Papers by Keyword: Accumulation

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Authors: Chun Rong Zhang, Chun Jin Zhang, Zheng Long Wu, Zong Jun Gao
Abstract: To study the impact of atmospheric Cd exerts on the soil accumulated of Qingdao urban area, atmospheric dust and soil samples are collected and analyzed. Based on these tested samples, this paper firstly analyzed the geochemistry characters of Cd in atmospheric dusts and soils using the statistic analysis method. Then according to the time accumulation model about the influence of Cd exerts on soil, this paper predicates the influence that atmospheric Cd in dust exerts on soil 20 years later. Analysis results show that atmospheric Cd has great influence on the accumulated soil. For example, it can cause the deterioration of soils quality. Therefore, to prevent soil from Cd pollution, the detection and control of atmospheric Cd should be strengthen.
Authors: Jian Guo Liu, Yi Cheng Huang, Ming Xin Wang
Abstract: Cadmium (Cd) accumulation and distribution in rice plants were investigated with six rice cultivars under different soil Cd levels. The results showed that Cd accumulations in different organs were in the order: root » stem > leaf > grain. The magnitudes of the differences among rice organs in Cd accumulations were larger for soil Cd treatments than for the control. The magnitudes of the variations among rice cultivars in Cd accumulations were the largest in grains, followed by roots, and the smallest in stems and leaves, and these were also larger for soil Cd treatments than for the control. Cd absorbed by rice plants were mostly accumulated in roots (about 80% for the control and more than 90% for soil Cd treatments), and only a very small portion was transferred into grains (about 2% for the control and less than 1% for soil Cd treatments). The magnitudes of the variations among rice cultivars in Cd distributions were larger for soil Cd treatments than for the control.
Authors: Hui Wang, Bao Shan Yang, Shu Hua Dai
Abstract: Soil organic carbon (SOC) is vital for the global carbon cycle and balance. In order to study the factors that affect the changes of SOC at different levels (0 ~ 20 cm, 20 ~ 40 cm) in degraded areas and continuous water supply area (3 years, 5 years, 7 years), Phragmites communis wetland of the Yellow River Delta were sampled. The results showed that the upper soil layer (0-20cm) had more SOC than the lower soil layer (20-40cm) in the restored sites. The SOC increased in the 0-20cm soil layer from 7.710±0.756 g/kg to 16.96±0.213 g/kg. Soil salinity and pH value decreased with the freshwater restoration, while SOC increased with the restoration time. SOC had extremely significantly negative correlation with pH (r = -0.564, P < 0.01). The correlation analysis of soil properties showed that SOC had significantly positive correlation with total nitrogen (TN) and NH4+-N (P <0.01) and had negative correlation with C/N. It suggested that wetland restoration not only increased soil organic carbon content, but also improved the ability of nitrogen mineralization.
Authors: Cai Yan Lu, Ya Jie Zhao, Zhi Quan, Jian Ma, Xin Chen, Yi Shi
Abstract: The amount of soil total soluble N (TSN), NH4+-N, NO3--N and soluble organic N (SON) declined significantly with increasing of sampling depth (P < 0.0001). Compared with CK, application of chicken manure significantly increased the amount of soil TSN and NO3--N by 77.0% and 213.0% in the CM20 treatment, and 176.4% and 766.4% in the CM 30 treatment, respectively (P < 0.0001). The amount of soil NH4+-N was lower in CM20 treatment than CK and CM30 treatments. However, the amount of soil SON was higher in CM20 treatment than CK and CM30 treatments (P < 0.0001). Proportion of NH4+-N to TSN was lowest. Application of chicken manure remarkably increased the proportion of NO3--N to TSN, and decreased that of NH4+-N and SON to TSN (P < 0.0001). Soil SON accounted for the majority of soluble N irrespective of soil layer in CK and CM20 treatments, and followed by NO3--N. However, the trend was reversed in CM30 treatments. This result indicated that application of chicken manure significantly increased the amount of soil soluble N, especially SON and NO3--N, which may extend N leaching risk into deeper soil layer.
Authors: Jie Min Tao, You Bao Wang, Jie Dai
Abstract: Chlorophytum comosum seedlings were treated with different Zinc (Zn) concentrations (CK, 200, 400, 600, 800, 1000, 1500, 2000 mg·kg-1dried growth medium) under controlled conditions. Physiological parameters and Zn content of roots and shoots were examined by pot-planting over a period of three months. The results showed that the length of roots, the fresh and the dried weight of plants were inhibited by Zn of all concentrations, while the length of aboveground parts and the volume of roots were stimulated by the lower Zn level. The Tolerance Index (TI) of C. comosum were above 50 in soil of Zn concentration less than 600mg·kg-1. In addition, results indicate that C. comosum can accumulate Pb up to 1093 mg·kg-1 and 4700 mg·kg-1 dry weight in roots and leaves respectively in Zn concentration of soil up to 2000 mg·kg-1.
