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Graduate Theses and Dissertations

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Full-Text Articles in Mechanical Engineering

Thermal Decomposition Of Chemical Warfare Agent Simulants Diisopropyl Methylphosphonate And Tributyl Phosphate, Patrick Sanderson Jan 2019

Thermal Decomposition Of Chemical Warfare Agent Simulants Diisopropyl Methylphosphonate And Tributyl Phosphate, Patrick Sanderson

Graduate Theses and Dissertations

The pyrolysis of chemical warfare agent simulants, diisopropyl methylphosphonate

(DIMP) and tributyl phosphate (TBP), were studied in a constant volume heated cell

using infrared spectroscopy (9:35 μm to 10:55 μm) over a temperature range of 50 C to

550 C. DIMP began decomposing at 130 C and was undetectable by 280 C. The ex-

pected decomposition products observed were propene, 2-propanol and methylphospho-

nic acid. One unexpected species, methanol, was observed, and isopropyl methylphospho-

nate was not observed. Tributyl phosphate began decomposing as low as 130 C and was

undetectable by 270 C. The pyrolysis of TBP had ...


A Locally-Implicit Lax-Wendroff Discontinuous Galerkin Scheme With Limiters That Guarantees Moment-Realizability For Quadrature-Based Moment Closures, Christine Wiersma Jan 2019

A Locally-Implicit Lax-Wendroff Discontinuous Galerkin Scheme With Limiters That Guarantees Moment-Realizability For Quadrature-Based Moment Closures, Christine Wiersma

Graduate Theses and Dissertations

A polydisperse multiphase flow is one in which one of the thermodynamic phases can be considered discrete while the other is assumed to be continuous. Examples include sprays and bubbly flows. Such flows can be modeled by kinetic models that describe the evolution of a probability density function (PDF) in phase space. Moments of this PDF describe physical observable quantities such as the mass, momentum, and energy in

the flow. From a computational perspective, kinetic models are expensive to solve since they require the resolution of a very high-dimensional phase space. In many polydisperse multiphase flow applications, the phase space ...


Collaborative Product Review Using Virtual Reality Interface Devices Performance Studying, Mihir Radia Jan 2019

Collaborative Product Review Using Virtual Reality Interface Devices Performance Studying, Mihir Radia

Graduate Theses and Dissertations

The study presents two research questions: 1) Can stereoscopic 3-D visualization (like Virtual Reality) improve a design reviewer’s ability to detect errors when reviewing a product model over a traditional CAD system in which 3D product models are viewed on a flat 2D computer screen? 2) Can two collaborating individuals be more effective (faster time or detect more errors) during a product design review than one individual operating alone? The answer to the first question will help provide product design reviewers, managers, and software designers in product design firms decide what features to include, and whether it is worthwhile ...


Graphene Humidity Sensor With Gold Nanoparticles, Jiawei Bao Jan 2019

Graphene Humidity Sensor With Gold Nanoparticles, Jiawei Bao

Graduate Theses and Dissertations

Humidity sensors can be used to monitor body sweat. Here, we studied a humidity sensor that comprised of a graphene layer between two electrodes. The operating principle is that the humidity sensor will respond when vapor reaches the graphene layer from the top. Based on the humidity diffusion, the sensor measures the relative humidity (RH) with different response times. Graphene is a material with high diffusivity and small thickness that can increase the sensitivity of a sensor. Based on the Micro Electro Mechanical Systems (MEMS) method, we modeled the humidity sensor using COMSOL Multiphysics transport of diluted species software. Finally ...


Interdisciplinary Research Into Architecture And Music: An Evaluation Of Acoustic Performance Of A Selection Of Spaces And Of Materials, Boram Kim Jan 2019

Interdisciplinary Research Into Architecture And Music: An Evaluation Of Acoustic Performance Of A Selection Of Spaces And Of Materials, Boram Kim

Graduate Theses and Dissertations

This research examines the acoustic comforts of different occupational building types and investigates the combination of building elements, especially focusing on building layout and materials that are considered significant sources of unwanted sound. A major part of the thesis relies on a series of sound pressure (decibel) measurements in three distinctive occupational types: residential, educational, and theater buildings on the Iowa State University campus, and evaluates them with the current standard of allowable sound levels. In addition, this thesis analyzes the existing spatial and material strategies of the three types. The selected materials and their acoustic qualities will be investigated ...


