Abstract: A cooling system for a downhole tool includes an insulating chamber disposed in the tool, wherein the chamber is adapted to house an object to be cooled; a Stirling cooler is disposed in the tool, the cooler has a cold end configured to remove heat from the chamber and a hot end configured to dissipate heat; and an energy source to power the Stirling cooler. A downhole tool includes: a tool body, and a cooling system with an insulating chamber; wherein the chamber is adapted to house an object to be cooled; a Stirling cooler is disposed in the tool, the cooler has a cold end configured to remove heat from the chamber and a hot end configured to dissipate heat; and an energy source to power the Stirling cooler.

Abstract: A method and apparatus for controlling fluidic torque in a downhole tool is provided. One or more rotatable components of the downhole tool comprise a deformable material, such as rubber or SMA, selectively deformable in response to the flow of fluid through the downhole tool. The rotatable components may include a rotor and/or a turbine of a generator in the downhole tool. Non-rotatable components, such as the stator of the generator, may also be deformable. The rotor, the stator, and/or turbine may comprise a deformable material capable of selectively deforming in response to the flow of drilling mud through the generator. The desired deformation and/or the desired torque may be controlled by adjusting the parameters of the components.