Xian Xue-fu

The compliance of three-point bend round beam specimens calculated with the slice synthesis method

Abstract The compliance of two kinds of three-point bend (3PB) round beam specimens is calculated with the slice synthesis method. In this method, the round beam is divided into a number of slices, and every slice is considered as a 3PB beam with a rectangular cross-section for which the compliance is known, then these slices are combined together to give the compliance of the round beam. The calculated results have shown good accuracy. It is postulated that the slice synthesis method can be used to obtain the compliance of bend specimens with a circular cross-section and various crack front shapes.

Research achievements and application in anaerobic treatment of organic solid wastes—A review

Anaerobic digestion is a good method, which possesses the optimal combination of volume reduction, probability of success and potential for resource and energy recovery. However, relatively little research has been done on the anaerobic digestion of organic solid wastes (OSW), especially in China. However, different substrates, start-up conditions, micro-organisms, processing technologies, pre-treatment methods could influence the result of anaerobic digestion. Anaerobic treatment of municipal OSW is less than that of wastewaters because some problems and obstructions need to be solved. Meanwhile, the application of anaerobic digestion of OSW is also discussed in the present paper.

Special and seasonal variations of trace metals in PM10 in Chongqing

Nineteen trace metals in PM10 were measured by X-ray fluorescence spectroscopy (XRF) at three sites in Chongqing. The special and seasonal variations of trace metals in PM10 samples collected in the downtown were different from those in the background area of Jinyunshan. The source identification indicated that particulate materials were contributed mainly by two sources.

Water soluble components of PM10 in Chongqing, China

The concentrations of water soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, NO3-, Cl-, and SO42-) in PM10 samples collected on cellulose filters by a medium-volume cascade impactor were determined, which were obtained from three kinds of areas in Chongqing: industrial area (Jiulongpo district), commercial and residential area (Jiangbei district) and background area (Jinyun Mountain in the Beibei district). The results showed that except for the background site, the annual average values of PM10 are 23% – 61% higher than the national air quality standard (GradeII) (0.1 mg/m3), even that the value of the control site is still 20% higher than American standard (0.05 mg/m3). This implied that serious pollution of fine particles occurred in Chongqing. Nine kinds of soluble ions in water of PM10 were analyzed by ion chromatography (IC) and the annual average concentrations follow the order of [SO42-] > [NO3-] > [Cl-] > [F-], and [Ca2+] > [NH4+] > [K+] > [Na+] > [Mg2+]. Their values were different in these areas: the industrial area > the commercial and living area > the control area. As for NH4+, K+, Ca2+, NO3- and SO42-, their seasonal average concentrations show a similar variation trend: the values in spring and fall were higher than those in summer and winter. The seasonal average concentrations of [Cl-], [F-], [Na+] and [Mg2+] are much lower than those of other ions. However, the concentrations of [Na+] changed more greatly in different seasons than those of the other three ions. Correlation coefficients showed that the three areas have been polluted by coal smoke and dust to different extents, while some local resources of pollution should be taken into consideration as well.