Evaluating Boom Height Control Performance With Variable Boom Roll Damping In A Suspended Boom System On Self-Propelled Sprayers, Evan Mellott Jan 2019

Evaluating Boom Height Control Performance With Variable Boom Roll Damping In A Suspended Boom System On Self-Propelled Sprayers, Evan Mellott

Graduate Theses and Dissertations

In this research, a method for improving spray boom height stability was developed and tested. Self-propelled sprayers played a critical role in agriculture by applying chemicals to crops to control the presence of weeds and pests. The spraying process needed to be controlled in a manner such that the spray boom maintained the necessary target height for uniform coverage. Deviation from target height allowed outside factors such as wind to become more prevalent during chemical application which generated opportunities for spray drift to occur and potentially harm neighboring crops and environment.

On a suspended spray boom system, terrain influences on ...


Calibration Of Structured Light System Using Unidirectional Fringe Patterns, Vignesh Suresh Jan 2019

Calibration Of Structured Light System Using Unidirectional Fringe Patterns, Vignesh Suresh

Graduate Theses and Dissertations

3D shape measurement has a variety of applications in many areas, such as manufacturing, design, medicine and entertainment. There are many technologies that were successfully implemented in the past decades to measure three dimensional information of an object. The measurement techniques can be broadly classified into contact and non-contact measurement methods. One of the most widely used contact method is Coordinate Measuring Machine (CMM) which dates back to late 1950s. The method by far is one of the most accurate method as it can have sub-micrometer accuracy. But it becomes difficult to use this technique for soft objects as the ...


Overcoming The Limitations Of Commodity Augmented Reality Head Mounted Displays For Use In Product Assembly, Jack Miller Jan 2019

Overcoming The Limitations Of Commodity Augmented Reality Head Mounted Displays For Use In Product Assembly, Jack Miller

Graduate Theses and Dissertations

Numerous studies have shown the effectiveness of utilizing Augmented Reality (AR) to deliver work instructions for complex assemblies. Traditionally, this research has been performed using hand-held displays, such as smartphones and tablets, or custom-built Head Mounted Displays (HMDs). AR HMDs have been shown to be especially effective for assembly tasks as they allow the user to remain hands-free while receiving work instructions. Furthermore, in recent years a wave of commodity AR HMDs have come to market including the Microsoft HoloLens, Magic Leap One, Meta 2, and DAQRI Smart Glasses. These devices present a unique opportunity for delivering assembly instructions due ...


Animated Rendering Of Cardiac Model Simulations, Xin Huang Jan 2019

Animated Rendering Of Cardiac Model Simulations, Xin Huang

Graduate Theses and Dissertations

Heart disease has been the leading cause of death both in the world and the United States

in the past decade. Computational cardiac modeling and simulation, especially patient-specific

cardiac modeling has been recognized as one of the best ways to improve diagnosis of heart

disease by providing insights in individual disease characteristics that cannot be obtained by

other means. However presenting the results of cardiac simulations to cardiologists in an

interactive manner can considerably improve the utility of cardiac models in understanding

the heart function. In this work, we have developed virtual reality and animated volume

rendering techniques to render ...


Deep Learning For Monitoring Cyber-Physical Systems, Tryambak Gangopadhyay Jan 2019

Deep Learning For Monitoring Cyber-Physical Systems, Tryambak Gangopadhyay

Graduate Theses and Dissertations

Different cyber-physical systems involving sequential data require accurate frameworks for predicting the state of the system leading to effective monitoring. If the framework is explanatory, the insights provided by the explanations can improve scientific understanding of the system. Detecting the transition to an impending instability is important to initiate effective control in a combustion system. Building robust frameworks is important in this context.

