Papers by Keyword: Plasma Focus

Abstract: Currently, most commercialized peripheral nerve regenerative products are constructed from biodegradable polymers into hollow conduits. To speed up the regeneration rate, we proposed a development of a biocompatible protein-filled conduit for anastomosis amputated peripheral nerve with growth factor controlled release function. Glutaraldehyde-crosslinked protein sponges were tested for their abilities to controlled release of nerve growth factor (NGF) in vitro in our previous experiments. Type B gelatin sponges were able to limit diffusions of NGF due to electrostatic interactions between them. The rate of growth factor releases would be depended on degradation of the crosslinked gelatin. A nerve conduit model was produced using perfluoro alkoxy (PFA) tubes filled with gelatin which had been crosslinked using X-ray from Argon plasma treatment. This method of crosslinking provided 21.22±3.03 % degree of crosslinking. Hollow nerve conduits fabricated from poly(l-lactide-co-caprolactone) (PLCL) had a thicknesses and an inner diameters of 0.31±0.03 mm and 1.63±0.07 mm respectively. Average pore sizes of the inner surfaces and outer surfaces were 9.70±3.44 µm and 1.24±0.77 µm respectively. PLCL film supported growth of L929 mouse fibroblasts. For continuing works, we are testing the protein-filled conduits for peripheral nerve regeneration in animals.

Abstract: The generation of deuteron beam from a 3 kJ Mather type plasma focus is studied. Two simple ion collectors made of copper plates are employed and are placed at the axis of the electrodes to detect the ion beam. The deuteron beam intensity at various deuterium gas pressures is determined together with ion beam energy using the time of flight method. For a series of discharges of the present plasma focus system operated at 15 kV discharge voltage, ion beams of energies ranging from 50 to 200 keV have been measured. The suitable deuterium filling pressure for ion beam production for electrodes lengths of 16 cm, 22 cm and 27 cm are 1 mbar, 0.7 mbar and 0.5 mbar respectively.

Abstract: A study of energy transfer in a small plasma focus device has been carried out during its axial phase. The snow-plough model has been used in the simulation as a basic model for the calculation of plasma dynamics. The energy transferred to the plasma is calculated by considering the work done by the electromagnetic piston during the axial phase. It was found that the plasma energy calculated by this model agrees well with the experimental data within the pressure range of 1 mbar to 4 mbar if the mass shedding effect is included in the model. According to the present computation, the energy transferred into the plasma, in the case of a plasma focus with 2.3 kJ initial energy operated with nitrogen gas within the pressure range of 1 to 4 mbar, is between 224 J to 250 J. This corresponds to energy transfer efficiency of 9.6% to 10.7%. The mass shedding factor decreases from 0.23 to 0.069 with increasing pressure. Correspondingly, the energy transfer efficiency changes slightly at a higher pressure.