Mechanical Engineering Commons^™

Shelf-Scale Mapping Of Fish Distribution Using Active And Passive Acoustics, Carrie Christy Wall

USF Tampa Graduate Theses and Dissertations

Fish sound production has been associated with courtship and spawning behavior. Acoustic recordings of fish sounds can be used to identify distribution and behavior. Passive acoustic monitoring (PAM) can record large amounts of acoustic data in a specific area for days to years. These data can be collected in remote locations under potentially unsafe seas throughout a 24-hour period providing datasets unattainable using observer-based methods. However, the instruments must withstand the caustic ocean environment and be retrieved to obtain the recorded data. This can prove difficult due to the risk of PAMs being lost, stolen or damaged, especially in highly …

Dual Mode Sensing With Low-Profile Piezoelectric Thin Wafer Sensors For Steel Bridge Crack Detection And Diagnosis, Lingyu Yu, Sepandarmaz Momeni, Valery Godinez, Victor Giurgiutiu, Paul Ziehl, Jianguo Yu

Faculty Publications

Monitoring of fatigue cracking in steel bridges is of high interest to many bridge owners and agencies. Due to the variety of deterioration sources and locations of bridge defects, there is currently no single method that can detect and address the potential sources globally. In this paper, we presented a dual mode sensing methodology integrating acoustic emission and ultrasonic wave inspection based on the use of low-profile piezoelectric wafer active sensors (PWAS). After introducing the research background and piezoelectric sensing principles, PWAS crack detection in passive acoustic emission mode is first presented. Their acoustic emission detection capability has been validated …

Numerical Simulation Of Natural Convection In Rectangular Enclosures Of Varying Aspect Ratios And Its Feasibility In Environmental Impact Management Studies, Charles R. Walker

College of Graduate Studies: Theses & Dissertations

Author's abstract: Numerical simulation was used to investigate natural convection in horizontal and vertical enclosures with and without an internal heat source. Natural convection in rectangular enclosures is found in many real-world applications. Included in these applications are the energy efficient design of buildings, operation and safety of nuclear reactors, solar collector design, passive energy storage, heat transfer across multi-pane windows, thermo-electric refrigeration and heating devices, and the design-for-mitigation of optical distortion in large-scale laser systems. Considering all these applications, especially controlling heat transfer in nuclear power plants, knowledge and research results of natural convection in enclosure play a vital …

Development And Validation Of Probabilistic Fatigue Models Containing Out-Life Suspensions, Noel S. Murray

College of Graduate Studies: Theses & Dissertations

Author's abstract: In the area of reliability engineering it is necessary to be confident that a component or system of components will not fail under use for safety and cost reasons. One major mechanism of failure to a mechanical component is fatigue. This is the repetitious motion of loading and unloading of the material, typically below the ultimate tensile strength of the material, which ultimately leads to a catastrophic failure. To ensure this does not happen, engineers design components based on tests to determine the life of these components. These tests are typically conducted on a bench type tester in …

A Planning Tool To Predict The Welding Angle In Laser Metal Deposition, Sriram Prabhu

Masters Theses

"Research in Laser Metal Deposition (LMD) has been done rigorously in the past. However, the main challenge that still exists is the production of complex part geometries having overhang features. Production of such features requires individual tracks with a high aspect ratio and wider bead angle. The use of destructible/ non-destructible support structures involves costly post production operations which increase production cost. Tilting or moving the deposition surface can be useful to create overhangs but are applicable only to special cases. Since such techniques have to be used by the manufacturing community, the techniques need to be simple in calculation …

Computationally Efficient Finite Element Models Of The Lumbar Spine For The Evaluation Of Spine Mechanics And Device Performance, Sean D. Smith

Electronic Theses and Dissertations

Finite Element models of the lumbar spine are commonly used for the study of spine mechanics and device performance, but have limited usefulness in some applications such as clinical and design phase assessments due to long analysis times. In this study a computationally efficient L4-L5 FSU model and a L1-Sacrum multi-segment model were developed and validated. The FSU is a functional spine unit consisting of two adjacent vertebral bodies, in this case L4 and L5. The multi-segment model consists of all lumbar vertebrae and the sacrum. The models are able to accurately predict spine kinematics with significantly reduced analysis times, …

