Engineering Commons^™

High Fidelity Computational Modeling And Analysis Of Voice Production, Weili Jiang

Electronic Theses and Dissertations

This research aims to improve the fundamental understanding of the multiphysics nature of voice production, particularly, the dynamic couplings among glottal flow, vocal fold vibration and airway acoustics through high-fidelity computational modeling and simulations. Built upon in-house numerical solvers, including an immersed-boundary-method based incompressible flow solver, a finite element method based solid mechanics solver and a hydrodynamic/aerodynamic splitting method based acoustics solver, a fully coupled, continuum mechanics based fluid-structure-acoustics interaction model was developed to simulate the flow-induced vocal fold vibrations and sound production in birds and mammals. Extensive validations of the model were conducted by comparing to excised syringeal and …

Evaluating Tlb (Translation Lookaside Buffer) Performance Overhead For Nvm (Non-Volatile Memory) Hybrid System, Xiang Guo

Electronic Theses and Dissertations

As the non-volatile memory (NVM) technology offers near-DRAM performance and near-disk capacity, NVM has emerged as a new storage class. Conventional file systems, designed for hard disk drives or solid-state drives, need to be re-examined or even re-designed for NVM storage. For example, new file systems such as NOVA, HMFS, HMVFS and Ext4-DAX, have been developed and implemented to fully leverage NVM’s characteristics, such as fast fine-grained access. This thesis research uses a variety of I/O workloads to evaluate the performance overhead of the TLB (translation lookaside buffer) in various file systems on emulated NVM storage systems, in which NVM …

Use Of Gis To Find Optimum Locations For Anaerobic Digestion Or Composting Facilities In Maine, Usha Humagain

Electronic Theses and Dissertations

As per US EPA, in 2017, 41 million tons of food waste was generated, but only 6.3% was diverted from landfills (US EPA, 2020). When landfilled or incinerated, organic waste (food waste, sludge, manure, agricultural waste) causes environmental pollution through greenhouse gas emissions, land, water, and air pollution. In contrast, if we compost or digest organic waste, we can generate soil additives and a mixture of methane and carbon dioxide gas to produce electricity or energy. Both digestion and composting reduce greenhouse gas emissions, improve the land through additives, and boost the economy. Many countries are adopting anaerobic digestion and …

An Experimental Investigation Of Alternative Wave Attenuation Mechanisms For A Modular Breakwater, Richard Perry

Electronic Theses and Dissertations

Global warming and sea level rise threaten to render traditional coastal protection structures as less effective. Floating breakwaters offer the advantages of adapting to rising sea level, allowing important material transport to occur, and being able to deploy and adapt to varying environmental conditions (seabed, depth, etc.). Traditional floating breakwaters typically consist of reflective concrete structures that are limited semi-sheltered locations. This research aimed to construct floating breakwaters out of lightweight materials with a smaller footprint while utilizing alternative attenuation mechanisms. Three breakwaters consisting of a box, beach, and pipe designs were constructed at 1:40 scale and tested in a …

Modeling Of Non-Newtonian Fluid Flow In A Porous Medium, Hamza Azzam

Electronic Theses and Dissertations

Flows of Newtonian and non-Newtonian fluids in porous media are of considerable interest in several diverse areas, including petroleum engineering, chemical engineering, and composite materials manufacturing. In the first part of this thesis, one-dimensional linear and radial isothermal infiltration models for a non-Newtonian fluid flow in a porous solid preform are presented. The objective is to investigate the effects of the flow behavior index, preform porosity and the inlet boundary condition (which is either a known applied pressure or a fluid flux factor) on the infiltration front, pore pressure distribution, and fluid content variation. In the second part of the …

Understanding Biomass Upgrading Through Hydrogenolysis Reactions: Kinetics And Mechanism, Jalal Tavana

