Digital Commons Network^™

A New Boundary Interlock Geometry Design Method For Fdm Multi-Material Part Strengthening, Shivaram Sree Venkata Shanmukha Kakaraparthi

Graduate Research Theses & Dissertations

Multi-material Fused Deposition Modelling (FDM) enables the cost-effective realization of designs in complex geometries built with multiple materials. However, achieving an adequate level of bonding strength between different materials remains a significant challenge. Besides the traditional way of addressing this challenge by strengthening material bonding at the molecular scale by optimizing the printing parameters, introducing a new design methodology that creates stronger multi-material interface geometry could also offer effective solutions. This work studied the mechanical properties of multi-material printed objects, with a particular focus on the interface zone formed between different materials at their geometrical boundaries. A new mathematical simulation …

Biomechanical Evaluation Of Hand Representation For Typing In Virtual Reality, Mobasshira Zaman

Graduate Research Theses & Dissertations

Virtual reality (VR) is becoming popular in the workplace recently. Text entry is thus now important for efficient office use and occupational use of VR, and VR paired with a conventional keyboard is suitable for long text entry. There has been a lack of research on physical demand, posture, motion, and cognitive demand, along with the performance of typing on VR. Presence of virtual hands while typing in VR may affect typing performance, physical demand, and posture. The focus of this study was to evaluate the biomechanical effect of hand representation for typing on VR using a conventional keyboard. Fifteen …

Engagement Detection Using Prosodic Cues: An Approach For Measuring Child Emotional Engagement Level In Child-Robot Interaction Scenario, Mustafa Oztoprak

Graduate Research Theses & Dissertations

The ultimate goal of advanced child-robot interaction is to develop a high-level intelligencecommunication channel in a closed-loop configuration with the child as the focal point of the instructional scenario. This goal can be met by establishing efficient sensing mechanisms on the robot’s side, such as automatic engagement measuring, which will allow the robot to alter its behavior or even the instructional scenario’s execution.Recent researches, regarding engagement recognition systems mostly based on facial or multi-modal features.We would like to investigate this topic using prosodic cues only. We believe speech characteristics are more likely to be related to child speaker engagement level.This …

Experimental Analysis Of Flowing Layer Characteristics In Equilateral Triangular Tumblers For Quasi-2d Macro-Particle Flow, Jason Quinn Ostenburg

Graduate Research Theses & Dissertations

Rotating tumblers are used in a wide variety of industrial applications from mixing anddeburring to flow regulation and storage. Almost all model tumblers previously analyzed, both theoretically and experimentally, had circular cross sections that produced consistent flowing layer dimensions and steady state flow. In contrast, tumblers with triangular cross sections produced unsteady flow as a direct result of the dynamic dimensions of the flowing surface. Although unsteady, the flow produced in triangular tumblers is periodic every 120◦ of rotation after an initial mixing period. The mechanisms by which the flow characteristics vary as a triangular tumbler rotates and the number …

Warm Unit Stand Analysis For Proton Improvement Project Ii, Michael William Pavlick

Graduate Research Theses & Dissertations

The Proton Improvement Project II, commonly referred to as PIP II, is a linear accelerator overhaul at Fermilab to eventually double the output of its existing proton beam to continue to be the leading force in high energy physics. The proton beam is created through a series of high frequency cryomodules that must be connected utilizing a combination of magnets and vacuum pumps to ensure the beam is properly aligned. A housing mechanism for the magnets and vacuum pumps (Warm Units) will be placed between the cryomodules for realignment and require multiple stages of 6 degree-of-freedom adjustment options, to ensure …

Stress Analysis On Walls In Complex Fluids With Fluid-Solid Interaction, Dehong Fang

Graduate Research Theses & Dissertations

The wall shear stress (WSS) in blood vessels influences many biological processes, such as atherosclerosis, clot growth, angiogenesis, aneurysm rupture, and blood cell transport and adhesion. The deformable red blood cells (RBCs) in blood flow make the WSS even more complex. To analyze the WSS in complex fluids with cell suspensions, numerical simulations of blood flows in simple straight channels were conducted, where the fluid-solid interactions were simulated by immersed boundary-lattice Boltzmann method. The spatiotemporal dynamics of WSS were analyzed using dynamic mode decomposition (DMD), which is a technique that can extract the low-rank spatiotemporal features from complex fluids. The …

Investigation Of A Piezoelectric Pressure Sensing To Drive An Igbt Circuit, Sonali Rawat

