Charles Hampton Perry

Magnetic exchange between Ti3+ ions in titanium phosphate glass

Magnetic properties of reduced titanium phosphate glasses are reported. Magnetic susceptibility measurements from 1.0° to 400°K indicates behavior typical for amorphous antiferromagnetism. The more reduced glasses show an anomalous field dependence in the susceptibility suggestive of ferromagnetism. A microstructural model for the glasses is developed from physical, chemical and magnetic data. Using the model, a theoretical magnetic susceptibility equation is derived. The equation includes contributions to a total susceptibility from isolated Ti(3+) ions and ion pairs which participate in exchange. From electron spin resonance results, the theoretical susceptibility equation and the experimental Ti(3+) ion concentration in the glasses, a good fit to the experimental magnetic susceptibility data is obtained. Results from the theoretical equation indicates that ferromagnetic and antiferromagnetic interaction between exchange‐coupled Ti(3+) ions may occur. At low temperatures a downward curve toward the orig...

Electrical fails specific to Pressure Cooker Test

This paper emphasizes the need for thorough failure analysis and understanding of the failure mechanism to utilize the Pressure Cooker Test (PCT). The high relative humidity extracted bromide ions from the Flip Chip Plastic Ball Grid Array (FCPBGA), which catalyzed growth of unusual tin oxides and drove the extrusion of solder causing shorts.

Analysis of Single Side Axial Flux Brushless DC Motor with Two Different Stator Geometries

Finite element analysis was conducted for an axial flux single side three-phase brushless DC motor with two different stator geometries. Each motor has thirty two permanent rotor magnets and twelve stator electromagnetic poles. One of the motor has one stator segment with twelve electromagnetic poles and the other one has two stator segments with six electromagnetic poles on each stator segment. ANSOFT Maxwell 3D finite element analysis software was used to create 3D motor geometries and analyze motor models. Finite element analysis was conducted under transient solution type with mechanical motion. During the simulation, the applied load torque was non-linearly increased with the rotor speed. Mechanical and electromagnetic characteristics of the motor models were observed and recorded. According to the results, motor model with one stator segment has higher initial acceleration. On the other hand, both models have approximately similar steady state average speed and torque. Therefore, dividing the stator into two segments with same number of electromagnetic poles does not change the motor performance at the steady state.

Magnetic Susceptibility and EPR Studies of Reduced Titanium Phosphate Glass

The magnetic properties of Ti3+ in glass has not been extensively investigated. There has been little reported research on the magnetic properties of glasses high in Ti3+ ions. Most papers report on glasses in which the Ti3+ ions are induced by irradation, produced by preparing the glass under a reducing atmosphere, or due to the slight reduction of Ti4+ to Ti3+ at the melt temperature. Arafa and Bishay [1] were among the first to study the nature of radiation induced Ti3+ ions in borate glass using EPR techniques. Kim and Bray [2] also reported on gamma-irradated alkali titanate glasses. EPR studies of Ti3+ ions in silicate and phosphate glasses have been reported by Yafaev and Yablokov [3]. Ti3+ was induced in these glasses by melting the batch materials in a strongly reducing atmosphere.