Engineering Commons^™

Design And Synthesis Of Dynamic Covalent Polymer Scaffolds With Controlled Architectures, Emily Annette Hoff

Dissertations

The design and synthesis of functional, controlled polymer architectures is essential to the development of new materials with precise and tailorable properties or applications. The work described in this dissertation focuses on the development of controlled polymer architectures with dynamic linkages for the design of multifunctional materials and surfaces via robust, efficient, and stimuli-responsive strategies.

In Chapter III, a post-polymerization modification strategy based on ambient temperature nucleophilic chemical deblocking of polymer scaffolds bearing N-heterocycle blocked isocyanate moieties is reported. Room temperature RAFT polymerization of three azole-N-carboxamide methacrylates, including 3,5-dimethyl pyrazole, imidazole, and 1,2,4-triazole derivatives, afforded reactive polymer scaffolds …

Nanostructured Morphologies In Glassy Polymer Networks, Brian Greenhoe

Dissertations

The body of this work describes a novel approach for the dispersion of multi-walled carbon nanotubes in a high T_g epoxy prepolymer matrix using a twin screw high-shear continuous reactor. The method demonstrated improves on previous dispersion methods in several ways. It offers increased efficiency through excellent heat transfer, while being solvent-less, scale-able, and tailorable to drive dispersion states to judiciously chosen dispersion states. Furthermore, it was shown that dispersion state and agglomerate morphology can be directed, in several ways, through processing conditions and also by controlling the matrix viscosity profile through cure. Broadband dielectric spectroscopy, optical hot-stage microscopy, …

Development Of Printed Cross-Functional Sensors For Gearbox Lubricant Prognostics, John Omondi Manyala

Dissertations

Lubricant oil degradation is a major cause of failures in transportation machinery such as pumps, engines, and gearboxes. Proactive oil maintenance techniques such as the off-line oil sampling for laboratory analysis are not only costly but are also susceptible to various influences during the oil sampling, transportation and testing. In this study, an on-line oil condition monitoring system is presented with an integrated predictive prognostic scheme, describing the evolution in time of the identified fault indicators for purposes of estimating the remaining useful life of oil in real-time inside the gearbox. The proposed methodology facilitates on-demand gearbox maintenance rather than …

Design And Validation Of An Electro-Hydraulic Pressure-Control Valve And Closed-Loop Controller, Jerry Boza

Dissertations

Electro-hydraulic pressure-control valves are used in many applications, such as manufacturing equipment, agricultural machinery, and aircrafts to name a few. They are often used to actuate hydraulic clutches, such as those found in power shift transmissions. A traditional pressure-control valve with open-loop control algorithm is typically used in clutch applications. This scheme often results in inconsistent or undesirable system behavior due to the nature of open-loop control as well as the nonlinear system dynamics and uncertainties.

In this research two new electro-hydraulic pressure-control valves were designed in order to decouple the valve and control port (hydraulic) dynamics. This was achieved …

Indoor Localization Of Mobile Devices Based On Wi-Fi Signals Via Convex Optimization And Bregman Divergence, Osamah Ali Abdullah

Dissertations

Indoor positioning systems (IPS) have been the subject of intense academic and industrial research due to the significance of such systems in a wide range of applications. Applications of IPS include indoor navigation and its associated user services, especially by users in large complex buildings, by emergency healthcare services to locate a patient, and people with vision impairments. IPS can also play an important role in other applications that require tracking and observation, such as those used in care for the elderly or security purposes. Therefore, much research has been focused on IPS methods that fingerprint the Received Signal Strength …

Support Vector Machines And Artificial Neural Networks: Assessing The Validity Of Using Technical Features For Security Forecasting, James Dipadua

Dissertations

Stock forecasting is an enticing and well-studied problem in both finance and machine learning literature with linear-based models such as ARIMA and ARCH to non-linear Artificial Neural Networks (ANN) and Support Vector Machines (SVM). However, these forecasting techniques also use very different input features, some of which are seen by economists as irrational and theoretically unjustified. In this comparative study using ANNs and SVMs for 12 publicly traded companies, derivative price “technicals” are evaluated against macro- and microeconomic fundamentals to evaluate the efficacy of model performance. Despite the efficient market hypothesis positing the ill-suitability of technicals as model inputs, this …

