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Full-Text Articles in Mechanical Engineering

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 ...


Synthesis And Characterization Of Alpha-Hematite Nanomaterials For Water-Splitting Applications, Hussein Alrobei Jul 2018

Synthesis And Characterization Of Alpha-Hematite Nanomaterials For Water-Splitting Applications, Hussein Alrobei

Graduate Theses and Dissertations

The recent momentum in energy research has simplified converting solar to electrical energy through photoelectrochemical (PEC) cells. There are numerous benefits to these PEC cells, such as the inexpensive fabrication of thin film, reduction in absorption loss (due to transparent electrolyte), and a substantial increase in the energy conversion efficiency. Alpha-hematite ([U+F061]-Fe2O3) has received considerable attention as a photoanode for water-splitting applications in photoelectrochemical (PEC) devices. The alpha-hematite ([U+F061]-Fe2O3) nanomaterial is attractive due to its bandgap of 2.1eV allowing it to absorb visible light. Other benefits of [U+F061]-Fe2O3 include low cost, chemical stability ...


Toward Verifiable Adaptive Control Systems: High-Performance And Robust Architectures, Benjamin Charles Gruenwald Jun 2018

Toward Verifiable Adaptive Control Systems: High-Performance And Robust Architectures, Benjamin Charles Gruenwald

Graduate Theses and Dissertations

In this dissertation, new model reference adaptive control architectures are presented with stability, performance, and robustness considerations, to address challenges related to the verification of adaptive control systems.

The challenges associated with the transient performance of adaptive control systems is first addressed using two new approaches that improve the transient performance. Specifically, the first approach is predicated on a novel controller architecture, which involves added terms in the update law entitled artificial basis functions. These terms are constructed through a gradient optimization procedure to minimize the system error between an uncertain dynamical system and a given reference model during the ...


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 ...


Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau Jun 2018

Simulation Of Radiation Flux From Thermal Fluid In Origami Tubes, Robert R. Bebeau

Graduate Theses and Dissertations

Spacecraft in orbit experience temperature swings close to 240 K as the craft passes from the shadow of the Earth into direct sunlight. To regulate the craft’s internal energy, large radiators eject unwanted energy into space using radiation transfer. The amount of radiation emitted is directly related to the topology of the radiator design. Deformable structures such as those made with origami tessellation patterns offer a mechanism to control the quantity of energy being emitted by varying the radiator shape. Three such patterns, the Waterbomb, Huffman Waterbomb, and Huffman Stars-Triangles, can be folded into tubes. Origami tubes offer greater ...


Design And Testing Of A Passive Prosthetic Ankle Foot Optimized To Mimic An Able-Bodied Gait, Millicent Schlafly Jun 2018

Design And Testing Of A Passive Prosthetic Ankle Foot Optimized To Mimic An Able-Bodied Gait, Millicent Schlafly

Graduate Theses and Dissertations

Currently there are nearly 2 million people living with limb loss in the United States [1]. Many of these individuals are either transtibial (below knee) or transfemoral (above knee) amputees and require an ankle-foot prosthesis for basic mobility. While there are an abundance of options available for individuals who require an ankle-foot prosthesis, these options fail to mimic an intact ankle when it comes to key evaluation criteria such as range of motion, push-off force, and roll over shape. The roll over shape is created by plotting the center of pressure during a step in a shank-based coordinate system. To ...


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 ...