No abstract

The advanced oxidation of 2,4-dinitrophenol (DNP), 2,5-DNP, and 3,4-DNP in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge. Dielectric barrier discharge was operated in the aqueous solution and gas boundary. The degradation was measured by high performance liquid chromatography (HPLC). The acceleration of the advanced-oxidation has been investigated by the combination of the anion exchange polymer membrane. The result indicated that the degradation pathways involve a rapid detachment of the nitro group and a slow opening of the aromatic-ring. The hydroxyl radical and the excited hydroxyl anion are responsible for the primary attack of the DNP with the production of dihydroxy-nitrobenzenes. The attack of hydroxyl radical occurs at the benzene ring carbon activated by the presence of a phenolic OH group and a nitro group. The result suggested that the reaction is dominated by a pseudo-first order kinetic reaction. The degradation process is interpreted using Molecular Orbital Theory.

The advanced oxidation of aromatic compounds in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge, and the degradation rate was measured by high performance liquid chromatography (HPLC). In the degradation experiment of 2,5 -DNP, an accelerated degradation pathway was suggested in the transient state, using the molecular orbital calculation of the enhancement of the degradation of oxidation depending on the para-position of nitro-groups. From the nature-friendly technological point of view, a growth of the radish sprout in the hypo-culture was tested after the pH-neutralization of the air-plasma treated water.

The advanced oxidation of 2, 4-dinitrophenol (DNP), 2, 5-DNP, and 3, 4-DNP in aqueous solution has been investigated using a multi-gas, dielectric barrier discharge, and the degradation was measured by high performance liquid chromatography (HPLC). The acceleration of the advanced-oxidation has been investigated by the combination of the anion exchange polymer. The degradation pathway was suggested involving a rapid detachment of the nitro group followed by a slow opening of the aromatic-ring. The hydroxyl radical and the excited hydroxyl anion are responsible for the primary attack of the DNP with the production of dihydroxynitrobenzenes. The attack of hydroxyl radical occurs at the benzene ring carbon activated by the presence of a phenolic OH group and a nitro group. The reaction is dominated by a pseudo-first order kinetic reaction. The degradation process is interpreted using Molecular Orbital Theory.

Nowadays, fiber lasers have become a main energy source in laser cutting because of their highly electro-optical conversion efficiency and high beam quality. However, the amount of dross produced by fiber laser cutting is larger than that by CO2 laser cutting, and postprocessing is required to obtain a flat surface without dross, which leads to increasing the processing cost. If fiber laser achieves dross-free cutting of a steel plate, further expansion of cutting applications can be expected. Therefore, in order to achieve further reduction of dross, the influence of beam intensity distribution on dross height was investigated by fiber laser cutting experiments and ray tracing analysis. The laser cutting experiment of steel plate cold commercial with 3.2 mm thickness was carried out by a 3 kW fiber laser with nitrogen assist gas, and a round Gaussian mode of 114 μm spot diameter and a square top-hat mode of 132 μm were used. The square top-hat mode can achieve smaller dross height below 12 μm, which is approximately half of the round Gaussian mode. Ray tracing analysis revealed that the square top-hat mode increased the uniformity of absorbed energy on the cutting front surface, and the more uniform intensity distribution contributed to a small ellipticity of the cutting front shape of the kerf. It was clarified that the shape of the cutting front with a small ellipticity reduced the amount of molten metal ejected from the side of the kerf, which resulted in the reduction of dross height by the fiber laser cutting.