Engineering Commons^™

Electrical Properties Of Metal/Wse2structures, Zeel Rajiv Gandhi

Theses

The formation of low resistance metal contacts on two-Dimensional layer (2-D) of WSe2 is a big challenge. In this research, a comparative study is presented on the electrical properties of metal/WSe2 Schottky barrier diodes with various metals such as Au, In, Al, and Ga in the temperature range of 80K to 400K well within the domain of thermionic emission theory.

Topics covered here include the factors that determine the Schottky barrier height, the device capacitance, and its current-voltage (I-V) characteristics. I-V curves for different metals on WSe2 are analyzed as function of temperature. Barrier height is determined from Au-nWSe2 Schottky …

Comparative Analysis Of The Dissolution Performance Of Aspirin Tablets In The Usp Apparatus 2 And In A Minivessel Dissolution System, Annmarie C. Walker

Theses

Dissolution testing is a critical component of quality control procedures in the pharmaceutical industry in order to ensure that the final solid dosage forms have consistent dissolution properties. Dissolution tests are also routinely conducted to evaluate the in-vitro performance of solid dosage forms during pharmaceutical development, to aid in the behavior of formulations, and to optimize drug release from dosage forms.

The use of compendial dissolution test apparatus and techniques, such as the USP 2 (Paddle), to characterize the dissolution performance of oral drug delivery system is an established area of pharmaceutical science. However, this method is not always appropriate, …

Computational And Experimental Determination Of The Mixing Efficiency Of A Microfluidic Serpentine Micromixer, Siril Arockiam

Theses

In microfluidics, efficiency and mixing time are the greatest disadvantages. These parameters hinder the application of microfluidic devices for biochemical and immunological assays. However, once these disadvantages have been overcome by optimizing the parameters of the microfluidic device, it becomes the important analytical tool. In this experiment, various designs of microfluidic devices have been both simulated using COMSOL software, and experimentally verified to obtain the optimized parameter such as depth and velocity for better mixing efficiency. The COMSOL model has been validated by comparing the results with fluorescent images data of the experiment. The microfluidic device is built with Adhesive …

Carbon Fiber Electrodes For In Vivo Neural Recording, Esma Cetinkaya

Theses

Multi-channel micro electrodes for neural recording is a growing field that thrives on novel materials and fabrication techniques offered by micro fabrication technology. The material and the design of microelectrodes have a critical role on the quality of neural signals recorded. The neural signals collected by chronic implantation of these devices in experimental animals reveal new information about the brain functions and guide the development of new diagnostic and treatment options for neurological disorders.

Ideally, a microelectrode should meet two important criteria: longevity after implantation and minimal tissue insult. Carbon fibers` high tensile strength and flexibility allow fabrication of micro-scale …

Formulation Of Uv Curable Resins Utilized In Vat Photo Polymerization For The Additive Manufacturing Of Gun Propulsion Charge In 3d Printers, David T. Bird

Theses

Formulating resins for Additive Manufacturing (AM), utilizing UV laser stereolithography, is a new technique that makes it possible for the fabrication of complex geometries with high dimensional resolution. This layer by layer photopolymerization approach spans various industrial sectors from adhesives, inks and optical fibers to nanotechnology and biomaterials. UV curable resins such as epoxides, vinyl ethers and other acrylates are important monomers that offer effective mediums for energetic materials, and the potential exists to develop environmentally friendly formulations with suspended energetic materials at various solids loading levels.

