Engineering Commons^™

Interventions Of Waterjet Technology In Skin Incisions, Nadi Atalla

Dissertations

This research explores the use of waterjet (WJ) technology in performing skin incisions. The study defines the analytical relationships between the skin properties and the operating parameters of the WJ which include the skin thickness, its elastic modulus, the WJ pressure, the nozzle’s orifice diameter, its stand-off distance and the traverse speed of the WJ as well as the duration of applying the WJ pressure. An analytical model is developed to measure the depth incision of the skin, the water pressure and the water velocity, while using a WJ. Systemization and optimization models that determine the optimal operating parameters levels …

Epitaxial Growth Of Iii-Nitride Nanostructures And Their Optoelectronic Applications, Moab Rajan Philip

Dissertations

Light-emitting diodes (LEDs) using III-nitride nanowire heterostructures have been intensively studied as promising candidates for future phosphor-free solid-state lighting and full-color displays. Compared to conventional GaN-based planar LEDs, III-nitride nanowire LEDs exhibit numerous advantages including greatly reduced dislocation densities, polarization fields, and quantum-confined Stark effect due to the effective lateral stress relaxation, promising high efficiency full-color LEDs. Beside these advantages, however, several factors have been identified as the limiting factors for further enhancing the nanowire LED quantum efficiency and light output power. Some of the most probable causes have been identified as due to the lack of carrier confinement in …

N8- Polynitrogen Stabilized On Carbon-Based Supports As Metal-Free Electrocatalyst For Oxygen Reduction Reaction In Fuel Cells, Zhenhua Yao

Dissertations

The sluggish oxygen reduction reaction (ORR) kinetics at the cathode is one of the key factors limiting the performance of polymer electrolyte membrane fuel cell (PEMFC). Platinum-based materials are the most widely studied catalysts for this ORR reaction while their large-scale practical application in fuel cells is hindered due to their scarcity and low stability. Therefore, highly active, low cost and robust non-Pt catalysts are being developed to overcome the drawbacks. Recently, a novel polynitrogen N8- (PN) stabilized on multiwall carbon nanotube (MWNT) was synthesized under ambient condition for the first time by our group and demonstrated high ORR activities. …

Surface-Enhanced Raman Detection Of Glucose On Several Novel Substrates For Biosensing Applications, Laila Saad Alqarni

Dissertations

The small normal Raman cross-section of glucose is considered to be a major challenge for its detection by Surface Enhanced Raman Spectroscopy (SERS) for medical applications. These applications include blood glucose level monitoring of diabetic patients and evaluation of patients with other medical conditions, since glucose is a marker for many human diseases. This dissertation focuses on Surface-Enhanced Raman Scattering primarily for the detection of glucose. Some experiments also are carried out for the detection of the corresponding enzyme glucose oxidase that is used in electrochemical glucose sensors and in biofuel cells. This project explores the possibility of utilizing Surface …

Workload Allocation In Mobile Edge Computing Empowered Internet Of Things, Qiang Fan

Dissertations

In the past few years, a tremendous number of smart devices and objects, such as smart phones, wearable devices, industrial and utility components, are equipped with sensors to sense the real-time physical information from the environment. Hence, Internet of Things (IoT) is introduced, where various smart devices are connected with each other via the internet and empowered with data analytics. Owing to the high volume and fast velocity of data streams generated by IoT devices, the cloud that can provision flexible and efficient computing resources is employed as a smart "brain" to process and store the big data generated from …

Fouling And Aging In Membrane Filtration : Hybrid Afm-Based Characterization, Modelling And Reactive Membrane Design, Wanyi Fu

Dissertations

Membrane filtration has been extensively used in water and wastewater treatment, desalination, dairy making, and biomass/water separation. However, membrane fouling, aging and insufficient removal efficiency for dissolved organic matters remain major challenges for wider industrial applications. In order to tackle these challenges, this doctoral dissertation investigates mechanisms of membrane fouling and development of antifouling membrane filtration technologies. Specifically, four major research areas are explored: (i) nanoscale physicochemical characterization of the chemically modified polymeric membranes; (ii) quantitative modelling between membrane properties and membrane fouling and defouling kinetics; (iii) development of quantitative structure-activity relationships for membranes that undergo thermal and chemical aging …

