[en] Highlights: • New catalyst material for biodiesel production. • New utilization approach of waste carbide slag. • Detailed characterization of carbide slag used as transesterification catalyst. • Optimal parameters for biodiesel production obtained by response surface methodology. • Effect of impurities on catalytic activity of carbide slag in transesterification. - Abstract: After activated at 850 °C under air condition, calcium hydroxide and calcium carbonate in carbide slag are transformed into calcium oxide. The prepared transesterification catalyst, labeled as CS-850, gains surface area of 8.00 m"2 g"−"1, functional groups of vanishing O−C−O and O−H bonds, surface morphology of tenuous branch and porous structure and basic strength of 9.8 < H_– < 15.0. From aspects of the molar ratio of methanol to oil (γ), the catalyst added amount (ζ) and the reaction temperature (T_r), transesterification catalyzed by CS-850 is optimized through the Box–Behnken design of the response surface methodology (BBD–RSM). A quadratic polynomial model is preferred for transesterification efficiency prediction with coefficient of determination (R"2) of 0.9815. The optimal parameters are predicted to be γ = 13.8, ζ = 6.7% and T_r = 60 °C with the efficiency of 94.70% and validated by experimental value of 93.83%. Meanwhile, γ is demonstrated to be the most significant variable for the minimum p-value. Besides, CS-850 performs acceptable reusability and for the fifth time reusage, efficiency of 82.61% could still be supplied. Aluminium oxide is proved to have the greatest effect on the catalytic activity of CS-850 among other small quality oxides. Physicochemical properties of the purified biodiesel meet American Society for Testing and Material (ASTM) standard

[en] The H_α emission from ECRH plasma in the MM-2 simple mirror device were measured by using H_α spectroscopy. This method along with the Langmuir probe, X-ray detector and diamagnetic probe etc, gives the preionization and time features of the H_α emission of ECRH plasma. The results show that the H_α emission emerges before the build-up of a hot electron ring but still exists after the break-down of the ring. The decay time constant of the H_α emission is larger than that of the hot electron ring. The results are consistent with those measured with a X-ray detector

[en] The properties of H_α area-emission come from ECRH (electron cyclotron resonant heating) in the MM-2 simple mirror device is described by using measured H_α spectra. This method combined with the Langmuir probe, X-ray detector and diamagnetic probe etc, gives the properties of the pre-ionization and time feature of H_α emission of ECRH plasma. The results show that during pre-ionization the H_α has already emerged before hot electron ring is built and still presents after hot electron ring has broken away. The decay time constant is larger than that of hot electron ring. This is conformed with results measured by use of X-ray detector

[en] The experimental study results on properties of the non-equilibrium plasma produced by silent discharge are presented. The experimental results of ozone synthesis in both oxygen and air plasma are given in detail. When oxygen is used as the discharge gas, the mass concentration of ozone C is 18.9 mg·L^-1 and the production rate Q is 1800 mg·h^-1, the specific energy yield η is 70 g·(kW·h)^-1. The mass concentration of ozone rises with the increase of voltage applying on the electrodes and reduces with the increase of the gas flow rate. The properties of the dielectric material and its thickness will strongly influence the performance of the ozone generator. The experimental results show that ozone can be used in the disposal of pulp waste liquor because of its strong oxidizing ability

[en] The diagnostic methods, experiment results and some discussin in MM-2 ECRH experiment for heating plasma and building a hot electron ring have been presented in this paper. By use of multigrid energy analyzer we measured the parameters: T_ec, n_ec, T_ic, n_ic and the profile of electron density in radial and the endloss. The method to measure the low-frequency fluctuation has been described briefly. From this measurement, the formtime and life time of the electron ring can be detected

[en] The application of ICRH (Ion Cyclotron Resonance Heating) in the MM-2U simple mirror plasma which is created and heated by ECRH (Electron Cyclotron Resonance Heating) can result in the increase of plasma temperature and density. The confinement performance of plasma also can be improved. The ion and electron temperatures and the plasma density are measured in detail by using the ISP (Ion Sensitive Probe). The plasma floating potential profile are measured in both the radial and the axial direction. The experimental results show that ICRF (Ion Cyclotron Radio Field) can be used for stabilizing ECRH plasma and for improving the confinement performance of plasma

[en] The hard X-ray pinhole imaging method and its application in a simple mirror for measuring the radiation properties of ECR plasma are presented. This imaging method can directly display the spatial structure of the hot electron annulus without disturbing the plasma. Clear visual pictures of the electron annulus can be taken at suitable discharge conditions and a two dimensional contour of radiation intensity is deduced. Usually, the electron annuli with azimuthal asymmetry were observed and there is a gap at the ring. The azimuthal asymmetry of annulus is changed as the microwave injection power is changed

[en] The plasma is created by high power microwave injection into the MM-2 simple mirror. Simply by using tiny movable probes to measure the floating potential profile, along with diamagnetic and X-ray measurements, the drifting and bouncing motions of hot electrons associated with the formation process of the electron ring are detected. The radius of the hot electron ring is found to be 7 cm; its thickness is about 4 cm. The axial boundary of the ring extends from z = 10 cm to 20 cm, where z is the distance from the central plane of the device. The hot electron temperature is 140 to 170 keV, and the average beta value of the electron ring is about 4 to 5%. (author). 2 refs, 3 figs

[en] A hot electron ring of 4 ∼ 5 cm radius was established on MM-2 simple mirror through ECRH of 15 kW, 15GHz microwave injection. The suppression of hot electron ring on low frequency fluctuations in plasma has been observed experimentally. It can be inferred from the burst, moment of those fluctuations that the ring can exist about 10 ∼ 15 ms after cutting off the microwave injection, even the X-ray radiation from hot electron can insist for 50 ∼ 70 ms. The preionization of H₂ will expend the beginning 2 ms of microwave pluse. The optimum background hydrogen pressure is 1.2 x 10^-3 Pa to establish the hot electron ring if 15 kW microwave is injected for 9 ms

[en] The measuring method and results of the ECR plasma properties taken from hard X-ray pinhole camera on the MM-2 magnetic mirror are presented. This non-destructive imaging method can directly display the spatial distribution of hot electron plasma. A frame of clear picture could be taken at one shot of discharge. The relationships between emission intensity and discharge parameters are also shown by experimental pictures