Engineering Commons^™

An Exploration Of The Relationship Between The Partisan-Business Cycle And Economic Inequality Within Developed Economies, Richard O'Doherty

Dissertations

Recent contributions to the study of inequality have provided strong evidence towards the presence of an established trend, over several decades, of growing economic inequality (with a particular focus on distribution within their tails; i.e. top 10%, 1%) across countries with developed economies and indications of similar trends across developing economies. While the causality and influencing factors to these trends has widely been discussed, and has range from declining domestic growth rates as economies move towards high mass consumption states to globalisation, political decision making and policy application been referred to as both contributory or an instrument for dampening such …

Characterization Of Geolocation Accuracy Of Suomi Npp Advanced Technology Microwave Sounder Measurements, Yang Han, Fuzhong Weng, Xiaolei Zou, Hu Yang, Deron Scott

Electrical and Computer Engineering Faculty Publications

The Advanced Technology Microwave Sounder (ATMS) onboard Suomi National Polar-orbiting Partnership satellite has 22 channels at frequencies ranging from 23 to 183 GHz for probing the atmospheric temperature and moisture under all weather conditions. As part of the ATMS calibration and validation activities, the geolocation accuracy of ATMS data must be well characterized and documented. In this study, the coastline crossing method (CCM) and the land-sea fraction method (LFM) are utilized to characterize and quantify the ATMS geolocation accuracy. The CCM is based on the inflection points of the ATMS window channel measurements across the coastlines, whereas the LFM collocates …

Approximation Assessment Of Photocatalytic Air Cleaning Pavements, James E. Alleman, Joel K. Sikkema, Peter C. Taylor

Faculty Work Comprehensive List

This paper examines an approximation method to qualitatively assess the air-cleaning performance (i.e., specifically the elimination of aerial nitrogen oxide, NO, released within vehicular exhaust) by full-scale pavements which contain photo-catalytically reactive titanium dioxide under optimal conditions. Two hypothetical road configurations were considered using this method, including both a two-lane, low traffic density (i.e., 4,000 full-day AADT) and a four-lane, moderate traffic density (i.e., 10,000 full-day AADT) design. These options were then comparatively examined on the basis of expected European Union or United States vehicular emission levels. In each case, this method’s day-time-only percentile elimination approximation results were derived using …

Robot Installed At Engineering & Computer Science: Vickers Engineering Donates Functioning Robot For Labs, Chris Mclean-Wheeler

Andrews Agenda: Campus News

No abstract provided.

Light-Activated Photocurrent Degradation And Self-Healing In Perovskite Solar Cells, Wanyi Nie, Jean-Christophe Blancon, Amanda J. Neukirch, Kannatassen Appavoo, Hsinhan Tsai, Manish Chhowalla, Muhammad A. Alam, Matthew Y. Sfeir, Claudine Katan, Jacky Even, Sergei Tretiak, Jared J. Crochet, Gautam Gupta, Aditya D. Mohite

Publications and Research

Solution-processed organometallic perovskite solar cells have emerged as one of the most promising thin-film photovoltaic technology. However, a key challenge is their lack of stability over prolonged solar irradiation. Few studies have investigated the effect of light soaking on hybrid perovskites and have attributed the degradation in the optoelectronic properties to photochemical or field-assisted ion migration. Here we show that the slow photocurrent degradation in thin-film photovoltaic devices is due to the formation of light-activated meta-stable deep-level trap states. However, the devices can self-heal completely by resting them in the dark for <1 min or the degradation can be completely prevented by operating the devices at 0°C. We investigate several physical mechanisms to explain the microscopic origin for the formation of these trap states, among which the creation of small polaronic states involving localized cooperative lattice strain and molecular orientations emerges as a credible microscopic mechanism requiring further detailed studies.

Energy Models Of The Txaire Houses, Tajudeen Amadu Annafi

Mechanical Engineering Theses

Model calibration is important as its functions improve building models. A calibrated model of the TxAIRE Houses #1 and #2 have been developed using the OpenStudio software. The model was developed and calibrated with data of the year 2014 but can be used predict electricity consumption of any year.

An actual meteorological year (AMY) weather file was also created for the houses which was used for calibration. The data used to develop this weather file were measured on-site which improved the accuracy of the model. It was found that an error difference of -1.0 % and -4.2 % occurred between …

Mechanical Engineering News, Georgia Southern University

Mechanical Engineering: News & Publications (2013-2023)

• STEM Day at Statesboro High

Fabrication Of A Mems Comb Drive Actuator, Adam Banees

Journal of the Microelectronic Engineering Conference

Comb drives are common in many microelectromechanical systems (MEMS) applications such as gyroscopes, accelerometers and resonators in different fields such as optical communication, wireless communication, and biomedical engineering. A comb drive actuator uses electrostatic forces between the combs to create capacitive actuation. The goal of these devices was to achieve a maximum displacement of the movable combs with the lowest amount of drive voltage. Comb drive actuators were designed and then fabricated. It was found that comb fingers were not defined properly as the fingers were either too skinny or have been completely destroyed. This was due to the STS …

Poster - Fabrication Of A Mems Comb Drive Actuator, Adam Banees

Journal of the Microelectronic Engineering Conference

No abstract provided.

