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<p>This thesis presents the proof-of-concept of electro-erosion edge (EE) honing as a novel edge preparation process that is based on micro-shaping of the cutting edges of metal cutting tools by electro discharge machining (EDM). This process in its simplest form is first applied to straight edge high speed steel cutting tools which results in a four-fold enhancement in the lives of these tools as compared to the sharp unprepared ones. In the next step the EE-honing application is expanded to hone carbide tools of a complex geometry through the innovative idea of using foil counterfaces. Foil counterface ensures the uniform processing of the entire edge length irrespective of macrogeometric complexities such as curvilinear cutting edges and nose radii. By employing this technique, cutting tools of a complex geometry can be prepared with only 13% edge radius variation which is significantly lower than 40% variation reported for conventional edge preparation processes. ED-machining of cemented carbides necessitates the systematic identification of optimal process parameters to preserve process stability and surface integrity. It is shown that by the application of optimal EE-honing process parameters, EE-honed tools achieved the same life of conventionally prepared ones with the same radii. The advent of advanced edge preparation techniques like EE-honing process has led to the emergence of engineered cutting edge microgeometries most of which cannot be represented by a single edge radius value. In this regard, a novel idea of using parametric quadratic curves for comprehensive cutting edge characterization is presented in the next part of this thesis. The free-knot B-spline approximation enables the unique identification of cutting edge separation points from the clearance and rake faces. Subsequent to the edge identification, quadratic parametric polynomials are employed to characterize the cutting edge by four characterization parameters. These parameters are contour-based and easy to visualize. As the final part of the thesis, the EE-honing process is simulated numerically to gain a better insight into the process. Simulation can model the generation of symmetrical and asymmetrical edges and predict edge geometry with the maximum of 14% error.</p> / Doctor of Philosophy (PhD)

This study attempts to resolve to what extent individuals with Down syndrome benefit from advance information provided visually, versus the same information provided verbally when performing a manual aiming task. Adults with Down syndrome and undifferentiated developmental handicaps, as well as control subjects without a developmental handicap, performed manual aiming movements to targets 10.5 cm. away. On a particular trial, subjects were cued about the specific movement either visually or verbally. The cue provided either 50% or 80% certainty. Nonhandicapped control subjects initiated and completed their manual aiming movements more quickly than subjects with mental handicaps. As well, individuals with Down syndrome were found to be slower and more variable in reaction time than individuals in the other mentally handicapped group when valid information was provided verbally but not when the cue was provide visually. These results provide support for the Elliott and Weeks (1990) model of biological dissociation. Specifically, the atypical hemispheric lateralization for speech perception exhibited by individuals with Down syndrome results in a disruption in communication between functional systems responsible for the processing of verbal langauge, and the organization of complex movement. / Thesis / Master of Science (MS)