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2008

Doctoral Dissertations

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Articles 1 - 16 of 16

Full-Text Articles in Mechanical Engineering

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 ...


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 ...


A Finite Difference Method For Studying Thermal Deformation In Three-Dimensional Thin Films Exposed To Ultrashort Pulsed Lasers, Suyang Zhang Jul 2008

A Finite Difference Method For Studying Thermal Deformation In Three-Dimensional Thin Films Exposed To Ultrashort Pulsed Lasers, Suyang Zhang

Doctoral Dissertations

Thermal analysis related to ultrashort-pulsed lasers has been intensely studied in science and engineering communities in recent years, because the pulse duration of ultrashort-pulsed lasers is only the order of sub-picoseconds to femtoseconds, and the lasers have exclusive capabilities in limiting the undesirable spread of the thermal process zone in the heated sample. Studying the thermal deformation induced by ultrashort-pulsed lasers is essential for preventing thermal damage. For the ultrashort-pulsed laser, the thermal damage is different from that caused by the long pulsed lasers and cracks occur after heating.

This dissertation presents a new finite difference method for studying thermal ...


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 ...


Friction Stir Channeling: An Innovative Technique For Heat Exchanger Manufacturing, Nagarajan Balasubramanian Jan 2008

Friction Stir Channeling: An Innovative Technique For Heat Exchanger Manufacturing, Nagarajan Balasubramanian

Doctoral Dissertations

"Friction stir processing (FSP) is an emerging processing technique based on the principles of friction stir welding (FSW), which is a relatively new solid-state metal joining process developed by The Welding Institute, UK. Some of the unique features of FSW such as the low amount of heat generated, extensive plastic deformation and controlled flow of material is being exploited to develop new material modification and manufacturing processes. Friction stir channeling (FSC) is one such adaptation of FSP that can produce continuous and stable internal channels for application in heat exchanging equipment. Friction stir channeling produces these channels if the defect ...


Addressing Nonlinear Combustion Instabilities In Highly Dilute Spark Ignition Engine Operation, Brian C. Kaul Jan 2008

Addressing Nonlinear Combustion Instabilities In Highly Dilute Spark Ignition Engine Operation, Brian C. Kaul

Doctoral Dissertations

"Dilute operation is a promising approach for increasing spark-ignition engine efficiency, in the form of either lean burn (air dilution) or EGR (inert dilution). High levels of charge dilution, however, lead to cyclic variability that is largely deterministic in nature. The determinism and nonlinear nature of the system indicate that it should be possible to reduce the cycle-to-cycle variations by implementing an electronic controller. Several needs arise when considering the development of such a controller. Three topics of interest are covered herein. First, a method of analysis for nonlinear dynamical systems is applied to engine data in order to estimate ...


Virtual Prototyping With Surface Reconstruction And Freeform Geometric Modeling Using Level-Set Method, Weihan Zhang Jan 2008

Virtual Prototyping With Surface Reconstruction And Freeform Geometric Modeling Using Level-Set Method, Weihan Zhang

Doctoral Dissertations

"More and more products with complex geometries are being designed and manufactured by computer aided design (CAD) and rapid prototyping (RP) technologies. Freeform surface is a geometrical feature widely used in modern products like car bodies, airfoils and turbine blades as well as in aesthetic artifacts. How to efficiently design and generate digital prototypes with freeform surfaces is an important issue in CAD. This paper presents the development of a Virtual Sculpting system and addresses the issues of surface reconstruction from dexel data structures and freeform geometric modeling using the level-set method from distance field structure. Our virtual sculpting method ...


Unsteady Flow And Heat Transfer In Periodic Complex Geometries For The Transitional Flow Regime, Li-Kwen Chen Jan 2008

Unsteady Flow And Heat Transfer In Periodic Complex Geometries For The Transitional Flow Regime, Li-Kwen Chen

Doctoral Dissertations

"Diesel engines are facing significant challenges with upcoming changes in emissions standards. In general, meeting the increased emission standards will require a larger fraction of the engine heat rejection to occur in the vehicle cooling system. For certain applications, the surface geometry must also be such that it resists particulate fouling, precluding common interrupted surfaces such as louvered fins. Although acceptable continuous surface geometries such as bumped fin geometries are in use, the impacts of changing the parameters of this geometry are unknown. This study investigates the transport characteristics of bumped fins in the transitional flow regime using unsteady multi-dimensional ...


