Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mechanical Engineering (14)
- Manufacturing (5)
- Acoustics, Dynamics, and Controls (3)
- Aerospace Engineering (3)
- Applied Mechanics (3)
-
- Biomechanical Engineering (3)
- Computer-Aided Engineering and Design (3)
- Materials Science and Engineering (2)
- Bioimaging and Biomedical Optics (1)
- Biomechanics and Biotransport (1)
- Biomedical Engineering and Bioengineering (1)
- Chemical Engineering (1)
- Controls and Control Theory (1)
- Electrical and Computer Engineering (1)
- Electro-Mechanical Systems (1)
- Environmental Sciences (1)
- Metallurgy (1)
- Navigation, Guidance, Control and Dynamics (1)
- Operational Research (1)
- Operations Research, Systems Engineering and Industrial Engineering (1)
- Other Aerospace Engineering (1)
- Physical Sciences and Mathematics (1)
- Polymer and Organic Materials (1)
- Propulsion and Power (1)
- Space Habitation and Life Support (1)
- Space Vehicles (1)
- Structures and Materials (1)
- Sustainability (1)
- Systems Engineering and Multidisciplinary Design Optimization (1)
- Keyword
-
- Turbulence (2)
- 3D DENSE Plugin for Crescent Organ (1)
- 3D Lagrangian Strains (1)
- 3D printing (1)
- Acoustic radiation efficiency (1)
-
- Angle of Attack (1)
- Anisotropic behavior (1)
- Antenna Pattern Localization (1)
- Atmospheric Boundary Layer (1)
- Biventricular (1)
- Bluetooth Low Energy (1)
- Burnishing (1)
- CFRP composite (1)
- Capillary (1)
- Circular Economy (1)
- Coincidence frequency (1)
- Compression molding (1)
- Core Circulation (1)
- Cryogenic (1)
- DENSE MRI (1)
- Decentralized Control (1)
- Displacement (1)
- Efficiency (1)
- Electro Magnetic Formation Flying (1)
- Finite Element Modeling (1)
- Finite Element Simulation (1)
- Finite element Analysis (1)
- Five-hole probe (1)
- Flow-Induced Noise (1)
- Helical Economy (1)
Articles 1 - 16 of 16
Full-Text Articles in Engineering
Quantification Of Myocardial Mechanics In Left Ventricles Under Inotropic Stimulation And In Healthy Right Ventricles Using 3d Dense Cmr, Zhan-Qiu Liu
Theses and Dissertations--Mechanical Engineering
Statistical data from clinical studies indicate that the death rate caused by heart disease has decreased due to an increased use of evidence-based medical therapies. This includes the use of magnetic resonance imaging (MRI), which is one of the most common non-invasive approaches in evidence-based health care research. In the current work, I present 3D Lagrangian strains and torsion in the left ventricle of healthy and isoproterenol-stimulated rats, which were investigated using Displacement ENcoding with Stimulated Echoes (DENSE) cardiac magnetic resonance (CMR) imaging. With the implementation of the 12-segment model, a detailed profile of regional cardiac mechanics was reconstructed for …
Indoor-Wireless Location Techniques And Algorithms Utilizing Uhf Rfid And Ble Technologies, Ann M. Whitney
Indoor-Wireless Location Techniques And Algorithms Utilizing Uhf Rfid And Ble Technologies, Ann M. Whitney
Theses and Dissertations--Mechanical Engineering
The work presented herein explores the ability of Ultra High Frequency Radio Frequency (UHF RF) devices, specifically (Radio Frequency Identification) RFID passive tags and Bluetooth Low Energy (BLE) to be used as tools to locate items of interest inside a building. Localization Systems based on these technologies are commercially available, but have failed to be widely adopted due to significant drawbacks in the accuracy and reliability of state of the art systems. It is the goal of this work to address that issue by identifying and potentially improving upon localization algorithms.