Engineered Excipients Via Dry Particle Coating, Liang Chen

Dissertations

Excipients with good flowability, bulk density as well as compaction properties are desired for use in tableting since they play important roles in formulation development and processing, including, handling, mixing, feeding and compaction. However, it is often difficult to manufacture excipients that simultaneously possess all three desirable properties, particularly if their size is fine. In addition, it is desirable that the excipients promote direct compression of poorly compactable fine cohesive drug powders at sufficiently high drug loading, and not just achieve the desired high functional properties in placebo formulations. This dissertation aims to developed engineered excipients towards this unmet industry …

Enzyme-Assisted Development Of Hydrogels As Medical Materials With Injectable, Biodegradable And Biocompatible Properties, Yung-Hao Tsou

Dissertations

Hydrogels were first discovered in the year 1960 by Wichterle and Lim [1], and in the following decades, they have been widely studied because of their unique characteristics including their hydrophilic nature, biocompatibility, and capacity to mimic the extracellular matrix (ECM). Hydrogels based on natural or synthetic polymers have continued to be of interest for tissue engineering and drug delivery due to their ability to encapsulate living cells and control the release rate of drugs or other bioactive molecules such as pharmaceutical proteins.

In the first part of this dissertation, dopant-free photoluminescent hydrogels formed in situ by crosslinking of biocompatible …

Temporal And Functional Cortical Aspects Related To Mirror Visual Feedback During Target-Directed Movement In Healthy And Stroke Individuals, Maryam Rohafza

Dissertations

Stroke is the leading cause of disability in the United States (American Heart Association, American Stroke Association) affecting 800,000 individuals annually (i.e., one person every 45 seconds). Therapy for stroke often uses repetitive task practice, which is difficult to perform for patients due to impairment. Mirror visual feedback (MVF) based rehabilitation uses the effect of observing the mirror reflection of volitional movement of one limb, to activate visuomotor brain areas that process movement of the opposite limb. In persons with hemiplegia due to stroke, exercising the less affected limb while observing its reflection, perceived by them as the motion of …

“Polysoaps” Via Raft Copolymerization To Form Well-Defined Micelles For Water Remediation And Targeted Drug Delivery Applications, Phillip Pickett

Dissertations

Amphiphilic copolymers have become increasingly important for environmental and biological applications due to their behavioral characteristics in aqueous solution. For example, structurally-tailored statistical amphiphilic copolymers or “polysoaps” can self-assemble into micelles or other architectures in water at various concentrations. Polysoaps may be differentiated from small molecule surfactant micelles in their capability to self-assemble into unimolecular associates (unimolecular micelles) with no dependence on concentration. Such micelles offer enormous potential for dispersion of hydrophobic species in water at high dilution. Importantly, each polymer chain forms its own micelle and upon dilution, these micelles remain intact and capable of dispersing hydrocarbon material in …

Engineering Multifunctional And Morphologically Diverse Polymer Brush Surfaces, Cassandra M. Reese

Dissertations

The combination of surface-initiated polymerization (SIP) and post-polymerization (PPM) serves as a powerful approach to fabricate complex, multifunctional polymer films, which can be precisely tuned for desired surface engineering applications. Careful manipulation of PPM parameters such as reaction conditions, the tethered brush parameters, and the physical properties of the unbound post-modifier greatly influence the depth of penetration of the post-modifier and the polymer brush compositional heterogeneity. This dissertation focuses on engineering polymer brush surfaces with multifunctional chemistries and tunable morphologies by investigating the PPM parameters that dictate the distribution of post-modifiers on grafted polymer brush surfaces.