Developing techniques for UV curing formulations of highly loaded energetic suspensions is a …

Studies On Stable Crack Growth, Mohammed Juma Humaid Al-Ghafri

Theses

The goal of this work is to experimentally investigate the stable crack growth (SCG) fracture behavior of AISI 4340 alloy steel. A series of mode I and mixed mode SCG fracture tests were carried out on 8 mm thick compact tension (CT) specimens subjected to quasistatic loading. The wire cutting technique was used to introduce a pre-notch/ pre-crack of 0.05 mm root radius to the specimen. Five different loading angles Ψ between the loading axis and the crack surface were employed; 90° (mode I), 75°, 65°, 60° and 50°. Five different ratios of original crack length to specimen width a …

Experimental Study Of Low Salinity Water Flooding And Fracturing Effects In Low Permeability Carbonate Reservoir, Benny Arianto Harahap

Theses

In past decades, there were numerous research works demonstrated that salinity alteration of injected water could enhance the oil recovery. Low salinity water (LSW) injection is a type of Enhanced Oil Recovery (EOR) method, which attracts the industrial, and researchers because of its simplicity to use the implications,

Environment-friendly nature, and less cost. In addition to, hydraulic fracturing, also known as hydraulic stimulation, is another EOR method that improves hydrocarbon flow by creating fractures in the Low Permeability Formation (LPF) that connects the reservoir and wellbore. Fractures will increase the permeability of reservoir and give the flow path for hydrocarbon …

Iterative Learning Control For Improved Tracking Of Fluid Percussion Injury Device, Steve Susanibar

Theses

Traumatic brain injury (TBI) afflicts over 10 million people around the world. Injury to the brain can occur from a variety of physical insults and the degree of disability can greatly vary from person to person. It is likely that the wide range of TBI outcomes may be due to the magnitude, direction, and forces of biomechanical insult acting on the head during such TBI events. Lateral Fluid Percussion (FPI) brain injury is one of the most commonly used and well-characterized experimental models of TBI. A Fluid Percussion Injury (FPI) device in the laboratory is used to replicate the injury …

Subject And Group Level Changes And Comparison In Functional Connectivity Under Low Vs. High Cognitively Demanding Naturalistic Viewing Conditions Using Fmri, Rakibul Hafiz

Theses

Resting State fMRI is used extensively for analysing brain regions. fMRI is also used to determine task induced activations from cerebral networks. This study involves both rest and task activation data and implements statistical methods applied on Blood Oxygenation Level Dependent (BOLD) signals. The conventional task based designs are very specific and may not reflect day to day activities. The two task conditions in this study are watching a movie called INSCAPE with low cognitive load and segments of contextual Hollywood movies under continuous and natural conditions.

The aim is to investigate individual and group level Functional Connectivity changes between …

Spatial And Temporal Deformation Pattern Of The Brain From Blunt Trauma, Abdus Ali

Theses

It is widely accepted that under extreme loadings the soft tissue of the brain will deform inside the skull, creating large amounts of both stress and strain on the tissue. This can result in a focal injury, or in the case of acceleration and deceleration, diffuse injuries. Any attempt at understanding the underlying mechanisms and effects of TBI, have to start by focusing on what is actually occurring within the brain. The objective of this experiment is to record differences in the spatial and temporal patterns of deformation within the brain during blunt trauma when changing impact parameters. A linear …

Numerical Simulation For Identification Of Insects Using A Cw Lidar System, Christo Videlov

Theses

Mosquitos are the most common vector of disease in the world, causing millions of deaths a year. While curing the diseases they cause is one approach to this problem, another could be to avoid the mosquitos in the first place. Knowing their flight patterns, location, and population in one area could aid in this. Additionally, classifying the mosquitos in an area would be helpful. The age and sex of the mosquito is important to find as they affect the chances of the insect carrying diseases such as malaria or yellow fever.

Many current methodologies to monitor insects are based on …

Interaction Of Voluntary Activity And Functional Electrical Stimulation In The Upper Extremity As A Method For Short-Term Alteration Of Corticospinal Excitability And Force Control, Katherine Maia Gerton

Theses

Repetitive movement training (RMT) is a well-established method for rehabilitating functional movement. However, many stroke survivors are not able to participate in RMT for the necessary duration to produce results due to rapid muscle fatigue or inability to perform the desired movement at all. Often, functional electrical stimulation (FES) is applied passively, as a rehabilitative therapy, to stroke subjects who are unable to participate in RMT. The effects of voluntary contraction and FES are not well understood for the upper extremity following a stroke. This experiment was designed to elucidate the mechanisms of functional and neurophysiological changes associated with combining …