Experimental Testing And Finite-Element Modeling To Evaluate The Effects Of Aggregate Angularity On Bituminous Mixture Performance, Leonardo T. Souza, Yong-Rak Kim, Flavio V. Souza, Leandro S. Castro

Department of Engineering Mechanics: Faculty Publications

This study evaluates the effects of aggregate angularity in bituminous mixtures. Previous studies have predominantly focused on the effects of aggregate angularity on the resistance to permanent deformation, while little work has investigated the role of aggregate angularity related to mixture volumetrics and fatigue fracture performance. To investigate the effect of aggregate angularity on mixture performance and characteristics, five mixes with different combinations of coarse and fine aggregate angularity are evaluated by performing the uniaxial static creep test and the indirect tensile fracture energy test. The asphalt pavement analyzer test is also performed with five-year field project mixtures. Fracture energy …

Explicit Finite Element Modeling Of The Human Lumbar Spine, Milind Rao

Electronic Theses and Dissertations

Validated finite element (FE) models of the functional spinal unit (FSU) and lumbar spine are essential in design-phase device development and in assessing the mechanics associated with normal spine function and degenerative disc disease (DDD), as well as the impact of fusion and total disc replacement (TDR). Although experimental data from fully intact specimens can be used for model calibration and validation, the contributions from the individual structures (disc, facets, and ligaments) may be inappropriately distributed. Hence, creation of decompression conditions or device implantations that require structure removal may not have the proper resulting mechanics. An explicit FE formulation may …

Systems And Synthetic Biology Of The Vessel Wall, Jennifer Frueh, Nataly Maimari, Ying Lui, Zoltan Kis, Vikram Mehta, Negin Pormehr, Calum Grant, Emmanuel Chalkias, Mika Falck-Hansen, Sandra Bovens, Ryan M. Pedrigi, Taka Homma, Gianfillippo Coppola, Rob Krams

Department of Mechanical and Materials Engineering: Faculty Publications

Atherosclerosis is intimately coupled to blood flow by the presence of predilection sites. The coupling is through mechanotransduction of endothelial cells and approximately 2000 gene are associated with this process. This paper describes a new platform to study and identify new signalling pathways in endothelial cells covering an atherosclerotic plaque. The identified networks are synthesized in primary cells to study their reaction to flow. This synthetic approach might lead to new insights and drug targets.

Nanotopographic Cell Culture Substrate: Polymer-Demixed Nanotextured Films Under Cell Culture Conditions, Jung Yul Lim, Christopher A. Siedlecki, Henry J. Donahue

Department of Mechanical and Materials Engineering: Faculty Publications

Modulating physical cell culture environments via nanoscale substrate topographic modification has recently been of significant interest in regenerative medicine. Many studies have utilized a polymer-demixing technique to produce nanotextured films and showed that cellular adhesion, proliferation, and differentiation could be regulated by the shape and scale of the polymer-demixed nanotopographies. However, little attention has been paid to the topographic fidelity of the polymer-demixed films when exposed to cell culture conditions. In this brief article, two polymer-demixing systems were employed to assess topographic changes in polymer-demixed films after fibronectin (FN) extracellular matrix protein adsorption and after incubation in phosphate-buffered saline at …

Usability Assessment Of Two Different Control Modes For The Master Console Of A Laparoscopic Surgical Robot, Xiaoli Zhang, Carl A. Nelson, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

The objective of this study is to evaluate potential interface control modes for a compact fourdegree- of-freedom (4-DOF) surgical robot. The goal is to improve robot usability by incorporating a sophisticated haptics-capable interface. Two control modes were developed using a commercially available haptic joystick: (1) a virtually point-constrained interface providing an analog for constrained laparoscopic motion (3-DOF rotation and 1-DOF translation), and (2) an unconstrained Cartesian input interface mapping more directly to the surgical tool tip motions. Subjects (n = 5) successfully performed tissue identification and manipulation tasks in an animal model in point-constrained and unconstrained control modes, respectively, with …

Tool Sequence Trends In Minimally Invasive Surgery: Statistical Analysis And Implications For Predictive Control Of Multifunction Instruments, Carl A. Nelson, Evan Luxon, Dmitry Oleynikov

