Effect Of Oxygen Atmosphere Research Articles

Gas emission characteristics of sewage sludge co-combustion with coal: Effect of oxygen atmosphere and feedstock mixing ratio

Rapid urbanization brings increasing production and accumulation of sewage sludge (sludge for short) challenging ecological environment sustainability. Combustion can achieve sludge reduction and harmless treatment, but faces pollutant emission problems. This work explored gas emission characteristics of sludge co-combustion with coal in oxygen atmosphere. The results showed that sludge combustion in oxygen atmosphere could worsen SO2 and CO emission. The optimum desulfurization temperature for sludge combustion was 800 °C in oxygen atmosphere. Due to relatively low N and S contents in coal, NO and SO2 emission were significantly reduced when adding 25% coal in co-combustion. However, increasing oxygen content in oxygen atmosphere induced NO and SO2 emission in co-combustion. An oxygen atmosphere with 30% of oxygen content was recommended for co-combustion, which had less effect on emission performance and improved combustion performance.

氧气氛环境对无氢类金刚石膜红外性能的影响

氧气氛环境对无氢类金刚石膜红外性能的影响

Effects of oxygen atmosphere, FeOx and basicity on mineralogical phases of CaO–SiO2–MgO–Al2O3–FetO–P2O5 steelmaking slag

ABSTRACTThe mineralogical phase of slag after crystallisation is essential to utilisation of steelmaking slag. The mineralogical phases of cooled multicomponent CaO–SiO2–MgO–Al2O3–FetO–P2O5 slag with different iron oxide contents and basicities (defined as the ratio of mass percentage of CaO to mass percentage of SiO2 (w(CaO)/w(SiO2))) in different atmospheres were investigated in the present work by scanning electronic microscopy and energy dispersed spectroscopy analysis and X-ray diffraction. The mineralogical phases in steelmaking slag cooled in argon are mainly nCa2SiO4-Ca3(PO4)2 (thereafter nC2S-C3P) solid solution, (Fe, Mn, Mg)O (RO) phase. Some CaMgSiO4 phases could be found in slag with lower basicity. The mineralogical phases in steelmaking slag cooled in air are mainly nC2S-C3P solid solution, spinel phase. The overall crystallisation of slag cooled in both argon and air was enhanced with increasing basicity. However, the crystal sizes become smaller in sample with high basicity. The Fe-enriched phases were transformed from non-faceted RO phase in sample cooled in argon to faceted spinel phases in sample cooled in air. The crystallisation of slag cooled in both argon and air was promoted with increasing FeOx content. The phosphorus content in solid solution was elevated with decreasing basicity and increasing FeOx content. It was implied by the present work that appropriate basicity and air oxidation would be beneficial to magnetic separation and phosphorus utilisation.

Effect of oxygen atmosphere on the structure and refractive index dispersive behavior of KTa0.5Nb0.5O3 thin films prepared by PLD on Si(0 0 1) substrates

KTa0.5Nb0.5O3 thin films were deposited on Si(001) substrates by pulsed laser deposition (PLD) with different oxygen pressures (10Pa, 15Pa, 20Pa, 25Pa and 30Pa). The effect of oxygen atmosphere on the structure and refractive indices of the films were studied. It is found that the phase structure, the scale of the grains, the surface roughness and the optical properties of the films are sensitive to oxygen atmosphere variation. The refractive indices of the films were investigated by ellipsometer and the dispersive behavior was analyzed by Cauchy dispersion model. The films grown with 15Pa oxygen pressure show the pure perovskite structure and the dispersion behaviors possess the normal dispersion shape; and other influence on the quality and properties of KTa0.5Nb0.5O3/Si(001) films were discussed.

Effects of oxygen atmosphere on surface properties of ScO/W(100) system as Schottky emitter at high temperature

AbstractThe dependence of properties of the ScO/W(100) system on the partial pressure of oxygen was investigated by means of Auger electron spectroscopy, low‐energy electron diffraction and work function measurement. The (1 × 1)‐ScO/W(100) surface having a low work function, which was prepared by heating at 1700 K under ultrahigh vacuum (UHV) conditions, hardly showed any changes in surface properties at 1500 K, the operating temperature of the ScO/W(100) emitter, in a UHV of ∼5 × 10−10 Torr. In contrast, the (1 × 1) ScO/W(100) surface was changed to the (2 × 1)‐(1 × 2) ScO/W(100) surface having a high work function by heating at 1500 K in an oxygen atmosphere of even 5 × 10−9 Torr. The present results revealed that the partial pressure of oxygen around the ScO/W(100) tip is one of the most important factors for determining the optimum preparation and operating conditions of the ScO/W(100) emitter. Copyright © 2006 John Wiley & Sons, Ltd.

Hillock formation by surface diffusion on thin silver films

The kinetics of hillock formation on silver films annealed in oxygen have been observed by recording the point of substantial completion of their growth. The effects of temperature and film thickness are accounted for in a quantitative model which describes hillock growth as proceeding by surface diffusion to reduce compressive stresses caused by differential thermal expansion between film and substrate. The effects of oxygen atmospheres are accounted for in terms of the energetics of hillock nucleation, and the mechanism of surface diffusion in oxygen is discussed.

Thermoluminescent Dating

The principle and the present status of the thermoluminescent (TL) dating are reviewed. The method is still in research stage.There exist a number of problems to be solved concerning various factors affecting TL light output. Among them, the effect of radiation quality (sometimes called the LET effect), non-linearity of the relation between the light output and the absorbed dose, fading of TL during burial or storage, bleaching of TL by irradiation of light, the pressure effect, the effect of grinding of the sample, the effect of oxygen atmosphere during TL measurement, change of the susceptibility by initial heating, inhomogeneity in the sample structure, the radioactive disequilibrium in uranium series, and the effect of temperature gradient in the sample during heating are mentioned and possible solutions are described.

Physiological Effects of Oxygen Atmospheres Diluted by Nitrogen

Physiological Effects of Oxygen Atmospheres Diluted by Nitrogen