We summarize and discuss some of the available experimental and theoretical data important for understanding the role played by subsurface sites in dissociative chemisorption calculations for the H2/Pd(111) system. Then we use a semi-empirical potential energy surface (PES) to model the interaction of a H2 molecule impinging on a Pd(111) surface. The London-Eyring-Polanyi-Sato (LEPS) constructi...

We model the transport of gas through the martian subsurface in order to quantify the timescales of release of a trace gas with a source at depth using a Fickian model of diffusion through a putative martian regolith column. The model is then applied to the case of methane to determine if diffusive transport of gas can explain previous observations of methane in the martian atmosphere. We inves...

Ground penetrating radar (commonly called GPR) is a high resolution electromagnetic technique that is designed primarily to investigate the shallow subsurface of the earth, building materials, and roads and bridges. GPR has been developed over the past thirty years for shallow, high resolution investigations of the subsurface. GPR is a time-depen­ dent geophysical technique that can provide a 3...

While subsurface scattering is common in many real objects, almost all separation algorithms focus on extracting specular and diffuse components from real images. In this paper, we propose an appearance-based approach to separate non-directional subsurface scattering reflectance from photometric images, in addition to the separation of the off-specular and non-Lambertian diffuse components. Our...

■ Abstract Ground penetrating radar (GPR) is a near-surface geophysical technique that can provide high resolution images of the dielectric properties of the top few tens of meters of the earth. In applications in contaminant hydrology, radar data can be used to detect the presence of liquid organic contaminants, many of which have dielectric properties distinctly different from those of the ot...

Simulations in the subsurface environment represent a broad range of phenomena covering an equally broad range of scales. Developing modelling capabilities that can integrate models representing different phenomena acting at different scales present formidable challenges both from the algorithmic and computer science perspective. This paper will describe the development of an integrated framewo...

In an inversion for the subsurface conductivity distribution using frequency-domain Controlled-Source Electromagnetic data, various amounts of horizontal components may be included. We investigate which combination of components are best suited to invert for a vertical transverse isotropic (VTI) subsurface. We do this by probing the solutionspace using a genetic algorithm. We found, by studying...

Subsurface scattering is a technique that has been of great interest to me for some time now. As a 3D lighting artist, the technique has played a huge part in the quality of my renders. My goal with this project was to gain a deeper understanding of the technique so that I may use it in a more intelligent and efficient manner within my art. Figure 1: Example of subsurface scattered light; left ...