As one of the early applications of characterizing instability in a combustion system using Deep Neural Networks, we train our proposed deep convolutional neural network (CNN) model on sequential image frames extracted from hi-speed flame videos by ...


Data-Driven Approaches For Improving Failure Resilience Of Engineered Systems, Mohammadkazem Sadoughi Jan 2019

Data-Driven Approaches For Improving Failure Resilience Of Engineered Systems, Mohammadkazem Sadoughi

Graduate Theses and Dissertations

Since the 1980s, major industries and government agencies worldwide have faced increasing challenges in ensuring the reliability and resilience of engineered systems. The goal of this dissertation is to create novel probabilistic analysis and design methodologies that enable engineered systems to achieve and sustain near-zero breakdown performance. Specifically, this dissertation is focused on developing new methods for simulation-based design and sensor-based diagnostics and prognostics that can be used to design engineered systems for failure resilience. The research contributions are in the areas of engineering design under uncertainty and post-design fault diagnostics which focuses on applications within wind turbines (energy generation ...


Acoustofluidic Self-Assembly Of Colloidal Materials For Additive Manufacturing, Meghana Akella Jan 2019

Acoustofluidic Self-Assembly Of Colloidal Materials For Additive Manufacturing, Meghana Akella

Graduate Theses and Dissertations

Additive manufacturing techniques like 3D printing are being used extensively to produce custom-designed products in all walks of life- from household items to human organs to space shuttle parts. However, most additive manufacturing platforms use single materials or use extremely complicated processes to print multi-material products. Also, the microstructure of the materials cannot be controlled in many cases. The 3D printing sector is a USD 7 Billion market and is expected to grow at a rate of 25% per annum. At this rate of development, the use of printing multi-material components and creating programmable material structures will be crucial for ...


Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng Jan 2019

Study Of Combustion Performance Of Al/Ptfe B/Ptfe And B/Al/Ptfe Composites, Liyun Feng

Graduate Theses and Dissertations

Metal particles like aluminum and boron are of great interest as additives to energetic materials due to their high gravimetric and volumetric heat of combustion. However, the ignition temperatures of metals are quite high and their burning rates which depend upon the surface area of the burning metal agglomerates are quite slow. The naturally formed oxide layer on the surface of metal particles can further inhibit their ignition and combustion by limiting fuel/oxidizer transport. The boron oxide layer on boron particles is of particular interest due to the strong diffusion barrier formed by its presence. However, the ignition temperature ...


Analysis Of Printed Electronic Adhesion, Electrical, Mechanical, And Thermal Performance For Resilient Hybrid Electronics, Clayton Neff Nov 2018

Analysis Of Printed Electronic Adhesion, Electrical, Mechanical, And Thermal Performance For Resilient Hybrid Electronics, Clayton Neff

Graduate Theses and Dissertations

Today’s state of the art additive manufacturing (AM) systems have the ability to fabricate multi-material devices with novel capabilities that were previously constrained by traditional manufacturing. AM machines fuse or deposit material in an additive fashion only where necessary, thus unlocking advantages of mass customization, no part-specific tooling, near arbitrary geometric complexity, and reduced lead times and cost. The combination of conductive ink micro-dispensing AM process with hybrid manufacturing processes including: laser machining, CNC machining, and pick & place enables the fabrication of printed electronics. Printed electronics exploit the integration of AM with hybrid processes and allow embedded and/or ...


Acoustic Source Localization With A Vtol Suav Deployable Module, Kory Olney Nov 2018

Acoustic Source Localization With A Vtol Suav Deployable Module, Kory Olney

Graduate Theses and Dissertations

A real time acoustic direction-finding module has been developed to estimate the ele- vation and azimuth of an impulsive event while function aboard a small unmanned air- craft vehicle. The generalized cross-correlation with phase transform method was used to estimate time differences of arrival in an 8 channel microphone array. A linear least squares approach was used to calculate an estimate for the direction of arrival. In order to accomplish this task, a vertical takeoff and landing small unmanned aircraft system was assembled to host the direction finding module. The module itself is made up of an eight-channel synchronous analog-to-digital ...