Graduate Research Theses & Dissertations

In this thesis, piezoelectric pressure sensing element circuit has been proposed and designed to drive the IGBT. The idea behind this work is to integrate and develop the IGBT as pressure sensor. By the application of pressure on the sensing element, the output voltage can turn on the IGBT. The relationship between the force applied and generated voltage of the electromechanical model has been analyzed theoretically.The piezo material used for this work is PZT due its best-known properties. The PZT is also modeled in COMSOL, and its output voltage results are compared with the LT SPICE and theoretical calculation for …

Comparison Of Three Phase Resonant Converter Topologies, Mohammed Adnan Shareef

Graduate Research Theses & Dissertations

There is an increasing demand for power converters with small size, light weight, high conversion efficiency and higher power density. Also, in many applications, there is a need for DC-to-DC converters to accept DC input voltage and provide regulated and/or isolated DC output voltage at a desired voltage level including telecommunications equipment, process control systems, electric vehicles (EVs), renewable energy applications and in industry applications. At higher power levels (e.g., greater than 1kW), three-phase resonant converters have significant advantages over single-phase ones due to reduced component stresses, smaller filter size requirements, and higher power density. The LLC converter is deemed …

Synthesis And Advanced Characterization Of Energy Materials, Erik Sarnello

Graduate Research Theses & Dissertations

Catalysts are used in an extremely broad range of systems including everything from biological systems to industrial processes. An ideal catalyst offers robust stability and high activity. This work focuses on the synthesis and characterization of materials that show promise in the field of catalysis. Advanced synchrotron characterization techniques and unique experimental design are highlighted to provide foundation work that will provide the necessary information to aid in designing and fabricating catalytic materials. Supported metal nanoparticle (SMN) catalysts are enormously crucial for many catalytic applications. However, catalyst deactivation, caused by sintering and coke formation, is a ubiquitous problem that significantly …

Risk-Aware Path Planning For Autonomous Vehicles, Shaghayegh Gaeini

Graduate Research Theses & Dissertations

Autonomous vehicles have been the subject of intense research leading to great improvements in safety, comfort, accessibility, efficiency, etc. Path planning which provides the autonomous vehicle with a smooth, collision-free, and safe path towards its destination, is a crucial part of autonomous vehicles (AVs). Various path planning techniques have been developed in the past decades that can successfully plan a smooth and safe path in various driving scenarios. Nevertheless, these algorithms perform poorly in critical situations where the vehicle needs to quickly make a decision. To address this issue, a couple of algorithms have been proposed to replace the AV’s …

Temperature Analysis Of A Square Lid-Driven Cavity With Particle Suspensions, Justin Kortge

Graduate Research Theses & Dissertations

Computational fluid dynamics (CFD) and discrete element method (DEM) are powerful tools for simulating systems that contain fluids and particles. Studies of particle fluid systems greatly vary in their applications and complexity, and yet there is a scarcity of studies focused on the thermal characteristics of the fluid. A computational analysis is conducted on two-dimensional flow in a square thermal lid-driven cavity to assess the effect of particle suspensions on the thermal characteristics of the cavity. Most studies analyzing the effect of suspensions in a thermal lid-driven cavity treat the medium as a single homogeneous nanofluid. Those that do treat …

A Parametric Study Of Thermochemical Energy Storage Using Chemical Looping For Concentrated Solar Power (Csp) Plants, Imran Anees Mohammed

Graduate Research Theses & Dissertations

The use of conventional fossil fuels to generate power has caused great harm to the environment. These fossil fuels, when burnt, release copious amounts of CO_2, causing global warming. Therefore, it is imperative that current energy sources are substituted with renewable energy sources. However, the critical obstacle with renewable energy sources is their intermittency. Solar energy is being captured through photovoltaic plants and concentrated solar power plants. Photovoltaic plants use batteries, which makes the storage of energy limited. Furthermore, an alternative downside is that the constant use of many batteries will considerably increaseincrease the project’s cost. Concentrated solar power plants …

A Machine Learning Approach To Intended Motion Prediction For Upper Extremity Exoskeletons, Justin Berdell

Graduate Research Theses & Dissertations

A fully solid-state, software-defined, one-handed, handle-type control device built around a machine-learning (ML) model that provides intuitive and simultaneous control in position and orientation each in a full three degrees-of-freedom (DOF) is proposed in this paper. The device, referred to as the “Smart Handle”, and it is compact, lightweight, and only reliant on low-cost and readily available sensors and materials for construction. Mobility chairs for persons with motor difficulties could make use of a control device that can learn to recognize arbitrary inputs as control commands. Upper-extremity exoskeletons used in occupational settings and rehabilitation require a natural control device like …