Multi-Population-Based Differential Evolution Algorithm For Optimization Problems, Ishani Chatterjee

Theses

A differential evolution (DE) algorithm is an evolutionary algorithm for optimization problems over a continuous domain. To solve high dimensional global optimization problems, this work investigates the performance of differential evolution algorithms under a multi-population strategy. The original DE algorithm generates an initial set of suitable solutions. The multi-population strategy divides the set into several subsets. These subsets evolve independently and connect with each other according to the DE algorithm. This helps in preserving the diversity of the initial set. Furthermore, a comparison of combination of different mutation techniques on several optimization algorithms is studied to verify their performance. Finally, …

Measurement Of Finger Coordination During A Motor Learning Task, Robert Ebel

Theses

The focus of this study is to observe the changes in whole hand grasp strategy, in healthy subjects, over time in a series of isometric force control learning tasks. During a series of trials with real-time visual feedback of the five finger forces, subjects adapted their grasp strategy in order to reach the target in a time efficient manner. In early trials, it is very evident that subjects focus on controlling the force output of one finger at a time until they reach the goal. As the block of trials progresses, subjects alter their strategy to a more coordinated movement …

Nanocomposite Thermite Powders With Improved Flowability Prepared By Mechanical Milling, Ci Huang

Theses

Nanocomposite thermite powders are of interest to develop varieties of reactive parts and components. Manufacturing these components requires tailoring properties of the thermite powders such as their particle size distributions, particle shapes, and powder flowability. For example, an improved flowability is desired to use these powders as feedstock in additive manufacturing. Arrested reactive milling (ARM) offers a versatile and practical approach for preparing various nanocomposite thermites with fully dense particles, which will retain their structures and mixedness between reactive components while being stored, handled, and processed. However, ARM products usually have broad particle size distributions, rock-like particle shapes, and poor …

Memorizing Chromic Response To Pressure, Maulik Kiritkumar Padh

Theses

Almost all appliances are prone to mechanical stress in one form or the other. An increasing dependence on machines in daily life calls for a need to increase their maintenance quality. Various materials, methods and configurations to observe mechanical pressure have been devised and this paper discusses one such technique. The use of gold nanoparticles in its one dimensional array causes plasmonic coupling between the nanoparticles, which when disrupted creates a plasmonic shift in its assembly. Such a film, when casted on a polymer with a known elastic limit, causes deformation by an application of stress. This forces the film …

Field Oriented Control Of Permanent Magnet Synchronous Motor With Third-Harmonic Injection Pulse Width Modulation To Reduce Quadrotors’ Speed Ripples, Yuxi Shi

Theses

The world’s commercial unmanned aerial vehicle (UAV) industry has witnessed unprecedented boom in recent years. Delighted with an ample supply of this excellent high-tech product, global consumers are paying more attention on UAVs. Civilian UAVs now vastly outnumber military ones, with the estimate of over a million sold by 2016. An UAV has various degrees of autonomy as enabled by the use and precise control of motors. Traditional Direct Current (DC) motors are replaced by permanent magnet synchronous motors (PMSM) associated with the new power electronic inverters. Because of a PMSM’s higher power density than a DC motor, it reduces …

Corrosion Studies Of Stainless Steel Blades, Dhruv S. Kothari

Theses

Corrosion is a subject of interest to interdisciplinary research communities that includes fields of materials science, chemistry, physics, metallurgy and chemical engineering. In order to understand the mechanisms of corrosion and the function of corrosion inhibitors, the reactions at the interfaces between the corrosive electrolyte and a steel surface, particularly at the initial stages of the corrosion process, need to be described. Naturally, these reactions are strongly affected by the nature and properties of the steel surfaces. It is however seen that the majority of recent corrosion and corrosion-inhibition investigations are limited to electrochemical testing, with ex situ analysis of …

Preemptive Efficient Queueing For Scheduling Deadline-Bound Data Center Flows, Vinaykrishna Gopalakrishna