Support Vector Machines And Artificial Neural Networks: Assessing The Validity Of Using Technical Features For Security Forecasting, James Di Padua

Dissertations

Stock forecasting is an enticing and well studied problem in both finance and machine learning literature with linear based models such as ARIMA and ARCH to nonlinear Artificial Neural Networks (ANN) and Support Vector Machines (SVM). However, these forecasting techniques also use very different input features, some of which are seen by economists as irrational and theoretically unjustified. In this comparative study using ANNs and SVMs for 12 publicly traded companies, derivative price “technicals” are evaluated against macro and microeconomic fundamentals to evaluate the efficacy of model performance. Despite the efficient market hypothesis positing the ill suitability of technicals as …

Using Spatialisation To Support Exploratory Search Behaviour, Clement Roux

Dissertations

Information-seekers traditionally interact with digital content through keyword-based search interfaces displaying results in list views. Well-defined lookup search tasks are performed brilliantly with these interfaces, enabling users to find relevant information and develop a relative understanding of the underlying information space. However, it is feasible to suggest that ill-defined and abstract search tasks could be better supported with a different interface that could allow the user to explore a library’s content and develop an appropriate mental model of the information space. One such approach is based on the use of visualisation, an approach to data analysis that aims to reduce …

A Regression Study Of Salary Determinants In Indian Job Markets For Entry Level Engineering Graduates, Rajveer Singh

Dissertations

The economic liberalisation of Indian markets in early 90s boosted the economic growth of the nation in various sectors over the next two decades. One such sector that has seen a massive growth in this time is Information Technology (IT). The IT industry has played a very crucial role in transforming India from a slow moving economy to one of the largest exporters of IT services. This growth created a huge demand in the labour markets for skilled labour, which in turn made engineering one of the top choices of study after high school over the years. In addition, the …

Investigating The Impact Of Unsupervised Feature-Extraction From Multi-Wavelength Image Data For Photometric Classification Of Stars, Galaxies And Qsos, Annika Lindh

Dissertations

This thesis reviews the current state of photometric classification in Astronomy and identifies two main gaps: a dependence on handcrafted rules, and a lack of interpretability in the more successful classifiers. To address this, Deep Learning and Computer Vision were used to create a more interpretable model, using unsupervised training to reduce human bias.

The main contribution is the investigation into the impact of using unsupervised feature-extraction from multi-wavelength image data for the classification task. The feature-extraction is achieved by implementing an unsupervised Deep Belief Network to extract lower-dimensionality features from the multi-wavelength image data captured by the Sloan Digital …

An Exploration Of The Impact Of Animal Agriculture On Human Sustainable Development Index And The Child Health Indicator, Hithesan Pandian

Dissertations

Several studies have shown that animal agriculture is one of the major contributors to climate change due to greenhouse gas emissions, deforestation, land degradation, freshwater shortages, general environmental pollution and world hunger. Apart from this, meat consumption is strongly associated with certain fatal health conditions such as cancer, cardiovascular disease and diabetes (Wu, 2014). Although meat production and export could be economically beneficial in the short run, it could lead to over-exploitation of natural resources and in turn the destruction of the environment in the long run. Hence, it is essential for the leaders of a nation to make smart …

Electrical Characterization Of High-K Gate Dielectrics For Advanced Cmos Gate Stacks, Yi Ming Ding

Dissertations

The oxide/substrate interface quality and the dielectric quality of metal oxide semiconductor (MOS) gate stack structures are critical to future CMOS technology. As SiO₂ was replaced by the high-k dielectric to further equivalent oxide thickness (EOT), high mobility substrates like Ge have attracted increasing in replacing Si substrate to further enhance devices performance. Precise control of the interface between high-k and the semiconductor substrate is the key of the high performance of future transistor. In this study, traditional electrical characterization methods are used on these novel MOS devices, prepared by advanced atomic layer deposition (ALD) process and with pre …

