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Articles 13291 - 13320 of 30103

Full-Text Articles in Mechanical Engineering

Role Of Dispersion And Functionalization On Mechanical Properties In Carbon Nanotube - Polymer Composite, Medisetti Sai Praveen Kumar May 2017

Role Of Dispersion And Functionalization On Mechanical Properties In Carbon Nanotube - Polymer Composite, Medisetti Sai Praveen Kumar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Polymer composites with carbon nanotubes (CNT) as filler material is an exciting research area, having a huge potential of offering better mechanical properties. One of the main challenges of using CNT as a filler material is mixing of CNTs within the matrix material, as this mixing determines the strength of the composite. Some of the methods being researched for improving mixing are chemical, mechanical and surfactants. Many studies have suggested high frequency mechanical stirring as the preferred way for better mixing, but challenges exist with finding the proper solvent which can be used for stirring and at the same time …


Mechanical Performance Of Natural / Natural Fiber Reinforced Hybrid Composite Materials Using Finite Element Method Based Micromechanics And Experiments, Muhammad Ziaur Rahman May 2017

Mechanical Performance Of Natural / Natural Fiber Reinforced Hybrid Composite Materials Using Finite Element Method Based Micromechanics And Experiments, Muhammad Ziaur Rahman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A micromechanical analysis of the representative volume element (RVE) of a unidirectional flax/jute fiber reinforced epoxy composite is performed using finite element analysis (FEA). To do so, first effective mechanical properties of flax fiber and jute fiber are evaluated numerically and then used in evaluating the effective properties of flax/jute/epoxy hybrid composite. Mechanics of Structure Genome (MSG), a new homogenization tool developed in Purdue University, is used to calculate the homogenized effective properties. Numerical results are compared with analytical solution based on rule of mixture, Halpin-Tsai as well as Tsai-Hahn equations. The effect of the volume fraction of the two …


Nonlinear Photothermal Radiometry And Its Applications To Pyrometry And Thermal Property Measurements, Austin Drew Fleming May 2017

Nonlinear Photothermal Radiometry And Its Applications To Pyrometry And Thermal Property Measurements, Austin Drew Fleming

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Accurate temperature and thermal property measurements are critical for the modeling and prediction of heat transfer. In many industries thermal management is a limiting factor of performance, and rely on advanced modeling techniques to develop and design methods to better manage thermal energy. This study expands the thermal property and pyrometry measurement capabilities by developing three new techniques based on thermal emission’s nonlinear dependence on temperature.


Safer Sweep Auger Operation Using Robotics, Nathan A. Wulf May 2017

Safer Sweep Auger Operation Using Robotics, Nathan A. Wulf

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This thesis presents a remotely controlled robotic solution for those who must sometimes enter agriculturally confined spaces in attempts to assist with grain bin cleanout, particularly by manipulating the sweep auger. In 2015 alone, there were at least 47 documented incidents that occurred in agriculturally confined spaces, of which more than half were fatal. While there have been several advancements in the quality and effectiveness of sweep augers, there have been very few that offer the safety and adaptability of the robotic solution proposed. This robotic solution is a four-wheeled, skid-steering style robot with camera and lighting attachments that allow …


Peridynamic Models For Fatigue And Fracture In Isotropic And In Polycrystalline Materials, Guanfeng Zhang May 2017

Peridynamic Models For Fatigue And Fracture In Isotropic And In Polycrystalline Materials, Guanfeng Zhang

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

To improve design and reliability, extensive efforts has been devoted to understanding damage and failure of materials and structures using numerical simulation, as a complement of theory and experiment. In this thesis, peridynamics is adopted to study fatigue and dynamic failure problems.