Theses

This thesis introduces a new deadline aware flow scheduling scheme called Preemptive Efficient Queuing (PEQ). Unlike other schemes which use policies like EDF, SJF or fair share, this scheme aims to procrastinate flows as much as they can afford to, while keeping with their deadlines. Thereby, PEQ prioritizes more urgent flows that have shorter time to procrastinate, or cushion time. Results of PEQ are compared with state-of-the-art schemes for the transport of data-center flows, such as Preemptive Distributed Quick (PDQ) and Deadline-Driven Delivery (D³). The results show that PEQ outperforms D³ and PDQ. We identify results …

Decision Tree Rule-Based Feature Selection For Imbalanced Data, Haoyue Liu

Theses

A class imbalance problem appears in many real world applications, e.g., fault diagnosis, text categorization and fraud detection. When dealing with an imbalanced dataset, feature selection becomes an important issue. To address it, this work proposes a feature selection method that is based on a decision tree rule and weighted Gini index. The effectiveness of the proposed methods is verified by classifying a dataset from Santander Bank and two datasets from UCI machine learning repository. The results show that our methods can achieve higher Area Under the Curve (AUC) and F-measure. We also compare them with filter-based feature selection approaches, …

A Fuzzy Logic-Based Text Classification Method For Social Media, Keyuan Wu

Theses

Social media offer abundant information for studying people’s behaviors, emotions and opinions during the evolution of various rare events such as natural disasters. It is useful to analyze the correlation between social media and human-affected events. This study uses Hurricane Sandy 2012 related Twitter text data to conduct information extraction and text classification. Considering that the original data contains different topics, we need to find the data related to Hurricane Sandy. A fuzzy logic-based approach is introduced to solve the problem of text classification. Inputs used in the proposed fuzzy logic-based model are multiple useful features extracted from each Twitter’s …

Experimental Study Of Bubble Rupture During Shock-Fluid Interaction, Subhalakshmi Chandrasekaran

Theses

Head injuries are associated with exposure to high energy explosive detonation. There are four distinct types of blast induced neurotrauma (BINT): 1) these caused by supersonic shock waves propagating in the atmosphere (primary), 2) high velocity impact of shrapnel and debris (secondary) 3) acceleration and deceleration of the body and collision with the solid objects in the field (tertiary) and 4) exposure to high temperature and toxic gases (quaternary). One of the mechanisms implicated in non-impact primary blast-induced traumatic brain injury (bTBI) is cavitation. It is hypothesized that cavitation can occur in the cerebrospinal fluid (CSF) layer, brain interstitial fluid, …

Iii-Nitride Nanowire Light-Emitting Diodes: Design And Characterization, Dipayan Datta Choudhary

Theses

III-nitride semiconductors have been intensively studied for optoelectronic devices, due to the superb advantages offered by this materials system. The direct energy bandgap III-nitride semiconductors can absorb or emit light efficiently over a broad spectrum, ranging from 0.65 eV (InN) to 6.4 eV (AlN), which encompasses from deep ultraviolet to near infrared spectrum. However, due to the lack of native substrates, conventional III-nitride planar heterostructures generally exhibit very high dislocation densities that severely limit the device performance and reliability. On the other hand, nanowire heterostructures can be grown on lattice mismatched substrates with drastically reduced dislocation densities, due to highly …

Undersampling Ga-Svm For Network Intrusion Detection, Zhenyu He

Theses

Network intrusion detection is one of the hottest issues in the world. An increasing number of researchers and engineers deal with this problem by using machine learning methods. However, how to improve the identification accuracy of all the attack classes remains unsolved since the dataset is an imbalanced one with high imbalance ratio. This thesis work intends to build a classifier to achieve high classification accuracy. It proposes an undersampling Genetic Algorithm-Support Vector Machine (GA-SVM) method to handle this problem. It applies an undersampling method in GA-SVM. To solve the multiclassification problem with a binary classifier, this work proposes to …