A Quantitative Analysis Of Shape Characteristics Of Marine Snow Particles With Interactive Visualization: Validation Of Assumptions In Coagulation Models, Palak P. Dave Jun 2018

A Quantitative Analysis Of Shape Characteristics Of Marine Snow Particles With Interactive Visualization: Validation Of Assumptions In Coagulation Models, Palak P. Dave

Graduate Theses and Dissertations

The Deepwater Horizon oil spill that started on April 20, 2010, in the Gulf of Mexico was the largest marine oil spill in the history of the petroleum industry. There was an unexpected and prolonged sedimentation event of oil-associated marine snow to the seafloor due to the oil spill. The sedimentation event occurred because of the coagulation process among oil associated marine particles. Marine scientists are developing models for the coagulation process of marine particles and oil, in order to estimate the amount of oil that may reach the seafloor along with marine particles. These models, used certain assumptions regarding ...


Efficient Adjacency Queries And Dynamic Refinement For Meshfree Methods With Applications To Explicit Fracture Modeling, James Olliff Jun 2018

Efficient Adjacency Queries And Dynamic Refinement For Meshfree Methods With Applications To Explicit Fracture Modeling, James Olliff

Graduate Theses and Dissertations

Meshfree methods provide a more practical approach to solving problems involving large deformation and modeling fracture compared to the Finite Element Method (FEM). However meshfree methods are more computationally intensive compared to FEM, which can limit their practicality in engineering. Meshfree methods also lack a clear boundary definition, restricting available visualization techniques. Determining particle locations and attributes such that a consistent approximation is ensured can be challenging in meshfree methods, especially when employing h-refinement. The primary objective of this work is to address the limitations associated with computational efficiency, meshfree domain discretization, and h-refinement, including both placement of particles as ...


Simulation Of Turbulent Air Jet Impingement For Commercial Cooking Applications, Shantanu S. Shevade Jun 2018

Simulation Of Turbulent Air Jet Impingement For Commercial Cooking Applications, Shantanu S. Shevade

Graduate Theses and Dissertations

The research work in this dissertation focuses on turbulent air jet heat transfer for commercial cooking applications.

As a part of this study, convective heat transfer coefficient and its interdependency with various key parameters is analyzed for single nozzle turbulent jet impingement. Air is used as the working fluid impinging on the flat surface. A thorough investigation of velocity and temperature distributions is performed by varying nozzle velocity and height over diameter ratio (H/D). Nusselt number and Turbulent Energy are presented for the impingement surface. It was found that for H/D ratios ranging between 6 and 8, nozzle ...


Defect Detection In Additive Manufacturing Utilizing Long Pulse Thermography, James Pierce Mar 2018

Defect Detection In Additive Manufacturing Utilizing Long Pulse Thermography, James Pierce

Graduate Theses and Dissertations

Additive Manufacturing (AM), over the years, has seen a tremendous amount of research for improving the manufacturability of materials into final products. The main advantages of additive manufacturing are the minimizing of waste material as it is an additive process. As well as the ability to create custom low-volume products without the need for creation of expensive tooling or programming before manufacturing begins. Because of these advantages, however, AM is susceptible to unique challenges in the quality side of manufacturing. These challenges include minimizing and detecting defects during the build. The focus of this research looks at the capability of ...


Design And Testing Of A Linear Compliant Mechanism With Adjustable Force Output, William Niemeier Mar 2018

Design And Testing Of A Linear Compliant Mechanism With Adjustable Force Output, William Niemeier

Graduate Theses and Dissertations

This thesis presents a novel compliant mechanism with adjustable force output. The force comes from the bending of a rectangular cross section beam within the mechanism. By rotating this beam with a stepper motor, the force output of the mechanism changes. A model was made to simulate this mechanism, and a prototype was made based off of this data. A test apparatus was constructed around this mechanism, and a series of tests were performed. These tests adjusted parameters such as beam rotation speed and weight in order to characterize the system. Adjustments were made based on this information and the ...