Fatigue is a major failure mode in engineering structures. Predicting fracture/failure under cyclic loading is a challenging problem. Classical model cannot directly be applied to problems with discontinuities. A peridynamic model is adopted in this work because of important advantages of peridynamics in allowing autonomous crack initiation and propagation. A recently proposed peridynamic fatigue crack model is considered …


Applications Of Femtosecond Laser Processed Metallic Surfaces: Leidenfrost Point And Thermal Stability Of Rare Earth Oxide Coatings, Anton Charles Hassebrook May 2017

Applications Of Femtosecond Laser Processed Metallic Surfaces: Leidenfrost Point And Thermal Stability Of Rare Earth Oxide Coatings, Anton Charles Hassebrook

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

In this thesis, micro/nano structured surfaces were created through the use of Femtosecond Laser Surface Processing (FLSP). In the first part of the thesis, an experimental investigation of the effects of droplet diameters and fluid properties on the Leidenfrost temperature of polished and nano/microstructured surfaces has been carried out. Leidenfrost experiments were conducted on a stainless steel 304 polished surface and a stainless steel surface which was processed by a femtosecond laser to form Above Surface Growth (ASG) nano/microstructures. Surface preparation resulted in a root mean square roughness (Rrms) of 4.8 µm and 0.04 µm on the laser …


Development Of Peritoneal Microbubble Oxygenation As An Extrapulmonary Treatment For Hypoxia, Nathan Legband May 2017

Development Of Peritoneal Microbubble Oxygenation As An Extrapulmonary Treatment For Hypoxia, Nathan Legband

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Patients affected by a respiratory disease or injury experience a substantially impaired respiratory system and as a consequence are unable to obtain a sufficient amount of oxygen. Hypoxia can quickly result in developing permanent tissue damage or death. Currently, the medical methods of treating hypoxia are mechanical ventilation or extracorporeal membrane oxygenation. However, these treatments are ineffective in certain cases and possess significant additional risks including barotrauma, infection, hemorrhage, and thrombosis.

The extrapulmonary method of peritoneal oxygenation has been investigated by other research groups as a potential alternative to providing supplemental oxygen in hypoxic animals. In peritoneal oxygenation, the peritoneum, …


On The Wetting States Of Low Melting Point Metal Galinstan And Wetting Characteristics Of 3-Dimensional Nanostructured Fractal Surfaces, Ethan Allan Davis May 2017

On The Wetting States Of Low Melting Point Metal Galinstan And Wetting Characteristics Of 3-Dimensional Nanostructured Fractal Surfaces, Ethan Allan Davis

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Exergy, or the availability of energy for useful work, is a critical issue that must be addressed to accommodate growing energy demands of society. Increasing population and steady advancement of technology necessitates novel approaches to the management, conversion, and storage of energy. Per the Lawrence Livermore National Laboratory, approximately 60 percent of the energy used by the United States in 2015 was rejected as waste [1]; a large quantity of which can be assumed to be in the form of heat. Therefore, novel thermal management methods for waste heat are critical to increasing energy efficiency and sustainability in the future. …


Near-Field Thermal Radiation For Solar Thermophotovoltaics And High Temperature Thermal Logic And Memory Applications, Mahmoud Elzouka May 2017

Near-Field Thermal Radiation For Solar Thermophotovoltaics And High Temperature Thermal Logic And Memory Applications, Mahmoud Elzouka

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

This dissertation investigates Near-Field Thermal Radiation (NFTR) applied to MEMS-based concentrated solar thermophotovoltaics (STPV) energy conversion and thermal memory and logics. NFTR is the exchange of thermal radiation energy at nano/microscale; when separation between the hot and cold objects is less than dominant radiation wavelength (~1 μm). NFTR is particularly of interest to the above applications due to its high rate of energy transfer, exceeding the blackbody limit by orders of magnitude, and its strong dependence on separation gap size, surface nano/microstructure and material properties.

