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Interpretation Issues In Force Microscopy, Nancy Burnham, Richard Colton, Hubert Pollock
Interpretation Issues In Force Microscopy, Nancy Burnham, Richard Colton, Hubert Pollock
Nancy A. Burnham
In this paper, we will discuss force microscopy (FM) and its potential for determining mechanical properties of thin films. We will introduce the basic principles of FM, and demonstrate how FM can be used to determine materials properties as well as image surface topography, both with nanonewton or sub‐nanonewton force resolution and sub‐nanometer position resolution. As FM is still a new field, not all of the questions concerning interpretation have been fully answered. We will elucidate four current issues that must be resolved before the full potential of FM can be realized. They are: (1) the role of water vapor …
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Setting Time Effects On Bentonite Water-Well Annulus Seals, Fred L. Ogden
Fred L. Ogden
Shear strength tests are conducted in a model of a water well on four, commercially available, granular bentonite well sealing products. The time dependency of annulus seal shear strength and resistance to piping is examined. Dry bentonite samples are placed through water in the annular space between the casing and borehole and allowed to set for a specified time. Pressure is applied at a constant rate to one end of the clay seal until shear or piping failure occurs. Pressure and seal displacement data are recorded on a digital data acquisition system. Annulus seal strength and resistance to piping increase …