Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

Oxidative decomposition of low concentrations (50-1000 ppm) of diluted benzene in air was carried out in a nonthermal plasma (NTP) dielectric barrier discharge (DBD) reactor with the inner electrode made up of stainless steel fibres (SMF) modified with transition metal oxides in such a way to integrate the catalyst in discharge zone. Typical results indicate the better performance of MnOx and TiO2/MnOx modified systems, which may be attributed to the in situ decomposition of ozone on the surface of MnOx that may lead to the formation of atomic oxygen; whereas ultraviolet light induced photocatalytic oxidation may be taking place with TiO2 modified systems. Water vapour improved the selectivity to total oxidatio

Catalytic non-thermal plasma reactor for decomposition of dilute chlorobenzene

Oxidative decomposition of low concentrations of chlorobenzene (CB) in air was carried out in a NTP reactor. Typical results indicated the better performance on addition of metal oxide catalysts in plasma zone. It may be concluded that catalytic plasma approach has promise, especially for the removal of low concentraions of CB, where conventional techniques are not energetically feasible. Among the metal oxides studied, AgOx/MnOx showed the better performance than MnOx and CoOx. During the removal of 50 ppm of CB, AgOx/MnOx under humid conditions showed 100% selectivity to total oxidadtion at 260 J L-1, which may be assigned due to the formation of hydroxyl radical and/or due to in situ ozone decomposition on the catalyst surface that may lead to the formation of a powerful oxidant atomic oxygen. Oxidative decomposition of low concentrations of chlorobenzene in air was carried out in a NTP reactor. Results indicated the improved performance on addition of catalysts in plasma zone. It has been observed that the integration of metal oxides, promoted the total oxidation, whose activity was further enhanced on addition of water vapor. During the abatement of 50 ppm of CB, selectivity to CO2 was 100% at 260 J L-1 with AgOx/MnOx/SMF catalytic electrode

人の集団に関する新たな評価方法の考察

九州大学応用力学研究所研究集会報告 No.20ME-S7 「非線形波動の数理と物理」RIAM Symposium No.20ME-S7 Mathematics and Physics in Nonlinear waves本研究では、金融工学の手法を用いて人の混雑を評価する理論の構築を試みた。我々は、人の混雑を表すダイナミクスは確率項を含むLogistic 方程式に従うと仮定し、この動きを正味現在価値やリアルオプション法によって評価した。また、金融工学では、割引率を用いることによってタイミングによる価値の違いが表現されるが今回のモデルでは、割引率を人の効用を割り引くために導入し、実データに基づく推定・考察もあわせて行った

Hydrogen production from hydrogen sulfide in a packed-bed DBD reactor

The effect of different reactor packing materials on the nonthermal plasma (NTP) assisted decomposition of hydrogen sulfide (H 2S) in a coaxial dielectric barrier discharge (DBD) reactor has been described in the present investigation. The packing materials studied include ceramic beads, glass material with different geometries like spherical (glass beads), hollow cylinder (glass tubes) and honeycomb (glass wool), and for comparison the reaction was carried out in the absence of any packing material. The packing material studied in the present work do not exhibit any catalytic activity in the traditional sense; however, they do have different dielectric constants and morphologies that may influence the plasma discharge behavior and may also affect the residence time of the gas molecules in the discharge zone. From the experimental results, it has been found that the ceramic pellets and hollow cylindrical glass material packed reactor showed better performance for H 2S decomposition into H 2 and

Gold supported calcium deficient hydroxyapatite for room temperature co oxidation

Gold supported hydroxyapatite (HA) and calcium deficient hydroxyapatite (CDHA) was studied for the room temperature CO oxidation. Nanostructured gold catalyst has been prepared by deposition precipitation method, whereas HA was synthesized by microwave synthesis. Inorder to understand the influence of surface properties of HA, support HA was synthesized with different Ca/P ratios (1.67, 1.62, 1.57, 1.534 and 1.5). The gold supported catalysts were characterized by XRD, BET, ICP-OES and TEM. Typical results indicate that gold supported 1.57 HA shows higher activity compared to other HA catalysts (1.67, 1.62, 1.534 and 1.5) which may be due to the presence of optimum number of acidic and basic site

A Facile Approach for Direct Decomposition of Nitrous Oxide Assisted by Non-Thermal Plasma

Direct decomposition of nitrous oxide (N2O) was studied in a non-thermal plasma (NTP) dielectric barrier discharge (DBD) reactor operated under ambient conditions. Influence of various parameters like discharge gap, input power, residence time, and N2O concentration were studied to achieve high conversions. The conversion decreased with increasing flow rate and N2O concentration. Typical results indicated that N2O decomposition may be efficient at high residence time and low concentrations. The degree of N2O decomposition varied between 30 and 100% with the power variation between 0.5 and 2.7 W. Interesting observation is that packing the discharge volume with dielectric materials (ceramic, glass, and Al2O3 beads) improved the conversion. Under the same experimental conditions, the effect of the dielectric materials followed the order: ceramic beads > glass beads > Al2O3 beads > no packing. It was concluded that packed bed plasma reactor may be an efficient way for the reduction of N2O emissions

Degradation and mineralization of methylene blue by dielectric barrier discharge non-thermal plasma reactor

Advanced oxidation process based on dielectric barrier discharge at the gas water interface was used for the oxidative decomposition of dye contaminated wastewater. The advantage of plasma treatment over conventional physical methods of pollutants removal is the mineralization of pollutant, whereas in physical methods, pollutants may be transferred from one form to another. The effect of various parameters like applied voltage, gas flow rate, concentrations of dye, addition of Na2SO4 and Fe2+, formation of H2O2 and change in pH were investigated for methylene blue degradation. The high degradation yield up to 67 g/kW h was achieved during the present study. Hydrogen peroxide, a powerful oxidant formed during the reaction was confirmed and addition of Fe+2 improved the performance, possibly due to Fenton type reactions. It has been observed that dye degradation followed first order kinetics