Concentrated STPV system converts solar radiation to electricity using heat as an intermediary through a …


Design And Validation Of An In Vivo Long-Term Attachment Capsule Robot, Wanchuan Xie May 2017

Design And Validation Of An In Vivo Long-Term Attachment Capsule Robot, Wanchuan Xie

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The invention of capsule endoscopy (CE) made the non-invasive monitoring of the entire small bowel possible and became the primary means for diagnosing small bowel pathology. In the last decade, capsule robots have been transformed from diagnostic devices into a widely studied biomedical platform with the potential for active locomotion, drug delivery and therapeutic capabilities. To perform accurate on-site drug release and therapy, it is necessary for a capsule robot to be able to attach to the intestinal tissue and maintain its position long-term. Design challenges derive from the task of long-term mucosal adhesion which requires firm, quick-response attachment without …


Computer-Aided Design Integration In Virtual Reality Design Reviews For Improved Interaction With Engineering Models, Ian James Freeman May 2017

Computer-Aided Design Integration In Virtual Reality Design Reviews For Improved Interaction With Engineering Models, Ian James Freeman

Theses and Dissertations

Leveraging virtual reality (VR) technology to enhance engineering design reviews has been an area of significant interest for researchers since the advent of modern VR. The ability to interact meaningfully with 3D engineering models in these VR design reviews is an important, though often neglected, capability due to the difficulty of performing data translation between native CAD data and VR compatible file formats. A bi-directional interface was developed between a VR design review environment and a commercial CAD package that streamlines the data translation process. By transmitting both geometric data and selected metadata from the CAD system an improved format …


Blood-Brain Barrier-On-A-Chip Systems Based On 3d Printing, Cade I. Harding May 2017

Blood-Brain Barrier-On-A-Chip Systems Based On 3d Printing, Cade I. Harding

Mechanical Engineering Undergraduate Honors Theses

This research focused on the design and testing of a blood-brain barrier (BBB)-on-a-chip microfluidic device produced using 3D printing. First, COMSOL simulations were used to define dimensions of the microchannel that would most accurately replicate the flow environment imposed on the blood-brain barrier, the wall shear stress being the most important characteristic. In using COMSOL, water was used as the simulated fluid and also the testing fluid in the fabricated devices. Therefore, the microsystem is designed to produce the BBB environment using water instead of blood. The numerical simulation parameters were based on theoretical calculations performed to scale up the …


Optimization Of Reduced Graphene Oxide Deposition For Hydrogen Sensing Technologies, Matthew Pocta May 2017

Optimization Of Reduced Graphene Oxide Deposition For Hydrogen Sensing Technologies, Matthew Pocta

Mechanical Engineering Undergraduate Honors Theses

Graphene is known to be a key material for improving the performance of hydrogen sensors. High electrical conductivity, maximum possible surface area with respect to volume, and high carrier mobility are a few of the properties that make graphene ideal for hydrogen sensing applications. The problem with utilizing graphene is the difficulty in depositing uniform, thin layers onto substrate surfaces. This study examines a new method of optimizing graphene deposition by utilizing an airbrush to deposit both graphene oxide (GO) and reduced graphene oxide (rGO) onto glass substrates. The number of depositions were varied among samples to study the effect …


Surface Acoustic Wave Based Pumping In A Microchannel, Tao Wang, Qi Ni, Nathan B. Crane, Rasim Guldiken May 2017

Surface Acoustic Wave Based Pumping In A Microchannel, Tao Wang, Qi Ni, Nathan B. Crane, Rasim Guldiken

Faculty Publications

Pumping and manipulation of liquids in microfluidic channels is important for many mechanical, chemical and biomedical applications. Surface acoustic wave based devices fabricated on high-efficiency piezoelectric substrates have been recently investigated for mixing and separation application within microfluidic channels. In this paper, we introduce a novel integrated surface acoustic wave based pump for liquid delivery and precise manipulation within a microchannel. The device employs a hydrophobic surface coating (Cytop) in the device design for decreasing the friction force and increasing the bonding. Contrary to previous surface acoustic wave based pump, this device does not need precise layers of water and …


