Tadashi Akimoto

Hydrogen Evolution by Plasma Electrolysis in Aqueous Solution

Hydrogen has recently attracted attention as a possible solution to environmental and energy problems. If hydrogen should be considered an energy storage medium rather than a natural resource. However, free hydrogen does not exist on earth. Many techniques for obtaining hydrogen have been proposed. It can be reformulated from conventional hydrocarbon fuels, or obtained directly from water by electrolysis or high-temperature pyrolysis with a heat source such as a nuclear reactor. However, the efficiencies of these methods are low. The direct heating of water to sufficiently high temperatures for sustaining pyrolysis is very difficult. Pyrolysis occurs when the temperature exceeds 4000°C. Thus plasma electrolysis may be a better alternative, it is not only easier to achieve than direct heating, but also appears to produce more hydrogen than ordinary electrolysis, as predicted by Faradays laws, which is indirect evidence that it produces very high temperatures. We also observed large amounts of free oxygen generated at the cathode, which is further evidence of direct decomposition, rather than electrolytic decomposition. To achieve the continuous generation of hydrogen with efficiencies exceeding Faraday efficiency, it is necessary to control the surface conditions of the electrode, plasma electrolysis temperature, current density and input voltage. The minimum input voltage required induce the plasma state depends on the density and temperature of the solution, it was estimated as 120 V in this study. The lowest electrolyte temperature at which plasma forms is ~75°C. We have observed as much as 80 times more hydrogen generated by plasma electrolysis than by conventional electrolysis at 300 V.

Production of Heat during Plasma Electrolysis in Liquid

Plasma was formed on the surface of an electrode in a liquid solution when metal cathodes underwent high-voltage electrolysis. A real-time heat calibration system was designed for detecting the amount of heat generated during plasma electrolysis. The measured heat exceeded the input power substantially, and in some cases 200% of the input power. The heat generation process depended on the conditions for electrolysis. There was no excess heat at the beginning of plasma electrolysis. However, after plasma electrolysis for a long time, a large amount of heat was generated. The reproducibility would be 100% if all factors such as temperature, voltage and duration were optimized. Based on the heat and the products, we hypothesize that some unique reaction occurs on the cathode surface. This reaction may not occur at energy levels available during electrochemical electrolysis.

Light Emission from Pt during High‐Voltage Cathodic Polarization

Light emission from cathodically polarized Pt electrodes was investigated at cell voltages up to 200 V in aqueous electrolyte solutions. The emission of light was observed when intense cathodic polarization caused the temperature of the Pt electrodes to exceed the boiling temperature of the electrolyte. A thin vapor layer was formed at the metal‐electrolyte interface in which a high electric field ionized vapor molecules to generate a plasma state. The emission of light was caused by the glow discharge at relatively low cell voltages and by the spark discharge at high cell voltages. The spectra of the emitted light were assigned to the constituents of the electrolyte solution, electrode material, and gaseous hydrogen evolved at the electrode.

Neutron Evolution from a Palladium Electrode by Alternate Absorption Treatment of Deuterium and Hydrogen.

We observed neutron emissions from palladium after it absorbed deuterium from heavy water followed by hydrogen from light water. The neutron count, the duration of the release and the time of the release after electrolysis was initiated all fluctuated considerably. Neutron emissions were observed in five out of ten test cases. In all previous experiments reported, only heavy water was used, and light water was absorbed only in accidental contamination. Compared to these deuterium results, the neutron count is orders of magnitude higher, and reproducibility is much improved.

Advanced tokamak concepts

AbstractA coin-shaped proton conductor made from metal oxides of strontium and cerium can be charged in a hot D2 gas atmosphere to produce excess heat. Anomalous heat evolution was observed from the proton conductors charged with alternating current at 5 to 45 V at temperatures ranging from 400 to 700°C. The anomalous heat produced temperature increases as much as 50°C. Excess heat was estimated as a few watts in most cases, totaling up to several kilojoules.

A correction formula for the counting loss in using a time to pulse height converter and experimental verification of the formula

Abstract A correction formula for the counting loss in a TPHC-PHA time analyzer is verified experimentally, after deriving the formula by several methods and obtaining a more refined correction formula. The experiment is made by the application of a gate circuit, which inhibits irrelevant signals, to conventional electronic equipment for measuring the neutron time-of-flight spectra. Lastly we propose the application of the method used in our experiments to general spectra measurement.

Measurement of mass attenuation coefficients around the K absorption edge by parametric X-rays

When electrons at relativistic velocities pass through a crystal plate, such as silicon, photons are emitted around the Bragg angle for X-ray diffraction. This phenomenon is called parametric X-ray radiation (PXR). The monochromaticity and directivity of PXR are adequate and the energy can be changed continuously by rotating the crystal. This study measured the mass attenuation coefficient around the K-shell absorption edge of Nb, Zr and Mo as a PXR application of monochromatic hard X-ray radiation sources.

A dual-parameter multichannel analyzer using a personal computer

The design of a practical system for measuring two-parameter signals is reported. To obtain constantly changing energy spectral of nuclear reactor assemblies due to repeated insertion of pulsed neutron sources, the simultaneous acquisition of time and energy data is needed. A computer-based dual-parameter multichannel pulse-height analyzer was developed. The analyzer uses a personal computer, two analog-to-digital converters (ADCs), and a parallel interface board for handling these signals. The system is simple to operate, and because the memory size and coincidence resolution time can be changed by software operations, it is highly flexible. >

Anomalous γ peak evolution from SrCe solid state electrolyte charged in D2 gas

Abstract A proton conductor, the solid state electrolyte, made from an oxide of strontium, cerium, niobium and yttrium can be charged in a hot D2 gas atmosphere. Anomalous radioisotopes were detected in all samples charged with an alternating current with voltages ranging from 5 to 45 V, at temperatures ranging from 400 to 700 °C. No radioisotopes were detected from the sample treated in a H2 gas atmosphere. The radioisotopes may be induced from a catalytic reaction between the metal and oxide interface to deuterium atoms.

Calibration measurements for the efficiency and response function of the NE213 scintillator by a /sup 252/Cf spontaneous fission source-application of a two-dimensional pulse height analysis system

The authors describe calibration measurements for the efficiency and response function of the NE213 scintillator as an application of a two-dimensional pulse height analysis system. In this method, a /sup 252/Cf spontaneous fission source with a continuous spectrum is employed by taking each fission event as a pulsed neutron source, and the efficiency and response function of the NE213 scintillator can be estimated by two-dimensional measurements of the time-of-flight spectrum (neutron energy spectrum) and pulse height spectrum. >