Development of recycling method for CD-ROM using pulsed power

Summary form only given. In this paper, a pulsed power generator that consists of a magnetic pulse compressor (MPC) and a Blumlein-type pulse forming network (BPFN) has been developed. The pulsed power generator can be operated with high repetition rate, long lifetime and high reliability for water treatments such as sterilization of microorganisms, decomposition of harmful materials and ozone generation. An informative explanation about the simulation methodology using electromagnetic transient program (EMTP) was presented in order to give guidance for more efficient design of the pulsed power generator with MPC and BPFN. The comparison study of the simulation result with the experimental result was carried out. As a result, it was found that the simulation results and the experimental results with the manufactured MPC and BPFN showed reasonable agreement. In addition, a large volume of streamer discharge was successfully generated in water with the developed system

Recently, pulsed power technologies, including pulsed electric fields (PEFs) and time-modulated plasmas, are starting to be applied actively in agriculture and food processing. In the applications, compact pulsed power generators with moderate peak power and repetitive operation are developed for controlling discharge plasmas and electric field distribution. These applications are mainly based on the biological effects of a spatially distributed electric field and the chemically active species in the plasma. The PEFs are caused by applying pulse voltage between the electrodes and contribute to form pores on the cell membrane or to change conformation of protein. When the applied voltage exceeds the discharge onset criterion, plasmas are generated through the avalanche process of electron accelerated with intense electric field in a gas or liquids medium. The plasmas produce chemically active species, UV radiation, an intense electric field in the vicinity of discharge channel and shock waves, which also have different biological effects. The agricultural applications of pulsed power can be categorized as two phases: pre-harvest and post-harvest phases. The pre-harvest phase consists of seed germination, seedling growth, plant growth and growth mode change from vegetative to reproductive. Pulsed power technologies are used to promotion of seed germination, plant growth enhancement through direct stimulation or indirect effect such as inactivation of bacteria in soil and liquid hydroponic media, and promotion of mushroom fruit body formation. The post-harvest phase consists of harvesting the agricultural produce, storing the products, transporting the products to consumers and food processing such as drying, pasteurization (sterilization of bacteria), permeabilization and fermentation. The pulsed power technologies are also used to keep freshness of agricultural produce through decontaminating airborne, inactivating bacteria and decomposition of plant hormone in the storage containers. The poration of cell membrane by PEF contributes improvement of extraction of juice, nutritional agents, and antioxidant metabolites such as polyphenols from agricultural products. In this review, at first, a basis of pulsed power system for agricultural applications and bio-effect by high-electric field exposure is outlined. After that, pre-harvest and post-harvest agricultural applications are described. The utilization of pulsed power technologies to contribute efficient food processing and improve food safety and quality is also described.

In the present study, the degradation of organic contaminants by streamer discharge using a pulsed power generator under water is investigated. The experiments are conducted based on the decolorization of two dyes, Acid Red 1 and Acid Blue 74, and the decomposition of 1,4-dioxane. A gas-liquid separated reactor is developed and employed to achieve degradation with high energy efficiency. A tungsten wire electrode is placed in the gas phase, and a grounded 316 stainless steel wire is immersed in the water. The pulsed high voltage is generated by a magnetic pulse compression circuit and is applied to the wire electrode to generate streamer discharges in the gas region, which propagate into the bubble injected into the water. Oxygen and argon gases are injected to identify the dominant reactions of the degradation of organic contaminants. Acid Red 1 and Acid Blue 74 solutions are successfully decolorized by the discharges. The ozone produced by discharges in the gas region primarily decolorizes the dye solutions. The total organic carbon (TOC) of the 1,4-dioxane solution decreases due to discharge when argon is injected. The decrement rate of TOC does not increase through gaseous ozone injection or by discharges in the case of oxygen injection. These results show that the chemical species produced by discharges and by chemical reactions in the solution, such as hydroxyl and hydroperoxyl radicals, primarily decompose 1,4-dioxane. Iron ions dissolved by electrolysis enhanced the TOC decrement rate according to the Fenton reaction in acidic conditions.

