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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

FABRICATION AND CHARACTERIZATION OF DETERMINISTIC MICROASPERITIES ON THRUST SURFACES

Kortikar, Sarang Narayan 01 January 2004 (has links)
The deterministic microasperities play a vital role in reducing the coefficient of friction and wear of thrust surfaces and improve the tribological properties of the surfaces. Deterministic microasperities have a specific pattern in terms of size, shape and spacing. These specified geometries are controllable and repeatable. The microasperities are micron scaled asperities and cavities on a surface that form the surface roughness. The present thesis shows the detailed process to fabricate the deterministic microasperities on thrust surfaces, i.e. stainless substrate, using micro-fabrication processes such as lapping and ultra-violet photolithography in combination with an electroplating (nickel) process. A Novel alignment technique is used to align the photomask with the substrate to get repeatable and aligned patterns on the thrust surface. Deterministic microasperities are characterized by using precision instruments such as an Optical profilometer, Scanning Electron Microscope (SEM) and Optical microscope to study the various surface parameters such as Average roughness (Ra), Root mean square value (rms) and Peak value (PV) of the thrust surface.
2

Evaluation of Dynamic Prosthetic Alignment Techniques for Individuals with Transtibial Amputation

Chen, Wen Jia Caroline 21 November 2012 (has links)
Although dynamic prosthetic alignment is an important process for the rehabilitation of transtibial amputees, such alignment technique is subjective and inconsistent. Using biomechanical variables and questionnaire assessments, this study compared an instrument-assisted dynamic alignment technique using the Compas™ system and conventional alignment techniques on nine adults with unilateral transtibial amputation. A focus group discussion was conducted with six prosthetists to understand clinical practice of dynamic alignment and their perception of the Compas™ system. Results found that Compas™ produced more anterior weight line displacement and greater varus moment on the prosthesis than conventional alignment techniques. Alignment changes did not affect pelvic acceleration, and the instrument-assisted alignment technique produced certain biomechanical changes but not necessarily better alignments. Although the current version of the Compas™ system is not clinically feasible, it can be used as a teaching/justification tool. Further investigation with larger sample size and ankle alignment or moment measures is needed.
3

Evaluation of Dynamic Prosthetic Alignment Techniques for Individuals with Transtibial Amputation

Chen, Wen Jia Caroline 21 November 2012 (has links)
Although dynamic prosthetic alignment is an important process for the rehabilitation of transtibial amputees, such alignment technique is subjective and inconsistent. Using biomechanical variables and questionnaire assessments, this study compared an instrument-assisted dynamic alignment technique using the Compas™ system and conventional alignment techniques on nine adults with unilateral transtibial amputation. A focus group discussion was conducted with six prosthetists to understand clinical practice of dynamic alignment and their perception of the Compas™ system. Results found that Compas™ produced more anterior weight line displacement and greater varus moment on the prosthesis than conventional alignment techniques. Alignment changes did not affect pelvic acceleration, and the instrument-assisted alignment technique produced certain biomechanical changes but not necessarily better alignments. Although the current version of the Compas™ system is not clinically feasible, it can be used as a teaching/justification tool. Further investigation with larger sample size and ankle alignment or moment measures is needed.

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