Applied Mechanics and Materials Vols. 522-524

Abstract: Nuclear tracer technology is quantitative and it has a high priority, which provides a unique method for understanding the mechanism of urban soil and water loss. ¹³⁷Cs + ²¹⁰Pb_ex combination tracer was applied to study the characterization and evaluation of soil Erosion in Shenzhen. The results indicate that the following: 1)Disturbances from urbanization has greatly changed surface soil in Shenzhen.¹³⁷Cs background inventory in Shenzhen range at 99 Bq/m²-653 Bq/m². 2)²¹⁰Pb_ex background inventory increase with altitude rise, which is attributed to the movement of water vapor. 3)Soil erosion in Shenzhen has a wide distribution area and exacerbated by severe human disturbance. Land development and steep orchard are key factors that influence urban soil and water loss. 4)Shenzhen should strictly carry out projects for soil and water conservation, such as returning steep slopes into forests and grasslands, and other ecological management reforms.

Abstract: Huaibei Plain recently deposited silt by their causes can be divided into:1The recently deposited silt due to the divertion of Yellow River,is widely distributed in the Yellow River alluvial plain of Huaibei;2The deposited silt due to flooding of Huaihe River, mainly inFunan, Huaiyuan, as well as Wuhe near Huaihe River. Through the geological survey, exploration, and indoor and outdoor test data analysis, we had a research of Anhui Huaibei Plain recently deposited silt about its sediment characteristics, causes and distribution and Statistics of Anhui Huaibei Plain silt about the particle size composition, physical and mechanical properties;After comparison and analysis , the changing rule of soil physical and mechanical prosperties is evaluated in this paper.

Abstract: Construction of offshore artificial islands may cause change on hydrodynamic and erosion-deposition characteristics. By predicting the current and sediment field of LongKou Bay with Mike21 model, This paper assesses the influence of the construction of artificial islands in aspects of hydrodynamic and erosion-deposition environment. Simulating results show that the relative hydrodynamic characteristics have dramatically changed. The results also show that the deposition-dominating areas are located at the north and southwest side, while the west side area is dominated by erosion. The area inside the waterway of artificial islands deposits severely under the southwest windy condition.

Abstract: Understanding the air quality grade difference among cities in our country plays a role in promoting the improvement of the city air quality and the sustainable development of human environment. This paper analyzes the air quality of the main 31 cities in China with the methods of cluster analysis and correspondence analysis, and according to the index related to air quality, cluster analysis classifies these areas air quality into 5 kinds. The result shows that Haikou and Lhasa rank top 2 in air quality, but Lanzhou and Urumqis air has been polluted most heavily.

Abstract: In this paper, the influence of the soil moisture content on the the dust emission proceed is discussed by using an integrated numerical simulation and forecast system of dust storms based on the physical mechanisms of sand and dust emissions by wind erosion. The results show that the influence of soil moisture content on the dust emission is very distinguished, and soil moisture content is one of the most important parameters as input conditions in the forcasting model systems of dust storm. The prediction capability of numerical dust model is improved by estimated the surface soil moisture content for dust model system.

Abstract: Life Cycle Analysis was performed for 10 million tons of atmospheric and vacuum distillation operation unit, calculateing energy consumption and emissions of pollutants in five stages, including crude oil extraction, oil transport, crude oil processing, product using and product transport. Based on the analysis, it proposes several countermeasures of pollutant emissions. Subsequent articles discuss the two models of the life cycle costs in delayed coking process which using the actual refinery instance data.

Abstract: A gene encoding a putative C-4 sterol methyl oxidase was obtained by screening Monascus purpureus cDNA library. Bioinformatics analysis showed that this protein has a primary structure, a hydrophobicity profile and a pattern of histidine-rich motifs which are typical of C-4 methyl sterol oxidases. The deduced C-4 sterol methyl oxidase protein of M. purpureus contained 259 amino acid, with molecular mass of 30,299Da. Sequence alignment analysis revealed that M. purpureus deduced C-4 sterol methyl oxidase was closely related to C-4 sterol methyl oxidase from Aspergillus, Penicillium and Byssochlamys, and highly homologous to aforementioned and other known C-4 sterol methyl oxidase. The deduced protein is of a membrane protein with two transmembrane helices, which belongs to the fatty acid hydroxylase superfamily. The consistency of the comparison results of the primary structure, secondary structure and physicochemical properties suggests that the dedued protein may well be C-4 sterol methyl oxidase.

Abstract: The single cell gel electrophoresis (SCGE) is a rapid and sensitive procedure for measuring strand breaks in DNA. In the present study, sea urchin (Hemicentrotus pulcherrimus) was chosen as the test organism and SCGE was applied to assess DNA damage of its gonadal cells exposed to petroleum hydrocarbon. The gonadal cells of sea urchin had been seriously damaged above 50 mg/L of Water Accommodated Fractions (WAFs), whileas no damages occurred in the lower concentrations. There were good linear relationships between exposure days and DNA damage rate, percentage of DNA in the comet tail (%TDNA) as well as comet tail length (TL).

Abstract: The desorption process and desorption rate is an important factor that influence the bioavailability and remediation efficiency. PAH contaminated soils from former Beijing coking plant are remediated by Tween 80 solution. Desorption kinetics and efficiency enhancement of PAHs by Tween 80 are investigated in this paper. Results show that (1) For the relatively water-insoluble PAHs with high molecular weight, the time needed for desorption equilibrium is longer than that of relatively water-soluble PAHs with low molecular weight. The desorption kinetics of PAHs fit better to Elovich equation than to the first-order kinetics equation, especially for the PAHs with 4-6 ring numbers, which means that the desorption of PAHs from soil is an heterogeneous diffusion process; (2) Due to the severe sorption loss of Tween 80, and the difficulty in removing PAHs from aged contaminated soils, Tween 80 solution at a concentration of 5000 mg/L can only remove the PAHs with efficiencies of 11.31-18.23%. The desorption enhancement of PAHs is 7.62-14.04%, with the values of 4-6 ring number bigger than that of 2-3 ring number, which indicated that surfactant is more favorable to the desorption of PAHs with more ring numbers and thus more hydrophobic.

Abstract: Isoprene and monoterpenes have indirect effects on ozone concentration, methane lifetime and aerosol formation. At the same time, the atmospheric composition change (reflected in elevated CO₂ and O₃ concentrations) can affect the speciation of monoterpenes / isoprenoids and magnitude of isoprene and monoterpenes fluxes. Ambient concentrations of CO₂ and O₃ were 342 μmolmol^-1 and 40 nmolmol^-1, respectively. The effects of elevated CO₂ (700 μmolmol^-1) and O₃ (80 nmolmol^-1) concentrations on isoprenoid emission rates and patterns from Pinus tabulaeformis were studied in open top chambers (OTCs). The released volatiles were quantified by thermal desorption and gas chromatography with flame ionization detector (GC-FID). The study showed that α-pinene was the main compound emitted from P tabulaeformis, accounting for more 51.5 - 72.6% of the detected volatile compounds. The emissions of isoprene and monoterpenes were reduced in response to elevated CO₂ concentrations. Exposure to elevated O₃ for 3 years significantly promoted the isoprene and monoterpenes emissions (p<0.05). Compared with ambient, elevated O₃ concentration increased isoprene emission from P tabulaeformis by about 270.5 ± 13.5%. The response of monoterpene emission to elevated O₃ may vary during the course of exposure to the pollutant. The patterns of monoterpene and isoprene emissions under combined elevated CO₂ and O₃ concentrations were similar to those under elevated CO₂ concentration alone.