Pulsed power technology is gradually forming a development trend of civil-military integration, which puts forward more requirements for pulsed power generators. This paper takes magnetic switches (MSs) as the starting point and reviews recent advancements in pulse generators based on MSs. First, the working mechanism of the MS "rapid inductance drop after magnetic core saturation" is analyzed. Second, the basic uses of MSs are introduced with specific examples, namely, magnetic compression unit, saturated pulse transformer, and magnetic delay switches. Then, the typical topologies of pulse generators based on MSs are discussed, including transmission line, Marx, Fitch, linear transformer driver, and semiconductor opening switch pumping circuits. These circuits' technical characteristics and parameter levels are highlighted. Finally, the existing problems and future development trends of MS-based solid-state pulse generators are discussed.

Magnetic pulse compression (MPC) system has been widely used over a few decades as a technique for producing short duration, high peak power pulses reliably. Novel MPC system which do not contain external demagnetization circuits, have broadened the appliance of MPC systems, in which circuit in each level of storage energy capacitors is composed of two capacitors in series, and the two-capacitance combination is connected to the output of previous stage, so that not only the pulse is compressed but also the voltage is doubled as well. In this paper, a 20-kHz high repetition-rate pulse generator with adjustable output amplitude based on Novel MPC system is presented. The pulse generator makes use of commercially available insulated gate bipolar transistor (IGBT), switching a capacitor bank into a ferrite transformer together with a voltage doubling circuit. The capacitor bank is charged to 530 V by a three-phase rectifier, also switched by a commercial diode. The amplitude of the output voltage of the pulse generator is controlled by the amplitude of the gate voltage of the IGBTs. Pulses with a width of 70 ns can be generated with repetition rates up to 20 kHz in burst. The amplitude can be controlled from 5 to 40 kV into a $500~\Omega $ resistive load.

Recycling of electronic waste (E-waste) is an important subject from the viewpoint of resource conservation and environmental protection. Recently, application of pulsed power technology in the recycling field has attracted considerable attention. We have been investigating metal separation from CD-R as an example of metal-coated plastic, by applying pulsed power with concentric ring electrodes. We visualized discharges with an ultra-high-speed framing camera to clarify the mechanism of metal removal. During the first shot a fan-shape discharge was observed after the breakdown of a protective layer. It expanded until the current reached its peak value, and then gradually disappeared. The protective layer containing a metal layer was separated from the plastic substrate around the fan-shape discharge. Similar discharge pattern continued until the metal layer around the high voltage electrode was completely removed. Afterward, a surface discharge bridged between the high voltage electrode and the remaining metal layer, then continued with a fan shape. A similar discharge pattern lasted until complete removal of the metal layer. Precise observations revealed the characteristics of the fan-shape discharge, which was accompanied by the vaporization of the metal layer. Furthermore, the length and velocity of the discharge propagation were analyzed using an image processing software.

The discipline of pulsed power hydrodynamics is a new application of low-impedance, pulsed power technology, developed to study implosion hydrodynamics, instabilities, turbulence, and material properties in a highly precise, controllable environment at the extremes of pressure and material velocity. The discipline of pulsed power hydrodynamics arose in response to the need for economical, high-precision data to validate sophisticated numerical models used in current numerical simulations and to motivate the development of new models for future simulations. The international capability in pulsed power technology that has evolved over several decades in response to numerous other programmatic needs played a pivotal role in the development of the new discipline by enabling demonstrations of the techniques and production of introductory data long before a dedicated facility could be conceived, planned, and built. The high-precision, cylindrically imploding liner is the tool most frequently used to convert electromagnetic energy into the hydrodynamic (particle kinetic) energy needed to drive strong shocks, quasi-isentropic compression, or large volume adiabatic compression for the experiments. At typical parameters, a 30-gr, 1-mm- thick liner with an initial radius of 5 cm, driven by a current of 20 MA, can be accelerated to 7.5 km/sec producing mega-bar shocks in medium density targets. Velocities up to 20 km/sec and pressures >20 Mbar in high density targets are possible. The Atlas facility, designed and built by Los Alamos, houses the world's first laboratory pulsed power system designed specifically to explore this relatively new family of pulsed power applications. Constructed in the year 2000 and commissioned in August 2001, Atlas is a 24-MJ, high-performance capacitor bank delivering currents up to 30 Megamperes with a rise time of 5 to 6 musec. The first Atlas liner implosion experiments were conducted in September 2001, and 16 experiments were conducted in the first year of operation before Atlas was disassembled to be moved to the Nevada Test Site, where experiments began again in July 2005. Applications of pulsed power hydrodynamics techniques currently include material property topics such as: exploration of material strength at high rates of strain; material failure including fracture, damage, and spall; and interfacial dynamics at high relative velocities and high interfacial pressures. Implosion dynamics and a variety of complex hydrodynamic geometries have been explored and experiments to explore perturbation growth and transition to turbulence are under consideration. Longer term applications include the study of the behavior and properties of strongly coupled plasmas and the equation of state of metals and non-metals at pressures above 10 Mbar. This paper will provide an overview of the programmatic evolution that led to the birth of the discipline of pulsed power hydrodynamics.