The first chapter of …

Chemical And Physical Modification Of Thiol-Ene And Epoxy-Amine Networks For Advanced Control Of Gas Transport And Flame Retardant Behavior, Vivek Vasagar

Dissertations

Crosslinked polymers are widely used due to its several advantages not limited to high mechanical strength combined with the easy processability. Despite of its popular usage, the fundamental understanding of polymer structure affecting the desired properties is still lacking. This PhD thesis is in two parts, the first part is devoted to the design and developing a basic understanding of structure and chemical composition dependencies of gas transport, whereas in the second part a fundamental relationship between structure to the fire-retardant properties is established.

Membrane based gas separation technique has attracted interest of selective removal of carbon dioxide gas from …

Bioinspired Glycopolymers: Models To Investigate The Effect Of Saccharide Structure And Concentration On Amyloid Beta Aggregation, Pradipta Kumar Das

Dissertations

Aggregation and subsequent deposition of amyloid-β (Aβ) peptide on neuronal cell membranes have been implicated as a cause of Alzheimer’s disease. Gangliosides in their clustered form seed and promote the Aβ aggregation process. However, the effects of the structure and the concentration of ganglioside saccharides on Aβ aggregation are not well understood. We investigated how the specific structure of saccharides (β-D-galactose and β-D-glucose) affect the aggregation pathways, kinetics, and the aggregated structures of Aβ via in vitro experiments. The effects of the local concentration of saccharides on the Aβ aggregation were also investigated.

To mimic the multivalent effect of the …

Dual-Battery Empowered Green Cellular Networks, Xilong Liu

Dissertations

With awareness of the potential harmful effects to the environment and climate change, on-grid brown energy consumption of information and communications technology (ICT) has drawn much attention. Cellular base stations (BSs) are among the major energy guzzlers in ICT, and their contributions to the global carbon emissions increase sustainedly. It is essential to leverage green energy to power BSs to reduce their on-grid brown energy consumption. However, in order to furthest save on-grid brown energy and decrease the on-grid brown energy electricity expenses, most existing green energy related works only pursue to maximize the green energy utilization while compromising the …

Parameter Determination And Modeling Of Transformer Windings For Fast Transients Including Frequency Dependent Effects, Yazid Al-Kraimeen

Dissertations

Power transformers are static devices capable of transferring energy from one electrical circuit to another by means of electromagnetic induction at the same frequency. The most common application of transformers in an electric power system is to step up or down the voltage level of an electric grid. This is essential for the efficient transmission and distribution of electricity from generating plants to different types of consumers. Electrical energy used in residential, commercial and industrial settings is delivered to consumers by means of transformers, which normally operate 24 hours a day, 365 days a year. Therefore, design improvements that result …

Embedded Fault Class Detection Methodology For Condition-Based Machine Monitoring And Predictive Maintenance, Nagdev Amruthnath

Dissertations

Ever since the Second Industrial Revolution, manufacturing firms have continuously been working on minimizing the inefficiencies and maximizing the productivity of their system. This objective led to the creation of the Toyota Production System which follows the motto of “making [the] highest quality products at the least cost in the shortest lead time. (Ohno, 1988)” This philosophy is widely recognized and is utilized by various industries today.

Currently, we are going through the Fourth Industrial Revolution (also called, Industry 4.0) where internet technologies are utilized to additionally maximize the productivity in the production processes. Process synchronization is one of the …

Hardware/Software Co-Design Of A Reconfigurable Accelerator Platform For Fuzzy Logic-Based Spatial Image Processing Filters, Aous Hammad Kurdi

Dissertations

Rapid development in the architecture and fabrication technology of field programmable gate array (FPGA) and system on a chip (SoC) in the last two decades is dramatically increasing the reliability of those devices as a cost-effective alternative for traditional real-time image processing systems. Module reusability nature of FPGA and SoC development decreases design and implementation time noticeably. On-site reconfigurability allows for intensive design alterations to occur at a small cost. This study is presenting the design and implementation of a new hardware accelerator for an edge detector on Xilinx 7 series FPGA devices based on a fuzzy logic approach. The …

Network Equivalents Applied To Transient Analysis Of Large Distribution Systems, Ghassan Abdul-Hussein Bilal