Electronic Theses and Dissertations

This dissertation involves several hydrogenolysis reactions but is mainly focused on hydrodechlorination (HDC) of chlorobenzene (PhCl) and hydrodeoxygenation (HDO) of 2-furancarboxylic acid (FCA). Hydrodechlorination of PhCl has been the subject of research for some time. Here, we used a Pd/C catalyst to study this reaction though rigorous kinetics and mechanistic analyses in a CSTR reactor. The H₂/D₂ kinetic isotope effect (KIE) experiment revealed that H₂ is not involved in a rate controlling step. The kinetics data are in agreement with similar systems reported before and follow a first-order dependence on chlorobenzene, half order for hydrogen and …

Design And Fabrication Of A 3-Dimensional Capacitive-Based Force Sensor, Md Shafiqur Rahman

Electronic Theses and Dissertations

The detection of abnormal gait patterns is imperative for early diagnoses and treatment of serious health issues such as loss of mobility and balance, risk of falls, cardiovascular disease, etc. Human gait analysis is the tool used to detect abnormal gait patterns. Gait analysis also can help to understand the cause of gait abnormalities and to make a treatment plan for individual patients. Ground reaction forces (GRFs) at the foot during walking or running are essential for kinetic analysis of the human gait. However, there are no wearable systems that can directly measure three-directional (3D) forces during daily walking. Currently, …

Reaction Kinetics And Mechanism Investigations Of Renewable Chemicals Production From Biomass, Hussein Talib Abdulrazzaq

Electronic Theses and Dissertations

The development of the technologies and the improved processes for the production of high value bio-based chemicals is one of the most important challenges at the present time. This new movement is not only important from an environmental perspective, but also it is a profitable approach to provide affordable and efficient processes. Therefore, the chemical catalytic upgrading processes over various homogenous and heterogeneous catalysis could be an outstanding modification to upgrade biomass-derived platform molecule to high value applications. In this dissertation, we highlight our recent progress in developing new chemistries and processes for upgrading biomass-derived molecules and address the challenges …

The Design And Validation Of A Uav Propeller Intended For Extremely Low Reynolds Number Environments, Benjamin Hebert

Electronic Theses and Dissertations

Mars exploration and UAV development have both advanced significantly over the past century, and are now being considered in tandem. Currently needed are UAV propellers that can operate in the Martian atmosphere. Flow will be in the range of Re < 20,000, creating extreme conditions not typically examined. A Blade Element Momentum Theory (BEMT) algorithm is developed using a variety of corrections designed specifically for low Reynolds number and rotational flows. Due to both the simplicity of the basic BEMT formulation, corrections are easy to put in place and often necessary to achieve accurate estimates. Aerodynamic coefficients are determined from XFOIL code, and have questionable accuracy in this regime. To account for this, a correction model is developed by comparing XFOIL results to experimental results of airfoils at low Re. This is all tested against a previous low Re propeller experiment. The results of this comparison are used to adjust the values in the correction, to produce more accurate results for theoretical design.

From here, a design philosophy for the propeller is developed using established methods and previous experimental data. High thrust is prioritized, with efficiency being a secondary concern. A hard mach limit of 0.7 is set to avoid major drag penalties, limiting the usable ranges of RPM and radius. Airfoil designs are then examined, based on previous designs, theoretical intuition, and …

Durability Of Entrapped Gas In Quasi-Saturated Porous Media: Two Geotechnical Perspectives, Babak Mahmoodichanzab

Electronic Theses and Dissertations

Entrapped gas bubbles in quasi-saturated porous media are of practical importance in the field of science and engineering. Gas bubbles, which may occur naturally or be introduced artificially, significantly influence the mechanical behavior of soil. In this study, the durability of gas is examined from two geotechnical engineering perspectives. In the field of geotechnics, the artificial introduction of gas is being considered, as it has been widely recognized that entrapped gas, even in nearly-saturated sediments, has an appreciable influence on soil’s mechanical behavior. Entrapped gas bubbles in quasi-saturated sediments significantly increase the pore fluid compressibility and suppress the generation of …

Hydrogenation Of 2-Methylnaphthalene In A Trickle Bed Reactor Over Bifunctional Nickel Catalysts, Matthew J. Kline