Pulsed power technology provides a platform for investigating plasmas in strong magnetic fields using a university-scale machine. Presented here are methods for generating and measuring the 1–4-MG magnetic fields developed for the 1-MA Zebra pulsed power generator at the University of Nevada, Reno. A laser coupled with the Zebra generator produces a magnetized plasma, and experiments investigate how a megagauss magnetic field affects the two-plasmon decay and the expansion of the laser-produced plasma in both transverse and longitudinal magnetic fields.

High-voltage pulsed power is nowadays a very important research field and an expanding industrial technology with major worldwide economical impact, this technology being used in different applications (food processing, medicine…). For the development of PEF technology, it is necessary to have a wide variation interval of the different pulse parameters (amplitude, pulse width, frequency …). Conventional pulse generators do not allow it, prompting the researchers to focus on the development of pulse generators to make them more versatile to be used in different applications. With the development of solid-state electronics, solid-state devices are becoming more and more suitable for pulsed power application. They could provide the pulsed power systems with compactness, reliability, high repetition rate, and long life time. The rising of pulsed power generators using solid-state devices eliminates limitations of conventional components, and promises pulsed power technology to be widely used in commercial applications. However, solid-state switching devices such as Insulated Gate Bipolar Transistor (IGBT) available now are only rated up to a few kilo Volts. Most of pulsed power systems demand much higher voltage ratings. The aim of the present work is the development of a Marx modulator which is a unique circuit intended for voltage multiplication. Its functioning is based on charging capacitors in parallel and discharging them in series into the treatment chamber. The Marx bank developed comprises four stages, was constructed using 1200 V IGBTs and 10 µF capacitors. This generator is versatile; several factors could be varied such as the voltage level up to 3.6 kV, the repetition rate and the pulse width.

High repetition rate, high reliability and long lifetime are required for pulsed power generators for environmental applications. Also, it is necessary to optimize the pulsed power generator for each environmental application. Recent developments in pulsed power generators are described. In addition, recent research of gaseous phase pollution control using pulsed power, cleaning of lake and dam of algae bloom by discharges, and recycling of concrete by pulsed power is summarized.

Summary form only given. In this study, a SPPT (Solid Propellant Pulsed Plasma Thruster) driven by a MPC (Magnetic Pulse Compression) pulse generator is presented. Electromagnetic SPPT is well-known and is one of the most simple structures for electric propulsion: it is very lightweight and reliable and its thrust force can be easily controlled by the pulse discharge characteristics. In this type of system propellants are supplied from ablation of the solid propellant by surface discharge; therefore, it is difficult to regulate the propellant supply and ensure efficient use. This causes low performance of PPT. To achieve efficient utilization of the propellant, a MPC pulse generator was used as the power source of the SPPT. The magnetic switch which was used in the MPC has a magnetic saturation characteristic. When the magnetic switch is unsaturated, discharge current is restricted by the high inductance of the magnetic switch, and propellants are fed and excited by surface discharge. Later, when the magnetic switch is saturated, high current flows through the plasma and it is accelerated by the Lorentz force. Here, a high di/dt converted the mechanism to acceleration, quickly. It was contributed to reduce the Late-Time Vaporization by low rising temperature. Also, the main discharge was formed including pre-spread plasma and it accelerates the plasma efficiently. The pulse discharge of the MPC also composes the igniter which does not require an external power supply. A co-axial electrode type MPC-SPPT was designed and operated to demonstrate the system. The igniter was put as the center electrode and driven with a MPC pulse discharge. The 18 J MPC with a thruster body has a 41.6 nF energy storage capacitor and less than 80 nH of parasitic inductance. The peak discharge current is 15 kA, and the thrust performances were evaluated by a thrust target. From experimental results the advantages and capabilities of a MPC-SPPT system are discussed.