Upper Body Joint Angle Calculation And Analysis Using Multiple Inertial Measurement Units, Aaron S. Freedkin

Graduate Research Theses & Dissertations

A prominent area in biomechanics revolves around finding solutions to common issues like work-related musculoskeletal disorders (WMSDs). These are common in professions associated with unnatural postures like commercial fishing and farming. Understanding how these professions move on a day-to-day basis can help find solutions to WMSDs. While a motion capture system might be the most common equipment for body posture measurement, it lacks the portability to work in remote environments like commercial fishing and farming. Therefore, joint angle estimation using IMUs (Inertial Measurement Units) could provide a potential alternative.

An IMU consists of a triaxial accelerometer, gyroscope, and magnetometer, which …

Optimize The Niu Split Hopkinson Pressure Bar Apparatus For Conducting High Strain Rate Tensile Test On S304 Foils, Jiale Ji

Graduate Research Theses & Dissertations

Split Hopkinson Bar (SHB) methods are widely used to experimentally characterize the mechanical properties of materials such as metals, concrete, and ceramics undergoing rapid deformation. NIU had a split-Hopkinson tensile apparatus that can conduct coarse tensile test, but it can’t output the useful signal. The aim of this thesis is to optimize the existing apparatus, so the high strain rate tensile tests for the stainless steel 304 can be conducted and useful signal can be got. The alignment of the bars is critical for a good signal that has less noise. To eliminate the noise signal, some accurate fixture is …

Integrating Experimental Parameter Space For Granular Flow Within Polygon Tumblers, Michaela Mcmahon

Graduate Research Theses & Dissertations

Granular flows are complex phenomena bridging both fluid and solid mechanics and observed frequently in the natural world. The transitional dynamics of acceleration from solid body motion to rapid flow can affect many aspects including volume flow rates and mixing behaviors. In order to study the combination of both variables together within polygon-shaped tumblers, control systems are necessary with a corresponding user interface. This thesis reports an interface for changing variable inputs to the system. Predictions of rotation rates with corresponding interfaces with hardware connections are described. Results of image analysis verify output performance that incorporates the following variable changes: …

Mu2e Pion Degrader For Detector Calibration, Jessie Bouche Miles

Graduate Research Theses & Dissertations

Particle tracking within the Mu2e experiment can be accomplished through regulating the rate of capture at the stopping target with the addition of a thin, low atomic weight material, the “degrader.” Investigation of Mu2e studies and simulations provide initial data for degrader design. The overall thickness of the degrader plus structural components must fit between the last two solenoids during operation and resist displacement. The degrader area, perpendicular to the beamline, must exceed that of the stopping target during alignment and be able to clear outer diameters of the beamline components. Structural analysis will ensure all dimensional constraints are met …

Design And Fabrication Of A Small-Sized Omni-Directional Spherical Robot, Aayush P. Patel

Graduate Research Theses & Dissertations

As we have witnessed through an unprecedented pandemic crisis, a lack of or decreased level of social interactions could have a negative impact on people's mental health. Ample evidence indicates that similar phenomena take place in rodents as socially isolated rodents display a high level of stress and cognitive declination. While spherical robots have recently drawn significant interest in many areas such as education, entertainment, and surveillance due to their ability to move instantaneously in any direction, the objective of this thesis is to design and fabricate a small-sized, self-locomotive omnidirectional robot to provide those animals with physical interactions as …

Study Protocol To Analyze The Effects Of Posture And Exoskeleton On Human Exposure To Hand-Transmitted Vibration, Parisa Torkinejad Ziarati

Graduate Research Theses & Dissertations

Exposure to power hand tool-generated vibrations may lead to several health disorders collectively known as hand-arm vibration (HAV) syndromes. Power hand tools are often used in overhead postures in the manufacturing and construction industries. However, HAV risks are examined in the front-of-body posture in the existing safety standards and guidelines. Therefore, it is important to understand the effects of overhead working posture on vibration transmissibility (VT) in the upper extremities (UEs) and the spine. Secondly, there is a rising trend of using occupational exoskeletons (Exos) in the manufacturing and construction industries, especially involving overhead work with power hand tools. However, …