7,416 research outputs found
Influence of ac ageing on space charge dynamics in LDPE
No full textPolymeric materials have been widely used as insulation in power industry due to their excellent electrical properties. However, these properties deteriorate in time irreversibly when the material is subjected to electric stress. Although space charge is believed to play an important role in ac ageing, exact mechanisms are poorly understood due to very limited experimental data. In the present work efforts have been made to investigate the influence of ac ageing on space charge dynamics in low-density polyethylene (LDPE). LDPE films with 200mm were aged at 50 kV/mm at 50 Hz for various times at ambient temperature. Space charge dynamics in the samples prior to and after ageing were monitored using the pulsed electroacoustic (PEA) technique under dc electric stress. The results indicate that there is a significant amount of homocharge accumulation in the unaged sample due to charge injection. These injected charges are the captured by the deep traps originated from the interface between crystalline and amorphous regions in LDPE. Ageing under ac condition does not necessarily lead to an increase in amount of charge in the bulk but leads to an increase in mobility of charge carriers. Chemical analysis by infrared spectroscope (FTIR) reveals there are chemical changes taken place in the bulk of the material after ac ageing. It is believed that the chemical changes introduce shallow traps which promote the movement of charge carriers in the bulk. Consequently, the injected charges spread across the sample
Troy Morrison, 1952 Sophomore
No full textTroy Morrison was a sophomore at Jacksonville State Teachers College in 1951-1952.https://digitalcommons.jsu.edu/lib-ac-histimg/6180/thumbnail.jp
A power sharing series power BJT array with isolated low voltage control for AC power control applications
No full textA technique for a continuously variable AC resistance using a series BJT array is presented. This array provides high power dissipation capability and uniform voltage and power distribution across the individual transistors. The array, controlled using a set of optoisolators to maintain the electrical isolation between the control circuits and the power stage, could be used as the basis to develop several useful techniques including a solid state AC regulator with comparable performance to the commonly used ferro-resonant systems; a linear AC electronic load suitable for testing UPS and other power conditioners; and, in other AC power control applications such as switching capacitors in AC resonant circuits
William Jackson and Peggy Morrison, 1955-1956 Mimosa Staff
No full textWilliam Jackson and Peggy Morrison were members of the 1955-1956 Mimosa Staff at Jacksonville State College. Jackson covered Military and Morrison covered Business Staff.https://digitalcommons.jsu.edu/lib-ac-histimg/7922/thumbnail.jp
Billy Morrison, Scabbard and Blade
No full textBilly Morrison was a student at Jacksonville State College (now Jacksonville State University). In 1963-1964 he was a cadet in the Scabbard and Blade.https://digitalcommons.jsu.edu/lib-ac-histimg/31971/thumbnail.jp
Mike Morrison, 1974-1975 Baseball Player
No full textMike Morrison was a student and baseball player at Jacksonville State University in 1974-1975.https://digitalcommons.jsu.edu/lib-ac-histimg/50021/thumbnail.jp
Troy Morrison, 1953 SGA Treasurer
No full textTroy Morrison was a student at Jacksonville State Teachers College (now Jacksonville State University). In 1952-1953 he was Treasurer for the Student Government Association.https://digitalcommons.jsu.edu/lib-ac-histimg/4140/thumbnail.jp
Mike Morrison, 1975-1976 Baseball Player
No full textMike Morrison was a student and baseball player at Jacksonville State University in 1975-1976.https://digitalcommons.jsu.edu/lib-ac-histimg/36575/thumbnail.jp
Billy Morrison, ROTC Staff Officer 2
No full textBilly Morrison was a student at Jacksonville State College (now Jacksonville State University) in the mid 1960s. In 1964 he was a Staff Officer, Cadet Captain, as part of the ROTC First Battalion Staff.https://digitalcommons.jsu.edu/lib-ac-histimg/12606/thumbnail.jp
Troy Morrison, 1954 Scabbard and Blade 1
No full textTroy Morrison was a student at Jacksonville State College (now Jacksonville State University). In 1953-1954 he was a cadet of the Scabbard and Blade.https://digitalcommons.jsu.edu/lib-ac-histimg/10832/thumbnail.jp
- …
