Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed June 17, 2008). PDF text: XIV, 166 p. : ill. ; 5 Mb. UMI publication number: AAT 3288826. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph.D.) -- University of Texas at Arlington, 2007.

Surface roughness affects bone formation around orthopaedic implants in vivo and osteoblast functions in vitro. Osteoblast-like MG63 cells cultured on rough surfaces exhibited decreased cell number, increased differentiation and increased local factor production when compared to cells grow on smooth surfaces. In these experiments, roughness was characterized as average peak to valley height (Ra) which is not equal throughout the surface. Other features of roughness, including peak and valley area distributions and curvature of the valleys, will affect cell functions. In this study, novel titanium surfaces were prepared by photolithography to produce well designed microstructure and nanostructure. Smooth disks were made by producing craters of 10 micrometer, 30 micrometer and 100 micrometer diameters on titanium disks with constant curvatures. Craters were placed sparsely (10/1, 30/1, 100/1) or compactly (10/6, 30/6, 100/6). Smooth disks were also acid etched to make an overall roughness of Ra 0.7 micrometer or anodized to produce volcano-like nanostructure of Ra 0.4 micrometer. The results revealed the distinguishing contributions of microcrater size, crater spacing and nanostructures to surface effect on cell number, differentiation (alkaline phosphatase; osteocalcin) and local factor levels (TGF-beta1; PGE2). Cell attachment depends on crater spacing; cell growth and aggregation depend on crater dimension and cell morphology depends on the presence of nanostructural features. Cell differentiation and local factor production are modulated by acid etched roughness in concert with microstructure, and active TGF-beta1 level depends on nanoscale roughness.

No description available.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on April 15, 2008) Includes bibliographical references.

Thesis (m.s.)--University of Kentucky, 2004. / Title from document title page (viewed Jan. 5, 2005). Document formatted into pages; contains viii, 77p. : ill. Includes abstract and vita. Includes bibliographical references (p. 74-76).

Thesis (Ph.D)--Mechanical Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Major, J. Rhett; Committee Member: Melkote, Shreyes; Committee Member: Ozdoganlar, Burak; Committee Member: Shi, Jan; Committee Member: Ume, I. Charles. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (doctoral)--Lund University, 1994.

Burrs severely inhibit the performance and aesthetics in machined parts besides posing a safety risk to the user and manufacturer. Abrasive assisted brushing presents a fast and effective method for deburring these parts but is difficult to control. The dependence of deburring rate on the workpiece material, abrasive grit size, type and rotational speed of the brush is studied. It is found that deburring rate is proportional to initial burr height indicating fracture of the burr at the root. Deburring rate increases with spindle speed and is higher for diamond than SiC. The formation of burrs in micromilling of a thin nickel-titanium alloy (nitinol or NiTi) foil used in implantable biomedical device applications is analyzed as a function of micromilling process parameters such as spindle speed, feed, tool wear, backing material and adhesive used to attach the foil to the backing material. All factors except spindle speed are found to affect burr size. If initial penetration is sufficient to cause the foil to fail in tension, the foil tears with the crack starting closer to the upmilling side and thereby resulting in larger downmilling burrs. If penetration is insufficient, the foil plastically deforms until it tears typically in the middle of the cutter tooth path. A kinematic model that captures this behavior is used to predict burr widths and is verified through experiments. The thesis also presents an investigation of the abrasive impregnated brush deburring process for thin NiTi foils. Models based on Hertzian indentation and fracture mechanics are proposed to predict the rates of indentation and deburring during brushing and are validated using experiments. The predictions of the models are within the experimental variation. Burrs can be removed with this process within 12 minutes for a 6 mm long groove with no more than a micron change in foil thickness. Knowledge of burr formation and deburring is applied to a novel micromilled thin shape memory based NiTi foil device used for the surgical correction of Age-related Macular Degeneration (AMD), a leading cause of blindness in the western world in those over age 50. Burrs on the surface of the structure are used successfully to mechanically constrain and translocate an autograft to replace the diseased RPE-Bruch's membrane under the macula. The shape memory device is analyzed using experiments and simulations.

No description available.