Processing Of Cds/Cdte Solar Cell And The Growth Model Of Cdte Thin Film, Guogen Liu

Dissertations

Cadmium telluride is the only thin film photovoltaic (PV) technology to surpass crystalline silicon PV in the cost. The most common CdTe solar cells consist of a simple p-n heterojunction structure containing a p-doped CdTe layer and n-doped cadmium sulfide (CdS) layer, which acts as a window layer. Cadmium Sulfide (CdS) thin films are often deposited on glass substrates coated with TCO layers by the close-spaced sublimation (CSS) or sputter techniques in industrial because of in-line production integration. It is seldom reported that CdS is deposited by the chemical bath deposition (CBD) batch process. The bottleneck of CBD for commercial …

A Multimodal Investigation In Eye Movements, Raj Jaswal

Dissertations

While functional magnetic resonance imaging (fMRI) has identified which regions of interest (ROIs) are functionally active during a vergence movement (inward or outward eye rotation), task-modulated coactivation between ROIs is less understood. This study tests the following hypotheses: (1) significant task-modulated coactivation would be observed between the frontal eye fields (FEFs), the posterior parietal cortex (PPC), and the cerebellar vermis (CV); (2) significantly more functional activity and task-modulated coactivation would be observed in binocularly normal controls (BNCs) compared with convergence insufficiency (CI) subjects; and (3) after vergence training, the functional activity and task-modulated coactivation would increase in CIs compared with …

Biomimetic And Vascularized 3-D Liver Cancer Model, Derek Yip

Dissertations

Anti-angiogenic drugs have failed to show significant extended mortality, except when co-administered with chemotherapy drugs in clinical trials. This should be predicted by in vitro models, and yet 2D in vitro models of liver cancer co-administered with these two types of drugs show increased cell viability, contradicting clinical trials. In vitro models should mimic clinical trials in order to accurately predict drug outcomes. 2D in vitro models fail because they lack features of the cancer environment such as presence of stromal cells and a vasculature.

In order to achieve a biomimetic and vascularized in vitro model that would better recapitulate …

Optimization Of Headway, Stops, And Time Points Considering Stochastic Bus Arrivals, Liuhui Zhao

Dissertations

With the capability to transport a large number of passengers, public transit acts as an important role in congestion reduction and energy conservation. However, the quality of transit service, in terms of accessibility and reliability, significantly affects model choices of transit users. Unreliable service will cause extra wait time to passengers because of headway irregularity at stops, as well as extra recovery time built into schedule and additional cost to operators because of ineffective utilization of allocated resources.

This study aims to optimize service planning and improve reliability for a fixed bus route, yielding maximum operator’s profit. Three models are …

Application Of Inkjet Printing Technology To Flexible Batteries, Yuan Gu

Dissertations

Printing technologies have been considered as alternative methods to fabricate thin films in recent years. More and more functional devices like resistors, sensors, antennas and even energy storage devices have been fabricated by printing technologies. As a typical digital printing technology, inkjet printing has much more advantages over the traditional mechanical printing technologies such as: low cost, computer controllable shape design and precise deposition. In this investigation, application of inkjet printing is used to fabricate conductive tracks and rechargeable lithium ion batteries.

Particle free silver ink is developed to solve this problem. In this research, silver complex solution is printed …

Fabrication Of 3d Hydrogel-Based Microscale Tissue Analog Chip With Integrated Optofluidics, Venkatakrishnan Rengarajan

Dissertations

Lab-on-a-chip (LOC) is a device that integrates one or more laboratory functions in a single chip with dimensions ranging from a micrometer to a few millimeters. On-chip optofluidics, which combines microfluidics and tunable micro-optical components, is crucial for bio-sensing applications. However, recently reported optofluidic devices have only two-dimensional (2D) dielectric or metallic regions for sensing cellular activity, which fail to mimic the three-dimensional (3D) in vivo microenvironment of cells.

