Smaller, faster, denser and cheaper magnetic disk drives are demanded for information storage using magnetic media. Increase in high areal density in magnetic recording requires small bit cells with very small grain size. The reduction of bit cell volume and grain size will eventually be constrained by the undesirable thermal instability of magnetization due to the superparamagnetic effect, thu...

We examine the dependence of information stability on certain medium parameters, namely mean Curie temperature, grain height, and anisotropy constant ratio in 4 Tbpsi heat-assisted magnetic recording, for 10 years archiving. introduce a minimum normalized readout field H0 after archiving an degradation rate R0 during To interpret results, we investigate whether there is correlation between or e...

Background: Drilling is one of the most widely used process in orthopaedic surgical operation and the same drill bit is used a number of times in hospitals. Using the same drill bit a several times may be the cause of osteosynthesis and osteonecrosis. Methods: In the present work, the effect of repeated orthopaedic surgical twist drill bit on the tool wear, force, torque, temperature and chip m...

The use of high-pressure waterjets as a method for enhancing the performance of mechanical cutting tools has been well documented over the years. However, concurrent with this development for drag bit tools, there has been some evidence that the combination was not an effective one. By using sectioned samples of rock indented with a spherical indentor (of the type used in percussive drilling) t...

This paper extends the approach proposed by Richard et al (2007) to analyze the axial and torsional vibrations of drilling systems that are excited by the particular boundary conditions at the drag bit-rock interface, by basing the formulation of the model on a continuum representation of the drillstring rather than on a characterization of the drilling structure by a two degree of freedom syst...