Fabrication Of A Mems Comb Drive Actuator, Adam Banees

Journal of the Microelectronic Engineering Conference

No abstract provided.

Cd Reduction Through Annular Illumination And Sidewall Spacers, Corey Shay

Journal of the Microelectronic Engineering Conference

No abstract provided.

Cd Reduction Through Annular Illumination And Sidewall Spacers, Corey Shay

Journal of the Microelectronic Engineering Conference

No abstract provided.

Process Development Challenges Associated With Gallium Nitride Materials, Eric Evangelou

Journal of the Microelectronic Engineering Conference

While attempting to fabricate low resistance Ohmic contacts to n-GaN and n-AlGaN, processing setbacks necessitated the development of new procedures within the Semiconductor and Microsystems Fabrication Lab (SMFL) at RIT. Photoresist coating recipes usable on GaN pieces were developed for OiR-620 and LOR-5A photoresists, and GaN was etched for the first time on the LAM4600 reactive ion etcher (RIE). The etch was successful, etched GaN at a rate of 187.2 Å/min, and exhibited selectivity between GaN and hard-baked photoresist comparable to an inductively coupled plasma (ICP) etch of the same chemical makeup. An Ohmic Ti to n-GaN contact was fabricated, …

An Accurate Method Of Energy Use Prediction For Systems With Known Consumption, Jacob A. Mueller, Jonathan W. Kimball

Electrical and Computer Engineering Faculty Research & Creative Works

An improved method of nonintrusive load monitoring (NILM) using hidden Markov models is proposed. The proposed method is intended for electrical systems with a closed and known set of devices. Systems that meet this constraint are more commonly found in industrial or commercial contexts than the residential settings in which NILM is traditionally studied. The proposed method is designed to support applications relevant to these contexts, such as fault monitoring and system health assessments. To this end, the energy predictions of the disaggregation algorithm offer accurate descriptions of device behavior in time. The accuracy of the proposed method is validated …

Hydrodynamics And Mass Transfer In Bubble Columns, Onkar N. Manjrekar

McKelvey School of Engineering Graduate Student Theses & Dissertations

Bubble columns and slurry bubble columns are multiphase reactors used for a wide range of applications in the biochemical, chemical, petrochemical, and metallurgical industries. In spite of their widespread usage, the scale-up of bubble columns remains an ongoing challenge. Various scale-up approaches, based on concepts ranging from ideal mixing to complex 3-D multiphase CFD models, have been used for assessing the effect of column size and gas and liquid flow rates on column hydrodynamics and reactor performance. Among these approaches, phenomenological models based on either single-class or multi-class bubbles that were validated on cold flow systems have been successful in …

Development Of Steady-State And Dynamic Flux Models For Broad-Scope Microbial Metabolism Analysis, Lian He

McKelvey School of Engineering Graduate Student Theses & Dissertations

Flux analysis techniques, including flux balance analysis (FBA) and 13C-metabolic flux analysis (MFA), can characterize carbon and energy flows through a cells metabolic network. By employing both 13C-labeling experiments and nonlinear programming, 13C-MFA provides a rigorous way of examining cell flux distributions in the central metabolism. FBA, on the other hand, gives a holistic review of optimal fluxomes on the genome scale. In this dissertation, flux analysis techniques were constructed to investigate the microbial metabolisms.

First, an open-source and programming-free platform of 13C-MFA (WUFlux) with a user-friendly interface in MATLAB was developed, which allowed both mass isotopomer distribution (MID) analysis …

Semi-Empirical Modeling Of Two-Dimensional And Three-Dimensional Dynamic Stall, Ramin Modarres

McKelvey School of Engineering Graduate Student Theses & Dissertations

Helicopters are generally limited in their performance by the phenomenon of dynamic stall. The purpose of this work is to develop a method for modeling dynamic stall that is appropriate to preliminary design and flight simulator applications. Unlike other semi-empirical dynamic stall models, the model developed in this thesis, not only counts for the well-known, three-dimensional flow effects on the stalled loads but also captures the secondary vortex-shedding phenomenon that has been seen in experiments. The fundamental physics that modify dynamic-stall behavior and that have been extended from two-dimensional to three-dimensional flow are, namely: 1.) yawed flow, 2.) time-varying velocity, …

Optical Probes In Multiphase Reactors, Boung Wook Lee

McKelvey School of Engineering Graduate Student Theses & Dissertations

This dissertation examines the application of optical probe techniques in two predominant multiphase reactors used for contacting gas and liquid phases: bubble column reactors and gas-liquid stirred tank reactors. Multiphase reactors are ubiquitous in industry, and for most processes, successful operation depends on successful inter- and intra-phase contacting and mixing. Extensive modeling and experimental research efforts have been made for better reactor design, modeling, and scale-up, yet, much remains unknown about the gas phase.

