Engineering Science and Materials Commons^™

Comparative Properties Of Polymers Guiding The Development Of An Abdominal Aorta Model, Benjamin Michael Lamie

Masters Theses

Hemodynamics, the study of the forces involved in the circulation of blood, is an area that researchers have approached in various manners for many years. The study of how blood flows through arteries and veins as well as the effect of the composition of the blood has been defined and thoroughly characterized in past studies. Although in-depth studies have been performed on the flow characteristics of blood, most often the observations are made as the fluid flows through tubes composed of some rigid material. It is well known that the arteries and veins have a layered histology that show varying …

A Study Of Material Properties And Relevant Microstructure Parameters That May Influence The V50 Ballistic Limit Velocity Of Composite Ceramics, Adolphus Mcdonald

Masters Theses

The purpose of this research is to evaluate, compare, and correlate the microstructure and mechanical properties of a selected group of ceramic armor samples to the V₅₀ ballistic limit velocity. This study is to identify any relation between the desired material properties and the relevant microstructure parameters that significantly influence the ballistic limit velocity. The ceramic materials, silicon carbide and boron carbide, were produced and provided by five foreign companies. These companies were under contract by the United States Army, Research, Development, and Engineering Command to provide ceramic armor for comparative testing and material evaluation.

Ballistic testing was carried …

Determination And Comparison Of In Vivo Forces And Torques In Normal And Degenerative Lumbar Spines, Shaun Kevin Stinton

Masters Theses

In vivo motions of normal and degenerative lumbar spine patients performing extension/flexion were obtained using video fluoroscopy. 3-D models of each patient’s vertebrae were registered to the 2-D fluoroscopy images using a process developed at Rocky Mountain Musculoskeletal Research Laboratory. Temporal equations representing the motions were input into a math model and the forces at the contact point between vertebral levels and the body torques between the vertebrae were the output. The vertical forces in the normal and degenerative patients were similar and ranged from 0.35-0.42 times the body weight of the patient. The maximum torques were higher in the …

A Computational Model To Predict In Vivo Kinetics In Implanted And Non-Implanted Shoulders, Matthew Brennon-Kyle Kubo

Masters Theses

The purpose of this study was to develop and implement a computational model designed to input in vivo kinematic and predict in vivo forces and torques for the shoulder, elbow, and wrist in normal, rotator cuff-deficient (RCD), reverse shoulder arthroplasty (RSA) and total shoulder arthroplasty (TSA) shoulder subjects. Twenty subjects, divided evenly amongst the four shoulder types, performed a box-lift activity while under fluoroscopic surveillance. Three dimensional (3D) in vivo kinematics was determined for the subjects using implant models and bone models created from CT (computed tomography) scans in a 2D-to-3D registration process. The kinematics were used as input for …

Real-Time Monitoring And Quantification Of Drug Induced Changes In Endothelial Cytoskeleton Filaments Using A Cellular Impedance Biosensor, Vijay Nandakumar

Masters Theses

The analysis of electrical signals originating from biological cells and tissues have yielded a large amount of useful information over the past years. Technologies have been developed, wherein we can monitor the health of the biological material of interest using these electrical signals. Instruments for the study of living cells have historically been of significant importance for such things as basic neuroscience, cell biology, pharmaceutical screening, environmental monitoring, and toxin detection. One of the practical realizations of these methods was successfully implemented by Giaver and Keese with their Electric Cell-Substrate Impedance Sensing (ECIS) system. The purpose of this Masters Thesis …

Correlation Of Wear And Mechanics For Subjects Having A Metal-On-Polyethylene Total Hip Arthroplasty Measured In Vivo, Katherine Suzanne Alford

Masters Theses

Femoral head separation from the acetabular shell has been recorded, but clinical significance of this phenomenon has not yet been established. The objective of the study was to determine if there is a correlation between femoral head separation (sliding of the femoral head away from the acetabular cup), hip joint forces, and acetabular liner wear. Twenty subjects were strategically selected to participate in this study. All subjects were asked to perform gait on a treadmill while under fluoroscopic surveillance. The number of incidences involving femoral head separation was tallied and acetabular bearing surface forces were determined for each subject. A …

Dynamic Response Analysis Of The Human Knee Joint, Brandi L. Bohleber

Masters Theses

Objective. To perform frequency response analysis of passive intact and rneniscectomized human knee joints under body mass. The knee dynamic system parameters and their alterations with different preloads and displacement amplitudes will be determined.