Analysis Of Ni And Fe-Based Alloys For Turbine Seal Ring Applications, Dawei She Mar 2018

Analysis Of Ni And Fe-Based Alloys For Turbine Seal Ring Applications, Dawei She

Graduate Theses and Dissertations

Metal sealing rings have been used widely in compressors, turbines and hydraulic devices. Such rings can extend out due to elasticity, and keep close contact with the valve wall, resulting in the formation of a functional seal under pressure. In this project, the failure of metal sealing rings is considered. Sealing component failure due to stress relaxation can threaten the safety of the whole steam turbine. The object of this study was to examine the stress relaxation response and corresponding changes in microstructure of metal sealing rings used in nuclear steam turbine under high temperature and applied stress. The two ...


Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio Mar 2018

Developing Motion Platform Dynamics For Studying Biomechanical Responses During Exercise For Human Spaceflight Applications, Kaitlin Lostroscio

Graduate Theses and Dissertations

In future human spaceflight missions, with prolonged exposure to microgravity, resistive and aerobic exercises will be countermeasures for bone loss, muscle loss, and decreased aerobic capacity. Two of the exercises of interest are squats and rowing. The cyclic forces produced during these exercises are at relatively low frequencies which are likely to excite structural resonances of space vehicles. Vibration Isolation Systems (VIS) are being designed to be paired with future exploration exercise devices in order to prevent these cyclic exercise forces from impacting the space vehicle. The VIS may be configured such that a platform supports the human and exercise ...


Effectiveness Of Biocide Substitution And Management Plan Implementation For The Control Of, Adelmarie Bones Mar 2018

Effectiveness Of Biocide Substitution And Management Plan Implementation For The Control Of, Adelmarie Bones

Graduate Theses and Dissertations

After the notorious outbreak and discovery of Legionella bacteria in 1976, the waterborne pathogen was added to the list of disease-causing agents associated with the built environment. Legionella pneumophila was discovered when it was identified as the agent that caused 34 deaths and an outbreak of pneumonia-like symptoms in several attendees of the 1976 American Legion Convention held in Philadelphia (OSHA, 2017).

Recently published data from the year 2015 reported more than 6,000 Legionnaires’ cases identified in the United States (CDC, 2016). This is a concerning number given that one in every ten infected persons will die of the ...


A Surrogate Head System For Blunt Impact Experiments, Timothy J. Beavers Jan 2018

A Surrogate Head System For Blunt Impact Experiments, Timothy J. Beavers

Graduate Theses and Dissertations

Traumatic brain injury (TBI) following blunt force impact to the head yields symptoms that include confusion, headache, dizziness, and speech problems. The injury mechanism resulting in these symptoms is still not well understood, hindering the development of effective countermeasures.To increase our understanding of TBI (without skull fracture), we have designed an apparatus that can reproduce blunt impact forces in a controllable and repeatable manner. The apparatus consists of a simplistic cylindrical head system with tissue and fluid surrogates to represent the brain, cerebrospinal fluid (CSF), and skull. Resultant forces imparted on the outer layer of the skull are recorded ...


Distributed Optimization For Control And Learning, Zhanhong Jiang Jan 2018

Distributed Optimization For Control And Learning, Zhanhong Jiang

Graduate Theses and Dissertations

Large scale multi-agent networked systems are becoming increasingly popular in industry and academia as they can be applied to represent systems in diverse application areas, such as intelligent surveillance and reconnaissance, mobile robotics, transportation networks and complex buildings. In such systems, issues related to control and learning have been significant technical challenges to

affect system performance and overall cost. While centralized optimization approaches have been widely used by the engineering and computer science community, advanced and effective distributed optimization techniques have not been explored sufficiently and thoroughly in this regard. This study explores various categories of centralized and distributed optimization ...