Modeling Local Crabbing Dynamics In The Jleic Ion Collider Ring, Salvador Sosa Guitron, Vasiliy Morozov, Jean Delayen May 2017

Modeling Local Crabbing Dynamics In The Jleic Ion Collider Ring, Salvador Sosa Guitron, Vasiliy Morozov, Jean Delayen

Physics Faculty Publications

The Jefferson Lab Electron-Ion Collider (JLEIC) design considers a 50 mrad crossing angle at the Interaction Point. Without appropriate compensation, this could geometrically reduce the luminosity by an order of magnitude. A local crabbing scheme is implemented to avoid the luminosity loss: crab cavities are placed at both sides of the interaction region to restore a head-on collision scenario. In this contribution, we report on the implementation of a local crabbing scheme in the JLEIC ion ring. The effects of this correction scheme on the stability of proton bunches are analyzed using the particle tracking software elegant.


Optimization Under Uncertainty For Wake Steering Strategies, Julian Quick, Jennifer Annoni, Ryan King, Katherine Dykes, Paul Fleming, Andrew Ning May 2017

Optimization Under Uncertainty For Wake Steering Strategies, Julian Quick, Jennifer Annoni, Ryan King, Katherine Dykes, Paul Fleming, Andrew Ning

Faculty Publications

Wind turbines in a wind power plant experience significant power losses because of aerodynamic interactions between turbines. One control strategy to reduce these losses is known as 'wake steering,' in which upstream turbines are yawed to direct wakes away from downstream turbines. Previous wake steering research has assumed perfect information, however, there can be significant uncertainty in many aspects of the problem, including wind inflow and various turbine measurements. Uncertainty has significant implications for performance of wake steering strategies. Consequently, the authors formulate and solve an optimization under uncertainty (OUU) problem for finding optimal wake steering strategies in the presence …


Intensity Control Of Individual Dbd Plasma Filament. I. Experiment With A Needle Electrode, M. C. Paliwoda, J. L. Rovey May 2017

Intensity Control Of Individual Dbd Plasma Filament. I. Experiment With A Needle Electrode, M. C. Paliwoda, J. L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Filamentary volume dielectric barrier discharge (DBD) produces patterned plasma structures that are currently being explored for reconfigurable metamaterial applications. In this work, the presence and intensity of a single filament (within an array of filaments) are controlled by biasing a low voltage needle electrode by less than 7% of the driving voltage. The current, voltage, and time-averaged normalized light intensity were measured while varying the needle voltage through self-biasing resistors. For a 7.5 kV, 3.2 kHz DBD in air, the needle-controlled filament intensity varies from 80% to 0% of the light intensity of surrounding filaments. When the biased voltage prevents …


Intensity Control Of Individual Dbd Plasma Filament. Ii. Fundamental Physical Mechanism, M. C. Paliwoda, J. L. Rovey May 2017

Intensity Control Of Individual Dbd Plasma Filament. Ii. Fundamental Physical Mechanism, M. C. Paliwoda, J. L. Rovey

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Filamentary volume dielectric barrier discharge (DBD) produces patterned plasma structures that are currently being explored for reconfigurable metamaterial applications. Previous work has demonstrated control of the presence and intensity of a single DBD plasma filament (within an array of filaments) by biasing a low voltage needle electrode. The results were attributed to redistributed charge inside the DBD due to the modified electric field created by the needle electrode. In the present work, results from a 3D electrodynamic field simulation bolster this argument. Results show that increasing needle bias voltage causes changes in the transverse electric field structure, resulting in redistribution …


Infrared Metasurfaces Created With Off-Normal Incidence Microsphere Photolithography, Chuang Qu, Edward C. Kinzel May 2017

Infrared Metasurfaces Created With Off-Normal Incidence Microsphere Photolithography, Chuang Qu, Edward C. Kinzel