Dissertations

Frequency domain (FD) methods for electromagnetic transient analysis of electric power systems offer outstanding simplicity and accuracy when dealing with distributed parameter elements and components that exhibit frequency-dependent behavior. However, the use of FD methods is usually restricted to the simulation of small and simple networks, since it is commonly believed that their application implies a very large computational burden when compared to time domain methods. This study demonstrates that FD methods can accommodate the detailed simulation of large distribution networks within acceptable computer times and in a very straightforward manner, thus offering an attractive complement or alternative to common …

Development Of Piezoelectric Sensors And Methodology For Noninvasive Simultaneous Detection Of Multiple Vital Signs, Areen Abdallah Romi Allataifeh

Dissertations

The activity of piezoelectric material linked the applied electric field with the strain generated that can be translated into geometrical variations. Flexible steel substrate exhibits fascinating mechanical properties which enable their integration into the emerging field of flexible microelectronics. This work presents an extended technique based on capacitance-voltage dependency to extract the geometrical variations in thin-film piezoelectric materials deposited on a flexible steel. A 50 μm flexible steel sheet has been sandwiched by two PZT film layers, each of 2.4 μm in thickness deposited by sputtering. An aluminum layer of 370 nm has been deposited above each PZT layer to …

An Investigation Into The Predictive Capability Of Customer Spending In Modelling Mortgage Default, Donal Finn [Thesis]

Dissertations

The mortgage arrears crisis in Ireland was and is among the most severe experienced on record and although there has been a decreasing trend in the number of mortgages in default in the past four years, it still continues to cause distress to borrowers and vulnerabilities to lenders. There are indications that one of the main factors associated with mortgage default is loan affordability, of which the level of disposable income is a driver. Additionally, guidelines set out by the European Central Bank instructed financial institutions to adopt measures to further reduce and prevent loans defaulting, including the implementation and …

Analyzing Twitter Feeds To Facilitate Crises Informatics And Disaster Response During Mass Emergencies, Arshdeep Kaur

Dissertations

It is a common practice these days for general public to use various micro-blogging platforms, predominantly Twitter, to share ideas, opinions and information about things and life. Twitter is also being increasingly used as a popular source of information sharing during natural disasters and mass emergencies to update and communicate the extent of the geographic phenomena, report the affected population and casualties, request or provide volunteering services and to share the status of disaster recovery process initiated by humanitarian-aid and disaster-management organizations. Recent research in this area has affirmed the potential use of such social media data for various disaster …

An Investigation Of Three Subjective Rating Scales Of Mental Workload In Third Level Education, Nha Vu Thanh Nguyen

Dissertations

Mental Workload assessment in educational settings is still recognized as an open research problem. Although its application is useful for instructional design, it is still unclear how it can be formally shaped and which factors compose it. This paper is aimed at investigating a set of features believed to shape the construct of mental workload and aggregating them together in models trained with supervised machine learning techniques. In detail, multiple linear regression and decision trees have been chosen for training models with features extracted respectively from the NASA Task Load Index and the Workload Profile, well-known self-reporting instruments for assessing …

Multi-Sensory Deep Learning Architectures For Slam Dunk Scene Classification, Paul Minogue

Dissertations

Basketball teams at all levels of the game invest a considerable amount of time and effort into collecting, segmenting, and analysing footage from their upcoming opponents previous games. This analysis helps teams identify and exploit the potential weaknesses of their opponents and is commonly cited as one of the key elements required to achieve success in the modern game. The growing importance of this type of analysis has prompted research into the application of computer vision and audio classification techniques to help teams classify scoring sequences and key events using game footage. However, this research tends to focus on classifying …

Predicting Customer Retention Of An App-Based Business Using Supervised Machine Learning, Jeswin Jose

Dissertations

Identification of retainable customers is very essential for the functioning and growth of any business. An effective identification of retainable customers can help the business to identify the reasons of retention and plan their marketing strategies accordingly. This research is aimed at developing a machine learning model that can precisely predict the retainable customers from the total customer data of an e-learning business. Building predictive models that can efficiently classify imbalanced data is a major challenge in data mining and machine learning. Most of the machine learning algorithms deliver a suboptimal performance when introduced to an imbalanced dataset. A variety …