Electronic Theses and Dissertations

Biomass thermal conversion processes, such as pyrolysis, tend to produce mixtures of mono- and poly-aromatic species. While the high aromatic content is desirable in gasoline fractions, middle-distillate cuts, particularly jet fuel and diesel, require upgrading via hydrogenation and ring opening to achieve better combustion characteristics. There have been many proposed methods for producing drop-in fuels from woody biomass, one of them being Thermal DeOxygenation (TDO). The TDO process converts organic acids from cellulose hydrolysis into a low-oxygen bio-oil containing large amounts of substituted naphthalene compounds.

Poly-aromatic molecules, such as those found in TDO oil, have low cetane numbers (CN), particularly …

Understanding The Influence Of Nonlinear Seas On Wind Generated Waves, Taylor L. Bailey

Electronic Theses and Dissertations

An understanding of the influence of wind of the surface on irregular waves is important for improving ocean forecasting models. While many studies have investigated the phenomenon of wind wave suppression on the surface of mechanically generated waves in the laboratory, few studies have investigated the occurrence of this phenomenon for irregular waves. Chen and Belcher (2000) developed the first model to predict the suppression of wind waves as a function of the steepness of the long wave on which they travel. The Chen and Belcher (2000) model however, was only validated using monochromatic waves, not irregular waves, which are …

Wave Attenuation Capacity Of Suspended Aquaculture Structures With Sugar Kelp And Mussels, Longhuan Zhu

Electronic Theses and Dissertations

Large aquaculture systems may have the potential to damp wave energy for coastal protection. The performance of these systems are influenced by the dynamics of components such as flexible kelp blades and mussel droppers. In this thesis, the dynamics of kelp blades and mussel droppers were investigated with a consistent-mass cable model with focus on understanding the asymmetric motion of kelp blades. The results showed the asymmetric blade motion in symmetric waves is caused by the spatial asymmetry of the encountered wave orbital velocities due to blade displacements and the asymmetric action on the blade by vertical wave orbital velocities. …

Fabrication Of Silicon Microneedles For Dermal Interstitial Fluid Extraction In Human Subjects, Caleb A. Berry

Electronic Theses and Dissertations

The goal of this project is to design and develop a fabrication process for silicon microneedle arrays to extract dermal interstitial fluid (ISF) from human skin. ISF is a cell- free, living tissue medium that is known to contain many of the same, clinical biomarkers of general health, stress response and immune status as in blood. However, a significant barrier to adoption of ISF as a diagnostic matrix is the lack of a rapid, minimally invasive method of access and collection for analysis. Microfabricated chips containing arrays of microneedles that can rapidly and painlessly access and collect dermal ISF for …

Does Circularizing Source-Separated Food Waste Present A Risk To Our Food?, Astha Thakali

Electronic Theses and Dissertations

About a third of the food produced annually is wasted. Food waste recycling can be a way to close the loop and attain a more sustainable food system, however, the system must be carefully monitored and managed to avoid the introduction and build-up of contaminants. To study the potential presence of contaminants in food waste, source-separated food waste was collected and screened for five classes of contaminants (physical contaminants, heavy metals, halogenated organic contaminants, pathogens, and antibiotic resistance genes) from two separate regulatory environments (voluntary vs mandated food separation). The regulatory environment did not affect the level of contamination, except …

Understanding Latina Undergraduate Engineering Student Persistence, Yarissa I. Ortiz-Vidal

Electronic Theses and Dissertations

In summary, this study focused on understanding the persistence of 20 Latina undergraduate engineering students enrolled at two public four-year Hispanic Serving Institutions. Key findings in this study showed that in order to contribute to their own persistence in engineering majors these Latina students activated their community cultural wealth: (a) not only to resist different forms of oppression, but also to thrive and excel in academic settings, (b) to take control of difficult and challenging experiences, (c) to take/receive knowledge from others, but also to give/share their knowledge (cyclical tendencies of CCW), (d) as well as revealing that helping others …