Department of Mechanical and Materials Engineering: Faculty Publications

This paper presents an analysis of 67 minimally invasive surgical procedures covering 11 different procedure types to determine patterns of tool use. A new graph-theoretic approach was taken to organize and analyze the data. Through grouping surgeries by type, trends of common tool changes were identified. Using the concept of signal/noise ratio, these trends were found to be statistically strong. The tool-use trends were used to generate tool placement patterns for modular (multi-tool, cartridge-type) surgical tool systems, and the same 67 surgeries were numerically simulated to determine the optimality of these tool arrangements. The results indicate that aggregated tool-use data …

The Impact Of Wire Stent Fabrication Technique On The Performance Of Stent Placement, Shijia Zhao, Xiangyi (Cheryl) Liu, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Braided wire stents demonstrate distinct characteristics compared to welded ones. In this study, both braided and welded wire stents with the same nominal dimensions were crimped inside a sheath and then deployed into a stenosed artery using finite element analysis. The braided wire stent was generated by overlapping wires to form crisscross shape. A welded wire stent was created by welding the intersection points of wires to avoid sliding between wires. The effect of fabrication technique on mechanical behavior of Nitinol wire stents was evaluated. The results showed that relative sliding between wires reduced the deformation of the braided stent, …

Arterial Wall Mechanics And Clinical Implications After Coronary Stenting: Comparisons Of Three Stent Designs, Linxia Gu, Shijia Zhao, Stacey R. Froemming

Department of Mechanical and Materials Engineering: Faculty Publications

The goal of this work is to quantitatively assess the relationship between the reported restenosis rates and stent induced arterial stress or strain parameters through finite element method. The impact of three stent designs (Palmaz–Schatz stent, Express stent, and Multilink Vision stent) on the arterial stress distributions were characterized. The influences of initial stent deployment location, stent-tissue friction, and plaque properties on the arterial stresses were also investigated. Higher arterial stresses were observed at the proximal end of the plaque. The Multilink–Vision stent induced lesser stress concentrations due to the high stiffness of the Cobalt Chromium material and thinner strut …

Analysis Of A Monolithic, Two-Dimensional Array Of Quartz Crystal Microbalances Loaded By Mass Layers With Nonuniform Thickness, Nan Liu, J. S. Yang, Ji Wang

Department of Mechanical and Materials Engineering: Faculty Publications

We study free thickness-shear vibrations of a monolithic, two-dimensional, and periodic array of quartz crystal microbalances loaded by mass layers with gradually varying thickness. A theoretical analysis is performed using Mindlin’s two-dimensional plate equation. It is shown that the problem is mathematically governed by Mathieu’s equation with a spatially varying coefficient. A periodic solution for resonant frequencies and modes is obtained and used to examine the effects of the mass layers. Results show that the vibration may be trapped or untrapped under the mass layers. The trapped modes decay differently in the two in-plane directions of the plate. The mode …

Shear-Horizontal Vibration Modes Of An Oblate Elliptical Cylinder And Energy Trapping In Contoured Acoustic Wave Resonators, Huijing He, Jiashi Yang, John A. Kosinski

Department of Mechanical and Materials Engineering: Faculty Publications

We study shear-horizontal free vibrations of an elastic cylinder with an oblate elliptical cross section and a traction-free surface. Exact vibration modes and frequencies are obtained. The results show the existence of thickness-shear and thickness-twist modes. The energy-trapping behavior of these modes is examined. Trapped modes are found wherein the vibration energy is largely confined to the central portion of the cross section and little vibration energy is found at the edges. It is also shown that face-shear modes are not allowed in such a cylinder. The results are useful for the understanding of the energy trapping phenomenon in contoured …

Moisture Damage Characterization Of Warm-Mix Asphalt Mixtures Based On Laboratory-Field Evaluation, Yong-Rak Kim, Jun Zhang, Hoki Ban

Department of Mechanical and Materials Engineering: Faculty Publications

This study presents laboratory evaluation integrated with field performance to examine two widely used warm-mix asphalt (WMA) approaches—foaming and emulsion technology. For a more realistic evaluation of the WMA approaches, trial pavement sections of the WMA mixtures and their counterpart hot-mix asphalt (HMA) mixtures were implemented in Antelope County, Nebraska. Field-mixed loose mixtures collected at the time of paving were transported to the laboratories to conduct various experimental evaluations of the individual mixtures. Among the laboratory tests, three (two conventional and one newly attempted) were performed to characterize moisture damage potential which is the primary focus of this study. From …