An Evaluation Of Learning Employing Natural Language Processing And Cognitive Load Assessment, Mrunal Tipari

Dissertations

One of the key goals of Pedagogy is to assess learning. Various paradigms exist and one of this is Cognitivism. It essentially sees a human learner as an information processor and the mind as a black box with limited capacity that should be understood and studied. With respect to this, an approach is to employ the construct of cognitive load to assess a learner's experience and in turn design instructions better aligned to the human mind. However, cognitive load assessment is not an easy activity, especially in a traditional classroom setting. This research proposes a novel method for evaluating learning …

Noise Reduction In Eeg Signals Using Convolutional Autoencoding Techniques, Conor Hanrahan

Dissertations

The presence of noise in electroencephalography (EEG) signals can significantly reduce the accuracy of the analysis of the signal. This study assesses to what extent stacked autoencoders designed using one-dimensional convolutional neural network layers can reduce noise in EEG signals. The EEG signals, obtained from 81 people, were processed by a two-layer one-dimensional convolutional autoencoder (CAE), whom performed 3 independent button pressing tasks. The signal-to-noise ratios (SNRs) of the signals before and after processing were calculated and the distributions of the SNRs were compared. The performance of the model was compared to noise reduction performance of Principal Component Analysis, with …

Modeling And Evaluating Cost-Effectiveness Of Host-Microbiome Investigations, Renuka Panchagavi

Dissertations

Cost-effectiveness modeling accounts for how expenditures impact outcomes and is an appropriate step towards efficacy of the different methods used for modeling the dynamics of microbial communities. This will help to identify challenging aspects of microbiome studies and the associated costs, including the major differences in research designs (cross-sectional or time series-based) used for conducting such studies. The two major stages of our investigation were to first collect and model cost variable data for microbiome investigations, and then to evaluate how trade-offs related to sample size and expenditures impact investigational outcomes. We screened different potential sources of data for microbiome …

Mechanical Behavior Of Cement Paste At Nanoscale - Reactive Molecular Dynamics Modeling And Experimental Corroborations, Ingrid M. Padilla Espinosa

Dissertations

Concrete is the most used material for construction, and it is the most produced man-made product in the world. Concrete makes the contemporary architecture of the world conceivable and brings significant development to communities. Nevertheless, there are many downsides to the use of concrete such as the large amount of energy and water used in its production, large carbon footprint, shrinkage and expansion that can cause cracking and other failure mechanisms, and the required use of large amounts of material to ensure stability of concrete structures. These drawbacks create the need for engineering and tailoring the properties of concrete. An …

Managing Uncertainty In Sensor Data: An Evidence Theory Based Multisensor Data Fusion Approach, Gabriel Idowu Awogbami

Dissertations

Sensors play a critical role in the development of intelligent systems. Intelligent agents are equipped with an array of sensors to acquire information about themselves and the environment to make a reasonable decision. Information extracted from the sensor data is often characterized by uncertainty. Modeling and reasoning under such uncertainty poses a great challenge. Multisensor data fusion is a viable approach to address this problem. The Dempster Shafer (DS) theory of belief functions, also known as the evidence theory, is a well-known data fusion formalism due to its close relationship with other mathematical theories of uncertainty and its elegant way …

A Formal Systems Engineering Methodology For Cyber-Physical Systems: The Verifiable Design Process, Nadew S. Kibret

Dissertations

Cyber-physical systems (CPS) are systems that exhibit tight integration between their physical and computational components. They are hybrid systems containing continuous states and discrete states emanating from the physical and computational components, respectively. Systems engineering of these systems is challenging due to the tight integration of their computational, physical and communication technologies. As their level of acceptance increases in mission critical applications such as health care, smart grid, autonomous vehicles and smart cities, the need to ensure their safe operation is paramount importance as well. Therefore, design methodologies followed in their development are required to result in system behavior that …