Investigation Of Infiltration Measurements Using Wind Induced Pressure Response On An Enclosure, Aaron R. French

Electronic Theses and Dissertations

Air infiltration into a building is unintentional air leakage, resulting in heat losses or gains and the consequent energy usage to recondition the building to comfortable levels. Methods of evaluating air infiltration provide accurate measures of air exchange rate but must be done per building and take significant experimentation and data collection. This warrants investigation into ways to decrease the time to evaluate building infiltration to decrease the associated costs. For this reason, interior pressure response is the subject of investigation in the present work. Interior pressure of a building responds to a pressure rise on the building face when …

Leak Detection And Localization In Pressurized Space Structures Using Bayesian Inference: Theory And Practice, Joel Castro

Electronic Theses and Dissertations

Impact from micrometeoroids and orbital debris (MMOD) can cause severe damage to space vehicles. The crew habitat can begin to leak precious oxygen, critical systems can be punctured causing fatal failures, and an accumulation of impacts by MMOD can decrease the lifetime of any and all devices in space. Due to these and other potential dangers, MMODs have been considered the third largest threat to spacecraft after launch and re-entry. Many satellites and other spacecraft face this very problem inherent in all space travel on a daily basis, but often times they can be repaired. A major hurdle is to …

Development And Test Of High Temperature Surface Acoustic Wave Gas Sensors, Armando E. Ayes Moncada

Electronic Theses and Dissertations

The demand for sensors in hostile environments, such as power plant environments, exhaust systems and high-temperature metallurgy environments, has risen over the past decades in a continuous attempt to increase process control, improve energy and process efficiency in production, reduce operational and maintenance costs, increase safety, and perform condition-based maintenance in equipment and structures operating in high-temperature, harsh-environment conditions. The increased reliability, improved performance, and development of new sensors and networks with a multitude of components, especially wireless networks, are the target for operation in harsh environments. Gas sensors, in particular hydrogen gas sensors, operating above 200°C are required in …

A Linear Actuator/Spring Steel-Driven Glove For Assisting Individuals With Activities Of Daily Living, Daniel Chizhik

Electronic Theses and Dissertations

Over three million people in the U.S. suffer from forearm and hand disabilities. This can result from aging, neurological disorders (e.g., stroke), chronic disease (e.g., arthritis), and injuries. Injuries to hands comprise one-third of all work-related injuries worldwide. This can lead to difficulties with activities of daily living (ADL), where one needs to grasp, lift, and release objects in the household. There is a rise in demand for assistive orthoses and gloves that can allow many people to regain their grasping/releasing ability and, thereby, their independence. The main contribution of this thesis is developing an assistive glove with the actuating …

Impact Resistance Of Fiber-Reinforced Composites Using Computational Simulations, Maitham Alabbad

Electronic Theses and Dissertations

Composite materials are widely used in aerospace, automotive and wind power industries due to their high strength-to-weight and stiffness-to-weight ratios and their improved mechanical properties compared to metals. The damage resistance of composite materials due to low velocity impact depends on fiber breakage, matrix cracking and delamination between the interfaces. In this research, a numerical investigation of low velocity impact response of a multidirectional symmetric carbon-epoxy composite laminate is carried out and presented. Two different finite element models are developed for composite laminates made of non-crimp fabric to investigate their behavior under different levels of impact energy. In the first …

Uav 6dof Simulation And Kalman Filter For Localizing Radioactive Sources, John G. Goulet

Electronic Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) expand the available mission-space for a wide range of budgets. Using MATLAB, this project has developed a six degree of freedom (6DOF) simulation of UAV flight, an Extended Kalman Filter (EKF), and an algorithm for localizing radioactive sources using low-cost hardware. The EKF uses simulated low-cost instruments in an effort to estimate the UAV state throughout simulated flight.

The 6DOF simulates aerodynamics, physics, and controls throughout the flight and provides outputs for each time step. Additionally, the 6DOF simulation offers the ability to control UAV flight via preset waypoints or in realtime via keyboard input.

Using …