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Articles 1 - 13 of 13

Full-Text Articles in Mechanical Engineering

Numerical Analysis For Determination Of Fiber Orientation In Nonwoven Mats, Lee Reynolds Allen Dec 2008

Numerical Analysis For Determination Of Fiber Orientation In Nonwoven Mats, Lee Reynolds Allen

Masters Theses

The University of Tennessee Space Institute is interested in pitch-based carbon fibers. A need has arisen for characterizing relative alignment of nonwoven fiber mats, produced by the spinning gathering technology implemented. Knowledge of this alignment is relevant in the validation of production methodology as well as aiding in the analysis of carbon fiber composite materials made with the fiber mats. A digital image processing method was developed presented and evaluated in this thesis consisting of three steps: preprocessing using image smoothing, edge detection based upon local intensity gradients, and line detection via the Hough Transform. A summary of typical results ...


Label-Free Mapping Of Near-Field Transport Properties Of Micro/Nano-Fluidic Phenomena Using Surface Plasmon Resonance (Spr) Reflectance Imaging, Iltai Kim Dec 2008

Label-Free Mapping Of Near-Field Transport Properties Of Micro/Nano-Fluidic Phenomena Using Surface Plasmon Resonance (Spr) Reflectance Imaging, Iltai Kim

Doctoral Dissertations

My doctoral research has focused on the development of surface plasmon resonance (SPR) reflectance imaging technique to detect near-field transport properties such as concentration, temperature, and salinity in micro/nano fluidic phenomena in label-free, real-time, and full-field manner. A label-free visualization technique based on surface plasmon resonance (SPR) reflectance sensing is presented for real-time and full-field mapping of microscale concentration and temperature fields. The key idea is that the SPR reflectance sensitivity varies with the refractive index of the near-wall region of the test mixture fluid. The Fresnel equation, based on Kretschmann’s theory, correlates the SPR reflectance with the ...


Characterization Of Dynamic Response Of Afm Cantilevers For Microscale Thermofluidic And Biophysical Sensors, Seonghwan Kim Aug 2008

Characterization Of Dynamic Response Of Afm Cantilevers For Microscale Thermofluidic And Biophysical Sensors, Seonghwan Kim

Doctoral Dissertations

My doctoral research has focused on the characterization of dynamic response of atomic force microscope (AFM) cantilevers for thermofluidic and biophysical sensors, a novel scanning thermal microscopy technique development using a tipless microcantilever to investigate micro/nanoscale transport properties in liquid, and the characterization of the surface nanomechanical properties of biocompatible polyelectrolyte hydrogels with AFM for biomedical applications.

The temperature effects on Sader‟s viscous model for multilayered microcantilevers immersed in an aqueous medium were experimentally verified as a preliminary work. Next, temperature dependence of the near-wall oscillation of microcantilevers submerged in an aqueous medium was investigated to explore the ...


From Nearfield Nanoparticle Tracking To Intracellular Vesicle Tracking, Charles H. Margraves Aug 2008

From Nearfield Nanoparticle Tracking To Intracellular Vesicle Tracking, Charles H. Margraves

Doctoral Dissertations

The initial goal of this research was to measure the hindered Brownian motion of nanoparticles (100 nm to 500 nm in radii), in varying salinities of water, in order to compare the normal and tangential motion with existing theory. Using techniques developed from this work, brain cancer cells containing vesicles loaded with Nonsteroidal anti-inflammatory drug-Activated Gene-1 (NAG-1), tagged with a Green Fluorescent Protein (GFP), were examined to see what effect the glass cover slip played in hindering their motion.

Several microscopy techniques have been used in this work including Total Internal Reflection Fluorescent Microscopy (TIRFM) and Differential Interference Reflection Microscopy ...


Bandwidth On Demand For Laser Communications Satellites, Alexander M. Melin Aug 2008

Bandwidth On Demand For Laser Communications Satellites, Alexander M. Melin

Doctoral Dissertations

Narrow beamwidth satellites such as laser communication or imaging satellites present a unique problem in control and scheduling. The narrow beamwidth limits the sources of information avail- able to the satellite. This is especially true for laser communication satellites who can only point the laser at one user at a time. For the most part, this restricts the use of laser communications satellites to fixed connections or dedicated temporary connections. However, some classes of users can benefit from the speed and security of the lasercom connection. For example, a Globalhawk unmanned aerial vehicle with time sensitive battlefield imaging would be ...


The Effect Of Bluff Body Flameholders On The Inter-Turbine Burner Performance, Richard Jackson Holder Aug 2008

The Effect Of Bluff Body Flameholders On The Inter-Turbine Burner Performance, Richard Jackson Holder

Masters Theses

In this thesis, a three-dimensional numerical simulation has been conducted to study the complex reactive flows which are present during the combustion in an inter-turbine burner (ITB) with the inclusion of V-gutter flame holders. Optimal conditions for the V-gutter were then further studied through a parametric study. The ITB configuration with straight radial vanes (SRV) was based on the innovative, high efficiency, high-g Ultra-Compact Combustor (UCC) concepts developed at the Air Force Research Laboratory (AFRL).

For the first section, the V-gutter’s angle of attack was varied from -10 degrees to 10 degrees. The turbulent flow was modeled with a ...


Effects Of High Temperature Cyclic Aging On A Fully-Formulated Lean NoX Trap Catalyst, Nathan Andrew Ottinger Aug 2008

Effects Of High Temperature Cyclic Aging On A Fully-Formulated Lean NoX Trap Catalyst, Nathan Andrew Ottinger

Masters Theses

The thermal deactivation mechanisms of a lean NOx trap (LNT) are analyzed in this study. Accelerated lean/rich aging experiments are performed with a bench-flow reactor, and high temperature exotherms are achieved with pulses of reductants. Reduction in steady state NOx conversion as a result of aging is evaluated at a range of temperatures using the same bench-flow reactor. The results of these evaluations are used to show that NOx conversion in this study is a function of evaluating temperature, aging temperature, and number of aging cycles.

