[en] Foams from mill wastewater aeration ponds were collapsed and separated by a freeze, thaw, and filter method. The dried solids were of a brittle, resinous, nonfibrous type. They could release up to 30% of their mass into fresh water and confer foaming ability on the water extracts. Thus, solids accumulating in the treatment pond may serve as a reservoir for foaming agents and give rise to episodes of foaming in the final effluent even after further treatment. Measurements of foam stabilities, surface tensions, and estimation of alkali lignins and lignosulfonates by unltraviolet absorption spectrophotometry and the Pearl-Benson colorimetric method are reported

[en] The surface relief of αdouble_prime martensite plates in a polycrystalline Ti-4.74 at. pct Mo alloy was studied by atomic force microscopy (AFM). The orientation of matrix grains was measured by electron backscatter diffraction (EBSD), and measured surface tilt angles were compared with calculation by the crystallographic theory of martensite transformation. The observed maximum tilt angle was close to the predicted value of 7.57 deg. The overall agreement between measured and calculated tilt angles was improved significantly by taking into account not only the inclination of habit plane to the specimen surface, but also the shear direction predicted from the theory. The tile angle may vary with the moving direction of the interface unless the habit plane is perpendicular to the specimen surface. However, this effect was small in this transformation

[en] The role of fast particles in the edge transport barrier formation is discussed. Analysis of recent experiments on JET which has been carried out in H, D, T and DT mixture with NBI and ICRH heating is presented which supports the idea that the width of the edge transport barrier is controlled by the banana width of the fast beam ions in case of NBI heating and by the banana width of the thermal ions in case of ICRH minority heating. A simple theoretical model which can account for this effect is analysed. (author)

[en] Receptor-oriented source apportionment models are often used to identify sources of ambient air pollutants and to estimate source contributions to air pollutant concentrations. In this study, a PCA/APCS model was applied to the data on non-methane hydrocarbons (NMHCs) measured from January to December 2001 at two sampling sites: Tsuen Wan (TW) and Central and Western (CW) Toxic Air Pollutants Monitoring Stations in Hong Kong. This multivariate method enables the identification of major air pollution sources along with the quantitative apportionment of each source to pollutant species. The PCA analysis identified four major pollution sources at TW site and five major sources at CW site. The extracted pollution sources included vehicular internal engine combustion with unburned fuel emissions, use of solvent particularly paints, liquefied petroleum gas (LPG) or natural gas leakage, and industrial, commercial and domestic sources such as solvents, decoration, fuel combustion, chemical factories and power plants. The results of APCS receptor model indicated that 39% and 48% of the total NMHCs mass concentrations measured at CW and TW were originated from vehicle emissions, respectively. 32% and 36.4% of the total NMHCs were emitted from the use of solvent and 11% and 19.4% were apportioned to the LPG or natural gas leakage, respectively. 5.2% and 9% of the total NMHCs mass concentrations were attributed to other industrial, commercial and domestic sources, respectively. It was also found that vehicle emissions and LPG or natural gas leakage were the main sources of C₃-C₅ alkanes and C₃-C₅ alkenes while aromatics were predominantly released from paints. Comparison of source contributions to ambient NMHCs at the two sites indicated that the contribution of LPG or natural gas at CW site was almost twice that at TW site. High correlation coefficients (R² > 0.8) between the measured and predicted values suggested that the PCA/APCS model was applicable for estimation of sources of NMHCs in ambient air. - The PCA/APCS model provides an easy approach to identify source profiles and to estimate source strengths using ambient samples

[en] Impurity production and plasma impurity concentrations are surveyed over a wide range of operating conditions but with emphasis on ELMy H-mode operation using neutral beam heating. The Mk I divertor campaigns with carbon and beryllium targets are compared to the Mk II campaign which had carbon targets and a more closed divertor geometry. The beryllium target campaign has a significantly lower impurity level than those with carbon targets although the Z_eff is still dominated by carbon. The divertor geometry appears to have little effect on the impurity level but it is found that the ELM frequency has a marked effect on Z_eff, and the carbon and nickel concentrations, with maxima at an ELM frequency around 5-15 Hz. This occurs whether the ELM frequency is varied by changing the plasma triangularity, the input power or by increasing the fuelling rate. The absolute impurity influxes from the inner and outer target and from the inner wall have been estimated from the CII and CIII line intensities. These fluxes are compared to the central carbon concentration and an attempt is made to correlate the influxes and the concentrations in the confined plasma both in their time evolution and in their absolute values. (author)

[en] The isotopic effects on the edge transport barrier are investigated for the ELM-free hot-Ion H-mode discharges from the recent D-T experiments on JET. The role of fast particles is most clearly illustrated by comparing the pressure at the top of the edge transport barrier for the discharges with deuterium and tritium fast particle sources. The scaling of the experimental data from the D-D and D-T hot-ion H-modes supports the hypothesis that the width of the edge transport barrier can be controlled by the orbit losses of fast ions with a sufficient concentration in the edge. Based on this width scaling, the neoclassical theory predicts that the power losses through the separatrix scale as P_loss ∝ n_edge²Z_eff,edgeI_p^-1. It has now been demonstrated that this is consistent with the experimental data from the MkI and MkII divertors. However, a systematic increase in the loss power has been observed between the two divertor campaigns. A connection is proposed between this observation and the changes in the impurity production between the MkI and MkII divertors. The role of gas puff and edge recycling is also investigated. (author)