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Fabricating metasurfaces over large areas at low costs remains a critical challenge to their practical implementation. This paper reports on the use of microsphere photolithography (MPL) to create infrared metasurfaces by changing the angle-of-incidence of the illumination to steer the photonic jet. The displacement of the photonic jet is shown to scale with the diameter of the microsphere while the exposure dose scales with the square of the microsphere diameter. This process is robust in the presence of local defects in the microsphere lattice. The paper demonstrates patterning split ring resonators and tripole based metasurfaces using MPL, which are fabricated …


The Aerodynamic Effects On Flight Patterns And The Evolutionary Changes In Pterosaurs, Johnathan D. Talik May 2017

The Aerodynamic Effects On Flight Patterns And The Evolutionary Changes In Pterosaurs, Johnathan D. Talik

Maseeh Summer Undergraduate Research Experience

Early pterosaurs were the first vertebrates to achieve powered flight, and remained small-to-medium sized from the Triassic Period to the end of the Jurassic Period. During that interval, lasting from 210 million years ago to 66 million years ago, pterosaurs underwent a notable changes at the end of the Jurassic Period and through the Cretaceous Period. They were abruptly replaced by much larger forms, characterized by great size and peculiar head ornamentation, among other unique and notable morphological features. While many different explanations theorize why and how the features of the pterosaurs changed over the Cretaceous Period, the aerodynamic influences …


Deposition Velocity Dependence On Urban Morphology, Rawand Muzafar Rasheed May 2017

Deposition Velocity Dependence On Urban Morphology, Rawand Muzafar Rasheed

Maseeh Summer Undergraduate Research Experience

Understanding the interactions between the atmospheric boundary layer and urban structures provides insights into emerging problems such as green building design as well as dispersion and deposition of pollutants on urban structures. Characterization of deposition velocity dependence through the naphthalene sublimation method on model urban structures is conducted herein where the analogous fundamental transport mechanisms of momentum and mass transport is obtained via mass of naphthalene transferred. Via wind tunnel experiments, results show that deposition velocity of naphthalene from urban structures increases with increased number of urban structures ahead of the point of investigation. This is attributed to the wakes …


Flux Focusing Axial Magnetic Gear, Robert J. Rutherford May 2017

Flux Focusing Axial Magnetic Gear, Robert J. Rutherford

Maseeh Summer Undergraduate Research Experience

Power transmission is traditionally achieved with a mechanical gear. These gears require maintenance, cause vibration, and have no overload protection. Magnetic gears (MGs) offer an innovative solution to these drawbacks as they do not require regular maintenance, have no need for lubrication, create very little acoustic noise, have built in overload protection and as a result of these advantages, have a longer lifetime of operation. The flux focusing axial magnetic gear (FFAMG) was assembled for future testing of power transmission, conversion, and generation applications.

Gears are used to transmit power by converting low speed-high torque rotary motion into high speed-low …


Conditional Averaging And Classification In The Near Wake Of A Wind Turbine Array Boundary Layer, Sarah E. Smith May 2017

Conditional Averaging And Classification In The Near Wake Of A Wind Turbine Array Boundary Layer, Sarah E. Smith

Maseeh Summer Undergraduate Research Experience

Flow perturbation induced by interaction with a turbine rotor produces considerable turbulence which can alter the productivity of subsequent units within a wind farm. Previous methods have characterized near wake vorticity of a single turbine as well as recovery distance for various turbine array configurations. This study aims to build from previous methods of analysis from the perspective of the rotor well within a turbine array and develop a model to examine points of significant imposition in relation to rotational effects. Hot wire anemometry was employed downstream of a turbine located in the middle of the third row in a …


Analysis Of Tool Wear And Tool Life Of Cutting Tool Inserts Using Statistical Process Control Charts: A Case Study, Evan R. Ferrell Apr 2017

Analysis Of Tool Wear And Tool Life Of Cutting Tool Inserts Using Statistical Process Control Charts: A Case Study, Evan R. Ferrell

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Business and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Evan R. Ferrell on April 28, 2017.