Investigation Of Fundamental Transport And Physicochemical Phenomena In Lignocellulosic Fast Pyrolysis, Jordan A. Tiarks Jan 2018

Investigation Of Fundamental Transport And Physicochemical Phenomena In Lignocellulosic Fast Pyrolysis, Jordan A. Tiarks

Graduate Theses and Dissertations

Fast pyrolysis of biomass has the potential for high-yield production of valuable fuels and chemicals from renewable biological and agricultural waste feedstocks. Optimization of this technology is dependent on developing a deeper understanding of the complex transport and kinetic phenomena which drive product formation. In this dissertation, direct, time-resolved imaging of feedstock degradation and product formation mechanisms for the pyrolysis of whole biomass and several of its components has been made inside an optically accessible pyrolysis reactor. The reactor thermal and transport characterization allows the determination of dominant mechanisms of pyrolysis product formation in the multiphase reacting environment. This novel ...


An Optimization And Uncertainty Quantification Framework For Patient-Specific Cardiac Modeling, Joshua Mineroff Jan 2018

An Optimization And Uncertainty Quantification Framework For Patient-Specific Cardiac Modeling, Joshua Mineroff

Graduate Theses and Dissertations

Patient-specific cardiac models can be used to improve the diagnosis of cardiovascular diseases. However, practical application of these models is impeded by the computational costs and numerical uncertainties of fitting them to clinical measurements from individual patients. Reliable and efficient model tuning within medically-appropriate error bounds is a requirement for practical deployment in the time-constrained environment of the clinic. In this work, we present a framework to efficiently tune parameters of patient-specific mechanistic models using routinely acquired non-invasive patient data with a hybrid particle swarm and pattern search optimization algorithm.

The proposed framework is used to tune full-cycle lumped parameter ...


Techno-Economic Analysis Of Biochemicals And Biofuels Production Via Thermal And Electrochemical Processes, Denis Bbosa Jan 2018

Techno-Economic Analysis Of Biochemicals And Biofuels Production Via Thermal And Electrochemical Processes, Denis Bbosa

Graduate Theses and Dissertations

Climate change is leading to concerning fluctuations in weather patterns mainly due to anthropogenic activities such as deforestation and burning of fossil fuels which are and will affect different sectors such as food chains, wildlife and most importantly the human life. The upcoming generations must be left with an environment worth to live in thus humans must intervene to reduce the emissions of greenhouse gases and that is why sustainable means must be used to provide clean energy and renewable-based chemicals. For the U.S., the USDOE and USDA proposed a 25% and 20% vision for biomass-based chemicals and fuels ...


Fluid–Structure Interaction Modeling And Simulation Of Transcatheter Heart Valves, Cheng-Hao Wu Jan 2018

Fluid–Structure Interaction Modeling And Simulation Of Transcatheter Heart Valves, Cheng-Hao Wu

Graduate Theses and Dissertations

Bioprosthetic heart valves (BHVs) are prostheses fabricated from xenograft biomaterials for treating valvular disease. While these devices have mechanical and blood flow characteristics similar to the native valves, the durability remains limited to 10-15 years with device failure continues to result from leaflet structural deterioration mediated by fatigue and tissue mineralization. Improving BHV design remains an important clinical goal and represents a unique cardiovascular engineering challenge.

Transcatheter heart valves (THVs) have emerged as a minimally invasive alternative to surgical bioprosthetic heart valves therapy. THVs offer advantages such as less postoperative pain, faster rehabilitation, and better pressure gradients. However, issues such ...


Multiphysics Analysis Of Electrochemical And Electromagnetic System Addressing Lithium-Ion Battery And Permanent Magnet Motor, Abhishek Sarkar Jan 2018

Multiphysics Analysis Of Electrochemical And Electromagnetic System Addressing Lithium-Ion Battery And Permanent Magnet Motor, Abhishek Sarkar

Graduate Theses and Dissertations

Lithium-ion batteries are the leading energy storage technology in the electronic-driven society. With the need for portable, long-life electronics the demand for lithium batteries has escalated over the decade. Lithium-ion batteries show remarkable electrochemical characteristics, including but not limited to, long cycle-life, high cut-off voltages and high energy-density. However, lithium-ion cells are problematic to design due to their inherent thermal and/or mechanical instability. The objective of the current research framework is to establish the criteria causing thermo-mechanical failure of the battery systems, material properties effecting the performance, and model cycle-life degradation due to electrolyte loss by solid electrolyte interface ...