In this research, a 3D hydrogel-based micro-scale-tissue-analog-chip (µTAC) is fabricated with an integrated optofluidic design for biomedical applications. These 3D hydrogels act as a scaffold for the cellular studies and as …

Experimental Study Of Simulated Geophysical Buoyancy-Driven Vortical Flow, Mohammad Hady Makhmalbaf

Dissertations

This paper describes an experimental study on the flow within a rotating cylinder with a counter-rotating disk located below to mimic certain aspects of the unique flow structures of the Great Red Spot (GRS) in Jupiter using a simple laboratory setup. The special design of this setup makes it capable of spinning the side wall of a vertical cylinder in both directions as well as rotating the bottom of the cylinder independently, where both can rotate in wide ranges of spin rates. Also, different thermal conditions can be applied on the bottom of the disk. All of these conditions provide …

Multi-Sensory Emotion Recognition With Speech And Facial Expression, Qingmei Yao

Dissertations

Emotion plays an important role in human beings’ daily lives. Understanding emotions and recognizing how to react to others’ feelings are fundamental to engaging in successful social interactions. Currently, emotion recognition is not only significant in human beings’ daily lives, but also a hot topic in academic research, as new techniques such as emotion recognition from speech context inspires us as to how emotions are related to the content we are uttering.

The demand and importance of emotion recognition have highly increased in many applications in recent years, such as video games, human computer interaction, cognitive computing, and affective computing. …

The Influence Of The Electric Supply Industry On Economic Growth In Less Developed Countries, Edward Richard Bee

Dissertations

This study measures the impact that electrical outages have on manufacturing production in 135 less developed countries using stochastic frontier analysis and data from World Bank’s Investment Climate surveys. Outages of electricity, for firms with and without backup power sources, are the most frequently cited constraint on manufacturing growth in these surveys.

Outages are shown to reduce output below the production frontier by almost five percent in Africa and by a lower percentage in South Asia, Southeast Asia and the Middle East and North Africa. Production response to outages is quadratic in form. Outages also increase labor cost, reduce exports …

The Recent Development Of New Pigment Binders, Jae Young Shin

Dissertations

Pigment coatings are applied onto paper and paperboard to improve their appearance and printability. For pigmented coatings, pigments and binders are the most important ingredients so their selections are critical.

Pigment binders not only perform the basic required role of binding pigment particles to each other and bonding the base sheet, but also significantly influence the rheology, coater runnability, and drying behaviors of the coating formulation and the optical, viscoelastic, and printing properties of coated paper and paperboard products.

When considering the relative amount of binders to use in a coating, one may speak about main binder, co-binder and sole-binder. …

Agent-Based Modeling Of Abc Methods For Decision-Making In Highway Bridge Projects Including Uncertainty And Several Stakeholders, Abdul Wahed Mohammed

Dissertations

Accelerated Bridge Construction (ABC) methods that were recently introduced in the U.S. to reduce the on-site construction duration furnish several benefits to the public and highway agencies. Further, the traffic growth in addition to increasing number of functionally obsolete and structurally deficient bridges necessitates the increased implementation of ABC methods. In recent years, several Departments of Transportation (DOTs) in the U.S. have developed decision-making models to compare broadly ABC to conventional bridge construction for a particular site. However, with increased implementation and advancements in ABC methods, there is a need for specifying a particular ABC method and a superstructure system …

Sensing Gyroscopic Properties Of Rotating Magnetic Nanoparticles In Solution, Brian Gerald Krug

Dissertations

A new sensor using magnetic nanoparticles and rotating magnetic fields has been developed. By spinning the nanoparticles in a rotating magnetic field, it is feasible to infer angular position and inertia if an external force is applied to the system. The nanoparticles are treated as a multitude of miniature gyroscopes whose overall effect can be combined as one single gyroscope. Two sensors were built to test the feasibility, both containing Fe3O4 nanoparticles.