Rca: Use And Future Possibilities, Bushra Marium Islam

Theses

Reuse and recycling of concrete is essential for construction purposes. There has been progressive development in construction projects but at the same time it has an inverse effect on the environment. Concrete structures are built and demolished continuously all over the world, generating tons of waste materials which are actually reusable in concrete production itself. This paper emphasis on recycled concrete aggregate (RCA) and many characteristics of RCA. This paper studies RCA’s different properties. RCA’s replacement in the place of natural aggregate is discussed. The proper amount and researches done on RCA improvement have also been discussed for further in …

Thermal Swing Membrane Based Method For Co2 Capture From Flue Gas, Mukesh Kumar Kamad

Theses

Carbon dioxide, a greenhouse gas and a major contributor to global warming, is released in large amounts by flue gases. To limit climate change, such CO₂ emissions have to be reduced, CO₂ captured and sequestered. Conventional monoethanolamine (MEA)-based absorption techniques are costly due to high capital cost and high energy consumption since the absorbent has to be regenerated at a high temperature ~ 120°C. A temperature swing membrane absorption (TSMAB) process was described by Mulukutla et al. (2015) using a novel membrane contactor, novel absorbents and a cyclic process. In this device, the absorbent is on the shell …

Smart Polymeric Temperature Sensors – For Biological Systems, Greenee Anilkumar Sinha

Theses

The damaged brain is vulnerable to increase in brain temperature after a severe head injury. Continuous monitoring of intracranial temperature depicts functionality essential to the treatment of brain injury Many innovations have been made in the biomedical industry relying on electronic implants in treating condition such as traumatic brain injury (TBI) or other cerebral diseases. Hence, a methodical and reliable way to measure the temperature is crucial to assess the patient’s situation. In this investigation, an analysis of various approaches to detect the change in the temperature due to resistance, current-voltage characteristics with respect to time has been evaluated. Also, …

Power Dissipation And Power Correlations For A Retreatblade Impeller Under Different Baffling Conditions, Chadakarn Sirasitthichoke

Theses

Glass-lined stirred reactors and tanks are commonly used in the pharmaceutical industry because of their corrosion resistance, ease of cleanliness and minimization of product contamination. Most industrial glass-lined tank reactors are provided with a torispherical tank bottom and a retreat curve impeller with low impeller clearance from the vessel bottom. The power, P, dissipated by the impeller is a critical process parameter to mixing processes to achieve the desired mixing effect, especially since the power per unit volume, P/V, directly controls mass transfer processes and other mixing phenomena. However, little information has been published about the power dissipation and the …

High Performance Lattice Boltzmann Method Yield-Stress Calculations Based On Intravital Images Of Clot Formation In Live Mice, Vishnu Deep Chandran

Theses

Thrombo-embolic infarction is the major cause of mortality and morbidity in the United States, causing over 1 million strokes, heart attacks and other life-threatening thrombotic events each year in the United States. Conversely, deficiencies in these processes result in severe bleeding risks. The ability to access hydrodynamics stresses at which thrombus structure is likely to embolize can provide insight into the thrombogenesis process. Interestingly, the viscoelastic behavior exhibited by the thrombus resembles that of a Bingham fluid - a material that behaves as a rigid body at low stresses but flows as a viscous fluid when the stress exceeds critical …

Profiling The Neurovascular Cell Interactions In Alcohol Exposure And Hiv-1 Infection, Agnieszka Agas

Theses

Alcohol use is known to exacerbate the progression of human immunodeficiency virus associated acquired immunodeficiency syndrome or HIV/AIDS in the brain, known as the NeuroAIDS. The mechanisms of this accelerated progression are still poorly understood. The purpose of my thesis is to review the parameters contributing to the co-morbid effects of alcohol in the progression of NeuroAIDS. The first aim will evaluate the exacerbating effects of alcohol on HIV-1 transmission, infection, and the role of metabolic energy imbalance during NeuroAIDS progression, which will enable me to formulate the possible mechanism for NeuroAIDS progression. The second aim will help me establish …