Monitoring The Wall Mechanics During Stent Deployment In A Vessel, Brian Steinert, Shijia Zhao, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Clinical trials have reported different restenosis rates for various stent designs . It is speculated that stentinduced strain concentrations on the arterial wall lead to tissue injury, which initiates restenosis . This hypothesis needs further investigations including better quantifications of non-uniform strain distribution on the artery following stent implantation. A non-contact surface strain measurement method for the stented artery is presented in this work. ARAMIS stereo optical surface strain measurement system uses two optical high speed cameras to capture the motion of each reference point, and resolve three dimensional strains over the deforming surface. As a mesh stent is deployed …

Adjusting A Level At Which To Generate A New Tone With A Current Generated Tone, M. Nakagawa, Shun Takai

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Provided are a tone control device and a method for adjusting a volume level at which to generate a new tone and at least one current tone according to a target volume level and a current volume level. A note-on event associated with a received volume level is received from an input device. A current volume level is processed to determine a new volume level in response to receiving the note-on event while generating at least one current tone at the current volume level. The at least one current tone and a new tone associated with the received note-on event …

Underwater Object Detection And Identification Using Distributed Pressure Sensors, Audrey Maertens

Link Foundation Ocean Engineering and Instrumentation Fellowship Reports

Underwater vision is usually limited. Object detection and identification is therefore one of the main challenges of underwater navigation. A new sensing modality, specifically developed for underwater environments, would greatly increase the scope of underwater missions. Taking inspiration from the lateral line of fish, I believe that pressure sensing can be a viable alternative to vision in order to detect and identify obstacles. Recent advances in the area of micro-engineering will soon enable to build sensors that match the size and mimic the functions and organization of the lateral line. However, little is known about how the pressure distribution along …

Development Of A Predictive Model For Bulk-Flow Through A Porous Polymer Membrane Tube, Aaron Robert Meles

UNF Graduate Theses and Dissertations

While extensive mathematical and numerical work has been done in terms of modeling the mainstream flow in a tube with porous walls, very little has been done experimentally to confirm these various solutions, and what has been done has focused on large sintered metal tubes used in nuclear power applications. Furthermore, these solutions are quite mathematically complex and arduous to implement. In this work, the mainstream flow through a porous polymer membrane tube is examined and a method for calculating the through-membrane flow rate and axial pressure drop is presented. Two membrane tubes are tested experimentally, and a simple set …

5-Axis Tool Path Generation With Collision Detection For Finish Machining Of Freeform Surfaces, Jomy Francis

Masters Theses

"Research in the field of Tool path generation for freeform surfaces has been done intensively in the past. However, the main challenge that still exists is the computational efficiency related to the tool path generation. Tool path generation for freeform surface involves instantaneous calculation of new tool orientations which does not collide with the neighboring surfaces. Since the collision check of tool and neighboring surface is done repetitively at every instant of the tool, the calculations at every instant are to be computationally as easy as possible.

This thesis is composed of one paper. Paper I presents a novel extension …

Ultrasonic Communications System For Health Monitoring Of Hydrokinetic Turbine Blades, Andrew James Heckman

Masters Theses

"A health monitoring approach is investigated for hydrokinetic turbine blade applications. In-service monitoring is critical due to the difficult environment for blade inspection and the cost of inspection downtime. Composite blade designs provide a medium for embedding sensors into the blades for in-situ health monitoring. The major challenge with in-situ health monitoring is transmission of sensor signals from the remote rotating reference frame of the blade to the system monitoring station. In the presented work, a novel system for relaying in-situ blade health measurements in hydrokinetic systems is described and demonstrated. An ultrasonic communication system is used to transmit health …

Large-Eddy Simulation Of Axially-Rotating, Turbulent Pipe And Particle-Laden Swirling Jet Flows, Nicolas D. Castro

Mechanical & Aerospace Engineering Theses & Dissertations

The flows of fully-developed turbulent rotating pipe and particle-laden swirling jet emitted from the pipe into open quiescent atmosphere are investigated numerically using Large-Eddy Simulation (LES). Simulations are performed at various rotation rates and Reynolds numbers, based on bulk velocity and pipe diameter, of 5.3x103, 12x103, and 24x103, respectively. Time-averaged LES results are compared with experimental and simulation data from previous studies. Pipe flow results confirm observations in previous studies, such as the deformation of the turbulent mean axial velocity profile towards the laminar Poiseuille-profile, with increased rotation. The Reynolds stress anisotropy tensor shows a redistribution due to pipe rotation. …