Optical probes offer significant advantages for gas phase dynamics measurements. Consequently, they have been adapted by numerous researchers around the world for detailed fluid dynamic investigations …

Goggle Augmented Imaging And Navigation System For Fluorescence-Guided Surgery, Suman Bikash Mondal

McKelvey School of Engineering Graduate Student Theses & Dissertations

Surgery remains the only curative option for most solid tumors. The standard-of-care usually involves tumor resection and sentinel lymph node biopsy for cancer staging. Surgeons rely on their vision and touch to distinguish healthy from cancer tissue during surgery, often leading to incomplete tumor resection that necessitates repeat surgery. Sentinel lymph node biopsy by conventional radioactive tracking exposes patients and caregivers to ionizing radiation, while blue dye tracking stains the tissue highlighting only superficial lymph nodes. Improper identification of sentinel lymph nodes may misdiagnose the stage of the cancer. Therefore there is a clinical need for accurate intraoperative tumor and …

Relative Navigation In Gps Degraded Environments, Timothy Mclain, David Wheeler, Paul W. Nyholm, Daniel P. Koch, Gary J. Ellingson, Benjamin J. Lewis, Randall W. Beard

Faculty Publications

For unmanned aircraft systems to become fully integrated into society, safe and reliable methods for estimation and control are required even when global measurements such as GPS are degraded or unavailable. In these situations, estimating the vehicle's global state directly leads to inaccuracy and inconsistency. The relative navigation framework avoids these issues by estimating the vehicle's state with respect to a current local coordinate frame associated with a visual odometry algorithm. A globally consistent and localized pose-graph map is produced by compounding these local estimates and opportunistically incorporating additional constraints such as GPS measurements and loop closures. This architecture increases …

Double Alternating Minimization (Dam) For Phase Retrieval In The Presence Of Poisson Noise And Pixelation, Weimin Zhou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Optical detectors, such as photodiodes and CMOS cameras, can only read intensity information, and thus phase information of wavefronts is lost. Phase retrieval algorithms are used to estimate the lost phase and reconstruct an accurate effective pupil function, where the squared modulus of its Fourier transform is detected by a camera. However, current algorithms such as the Gerchberg-Saxton algorithm and Fienup-style algorithm do not consider the detector sampling rate and shot noise introduced by photon detection. If the sampling rate is low, we must interpolate the detected image in order to accurately reconstruct its pupil function. Here, we develop an …

Distributed Target Tracking And Synchronization In Wireless Sensor Networks, Jichuan Li

McKelvey School of Engineering Graduate Student Theses & Dissertations

Wireless sensor networks provide useful information for various applications but pose challenges in scalable information processing and network maintenance. This dissertation focuses on statistical methods for distributed information fusion and sensor synchronization for target tracking in wireless sensor networks.

We perform target tracking using particle filtering. For scalability, we extend centralized particle filtering to distributed particle filtering via distributed fusion of local estimates provided by individual sensors. We derive a distributed fusion rule from Bayes' theorem and implement it via average consensus. We approximate each local estimate as a Gaussian mixture and develop a sampling-based approach to the nonlinear fusion …

Revelation Of Yin-Yang Balance In Microbial Cell Factories By Data Mining, Flux Modeling, And Metabolic Engineering, Gang Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

The long-held assumption of never-ending rapid growth in biotechnology and especially in synthetic biology has been recently questioned, due to lack of substantial return of investment. One of the main reasons for failures in synthetic biology and metabolic engineering is the metabolic burdens that result in resource losses. Metabolic burden is defined as the portion of a host cells resources either energy molecules (e.g., NADH, NADPH and ATP) or carbon building blocks (e.g., amino acids) that is used to maintain the engineered components (e.g., pathways). As a result, the effectiveness of synthetic biology tools heavily dependents on cell capability to …

Environmental Fullerene Chemistry: Elucidating Critical Reaction Pathways And Resulting Products In The Aqueous Phase, Jiewei Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

As the production of fullerenes and fullerene-based materials approaches industrial scale, there are increasing interests/concerns regarding their (potential) environmental impact(s) upon release. To date, a number of critical, aqueous-based fullerene transformation pathways under environmentally relevant conditions remain poorly understood. Comprehensive, fundamental, and quantitative understanding of the potential (major) reaction pathways and resulting products of fullerene materials, particularly in aquatic systems, is now crucial for their accurate fate, transport, life cycle, risk assessment(s), and thus ultimate material sustainability.