[en] In the JET Mark I and Mark II divertors the in-situ chemical sputtering yield of the carbon target plates has been studied under a wide range of conditions. To evaluate the chemical yield, the incident hydrogenic flux is directly evaluated from Langmuir probe measurements while the methane production rate is inferred from the CD/CH molecular band emission calibrated using methane injection experiments. It is found that the chemical sputtering yield reduces at high flux densities >2 x 10²²m^-2s^-1) and low impact energies (<50eV). In the Mark II divertor both the absolute yield and the flux dependence depend upon the tile temperature with Y_chem ∝ Γ^-0.4 at 450K and Y_chem ∝ Γ^-0.7 at 360K. In the Mark I divertor the yield exhibits an even stronger flux dependence (Y_chem ∝ Γ^-1.25) which is consistent with the relatively low tile temperature of 300K. However, the increased flux densities are associated with reduced impact energies which may also contribute to the yield reduction. The chemical yield is also shown to depend strongly on the isotope mass (Y_chem ∝ m_ion) and is consistent with thermal reactions enhanced by radiation damage. (author)

[en] The North China Plain (NCP) is one of the biggest groundwater systems in the world, and the development and utilization of groundwater has led to severe land subsidence. The NCP has more than 80% of the total area of severe subsidence in China, so the situation of prevention and control of land subsidence is severe. Due to diverse sedimental environment, different geological conditions, and intensive groundwater abstraction, the mechanism of land subsidence is complex. With the help of earth observing technique and traditional monitoring tools, the disaster process of land subsidence was monitored, and the developing history and current situation were analyzed. Also, the difference features of land subsidence and the mechanism of hysteretic deformation were analyzed with the help of strain-stress diagrams and soil mechanics tests. The results show that the subsidence areas are mainly located in the areas of the Quaternary sedimentary depressions, having characteristics of west-east sub-zone and north-south subsection. The major contribution layers to the land subsidence have varied with the change of groundwater abstraction layers. The drought is an important and indirect factor enlarging the scale of land subsidence by reducing natural recharge and leading to the increase of groundwater abstraction for emergency water supply. The hysteresis of land subsidence is obvious, and the time of hysteresis can last for twenty-five years. Besides the consolidation, the creep is another important reason for the hysteresis which can reach 28.3% of the total deformation for the Late Pleistocene strata in the Cangxian uplift. The deformation characteristics of the soil layer bear strong relationship to the physical characteristics and variation pattern of groundwater levels. The strata at different depths have distinct deformation characteristics such as elastic, visco-elastic, and visco-elastic-plastic deformations, and shallow aquifer groups indicate typical elastic deformation.

[en] The effects of increased geometrical closure on the behaviour of the recycling and intrinsic impurities are investigated in JET MkI, MkIIA and MkIIGB pumped divertors. Increasing the divertor closure leads to a significant improvement in exhaust for both deuterium and recycling impurities. However, the impurity enrichment in the exhaust gases remains unchanged due to simultaneous increase in deuterium and impurity compression in the divertor. The comparison is made for He, Ne and Ar under different plasma conditions. In addition, the operation of the Mark II and Mark IIGB divertors has shown that Z_eff is reduced with the improved divertor closure in the L-mode discharges, although no obvious changes in the Z_eff values have been observed in the ELMy H-modes. The divertor target surface temperature has a strong influence on the intrinsic carbon production. The carbon source in the Mark II and Mark IIGB divertors is significantly higher than that in the Mark I divertor, which is attributed to the enhanced chemical sputtering at the increased divertor tile temperature of the Mark II and Mark IIGB divertors (related to the divertor cooling system), as opposed to the increased closure. The consequences of this elevated yield for plasmas under different operation conditions are discussed, and further evidence, obtained from a specific wall/divertor temperature reduction experiment, is presented. The effect of the divertor screening for the chemically produced impurities is investigated using the EDGE2D/NIMBUS/DIVIMP codes for the different recycling regimes and the comparisons are made with the experimental observations from Mark I and Mark II taking into account the change in the chemical sputtering yield due to the different tile temperatures of the Mark I and Mark II divertors. (author)

[en] Pure and rare earth ions doped yttrium oxide (Y₂O₃) waveguide films were prepared by a simple sol-gel process and dip-coating technique. Y₂O₃ were successfully synthesized by hydrolysis of yttrium acetate. The structural evolution of Y₂O₃ films with annealing temperature was investigated by X-ray diffraction, Fourier transform infrared spectroscopy, waveguide Raman spectroscopy and High-resolution transmission electron microscopy. The propagation loss of Y₂O₃ thin films at 632.8 nm measured by scattering-detection method is approximately 1.5 dB/cm. The fluorescence of Er³⁺ and Eu³⁺ doped Y₂O₃ waveguide thin films were studied under the waveguide configuration. The fluorescence intensities evolution with annealing temperature of Y₂O₃:Er³⁺ films has been studied and was explained by the multi-phonon non-radiative processes. Our results show that Y₂O₃ is a good host material for optically active waveguide thin films and sol-gel process is a useful method to derive pure and doped Y₂O₃ waveguide films