Study of relaxations in poly(methyl methacrylate)-magneto electrets by thermally stimulated depolarization current and surface-charge-decay mechanisms

2011 ◽  
Vol 122 (1) ◽  
pp. 29-34 ◽  
Author(s):  
A. S. Tewari ◽  
M. S. Qureshi ◽  
R. N. Dubey ◽  
M. M. Malik
Keyword(s):  
Methyl Methacrylate ◽  
Surface Charge ◽  
Depolarization Current ◽  
Poly Methyl Methacrylate ◽  
Thermally Stimulated Depolarization Current ◽  
Charge Decay ◽  
Thermally Stimulated Depolarization

The Storing Properties of Electric Energy in Bone

2011 ◽  
Vol 493-494 ◽  
pp. 170-174
Author(s):  
Rumi Hiratai ◽  
Miho Nakamura ◽  
Akiko Nagai ◽  
Kimihiro Yamashita
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Electric Fields ◽  
Electric Energy ◽  
Depolarization Current ◽  
Thermally Stimulated Depolarization Current ◽  
High Temperature And Pressure ◽  
Temperature And Pressure ◽  
Thermally Stimulated Depolarization ◽  
Inorganic Components

We have shown that hydroxyapatite (HA), which characteristics were similar to those of bone’s inorganic components, had polarization capability and was possible to accumulate electricity under high temperature and pressure. Then, we presumed that bones had polarization capability which enabled electrical storage and conducted the experiment to measure the polarization capability of bones using rabbit’s femurs. After preparing and polarizing bone samples using KOH treatment (koh), KOH and baking treatment (koh+bake) and decalcification treatment (decalcification) as well as the bone without any treatment (untreat), quantitative amounts of stored charge in samples were determined by thermally stimulated depolarization current (TSDC) measurement of these samples. Under the condition of 400 °C for 1 h with the electric fields of 5kV/cm, samples of koh, koh+bake, and untreat showed polarization capability. In addition, under the polarization condition of 37 °C for 1 hour with the electric fields of 5kV/cm, all samples showed polarization capability. Those findings can be summarized that bones have the polarization capability which enables electrical storage and polarization of bones is possible even under the low temperature condition, which was at 37 °C in our experiment, where polarization is impossible for HA.

Effect of Electrical Polarization on the Behavior of Bioactive Glass Containing MgO and B2O3 in SBF

2006 ◽  
Vol 309-311 ◽  
pp. 333-336
Author(s):  
Emiko Amaoka ◽  
Erik Vedel ◽  
Satoshi Nakamura ◽  
Yusuke Moriyoshi ◽  
Jukka I. Salonen ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
Simulated Body Fluid ◽  
Bioactive Glass ◽  
Body Fluid ◽  
Charged Surface ◽  
Depolarization Current ◽  
Electrical Polarization ◽  
Thermally Stimulated Depolarization Current ◽  
Thermally Stimulated Depolarization ◽  
Calcium Phosphate Precipitation

We investigated the electrical polarizability of MgO and B2O3 containing bioactive glass (MBG). The MBG material with good manufacturing properties but low bioactivity was electrically polarized at a high dc field. The electrical polarizability of MBG was evaluated by thermally stimulated depolarization current (TSDC) measurements and immersion in simulated body fluid (SBF). The early precipitation of calcium phosphate on the negatively charged surface of the treated MBG demonstrated the increased bioactivity of the material and confirmed its polarizability. It is suggested that the electrical interactions between the polarized MBG and ions in SBF promoted the formation of the calcium phosphate precipitation. Accordingly, the increased bioactivity of the MBG in SBF is suggested to demonstrate the conversion of MBG into electrovector ceramics by the polarization treatment.

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