Applied Mechanics and Materials Vol. 700

Abstract: Ultrafiltration test was carried out to simulate the pollution performance of humic acid (HA) solution. The HA adsorption properties on membrane surface was studied by static adsorption experiment. The influences of HA concentration on adsorption characteristics were taken into account. And Freundlich isotherm model was used to evaluate of adsorption isotherms.

Abstract: In this study, template method was applied to synthesize CdS hollow nanospheres via sonochemical method. The morphology, size of the nanospheres and crystal structure of the synthesized hollow CdS were characterized. The results showed that the hollow CdS nanospheres formed have pure cubic sphalerite structure and exhibit good monodispersity and size uniformity. The photocatalytic activity of the samples was evaluated by the decoloration of Rhodamine B (RhB), Methylene Blue (MB) and Methyl Orange (MO) aqueous solution under UV-vis light irradiation. The results indicated the hollow CdS had a good photocatalytic activity and show little selectivity of attack and are able to oxidize various organic pollutants. Moreover, the results of hydroxyl radical (^•OH) detection using fluorescent probe method was in accordance with the RhB decolorization efficiency, which the ^•OH is likely to be the main active species responsible for dye degradation.

Abstract: In order to know the key factors of callus development on single cell clone, characteristics of physiology and biochemistry and morphological structure on two types of Alfalfa callus was studied. The results showed that the cell membrane permeability and malondialdehyde content was same on two types of callus; but, their soluble sugar content and peroxidase activity in cells was larger different, the soluble sugar content: soft callus > huge callus, and soft callus was 2.09 times of huge callus; peroxidase activity: huge callus > soft callus, and huge callus was 1.35 times of soft callus. Huge callus cells were larger, loosely arranged, cell vacuolization and cytoplasm was thinner than soft callus. However, soft callus cells were smaller, loosely arranged, cell vacuoles was smaller and cytoplasm was thicker than hug callus. Huge cells had the same membrane metabolic with soft cells, but soft cells had higher sugar accumulation than huge cells, and soft cells metabolism are vigorous, while huge cells are more aging.

Abstract: The Non-Destructive Test techniques on concrete, which can assess the properties of materials without damages, have been developed as the deteriorations of existing structures increase. Among them, the ultrasonic pulse velocity (USPV) method is widely used because it can investigate the states of one material for a long time and repeatedly. However, there have been few researches on the NDT application to geopolymer concrete which is environment friendly construction material without any cement. This paper investigates the variations of ultrasonic pulse velocity and peak frequency of geopolymer concrete under monotonically increasing loads to assess the material conditions with various compressive strength levels by measuring P-wave signals. The pulse velocities and peak frequencies were higher in high strength geopolymer concrete specimens. There are not explicit relations between strength levels and peak frequencies but the peak frequencies are strongly influenced by the applied stress levels. In addition, a predicting equation for compressive strength of geopolymer concrete is derived based on experimental data in similar form for normal concrete.

Abstract: The effects of N and P addition on soil organic matter and nutrients, microbe and enzyme were investigated in a Eucalyptus urophylla stand to provide basis for soil management. Contents of organic matter, available P of N, P and N + P addition was significantly greater than the control, total N content of N and N+P addition was significant greater than the control, contents of total P, total K and available K of P and N + P addition was significantly greater than the control, available N content of N addition was significantly greater than the control, whereas that of P addition was significantly smaller than the control. N addition significantly increased the soil actinomyces number and urease activity, but had no significant effect on the number of soil bacteria and fungus, activities of phosphatase and catalase. Number of soil bacteria, fungus and actinomyces, activities of urease, phosphatase and catalase significantly increased after P addition, and biochemical indices except for bacteria number significantly increased after N + P addition.