Three-Dimensional Laminar And Turbulent Convection In Separated Flow, Magesh Thiruvengadam Jan 2008

Three-Dimensional Laminar And Turbulent Convection In Separated Flow, Magesh Thiruvengadam

Doctoral Dissertations

"Three-dimensional laminar and turbulent separated flow and heat transfer in plane symmetric sudden expansion and plane backward facing step is examined in this dissertation. In Papers I, II, and III, simulations of 3-D laminar forced convection in plane symmetric expansion is studied...In Paper IV, 3-D turbulent flow measurements using Laser Doppler Velocimeter are made in a backward facing step flow and the three velocity components and the Reynolds stresses are measured in the separated and redeveloping flow region...In Paper V, the 2-D behavior of a thin film that is shear driven by turbulent air flow is simulated"--Abstract ...


Modeling, Analysis And Experimentation For Building Ice Parts With Supports Using Rapid Freeze Prototyping, Frances D. Bryant Jan 2008

Modeling, Analysis And Experimentation For Building Ice Parts With Supports Using Rapid Freeze Prototyping, Frances D. Bryant

Doctoral Dissertations

"Rapid Freeze Prototyping (RFP) is a freeform fabrication method that freezes water droplets into ice in a layer-by-layer manner to additively create a 3-dimensional part. Each layer of a geometry is deposited and allowed to freeze before the next layer is added. Ice parts produced by RFP can be used in investment casting to replace wax patterns and in other applications which may benefit from the unconventional method of using ice as a pattern or mold. More recently, a sacrificial support material has been incorporated into RFP so that over-hung areas and complex geometries can be fabricated. The research presented ...


Uncertainty Analysis And Sensitivity Analysis For Multidisciplinary Systems Design, Jia Guo Jan 2008

Uncertainty Analysis And Sensitivity Analysis For Multidisciplinary Systems Design, Jia Guo

Doctoral Dissertations

"The objective of this research is to quantify the impact of both aleatory and epistemic uncertainties on performances of multidisciplinary systems. Aleatory uncertainty comes from the inherent uncertain nature and epistemic uncertainty comes from the lack of knowledge. Although intensive research has been conducted on aleatory uncertainty, few studies on epistemic uncertainty have been reported. In this work, the two types of uncertainty are analyzed. Aleatory uncertainty is modeled by probability distributions while epistemic uncertainty is modeled by intervals. Probabilistic analysis (PA) and interval analysis (IA) are integrated to capture the effect of the two types of uncertainty. The First ...


Integrated Process Planning For A Hybrid Manufacturing System, Lan Ren Jan 2008

Integrated Process Planning For A Hybrid Manufacturing System, Lan Ren

Doctoral Dissertations

"A hybrid manufacturing system integrated CNC machining and laser-aided layered deposition and achieves the benefits of both processes. In this dissertation, an integrated process planning framework which aims to automate the hybrid manufacturing process is investigated. Critical components of the process planning, including 3D spatial decomposition of the CAD model, improvement of the toolpath generation pattern, repairing strategies using a hybrid manufacturing system, etc., are discussed"--Abstract, page iv.


Modeling And Rendering For Development Of A Virtual Bone Surgery System, Qiang Niu Jan 2008

Modeling And Rendering For Development Of A Virtual Bone Surgery System, Qiang Niu

Doctoral Dissertations

"A virtual bone surgery system is developed to provide the potential of a realistic, safe, and controllable environment for surgical education. It can be used for training in orthopedic surgery, as well as for planning and rehearsal of bone surgery procedures...Using the developed system, the user can perform virtual bone surgery by simultaneously "seeing" bone material removal through a graphic display device, "feeling" the force via a haptic deice, and "hearing" the sound of tool-bone interaction"--Abstract, page iii.