Authors: Ke Zhang, Qiang Chen, Hong Bing Luo, Xiao Ting Li
Abstract: The trial of the earthworm-assisted phytoremediation of Cr in contaminated yellow soil was made to study the performance of earthworm in Cr accumulation of Vetiver Grass (vetiveria Zizanioides VG). Two groups were designed, adding earth worm (marked EM) and not adding earth worm (marked NEW).The result showed Vetiveria Zizanioides can absorb great amounts of chromium in soil, the decline rate of Cr was up to 75% and 78% respectively in EM and NEM at 60th day. Both root and shoot can accumulate Cr from soil. As the concentration of Cr gradually increased within 0-80mg/kg,the accumulation activity of two groups presented first increase and then decrease and reached maximum 644.31mg/kg, 943.14 mg/kg in root when the Cr concentration was 80 mg/kg. It began to decrease when the Cr concentration was above 120mg/kg.Vetiveria Zizanioides's accumulation ability differs in root and shoot. It presented root>shoot. With a comparative analysis, EM has higher accumulation and resistance of Cr at any designed treatments. In the analysis of relation between plants and soils, it was found that there was significant correlation in Cr contents between plants and soils (P<0.05). Furthermore, there was extremely significant correlation (P<0.01) between root and shoot in EM. There was a high retention rate of Vetiveria Zizanioides root to Cr. Retention rate of any treatments were all greater than 83% except 120mg/kg in EM. Plants kept much higher concentrations of Cr in roots than in their respective shoots. The biggest value was up to 96.23%. There was no obvious difference between EM and NEM in retention rate. Earthworm-assisted phytoremediation has high efficiency in Cr contaminated soil. It’s an idea method to Cr contaminated soil.
Authors: Andrzej Misiuk, Alexander G. Ulyashin, Adam Barcz, Peter Formanek
Abstract: Accumulation of hydrogen in Czochralski silicon implanted with N2+ (Si:N; N dose, DN=1–1.8x1018 cm-2; energy E=140 keV) or O2+ (Si:O; DO=1x1017 cm-2; E=200 keV), processed at up to 1400 K (HT) under enhanced Ar pressure, up to 1.2 GPa (HP), and followed by treatment in hydrogen (deuterium) plasma, was investigated by Secondary Ion Mass Spectroscopy. Implantation produces buried amorphous layer. As determined by transmission electron microscopy, subsequent HT-HP processing results in a formation of a specific sample microstructure. In plasma treated as-implanted Si:N, hydrogen accumulates at a depth of about 50 nm, up to concentration 2x1021 cm-3. This concentration is twice lower at a depth ≈ 80–250 nm. Deuterium content remains almost unchanged after plasma treatment of Si:N prepared by processing at 1270 K while it is strongly dependent on DN and on HP. In plasma treated Si:O, prepared by processing at 920-1230 K, hydrogen profile corresponds to that of implanted oxygen and decreases with HP. Comparative analysis of hydrogen accumulation and its subsequent release at 720-920 K in the Si:N and Si:O structures indicates that the capacity of buried layers in Si:O to getter and to preserve hydrogen is higher than that in Si:N.
Authors: Qing Liu, Xiao Hui Zhang, Na Li
Abstract: This paper proposes rapid extraction algorithm for identifying the main direction of smoke, according to internal small local movement feature of initial rising smoke and the overall presentation presents upward and both sides diffusion trend. The algorithm adopts Meanshift Kernel function of histogram to model movement characteristics and estimates the smoke pieces of motion vector direction by using Bhattachyarya coefficient. Smoke data block motion accumulation are analyzed statistically to estimate the proportion of each suspected smoke region in main movement to realize the identification of inside smoke moving direction. The obtained results from the thick black smoke experiment, gray smog experiment, human body movement interference experiment show that the algorithm is better able to extract the main direction features of smoke and has a strong ability to eliminate interference. It provides criterion for the further study of smoke recognition algorithm.
Authors: Bao Lin Xiong, Chun Jiao Lu
Abstract: Under cyclic load, the major shortcoming–ratcheting is produced in Wolffersdorff hypoplastic constitutive model. For eliminating ratcheting, Wolffersdorff hypoplastic model is ameliorated based on intergranular strain tensor. The added parameters in ameliorated model are determined by optimization method. Under cyclic load of triaxial consolidation undrained condition, the mechanics features of sand are described by the ameliorated Wolffersdorff hypoplastic constitutive model. Preliminary result shows that with increasing times of cyclic load excess pore water pressure is increased gradually and effective stress is reduced gradually. When effective is reduced to zero, the liquefaction happens. So in many projects, excess pore water pressure must dissipate by means of some measures. The sand liquefaction under the dynamic load is avoided.
Authors: Andrei V. Morozov, Anna V. Pityk, Sergei V. Ragulin, Aleksandra S. Soshkina
Abstract: The results of hand calculation of boric acid accumulation in the core in a new generation WWER-TOI reactor in case of LOCA are presented. Variants of reducing the H3BO3 concentration in the HA-3 system down to 1, 2, 4 and 8 g/kg are considered. The mass of boric acid deposits on the core internals depending on the value of boric acid concentration in the HA-3 system is determined. The obtained results allow concluding that the accumulation and crystallization of boric acid in the core is possible.
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