Geometrical modeling is a crucial aspect of simulations involving manufactured objects. Apart from the pure construction of curves and surfaces, the analysis of their quality is equally important in the design and manufacturing process. In computer-aided simulation, the original freeorm surfaces need to be tessellated into triangulated surfaces before the simulation procedure. To concurrently and interactively visualize the results from both simulation and surface interrogation in a virtual environment, I propose two novel surface interrogation algorithms for triangulated surfaces instead of the traditional freeorm surfaces. The novel algorithms are interactive and immersive versions of two well-established surface interrogation techniques ? reflection lines and generalized focal surfaces. These two algorithms have been designed to overcome some limitations of the traditional approaches and make them available for interactive and immersive applications. For reflection lines, the new algorithm maps the triangulated surface onto the light plane so that the computation of distance between reflection ray and light line in three dimensions can be reduced to computation of intersections between light lines and triangle edges in two dimensions, simplifying the computation. For generalized focal surfaces, the new algorithm estimates curvature by simple computation of the derivatives of a3rd degree triangular Bézier patch on each triangle and removes the requirement for a minimum number of neighbor points and implicit requirements on how the neighbor points are distributed. Proposed future work on real-time rendering of surface interrogation using a texture mapping technique is discussed.

Scanning electrochemical microscopy (SECM) was used for the study and characterization of catalytic and electrocatalytic processes occurring at electrodes. The Surface Interrogation mode (SI-SECM) was introduced for the detection and quantification of adsorbed intermediates and products of catalyzed chemical and electrochemical reactions at noble metals (Pt, Au). In SI-SECM two micro electrodes (i.e. an SECM tip and a substrate of the desired material) are aligned concentrically at a micrometric distance where SECM feedback effects operate. A contrast mechanism based on feedback effects allows for the detection of reactive adsorbed intermediates at the substrate: the SECM tip generates a reactive homogeneous species that “micro-titrates” the substrate adsorbates to yield an electrochemical signal that contains information about the amount of intermediate and about its kinetics of reaction with the redox mediator. The technique was used for the study of the reactivity of three model small adsorbates: 1) the reactivity of adsorbed oxygen on Au and Pt with a reducing mediator was explored and suggested the detection of “incipient oxides” at these surfaces; kinetic parameters of the reactivity of Pt oxides with mediators were obtained, fit to theory and used to explain observations about the electrocatalytic behavior of Pt under anodizing conditions; 2) the reactivity of oxidizing mediators with adsorbed hydrogen on Pt was studied and showed the cation of N,N,N,N-tetramethyl-p-phenylenediamine (TMPD) to be a successful interrogation agent, the detection of hydrogen generated by the decomposition of formic acid on Pt at open circuit was investigated; 3) electrogenerated bromine was used to catalytically interrogate carbon monoxide at Pt, this reaction was previously unreported. The mentioned applications of SECM were validated through the use of digital simulations of diffusion in the complex SECM geometry through flexible commercial finite element method software. / text