Surface characterization studies are used to determine changes in washcoat ...


Development And Implementation Of Mathematical Modeling, Vibration And Acoustic Emission Technique To Correlate In Vivo Kinematics, Kinetics And Sound In Total Hip Arthroplasty With Different Bearing Surfaces, Diana Andreeva Glaser Aug 2008

Development And Implementation Of Mathematical Modeling, Vibration And Acoustic Emission Technique To Correlate In Vivo Kinematics, Kinetics And Sound In Total Hip Arthroplasty With Different Bearing Surfaces, Diana Andreeva Glaser

Doctoral Dissertations

The evaluation of Total Hip Arthroplasty (THA) outcome is difficult and invasive methods are often applied. Fluoroscopy has been used as an in vivo diagnostic technique to determine separation which may lead to vibration propagation and audible interactions. The objective of this study was to develop a new, non-invasive technique of digitally capturing vibration and sound emissions at the hip joint interface and to correlate those with the hip kinematics derived from fluoroscopy. Additionally, an examination of the role of hip mechanics on walking performance in THA subjects of various bearings surfaces was performed.

In vivo kinematics, kinetics, corresponding vibration ...


Nonlinear Unsteady Combustion Of A Solid Propellant, Mark William Olles May 2008

Nonlinear Unsteady Combustion Of A Solid Propellant, Mark William Olles

Doctoral Dissertations

A nonlinear burning model is developed, valid across a wide range of frequencies, to allow for the incorporation of an admittance function into a nonlinear combustion instability (CI) framework. This is accomplished by extending two existing models to incorporate the effects of nonlinearity, the QSHOD ( Α Β ) model as described by Culick in his 1968 review paper and the 1973 T’ien model. The classical QSHOD model is marred by major limitations due to the simplifications and assumptions made. The most evident is the exclusion of the unsteady gas phase eliminating the high frequency response. The less recognized T’ien ...


Development Of An Accelerated Ash Loading Protocol For Rapid Evaluation Of Diesel Particulate Filters Including Comprehensive Characterization Of Ash-Loaded Substrates, Adam Daniel Youngquist May 2008

Development Of An Accelerated Ash Loading Protocol For Rapid Evaluation Of Diesel Particulate Filters Including Comprehensive Characterization Of Ash-Loaded Substrates, Adam Daniel Youngquist

Masters Theses

The accelerated ash loading of diesel particulate filters (DPFs) by lube-oil derived products is investigated in the present study. A 517-cc single-cylinder, naturally aspirated direct-injection diesel engine is used to accelerate ash formation by artificially increasing the rate of lube-oil consumption to approximately 40 times that observed during normal engine operation. Lube-oil consumption (LOC) is accelerated by blending diesel fuel with 5% by volume of standard 15-w40 lube oil and is subsequently injected through the fuel injector into the combustion chamber.

The ash loading protocol is a backpressure-based method of determining the amount of soot present within the DPF and ...


Experimental Measurement Of Thermal Conductivity Of An Unknown Material, Aaron Christopher Whaley May 2008

Experimental Measurement Of Thermal Conductivity Of An Unknown Material, Aaron Christopher Whaley

Masters Theses

The objective of this study was to determine effective thermal conductivity of an unknown material sample for sample temperatures up to 1000 degrees Celsius. A steady state, one-dimensional heat conduction test setup was designed, fabricated, assembled, and used to determine thermal conductivity of the sample. The measurement was accomplished by applying a heat flux from a radiant heater through a stack consisting of the test sample, reference plates, heat spreaders, and insulation layers. The heat transfer equation for steady state, one-dimensional conduction relates thermal conductivity of the sample to the thickness and cross-sectional area of the sample, the temperature difference ...


Mechanical Property Testing Apparatus For Use In A Scanning Electron Microscope, Robert Brian Peters May 2008

Mechanical Property Testing Apparatus For Use In A Scanning Electron Microscope, Robert Brian Peters

Masters Theses

The purpose of this design project is to develop a mechanical testing device to work in conjunction with a scanning electron microscope [SEM]. The objective of this work was to be able to perform a mechanical property measuring test and observe the small scale physical behavior of the sample with the SEM as the test progresses. The design process is presented from concept development through to the completion of the prototype device. Test data was acquired and analyzed and the results are compared to standard values for the materials being tested. Recommendations for future improvements in the next generation of ...


Robust-Adaptive Magnetic Bearing Control Of Flexible Matrix Composite Rotorcraft Driveline, Hans August Desmidt, Kon-Well Wang, Edward Smith Jan 2008

Robust-Adaptive Magnetic Bearing Control Of Flexible Matrix Composite Rotorcraft Driveline, Hans August Desmidt, Kon-Well Wang, Edward Smith

Faculty Publications and Other Works -- Mechanical, Aerospace and Biomedical Engineering

Recent studies demonstrate that a key advantage of Flexible Matrix Composite (FMC) shaft technology is the ability to accommodate misalignments without need for segmenting or flexible couplings as required by conventional alloy and graphite/epoxy composite shafts. While this is indeed a very promising technology for rotorcraft driveshafts, the high damping loss-factor and thermal stiffness and damping sensitivities of the urethane matrix, makes FMC shafting more prone to self-heating and whirl instabilities. Furthermore, the relatively low bending stiffness and critical speeds of FMC shafts makes imbalance vibration a significant challenge to supercritical operation. To address these issues and advance the ...