Herein, this dissertation is focused on identifying and elucidating aqueous transformation pathways of fullerene materials, focused on C60 as a model fullerene, under …

Modeling, Simulation, And Analysis Of Lithium-Ion Batteries For Grid-Scale Applications, Matthew Thomas Lawder

McKelvey School of Engineering Graduate Student Theses & Dissertations

Lithium-ion batteries have become universally present in daily life, being used across a wide range of portable consumer electronics. These batteries are advantageous compared to other forms of energy storage due to their high energy density and long cycle life. These characteristics make lithium-ion batteries advantageous for many new and developing applications that require large scale energy storage such as electric vehicles and the utility grid. Typical uses for lithium-ion batteries require consistent cycling patterns that are predictable and easy to approximate across all uses, but new large scale applications will have much more dynamic demands. The cycling patterns for …

Mechanics Of Early Retina And Lens Development In The Embryo, Alina Oltean

McKelvey School of Engineering Graduate Student Theses & Dissertations

Mechanical forces play an essential role in morphogenesis, the shaping of embryonic structures. This research focuses mainly on eye development, a problem that has been studied for decades using a variety of approaches. However, the mechanics of the early stages of eye formation remain incompletely understood.

The embryonic eyes begin as bilateral protrusions called optic vesicles (OVs) that grow outward from the anterior end of the brain tube. The optic vesicles contact and adhere to the overlying surface ectoderm (SE) via extracellular matrix (ECM). Then, both layers thicken in the region of contact to form the retinal and lens placodes, …

A General Framework Of Large-Scale Convex Optimization Using Jensen Surrogates And Acceleration Techniques, Soysal Degirmenci

McKelvey School of Engineering Graduate Student Theses & Dissertations

In a world where data rates are growing faster than computing power, algorithmic acceleration based on developments in mathematical optimization plays a crucial role in narrowing the gap between the two. As the scale of optimization problems in many fields is getting larger, we need faster optimization methods that not only work well in theory, but also work well in practice by exploiting underlying state-of-the-art computing technology.

In this document, we introduce a unified framework of large-scale convex optimization using Jensen surrogates, an iterative optimization method that has been used in different fields since the 1970s. After this general treatment, …

Cyclotron Production And Biomedical Imaging Applications Of The Pet Isotope Manganese-52, Andrew Lake Wooten

McKelvey School of Engineering Graduate Student Theses & Dissertations

Manganese is an important element for biomedical research because of its roles as an essential micronutrient and as a neurotoxin from chronic elevated exposure, as well as the role of manganese(II) as a paramagnetic core for contrast agents in T1-weighted magnetic resonance imaging (MRI). Using a radiotracer of manganese provides excellent sensitivity for studying these phenomena, but only 52Mn met the criteria for our experiments: (1) a half-life (t1/2=5.6 days) that was long enough to examine timepoints over several days, (2) a half-life that was short enough to emit sufficient counts for a realistic scan time, and (3) emitted radiation …

Feed-Forward Inhibitory Circuits In Hippocampus And Their Computational Role In Fragile X Syndrome, Sarah Lauren Wahlstrom Helgren

McKelvey School of Engineering Graduate Student Theses & Dissertations

Feed-forward inhibitory (FFI) circuits are canonical neural microcircuits. They are unique in that they are comprised of excitation rapidly followed by a time-locked inhibition. This sequence provides for a powerful computational tool, but also a challenge in the analysis and study of these circuits. In this work, mechanisms and computations of two hippocampal FFI circuits have been examined. Specifically, the modulation of synaptic strength of the excitation and the inhibition is studied during constant-frequency and naturalistic stimulus patterns to reveal how FFI circuit properties and operations are dynamically modulated during ongoing activity. In the first part, the FFI circuit dysfunction …

Photoenhanced Oxidation Of C60 In Water: Exploring The Roles Of H2o2 And Hydroxyl Radical Based Reactions, Yining Ou

McKelvey School of Engineering Graduate Student Theses & Dissertations

Transformation of water-stable C₆₀ clusters (nC₆₀) to oxidized, soluble C₆₀ derivatives via photoreactions (i.e., reactions in UV irradiation) and ground-state reactions (i.e., reactions in dark) with various oxidants, such as oxygen, ozone, free chlorine, among others, have been described as critical processes in understanding the ultimate environmental fate of fullerene-based materials. However, few studies have explored the oxidation of aqueous based C₆₀ (as water stable nC₆₀) with hydrogen peroxide (H₂O₂) / hydroxyl radical (^.OH), which are common oxidants in both natural and engineered systems. Herein, the aqueous …