Abstract: Through a pot experiment using rotatable central composite design (RCCD) with three factors, five levels, twenty runs, fine root biomass yield (BY), total length (TL), surface area (SA) and total volume (TV) of clone 004-1 of Catalpa bungei seedlings under different treatments was determined, and then the mathematical models were established to study the main factor effects, monofactor effect and coupling effects of soil water(W), nitrogen application (N) and phosphorus application (P) on fine root biomass yield and morphological characteristics of C.bungei seedlings. Results showed that N had a significantly positive effect on BY, TL, SA and TV, P had a significantly positive effect on BY, TL and SA, W had a significantly negative effect on TL and SA, and the size sequence of main factor effects was: N> P>W. Monofactor effect analysis results showed that the values of BY, TL, SA and TV first increased and then decreased with N increasing, and BY, TL, SA increased linearly with P increasing. For W, TL, SA decreased linearly and TV first increased and then decreased with W increasing. Interaction of W×N had a significantly positive effect on BY, TL, SA and TV of C. bungei seedlings, and the values of four parameters increased gradually with W and N increasing. However, interactions of W×P, N×P both affected four parameters non-significantly. In conclusion, root biomass and morphological characteristics of C. bungei seedlings showed distinct responses to soil water and fertilizer factors, and W, N and P also influenced fine root growth of C. bungei seedlings differently. We recommended that fine root growth of C. bungei seedlings could be promoted by the rational method combined irrigation and fertilizer application.

Abstract: This work regards the three main soil types in local area of eastern China as the research objects, that is, cinnamon, fluvo-aquic and brown soils are conducted corresponding investigations. In order to analyze the effects which Cu and Zn exert on urease’s and catalase’s activity as well as the microbial biomass carbon, the exogenous Cu and Zn were added to the gathered surface soil with the depth of 0-20cm.

Abstract: The distributions of net-phytoplankton and nutrients were studied in Xiangshan Bay in summer, 2012. The results showed that in summer, the higher values of net-phytoplankton cell abundance were distributed in the areas of Tie port, Huangdun port and Xihu Port. Whereas, the lower values were mainly found in the stations located in the outer area of Xiangshan Bay and the area around Liuheng Island. The content of nitrate in the middle of the bay was higher than that both in the bottom and the entrance of the bay. The concentration of nitrate in the bottom water was a little higher than that in the surface water. The distribution trends of the concentration of nitrite, ammonium and phosphate were almost the same. The higher values were discovered in the sea area of Tie port and Huangdun port and the lower were mainly distributed in the area of the outer Xiangshan Bay and the sea area around Liuheng Island. The distribution trends were almost the same no matter in the surface water or in the bottom water. From the bottom to the middle to the entrance of the bay, the values reduced in turn. In summer, in the water of Xiangshan Bay, net-phytoplankton cell abundance and nutrient (N, P) content didn’t have significant correlation. The concentration of the nutrients (Nitrate, Nitrite, Ammonium and Phosphate) was far more than the minimum threshold of the growth of phytoplankton.

Abstract: Increased concentrations of trace elements in rocks of teschenite-picrite association should also be reflected in the soils developed on these rocks. An addition of biochar to contaminated soils can be effective in decreasing of inorganic contaminants. The threshold of geochemical anomaly for soils overlying the teschenite association and the influence of chromium (Cr) concentration on its mobility after biochar amendment using F. candida as testing organism were determined. The inhibition was not demonstrated in the tested soil with a concentration of Cr at 400 mg Cr/kg. High concentrations of Cr in soils were associated with the presence of chromspinel, which is resistant to the weathering processes. A significant stimulatory effect was found after the addition of biochar made of wood in the sample with 10% of PL (p = 0.0402) amendment and the sample with 5 % of AC (p = 0.0229) amendment.

Abstract: Currently, NDVI are increasingly used to reflect dynamic changes of vegetation phenology in a wide range. Based on NDVI data in Qinling Area from 1998 to 2009, this paper estimates the start date, end date and time span of the growing season in the study area, using both smooth-moving average method and NDVI mean method. The results show that: (1) NDVI makes good reflection of plant phenology changes in the growing season, also conveys accurately the Growth Recovery Trend and Remote-Sensing Growing Season Elementary Period as an easily accessible parameter. (2) With the arrival of Remote-Sensing Growing Season Elementary Period, NDVI is 0.43. As Sequence Curve reaches the annual peak, when the Phenology ends, NDVI gradually declines to 0.41. (3) When the Active Period of Vegetation Growth advances, end date delays, NDVI in the Active Period has increased.