The typical input current was 250 milliamps. When the sensor deviated from its magnetic axis by a small angle, the input current changed between 1 and 2 milliamps …

Flexographic Printing Of Conductive Silver Inks Onto Pdms: Surface Treatment And Novel Processes For Creating Printed Electronic Devices, Michael James Joyce

Dissertations

For the continued advancement of the field of printed electronic (PE), there is a need for a better understanding of the interactions between functional inks and substrates, which is required to optimize printability, mechanical, and functional properties for the creation of more robust and efficient printed devices. This body of work aims to advance the knowledge of the material properties of poly-di-methyl-siloxane, PDMS, films, their interactions with flexo inks, and their flexographic printability. As the printing of metals (i.e., Ag & Au) is a known area of interest pertaining to PE, this work focused on the characterization and optimization of …

Development And Evaluation Of Matrix Material Formulations For Potential Integration Into Immunodiagnostic Biosensors, Payam Aminayi

Dissertations

This study supports the development, characterization and optimization of biosensor material formulations for immunodiagnostic applications based on experimental findings and hypotheses by Wang and Wu [1, 2], and using a test-plate apparatus and thin-film design developed by Young [3].

Certain biosensors working on the basis of conductance/impedance changes have demonstrated their potential to detect various bacteria, enzymes, and biomolecules due to their enhanced electrical properties with incorporated single-walled carbon nanotubes (SWNT). From the work conducted in our laboratory, we are attempting to determine and develop a matrix formulation containing highly dispersed SWNT, antibody and other components that elicit a significantly …

Vector Processor Virtualization: Distributed Memory Hierarchy And Simultaneous Multithreading, Seyedamin Rooholamin

Dissertations

Taking advantage of DLP (Data-Level Parallelism) is indispensable in most data streaming and multimedia applications. Several architectures have been proposed to improve both the performance and energy consumption for such applications. Superscalar and VLIW (Very Long Instruction Word) processors, along with SIMD (Single-Instruction Multiple-Data) and vector processor (VP) accelerators, are among the available options for designers to accomplish their desired requirements. On the other hand, these choices turn out to be large resource and energy consumers, while also not being always used efficiently due to data dependencies among instructions and limited portion of vectorizable code in single applications that deploy …

Cloud-Aided Wireless Systems: Communications And Radar Applications, Shahrouz Khalili

Dissertations

This dissertation focuses on cloud-assisted radio technologies for communication, including mobile cloud computing and Cloud Radio Access Network (C-RAN), and for radar systems.

This dissertation first concentrates on cloud-aided communications. Mobile cloud computing, which allows mobile users to run computationally heavy applications on battery limited devices, such as cell phones, is considered initially. Mobile cloud computing enables the offloading of computation-intensive applications from a mobile device to a cloud processor via a wireless interface. The interplay between offloading decisions at the application layer and physical-layer parameters, which determine the energy and latency associated with the mobile-cloud communication, motivates the inter-layer …

Instruction Fusion And Vector Processor Virtualization For Higher Throughput Simultaneous Multithreaded Processors, Yaojie Lu

Dissertations

The utilization wall, caused by the breakdown of threshold voltage scaling, hinders performance gains for new generation microprocessors. To alleviate its impact, an instruction fusion technique is first proposed for multiscalar and many-core processors. With instruction fusion, similar copies of an instruction to be run on multiple pipelines or cores are merged into a single copy for simultaneous execution. Instruction fusion applied to vector code enables the processor to idle early pipeline stages and instruction caches at various times during program implementation with minimum performance degradation, while reducing the program size and the required instruction memory bandwidth. Instruction fusion is …

On Greening Optical Access Networks, Mina Taheri Hosseinabadi

Dissertations

With the remarkable growth of fiber-based services, the number of FTTx subscribers has been dramatically increasing in recent years. Owing to the environmental concern, reducing energy consumption of optical access networks has become an important issue for network designers. In Ethernet passive optical network (EPON), the optical line terminal (OLT) located at the central office broadcasts the downstream traffic to all optical network units (ONUs), each of which checks all arrival downstream packets to obtain those destined to itself. Since traffic of ONUs changes dynamically, properly defining the sleep mode for idle ONUs can potentially save a significant amount of …