Transient Growth And Instability Control Using Iteration-Varying Filter Ilc In Flexible Dual Flywheel System, Tong Mu

Masters Theses

"In the field of precision motion control, many industrial systems have flexible modes. This is especially true for very high performance nanopositioning systems where traditional bearing systems are replaced with flexible structures in order to eliminate sliding friction. The precision motion control is difficult in flexible systems because the rapid phase transition around the resonant frequency must be accurately modeled in order to actively control the resonant motion. In order to experimentally study the effectiveness of various control algorithms on flexible systems, a dual-flywheel flexible system is constructed. The mechatronics system design strategy is presented in this thesis. The control …

On The Extraction Of Volatiles From Lunar Regolith Using Solar Power, Jorge Alberto Frias

Open Access Theses & Dissertations

Recent lunar missions have confirmed the presence of water and miscellaneous volatiles within the craters of the Moon's South Pole. If harvested, these resources have the potential to provide an incredible budget saving to the human space exploration program by dropping the total mass that astronauts need to carry from the Earth. The area that develops these technologies is called In-Situ Resource Utilization (ISRU). ISRU allows reducing the payload, and consequently reduces the energy consumption and cost of space exploration. The present thesis investigates methods for the extraction of volatiles from regolith within the shadowed craters of the Moon using …

Development Of Thermoelectric Temperature Sensors, Jennifer Jazmin Kuchle Ituarte

Open Access Theses & Dissertations

Temperature measurements in power generation systems can provide useful information on the performance parameters of the units. This paper presents a conceptual measurement technique using a simulated thermoelectric loop (signal transmitter). The transmitter simulates the induced current and magnetic field emanating from the center of an n and p loop. The receiver used in this study is a Hall Effect sensing device which measures the magnetic flux density produced by the transmitter. Three experimental setups were designed and built for the measurements. The first setup used a pendulum to move a coil simulating a loop thermoelectric generator thereby creating a …

An Investigation On Cocombustion Behaviors Of Hydrothermally Treated Municipal Solid Waste With Coal Using A Drop-Tube Reactor, Liang Lu, Yuqi Jin, Masato R. Nakamura, Marco J. Castaldi, Kunio Yoshikawa

Publications and Research

This work aims at demonstrating the feasibility of replacing Indonesian coal (INC) with hydrothermally treated municipal solid waste (MSWH) in cocombustion with high ash Indian coal (IC). The combustion efficiencies and emissions (CO, NO) of MSWH, INC and their blends with IC for a series of tests performed under a range of temperatures and air conditions were tested in a drop- tube reactor (DTR). The results showed the following. The combustion efficiency of IC was increased by blending both MSWH and INC and CO emission was reduced with increasing temperature. For NO emission, the blending of MSWH led to the …

An Experimental Investigation On Lox/Lch4 Reaction Control Thrusters, Arturo Acosta-Zamora

Open Access Theses & Dissertations

This work describes the development and preliminary testing of a thrust measurement system, in combination with a propellant feed and automation controls systems to test the performance of 8.9 to 35.6 N (2 to 8 lbf) LOX/Methane reaction control thrusters. LOX/LCH4 has come to be the main focus of next generation "green" propellants for future space exploration. As there is limited experience with this propellant combination, an effort is being conducted to research performance of rockets using these propellants. The development of a thrust measurement, propellant feed, and automation controls systems is necessary for proper testing and qualification of thruster …

Combustion And Compaction Of Lunar Regolith/Magnesium Mixtures, Armando Delgado

Open Access Theses & Dissertations

Feasible techniques that require low energy consumption and reduced costs are of vital importance to enable humans to explore and occupy space. In-Situ Resource Utilization (ISRU) is the branch in the Human Exploration Technology that studies the production of consumables and materials using indigenous lunar and planetary resources. ISRU represents an enabling opportunity for establishing long lasting human exploration missions. Construction materials produced in-situ are of special interest because of the high payload they represent when launching them from Earth. The in-situ production of construction materials that requires low energy input would be advantageous due to the limited energy in …