Potential Industrial Application of the One Atmosphere Uniform Glow discharge PlasmaOAUGDPTM

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Potential Industrial Application of the One
Atmosphere Uniform Glow discharge Plasma(OAUGDPTM)

• Abstract author J. Reece Roth, Ph.D
• Plasma Sciences Lab.
• University of Tennessee, Knoxville, tennessee
  37996, USA
• ELEC7730
• Presented By Hongtao Ma

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One Atmosphere Uniform Glow Discharge Plasma

• The technique is based on the idea of
  charge-trapping, and requires alternating
  electric fields across a volume of gas. The
  plasma produced is of the low-temperature, weakly
  ionized variety and is assumed to be able to
  interact with the surrounding neutral gas via ion
  neutral collisions. The fact that it is produced
  at one atmosphere means that heavy vacuum
  equipment is not needed in the plasma generation
  process.

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One Atmosphere Uniform Glow Discharge
PlasmaOAUGDPTM

• First introduced by Dr. Roth with Patent One
  atmosphere, uniform glow discharge plasma,
  Patent No. 5414324, 1995
• Consisted with two electrodes separated by a
  sufficient air gap and a power supply capable of
  producing high voltage at high frequencies.

United States Patent 5,414,324 Roth ,   et al.
May 9, 1995 One atmosphere, uniform glow
discharge plasma
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OAUGDPTM setup
Active noise control using glow discharge plasma
Panel, Chris. Merchant, M.S. Thesis, MIT,2001
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OAUGDPTM

• To generate a weakly-ionized plasma between the
  electrodes high voltage is applied across the air
  gap. Applied current continuously moves electrons
  to the electrode surface where the high voltages
  pull electrons into the gap and accelerate these
  free electrons to ionization energies. It has
  been observed that these electrons acquire the
  minimum energy required for ionization, which
  reduces the power required for plasma generation.
  Then via impact ionization, the energetic
  electrons strip electrons from the surrounding
  air molecules producing a large supply of
  positively-charged ions to mix with the free
  electrons. The mixture of both positively and
  negatively charged ions in the same region
  represents a weakly-ionized gas. The ions and
  electrons feel and electromaginetic force due to
  the applied electric between the electrodes. The
  force is the Lorentz force.

Active noise control using glow discharge plasma
Panel, Chris. Merchant, M.S. Thesis, MIT,2001
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OAUGDPTM

• By oscillating the electric field present between
  the electrodes, it is possible to spatially
  oscillate the ions and electrons. Using such a
  scheme, the difference in mobility between the
  particles can now be taken advantage of. Since
  ions are much bigger than electrons. so the ions
  move more slowly than the electrons, it will be
  possible to switch the electric field back and
  forth at certain frequencies and trap ions
  between the two electrodes without trapping the
  electrons, form the plasma layer. This is the
  charge-trapping method.

Active noise control using glow discharge plasma
Panel, Chris. Merchant, M.S. Thesis, MIT,2001
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OAUGDP Applications

• Sterilizing medical and dental equipment and air
  filters, killing bacteria and spores.
• Diesel soot removal, plasma aerodynamic effects
• Electrohydrodynamic flow control of the neutral
  working gas
• Increasing the surface energy of materials,
  increasing the wettabiltiy and wickability of
  fabrics
• Stripping of photoresists
• Plasma deposition and directional etching of
  possible microelectronic relevance.

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Sterilization Setup
Ref. K. Kelly-winterberg, J. R. Roth, etc.,
Journal o findudtrial Microbiology
Biotechnolotyy(1998)20, 69-74
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Sterilization Setup Cont.
Ref. Thomas C. Montie, Kimberly K-wintenberg, J.
R. Roth, IEEE Transactions on plasma Science,
Vol.28, No.1, Feb. 2000
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Sterilization Results
OAUGDP process kills microorganisms and spores at
room temperature by relatively simple safe and
fast process. The technique does not require
batch processing, does not expose materials to
high temperature and pressure, no degradation of
the tested materials
Ref. Thomas C. Montie, Kimberly K-wintenberg, J.
R. Roth, IEEE Transactions on plasma Science,
Vol.28, No.1, Feb. 2000
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Sterilization Results
Oxidization may be the reason of kill cells.
Reactive Oxygen Species (ROS) Membrane lipids
may be the most vulnerable macromolecule of the
cell, since their location near the cell surface,
and their sensitivity of ROS. S.aureus is
resistant to chemical change swiht a thick
polysaccharide on the outside of the sell, but
allows diffusion of ROS to the cytoplasmic
membrane which is again vulnerable to attack. So
in TEM S.aureus looks intact.
Ref. Thomas C. Montie, Kimberly K-wintenberg, J.
R. Roth, IEEE Transactions on plasma Science,
Vol.28, No.1, Feb. 2000
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Conclusions

• OAUGDPTM method is widely used in many areas,
  especially in sterilization
• Compare to other methods, this method has good
  uniformity, low damage to workpiece, good energy
  efficiency.
• Simple and safe.