High-Moment-Low-Moment Description of Magnetovolume Effects in Y(Mn x Al 1− x ) 2 and Y x Sc 1− x Mn 2
Based on the assumption of a high-moment-low-moment instability of the Mn atom, we construct a simple spin model with coupled magnetic and spatial degrees of freedom to describe the Laves phase systems Y(Mn x Al 1 m x ) 2 and Y x Sc 1 m x Mn 2 . Monte Carlo simulations of this model qualitatively reproduce anomalies observed in these materials like a discontinuous giant volume change and anomalous thermal expansion behavior.
First-principles calculations of the instability leading to the Invar effect.
An attempt is made to show the close connection between martensitic transformations, the Invar effect, magnetovolume instabilities, and associated low-moment-high-moment (LM-HM) transitions. For that purpose we study the volume dependence of electron occupation and magnetization of eg and μg states in ordered Fe 3 Ni. We show that in this compound the instability against small tetragonal distortions, the Invar behavior, and the LM⇄HM transitions are a consequence of the delicate balance of charge distribution and magnetic order from d orbitals having different bonding character
Economics of General-Purpose Assembly Robots
Summary A study of the comparative economics of various automatic assembly systems using general-purpose assembly robots is described. In the study, use is made of a “typical” candidate assembly whose profile is obtained from statistical analysis of actual products submitted by interested companies. It is shown that the choice of assembly system and the various parts presentation methods depends on three main factors, namely: the annual production volume per shift, the number of parts in the product and the equipment payback period.