Design. Using an Instron Mechanical Testing System, specially designed fixtures, and the following softwares: WaveMaker, Excel, LabView, and Matlab, the knees were dynamically tested and analyzed.

Background. Studies have been performed to analyze the dynamic behavior of the human knee. However, no experimental study has investigated the dynamic response of the knee joint under an axial compressive dynamic loading condition considering the effect of the upper …

Polyampholyte Hydrogel Characteristics And Detecting The Bacterial Interactions With These Hydrogels Using Digital Image Processing Methods, Ram Pratap Gangadharan

Masters Theses

In recent years, the unique physical properties of synthetic hydrogels have been exploited in a number of interesting and novel applications. In particular polyampholytes have been the subject of many theoretical studies since they provide a model for studying the longrange interactions found in proteins and other forms of soft condensed matter. In balanced polyampholytes the net electrostatic forces are attractive so that in low ionic salt concentration, the chains have a tendency to collapse into compact globules. Addition of salt, which screens these interactions, induces a swelling of the chain. However the electrostatic interactions between polymeric and mobile charges …

Assessments Of Vibratory Handheld Tools And Handle Interactions, Douglas Alan Logsdon

Masters Theses

There has been a broad history of injuries occurring as the result of vibratory hand-tool use. Following these findings, three human safety standards have been proposed. These standards declare that the dynamic properties with respect to acceleration frequency spectra must be determined for vibratory hand tools. These properties must meet specific tolerances in order to be considered acceptable for use.

The standards, however, do not recognize the significance of the coupling characteristics and the energy transfer between the user and vibrating handle. This interaction reveals the amount of vibratory energy that enters the user's hands. Epidemiological data for VWF shows …

Synthesis And Analysis Of Anionic Hydrogel Scaffolds For Endothelial Cell Tissue Engineering, Abitha Sundararajan

Masters Theses

Acidic hydrogels are cross-linked polymer networks that contain neutral and negatively charged monomers. The degree of negative charge on these soft materials plays a critical role in their biomedical applications. In particular, their use as a scaffold for cardiovascular applications depends on their charged and swollen states. The amount of negative charge, however, is a complicated function of the fabrication conditions, monomeric dissociation constants, ionic strengths and pH of the surround bath solution. This study, therefore, considered four representative acidic hydrogels and their physical properties and interactions with endothelial cells. The acidic monomers methacrylic acid (MAAc) and sulfoethylmethacrylate (SEMA) were …

A Method To Calculate The Femoro-Polyethylene Contact Pressures In Total Knee Arthroplasty In-Vivo, Adrija Sharma

Masters Theses

This study deals with the development of a computational method that generates the in-vivo contact pressures on the superior side of the polyethylene in total knee arthroplasty (TKA) based on in-vivo kinematic data. Ten clinically successful subjects (five fixed and five mobile bearing TKA), having Hospital for Special Surgery (HSS) knee scores greater than 90, were analyzed under fluoroscopic surveillance while performing a weight-bearing deep knee bend. 3D in-vivo contact positions and kinematics, determined using a 2D to 3D registration technique, and soft tissue locations derived from literature were entered into a 3D inverse dynamics mathematical model to determine the …

A Validation Simulation Of A Large Pool Fire, W. Reid Williams

Masters Theses

The capabilities of the Fire Dynamics Simulator (Version 3) (FDS3) have been examined to determine whether a large pool fire test can be reasonably simulated. Activities undertaken include 2-D and 3-D pool fire modeling in the absence of wind and heat sinks within the fire principally to compare flame height predictions to established correlations, wind field modeling specifically targeted at developing initial velocity and boundary conditions to use in the simulation of an actual pool fire, and simulation of a specific pool fire test conducted by Sandia National Laboratories in 1983. Processes were developed for determining flame heights based on …