdehi

Dissertations - ALL

Electric power systems (EPSs) are rapidly becoming more complex. Penetration of distributed generators (DGs) are increasing rapidly. Among them, DG units with intermittent renewables resources, such as solar or wind, are attracting more attention. Moreover, plug in electric vehicles (EVs) are expected to be deployed in large numbers over the next decade. These changes present opportunities as well as challenges for reliable and efficient operation of EPS.

Integrating EVs in large scale, would result in over-loading of EPS. Interconnection of DGs could impact adversely on the system operation including power quality and safety of the EPS. However, due to the …

Surface Plasmon Polaritons: Guided-Wave Devices And Applications, Ashish Chanana

Dissertations - ALL

The prospect of controlling the interaction of light with matter at nanoscale has been widely studied in recent years, and entails characterizing optical and optoelectronic devices at resolution higher than the diffraction limit. One technique that allows localization of light to sub-wavelength dimensions is through the use of surface plasmon polaritons (SPPs) wherein the interaction of light with free electrons on a metal surface can lead to a bound surface electromagnetic field that is confined to deep sub-wavelength dimensions. Studies based on SPPs merged with the field of nanotechnology have resulted in novel imaging technologies, nonlinear and quantum-optical devices and …

Control Of Inflammation Using Drug Delivery Strategies In In Vitro Models, Patricia R. Wardwell

Dissertations - ALL

Regulation of inflammation is a crucial component of the immune system in response to injury and infection. In otherwise healthy individuals, an initial acute inflammatory response will subside once the injury or infection is eradicated. However, in certain disease states including autoimmune disease and persistent infection, miscommunication between cells of the immune system leads to a chronic inflammatory response, contributing to disease pathology and exacerbating symptoms. A major regulator of inflammation communication at the cellular level is transcription factor (TF) NF-κB. Under normal conditions, NF-κB is bound to an inhibitor in the cytoplasm. In a chronic disease state, NF-κB is …

Thermally/Mechanically Responsive Polymeric Composites With Shape Memory/Self-Healing Properties, Hossein Birjandi Nejad

Dissertations - ALL

Smart materials with the ability to respond to external stimulus have attracted tremendous attention in both academic institutions and industry. Such unique aspect of these materials make them great candidates to address current challenges in the world of Materials Science including those that no human intervention is a necessity. The objective of this dissertation is to employ different techniques to develop novel thermally and mechanically responsive polymeric composites for several industrial applications.

In Chapter 2, the curing kinetics and polymerization induced phase separation (PIPS) of an epoxy matrix with and without a semicrystalline thermoplastic was investigated. Same PIPS technique studied …

Binary Program Integrity Models For Defeating Code-Reuse Attacks, Aravind Prakash

Dissertations - ALL

During a cyber-attack, an adversary executes offensive maneuvers to target computer systems. Particularly, an attacker often exploits a vulnerability within a program, hijacks control-flow, and executes malicious code. Data Execution Prevention (DEP), a hardware-enforced security feature, prevents an attacker from directly executing the injected malicious code. Therefore, attackers have resorted to code-reuse attacks, wherein carefully chosen fragments of code within existing code sections of a program are sequentially executed to accomplish malicious logic. Code-reuse attacks are ubiquitous and account for majority of the attacks in the wild. On one hand, due to the wide use of closed-source software, binary-level solutions …

A Unified And Green Platform For Smartphone Sensing, Xiang Sheng

Dissertations - ALL

Smartphones have become key communication and entertainment devices in people's daily life. Sensors on (or attached to) smartphones can enable attractive sensing applications in different domains, including environmental monitoring, social networking, healthcare, transportation, etc. Most existing smartphone sensing systems are application-specific. How to leverage smartphones' sensing capability to make them become unified information providers for various applications has not yet been fully explored. This dissertation presents a unified and green platform for smartphone sensing, which has the following desirable features: 1) It can support various smartphone sensing applications; 2) It is personalizable; 2) It is energy-efficient; and 3) It can …

Crosslinked Hyaluronic Acid Hydrogel Networks Designed As Mechanical Actuators, Pushkar S. Varde

Dissertations - ALL

Bioengineers are in constant pursuit of solutions to problems facing the medical and pharmaceutical field by designing biomaterials that closely mimic the target natural systems. A unique collection of polymers, known as polymeric actuators, have been devised with the ability to convert an external stimulus to a change in shape, size or permeability. The current options within polymeric biomaterials with multi-functionality include matrices that are biocompatible, biodegradable, quick transitioning / shape changing, and mechanically tunable. These properties have been harnessed for application such as stents, valves, semi permeable membranes, and dynamic cell culture substrates. For such applications quick and uniform …

A Study Of Certain Electromagnetic Interactions Among High Optical Conductivity Nanospheres And Dielectric Half-Spaces, Satvik Navin Wani

Dissertations - ALL

Electromagnetic coupling between a sphere and a semi-infinite substrate, and among several spheres present in the form of a composite were studied in this dissertation. Specifically, spheres made of noble metals such as Ag, Au and Cu and relatively high refractive index substrates and composite matrices. Such interactions need to be studied in order to understand and be able to design better devices such as plasmonic light devices as well as composites and fluids that have suspended plasmonic nanoparticles that have recently been shown to be technologically relevant in the context of device processing technologies and fluidic devices. For a …

Uncertainty-Integrated Surrogate Modeling For Complex System Optimization, Ali Mehmani