Semi-Annual Program Progress Performance Report For University Transportation Systems Pppr#7, Florida Solar Energy Center, David L. Block Apr 2017

Semi-Annual Program Progress Performance Report For University Transportation Systems Pppr#7, Florida Solar Energy Center, David L. Block

FSEC Energy Research Center®

The Electric Vehicle Transportation Center (EVTC) supports the U.S. Department of Transportation's strategic goal of planning for near-term integration of alternative fuel vehicles as a means to build a sustainable transportation system. The project objectives are to evaluate technologies, standards, planning and policies to ensure seamless integration of electric vehicles (EVs) into a complex transportation network and electricity grid. The EVTC bridges the gap between deployment of electric vehicles and the traditional transportation system. This document is a summary of the activities until April 28, 2017.


Kinematics Of The Lower Extremities During Fundamental Martial Arts Tricking Techniques, Kevin P. Grassie Apr 2017

Kinematics Of The Lower Extremities During Fundamental Martial Arts Tricking Techniques, Kevin P. Grassie

Honors Scholar Theses

Martial Arts Tricking (MAT) is a relatively new sport that combines martial arts, gymnastics, acrobatics, and breakdancing for the purposes of creating aesthetic and impressive combinations of kicks, flips and twists. It has been growing exponentially through social media and the overall athletic and entertainment communities. The sport is very unique in that the movements, with their blended influences, provide novel ways for athletes to generate and utilize their momentum in a creative way. The results often include off-axis flips and twists, single-leg landings, and complicated yet fluid techniques that easily chain together.

Due to the sport only being a …


Next Steps For Mentoring Program, Patrick Gray Apr 2017

Next Steps For Mentoring Program, Patrick Gray

Sustainability and Connectivity

This file provides a jump-off position for students in the fall 2017 semester who want to continue work toward a mentoring program.


Lean Process Improvement And Quality Analysis For Performance Rework, Paula R. Sloas Apr 2017

Lean Process Improvement And Quality Analysis For Performance Rework, Paula R. Sloas

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Business and Technology at Morehead State University in partial fulfillment of the requirements for the degree of Master of Science by Paula R. Sloas on April 19, 2017


Mapping And Integrating Value Creation Factors With Life-Cycle Stages For Sustainable Manufacturing, P. Bilge, S. Emec, G. Seliger, Ibrahim S. Jawahir Apr 2017

Mapping And Integrating Value Creation Factors With Life-Cycle Stages For Sustainable Manufacturing, P. Bilge, S. Emec, G. Seliger, Ibrahim S. Jawahir

Institute for Sustainable Manufacturing Faculty Publications

Instead of implementing each element individually, engineers must be aware of multiple interactions among all major value creation factors and their life-cycle stages. Interactions are analyzed by a set of factors and hierarchical levels within a production system based on empirical observations and described in analytical models. Such analyses and missing information about the current condition of the system and its parts remain limited to addressing specific aspects of interactions among factors and stages for multiple decision making. To build a case-based scope addressing the interactions among a set of factors and life-cycle stages, a comprehensive approach for mapping and …


Design Of A Cubesat Separation Mechanism, Ross Hiller Apr 2017

Design Of A Cubesat Separation Mechanism, Ross Hiller

Honors Theses

CubeSats are compact, relatively inexpensive satellites that are often used for space research. In order to perform research related to electric propulsion devices, the Western Aerospace Launch Initiative (WALI) requires a medium-sized CubeSat capable of separating into two bodies while in orbit. Intentional separation is not common in CubeSats, so two original concepts were designed and simulated using 3D CAD and finite element analysis software. These designs were compared based on factors including weight, cost, size, and their potential to fail due to creation of debris or binding between components, in order to determine which will more effectively execute the …