The work presented here breaks the process of localization …
The Effects Of System Characteristics, Reference Command, And Command-Following Objectives On Human-In-The-Loop Control Behavior, Seyyedalireza Seyyedmousavi
The Effects Of System Characteristics, Reference Command, And Command-Following Objectives On Human-In-The-Loop Control Behavior, Seyyedalireza Seyyedmousavi
Theses and Dissertations--Mechanical Engineering
Humans learn to interact with many complex physical systems. For example, humans learn to fly aircraft, operate drones, and drive automobiles. We present results from human-in-the-loop (HITL) experiments, where human subjects interact with dynamic systems while performing command-following tasks multiple times over a one-week period. We use a new subsystem identification (SSID) algorithm to estimate the control strategies (feedforward, feedforward delay, feedback, and feedback delay) that human subjects use during their trials. We use experimental and SSID results to examine the effects of system characteristics (e.g., system zeros, relative degree, system order, phase lag, time delay), reference command, and command-following …
Development Of A Muffler Insertion Loss Flow Rig, Jonathan Chen
Development Of A Muffler Insertion Loss Flow Rig, Jonathan Chen
Theses and Dissertations--Mechanical Engineering
Mufflers and silencers are commonly used to attenuate noise sources such as internal combustion engines and HVAC systems. Typically, these environments contain mean flow that can affect the acoustic properties of the muffler components and may produce flow generated noise. To characterize the muffler performance, common metrics such as insertion and transmission loss and noise reduction are used in industry. Though transmission loss without flow is often measured and is a relatively simple bench top experiment and useful for model validation purposes, mean flow can significantly affect the muffler performance. There are a few existing and commercial transmission loss rigs …
Quantification Of Papillary Muscle Motion And Mitral Regurgitation After Myocardial Infarction, Connor R. Ferguson
Quantification Of Papillary Muscle Motion And Mitral Regurgitation After Myocardial Infarction, Connor R. Ferguson
Theses and Dissertations--Mechanical Engineering
Change in papillary muscle motion as a result of left ventricular (LV) remodeling after posterolateral myocardial infarction is thought to contribute to ischemic mitral regurgitation. A finite element (FE) model of the LV was created from magnetic resonance images acquired immediately before myocardial infarction and 8 weeks later in a cohort of 12 sheep. Severity of mitral regurgitation was rated by two-dimensional echocardiography and regurgitant volume was estimated using MRI. Of the cohort, 6 animals (DC) received hydrogel injection therapy shown to limit ventricular remodeling after myocardial infarction while the control group (MI) received a similar pattern of saline injections. …
Transforming A Circular Economy Into A Helical Economy For Advancing Sustainable Manufacturing, Ryan T. Bradley
Transforming A Circular Economy Into A Helical Economy For Advancing Sustainable Manufacturing, Ryan T. Bradley
Theses and Dissertations--Mechanical Engineering
The U.N. projects the world population to reach nearly 10 billion people by 2050, which will cause demand for manufactured goods to reach unforeseen levels. In order for us to produce the goods to support an equitable future, the methods in which we manufacture those goods must radically change. The emerging Circular Economy (CE) concept for production systems has promised to drastically increase economic/business value by significantly reducing the world’s resource consumption and negative environmental impacts. However, CE is inherently limited because of its emphasis on recycling and reuse of materials. CE does not address the holistic changes needed across …
A Computational Study Of Patch Implantation And Mitral Valve Mechanics, Dara Singh
A Computational Study Of Patch Implantation And Mitral Valve Mechanics, Dara Singh
Theses and Dissertations--Mechanical Engineering
Myocardial infarction (i.e., a heart attack) is the most common heart disease in the United States. Mitral valve regurgitation, or the backflow of blood into the atrium from the left ventricle, is one of the complications associated with myocardial infarction. In this dissertation, a validated model of a sheep heart that has suffered myocardial infarction has been employed to study mitral valve regurgitation. The model was rebuilt with the knowledge of geometrical changes captured with MRI technique and is assigned with anisotropic, inhomogeneous, nearly incompressible and highly non-linear material properties. Patch augmentation was performed on its anterior leaflet, using a …
Analysis Of Surface Integrity In Machining Of Cfrp Under Different Cooling Conditions, Arjun Nagaraj
Analysis Of Surface Integrity In Machining Of Cfrp Under Different Cooling Conditions, Arjun Nagaraj
Theses and Dissertations--Mechanical Engineering
Carbon Fiber Reinforced Polymers (CFRP) are a class of advanced materials widely used in versatile applications including aerospace and automotive industries due to their exceptional physical and mechanical properties. Owing to the heterogenous nature of the composites, it is often a challenging task to machine them unlike metals. Drilling in particular, the most commonly used process for component assembly is critical especially in the aerospace sector which demands parts of highest quality and surface integrity.