Dissertations - ALL

Approximation models such as surrogate models provide a tractable substitute to expensive physical simulations and an effective solution to the potential lack of quantitative models of system behavior. These capabilities not only enable the efficient design of complex systems, but is also essential for the effective analysis of physical phenomena/characteristics in the different domains of Engineering, Material Science, Biomedical Science, and various other disciplines. Since these models provide an abstraction of the real system behavior (often a low-fidelity representative) it is important to quantify the accuracy and the reliability of such approximation models without investing additional expensive system evaluations (simulations …

Gate-Level Timing Analysis And Waveform Evaluation, Chaobo Li

Dissertations - ALL

Static timing analysis (STA) is an integral part of modern VLSI chip design. Table lookup based methods are widely used in current industry due to its fast runtime and mature algorithms. Conventional STA algorithms based on table-lookup methods are developed under many assumptions in timing analysis; however, most of those assumptions, such as that input signals and output signals can be accurately modeled as ramp waveforms, are no longer satisfactory to meet the increasing demand of accuracy for new technologies. In this dissertation, we discuss several crucial issues that conventional STA has not taken into consideration, and propose new methods …

Estimation Of Earthquake Input Energy, Hysteretic Energy And Its Distribution In Mdof Structures, Mebrahtom Gebrekirstos Mezgebo

Dissertations - ALL

Current seismic codes for building design often utilize a force or a displacement-based approach in their implementation. In a force-based approach, a structure is designed to ensure it possesses sufficient strength to resist the maximum forces imparted to it by an earthquake. In a displacement-based approach, a target displacement is calculated or identified and the structure is proportioned to achieve a specified performance level, defined by strain or drift limits, under a specified level of seismic intensity. A third approach, which has gained momentum in the earthquake engineering community, is the energy-based approach. In this approach, a design is considered …

Conceptual Design Of Wind Farms Through Novel Multi-Objective Swarm Optimization, Weiyang Tong

Dissertations - ALL

Wind is one of the major sources of clean and renewable energy, and global wind energy has been experiencing a steady annual growth rate of more than 20% over the past decade. In the U.S. energy market, although wind energy is one of the fastest increasing sources of electricity generation (by annual installed capacity addition), and is expected to play an important role in the future energy demographics of this country, it has also been plagued by project underperformance and concept-to-installation delays.

There are various factors affecting the quality of a wind energy project, and most of these factors are …

Capacity Analysis For Gaussian And Discrete Memoryless Interference Networks, Fangfang Zhu

Dissertations - ALL

Interference is an important issue for wireless communication systems where multiple

uncoordinated users try to access to a common medium. The problem is even more

crucial for next-generation cellular networks where frequency reuse becomes ever more

intense, leading to more closely placed co-channel cells. This thesis describes our attempt to understand the impact of interference on communication performance as well as optimal ways to handle interference. From the theoretical point of view, we examine how interference affects the fundamental performance limits, and provide insights on how interference should be treated for various channel models under different operating

conditions. From the …

Motion In The Field: A Study Of Movement In Computer Science, Catherine Martin

Honors Capstone Projects - All

In this project, I use a system that combines the use of a motion controller to obtain information about physical motion of a user with the transmission of outputs to a quadcopter that interacts with the physical environment. In the manual mode, the user sends commands to the quadcopter using hand controls. I utilized an existing system but increased usability to prevent accidental flight and created commands that are more intuitive for the user. In the automatic mode, the user gives a single command to the motion controller and it runs the A* path planning algorithm over a representation of …

Stress-Strain Behavior By Image Analysis, Mix Density And Pre-Strain Effects Of Eps Geofoam, Chen Liu

Theses - ALL

In order to have a deeper understanding of the engineering performances of EPS geofoam, it is necessary to study the stress-strain response and internal strain distribution when loaded. In this investigation, the key objective is to study the stress-strain behavior of EPS geofoam under different conditions and develop construction practical suggestions when using geofoam. The scope of this research is divided into three main sections: (1) study the effect of induced anisotropy on the stress-strain behavior of EPS geofoam; (2) evaluate stress distribution within EPS blocks by using image analysis system; (3) analyze the effect of combining different EPS densities …

Mechanically Active Electrospun Materials, Jaimee Marie Robertson

Dissertations - ALL

Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, active materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked …

Observing, Understanding, And Manipulating Biological Membranes, Ian Mc Cabe

Dissertations - ALL

The phospholipid bilayer is one of the hallmarks of eukaryotic life. This complicated two dimensionally fluid surface is composed of a double layer of lipids which have a region that is hydrophobic and a region that is hydrophilic. The lipid bilayer membranes of a cell act as a barrier that distinguishes the cells and the organelles interiors from the outside environment. In order for the cell to be able to effectively communicate across these impermeable barriers they have evolved many intricate systems of lipid and protein interaction that serve to transmit information from one side of the membrane to the …

Characterization Of Fundamental Communication Limits Of State-Dependent Interference Networks, Ruchen Duan

Dissertations - ALL

Interference management is one of the key techniques that drive evolution of wireless networks from one generation to another. Techniques in current cellular networks to deal with interference follow the basic principle of orthogonalizing transmissions in time, frequency, code, and space. My PhD work investigate information theoretic models that represent a new perspective/technique for interference management. The idea is to explore the fact that an interferer knows the interference that it causes to other users noncausally and can/should exploit such information for canceling the interference. In this way, users can transmit simultaneously and the throughput of wireless networks can be …