Searcharxiv⌕ Search

arXiv subjects

Efren Diez-Jimenez

Publications and source records attributed to Efren Diez-Jimenez.

4 recordsLinked to original sources
arXiv2024

Stable thrust on a finite-sized magnet above a Meissner superconducting torus

Forces and torques exerted by a superconducting torus on a permanent magnet have been mapped. It is demonstrated that stable orbits exist. Moreover, provided that the magnet remains in any of these orbits, the first critical field in the superconductor is never overpassed and the superconductor remains in the Meissner state. The consequent absence of hysteresis makes these kinds of device perfect candidates for non-frictional bearings or gyroscopes.

cond-mat.supr-con↗
arXiv2024

Characterization and Improvement of Axial and Radial Stiffness of Contactless Thrust Superconducting Magnetic Bearings

Contactless bearings based on both permanent magnets and superconducting magnetic levitation are interesting to avoid all the tribological problems associated with contact at very low temperature. Superconducting magnetic bearings (SMBs) find application in mechanical engineering where lack of contact is a requirement or an advantage. In comparison with active magnetic bearings (AMBs), SMBs solve their inherent instability and require less complex control strategies and electronics. However, one of the current limitations is their low mechanical stiffness. Force densities are considerably lower in SMB than the state-of-art values for AMB. This fact certainly limits their applications. In this chapter, we summarize some key strategies for the improvement of radial and axial stiffness among with a description of some SMB in terms of load capability or force relaxation and discuss their advantages and disadvantages.A set of rules for the mechanical design of high-stiffness thrust superconducting magnetic bearings are proposed and experimentally demonstrated. Keywords Low-temperature tribology

physics.app-ph↗
arXiv2024

Non-contact linear slider for cryogenic environment

A non-contact linear slider based on stable superconducting magnetic levitation with a long permanent magnet as a slider and two fixed superconducting disks which define the slide way has been designed, built and tested. The slider can be moved stably along a stroke of 11.5mm by supplying a low current in a coil located at the end of the stroke while the levitation remains stable providing a reliable mechanism for linear displacement in a cryogenic environment. The response is linear with a sensitivity of 52 μm/mA for displacements lower than 6 mm. Run out, pitch, yaw and roll have been measured demonstrating an overall good performance. In all cases the measured hysteresis was lower than 250 μm and the measured run out was also lower than 250 μm both for Y and Z axis. Roll and yaw were always below 300 μrad, that is one order of magnitude lower than the pitch (4500 μrad).

physics.app-ph↗