Conventionally, all composites are machined under dry conditions. While there are drawbacks related to dry drilling, for example, poor surface roughness, there is a need …
Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia
Design And Process Of 3d-Printed Parts Using Composite Theory, Jordan Garcia
Theses and Dissertations--Mechanical Engineering
3D printing is a revolutionary manufacturing method that allows the productions of engineering parts almost directly from modeling software on a computer. With 3D printing technology, future manufacturing could become vastly efficient. However, it is observed that the procedures used in 3D printing differ substantially among the printers and from those used in conventional manufacturing. In this thesis, the mechanical properties of engineering products fabricated by 3D printing were comprehensively evaluated and then compared with those made by conventional manufacturing. Three open-source 3D printers, i.e., the Flash Forge Dreamer, the Tevo Tornado, and the Prusa, were used to fabricate the …
Circulation Dependence Of The Interaction Between A Wing-Tip Vortex And Turbulence, Farshid Najarzadegan
Circulation Dependence Of The Interaction Between A Wing-Tip Vortex And Turbulence, Farshid Najarzadegan
Theses and Dissertations--Mechanical Engineering
Vortices are present in many fluid flows and depending on the context they may be either beneficial or harmful for different systems or processes. Planar particle image velocimetry was used to examine the vortex evolution and its decay under different turbulence intensities and vortex circulation. The vortex decayed faster in the presence of high turbulence intensity. Vortex trajectories were impacted by turbulence intensity and vortex strength. Trajectories with no turbulence intensity had less variation. The vortex wandering amplitude decreased with growth of vortex strength. The vortex decay was confined to the core of the vortex, with the tangential velocity at …
Single-Degree-Of-Freedom Experiments Demonstrating Electromagnetic Formation Flying For Small Satellite Swarms Using Piecewise-Sinusoidal Controls, Ajin Sunny
Theses and Dissertations--Mechanical Engineering
This thesis presents a decentralized electromagnetic formation flying (EMFF) control method using frequency-multiplexed sinusoidal control signals. We demonstrate the EMFF control approach in open-loop and closed-loop control experiments using a single-degree-of-freedom testbed with an electromagnetic actuation system (EAS). The EAS sense the relative position and velocity between satellites and implement a frequency-multiplexed sinusoidal control signal. We use a laser-rangefinder device to capture the relative position and an ARM-based microcontroller to implement the closed-loop control algorithm. We custom-design and build the EAS that implements the formation control in one dimension. The experimental results in this thesis demonstrate the feasibility of the …
Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill
Enhanced Surface Integrity With Thermally Stable Residual Stress Fields And Nanostructures In Cryogenic Processing Of Titanium Alloy Ti-6al-4v, James R. Caudill
Theses and Dissertations--Mechanical Engineering
Burnishing is a chipless finishing process used to improve surface integrity by severe plastic deformation (SPD) of surface asperities. As surface integrity in large measure defines the functional performance and fatigue life of aerospace alloys, burnishing is thus a means of increasing the fatigue life of critical components, such as turbine and compressor blades in gas turbine engines. Therefore, the primary objective of this dissertation is to characterize the burnishing-induced surface integrity of Ti-6Al-4V alloy in terms of the implemented processing parameters. As the impact of cooling mechanisms on surface integrity from SPD processing is largely unexplored, a particular emphasis …
Hot-Wire Anemometer Measurements Of Atmospheric Surface Layer Turbulence Via Unmanned Aerial Vehicle, Caleb A. Canter
Hot-Wire Anemometer Measurements Of Atmospheric Surface Layer Turbulence Via Unmanned Aerial Vehicle, Caleb A. Canter
Theses and Dissertations--Mechanical Engineering
An instrumented unmanned aerial vehicle (UAV) was developed and employed to observe the full range of turbulent motions that exist within the inertial subrange of atmospheric surface layer turbulence. The UAV was host to a suite of pressure, temperature, humidity, and wind sensors which provide the necessary data to calculate the variety of turbulent statistics that characterize the flow. Flight experiments were performed with this aircraft, consisting of a large square pattern at an altitude of 100 m above ground level. In order to capture the largest turbulent scales it was necessary to maximize the size of the square pattern. …
Trade-Off Balancing For Stable And Sustainable Operating Room Scheduling, Amin Abedini
Trade-Off Balancing For Stable And Sustainable Operating Room Scheduling, Amin Abedini
Theses and Dissertations--Mechanical Engineering
The implementation of the mandatory alternative payment model (APM) guarantees savings for Medicare regardless of participant hospitals ability for reducing spending that shifts the cost minimization burden from insurers onto the hospital administrators. Surgical interventions account for more than 30% and 40% of hospitals total cost and total revenue, respectively, with a cost structure consisting of nearly 56% direct cost, thus, large cost reduction is possible through efficient operation management. However, optimizing operating rooms (ORs) schedules is extraordinarily challenging due to the complexities involved in the process. We present new algorithms and managerial guidelines to address the problem of OR …
Determination Of Acoustic Radiation Efficiency Via Particle Velocity Sensor With Applications, Steven Conner Campbell
Determination Of Acoustic Radiation Efficiency Via Particle Velocity Sensor With Applications, Steven Conner Campbell
Theses and Dissertations--Mechanical Engineering
Acoustic radiation efficiency is defined as the ratio of sound power radiated to the surface vibration power of a piston with equivalent surface area. It has been shown that the radiation efficiency is maximized and may exceed unity when the structural and acoustic wavelengths are approximately equal. The frequency at which this occurs is called the critical frequency and can be shifted with structural modifications. This has proven to be an effective way to reduce noise. The standard radiation efficiency measurement is comprised of an intensity scan for sound power measurement and accelerometer array for spatially averaged vibration determination. This …
Design Process For The Containment And Manipulation Of Liquids In Microgravity, Chris Meek
Design Process For The Containment And Manipulation Of Liquids In Microgravity, Chris Meek
Theses and Dissertations--Mechanical Engineering
In order to enhance accessibility to microgravity research, the design process for experiments on the ISS must be streamlined and accessible to all scientific disciplines, not just aerospace engineers. Thus, a general design and analysis toolbox with accompanying best practices manual for microgravity liquid containment is proposed. The work presented in this thesis improves the design process by introducing a modular liquid tank design which can be filled, drained, or act as a passive liquid-gas separation device. It can also be pressurized, and used for aerosol spray. This tank can be modified to meet the design requirements of various experimental …