Anisakis is a parasite that is found in many marine products and can cause anisakiasis when present in fish consumed raw. The most common way to prevent anisakiasis is to freeze the fish, but this causes a noticeable decrease in the quality of the fish when eaten as sashimi. Although no practical method of killing anisakis other than freezing has been found, we have now succeeded in inactivating anisakis inside the fish meat by repeatedly and instantaneously applying electric current to the fish meat using pulsed power technology. The fish meat was placed in buffer saltwater, and pulsed power was applied multiple times. The immobilization rate was highest when the buffer saltwater was 5 mS/cm. The immobility ratio increased as the number of shots increased. Sensory evaluation of the fish meat after the pulse treatment confirmed that it retained its quality as sashimi. Breaking tests and color measurements were also conducted. We believe that this pulsed power treatment is a useful alternative to freezing as a method for killing anisakis.

In this introduction to the Special Issue on pulsed power and its applications, background information is provided for the nonspecialist to better understand the many challenges in designing pulsed power systems, and the wide diversity of applications that are now emerging. The approach to providing a tutorial on pulsed power technology is to make available to the reader the paper written by J. C. Martin which appeared in a Special Section of the Proceedings of the IEEE on pulsed power technology in June 1992. That paper is supplemented in this introduction with additional information that complements many of the invited papers composing this Special Issue.

A new method for stimulating platelet aggregation that does not rely on thrombin is based on the effect of ultrashort (nanosecond) pulsed electric fields. Nanosecond pulsed electric fields stimulate a variety of physiological responses, among them, Ca <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2+</sup> fluxes, which in turn lead to platelet activation. We have shown that when platelet rich plasma was pulsed with one 300 ns pulse at 30 kV/cm, platelets aggregated and a platelet gel was produced. In addition, platelet derived growth factor (PDGF) release from platelets was observed. Since platelet aggregation occurs just minutes after pulsing, the pulse generator, the platelet gel reactor and the gel delivery system need to be integrated into one, easy-to-use system. Another consideration is the volume of activated platelet gel required for a treatment. This requires a batch mode platelet exposure system where relatively large quantities of platelet gel can be treated in less than three minutes. We have built a compact, easy to use, pulsed power generator with a Blumlein line pulse-forming network that generates pulses of 300 ns duration. The impedance of the Blumlein line is 10 Omega, matching the resistance of the exposure cell, a custom-made 6-mm chamber, which contains 5.4 ml of the platelet rich plasma. The output voltage can be varied, up to 20 kV, allowing the generation of electric fields of up to 30 kV/cm in the chamber. In order to minimize the time required for activation of the 70 ml of platelet gel, we operate the system in a batch mode.

In pulsed power system, mechanical characteristic means the structure of the plasma reactor, and impedance matching between the pulse generator and the plasma reactor means the electrical characteristics. It is a very important issue in the industry because impedance matching is closely related to the efficiency and reliability of the pulsed power system. In this paper, the design and implementation for improving the energy density of the wire-plate plasma reactor are presented. The system configuration, impedance characteristics and structures of the plasma reactor are described, and the output characteristic of the plasma reactor according to the structure of the wires and plates is analyzed. The plasma reactor model is realized on the simulation tool, and the simulation results are compared with the experiment data. Based on the theoretical analysis and the simulated model, impedance matching between the wire-plate plasma reactor and the pulsed power generator can be more fully achieved.