Applied Mechanics and Materials Vols. 178-181

Abstract: An experiment was conducted under hydroponic culture conditions to determine effects of nutrient deficiencies on cadmium (Cd) accumulation of Tagetes erecta L. and its possible mechanisms. Seedlings of similar size were pre-cultured in either N- or P- deprived nutrient solution for 7 days before exposure to 0.1 mg Cd L^-1. The control plants had normal nutrient supply before and during Cd exposure. The plants were harveste after 7 days exposure to Cd. In N-deprived plants, Cd levels in roots, stems and roots were significantly reduced, which was consistent with a decrease of phytochelatins (PCs) in roots. Cd accumulation was the lowest in N-deficient plants, corresponding to substantial decreases in organic acids. In P-deprived plants, the obvious increase of Cd content in the root and stem and decrease of Cd content in the leaf accorded with increases of citric acid in the root and malic acid in the stem, supporting the suggestion that organic acids sequester soluble Cd and reduce Cd transport into the leaf.

Abstract: Wetland ecosystem is listed as one of three supreme ecosystems, which has various ecological functions of resisting flood, regulating runoff, improving the climate, controlling pollution, beautifying the environment and maintaining the regional ecological balance. The health of estuarine wetland ecosystem is very important for the river to maintain its healthy life and to achieve the sustainable development of resources and the environment. Based on the analysis of the Yellow River Delta wetland resources, the authors established a series of ecological evaluation systems and put forward countermeasures of wetland conservation and sustainable utilization.

Abstract: the organic matter contents in deferent treatments of the sludge compost were determined by using Comparison the potassium dichromate with the burning method ,in order to understand changes of the organic matter contents for the Sewage sludge compost in adding different treatments of Fermentation accelerant and nutrient agents . The results showed as following: 1, the organic matter content for the sludge single composting at the end (53.36%) was lower 8.65% than at the beginning of composting(58.41%), the other corresponding treatment in composting all declined 12.37% -7.98%, indicating that the sludge compost would made The organic matter content are significantly reduced. 2, adding Fermentation accelerant into the sludge from 8% to 40%, the organic matter contents of their composting at the end increased more 2.94% ~ 19.73% than that of the single sludge compost. the highest organic matter content occurred in treatment 6 (sludge +40% Fermentation accelerant, 63.89 %). 3, at adding 24% Fermentation accelerant in the sludge ,as adding 8~32% of nutrient agents, the organic matter contents at the end of composting have been increased more 10.48%, 7.46%, 6.39% and 2.42% than the sludge single treatment , indicating that the sludge Adding 24% Fermentation accelerant and adding more nutrient agents can significantly improved the level of the organic content. 4, the organic matter contents for the sludge adding 30-50% nutrient agents have been declined 4.10% ~ 6.90% than the single-sludge compost treatment. 5, comparison of two measurement results showed that the potassium dichromate method is More advantages in measuring organic matter content of sludge compost than the burning method.

Abstract: The electrochemical corrosion behaviors of Cu60Zr30-xHfxTi10(x=10,15,20) bulk metallic glasses (BMGs) were investigated in 3 mol/L NaOH solution by potentiodynamic polarization experiments and electrochemical impedance spectroscopy (EIS). The results showed that the BMGs had sufficient corrosion resistance in NaOH solution. The anodic showed grading passivation character, and the passivation current density were very low. The corrosion resistance changed with Hf content changing. The passivation current density of Cu60Zr15Hf15Ti10 alloy was lowest and the charge transfer resistance was largest, which means the best corrosion resistance for CuZrHfTi BMGs. Corrosion mechanisms were not changed, while the corrosion resistance decrease after crystallized for the BMGs.

Abstract: The networks of different types and scales in the modern cities can be integrated into larger network complexes serving multiple functions. The networked compact city can be a sustainable urban form in China. And it will bring hope to deal with complicated problems which emerge one after another during the procedure of urbanization; for example, the problems of landfill and pollution problems. In the traditional model, more than one-third of landfill waste is attributable to packaging. The concept of the sustainable packaging being discussed in this paper is to reconstruct the functions of the packaging and to build an independent packaging design centre that can benefit both the suppliers and users of the packaging. It consists of the networked cities’ interactive medium, information systems, and logistics systems; and consumes less energy, natural resources and creates less waste.

Abstract: With the building wastes contaminated by chromium in Haibei Chemical Plan in China as objects, it studied the contents of total Cr and Cr (Ⅵ) of different sizes, analyzed the effect of 6 different washing agents, discussed the removal mechanisms of 6 different washing agents for Cr in various forms, and finally selected applicable washing agent. As the results, particle size had little impact on the contents of total Cr and Cr (Ⅵ); after one washing with water, the removal rate of total Cr and Cr (Ⅵ) was 75% and 78%, respectively, and after the second washing with 6 agents, the removal rate of citric acid was the highest, above 90% for total Cr and above 99% for hexavalent chromium; the pH of building wastes were reduced by citric acid, and under acid condition, hexavalent chromium was reduced to trivalent chromium spontaneously by organic acid, which led to better removal rate of acid soluble Cr and reducible Cr; due to the complexing action, citric acid had best removal rate for oxidizable trivalent chromium. In conclusion, citric acid is the most applicable second washing agent for building wastes.

Abstract: The pyrolytic characteristics and kinetics of Xanthoceras sorbifolia oil were investigated pyrolysis in indifferent atmosphere and at heating rates of 10, 20 and 30 °C min-1 in an inert atmosphere. The most probable mechanism function and activation energy pre-exponential factors were calculated by the Popescu, FWO and KAS methods. Three stages appeared during pyrolysis: moisture evaporation, primary devolatilization and residual decomposition. Significant differences in the average activation energy, thermal stability, final residuals and reaction rates of the X. sorbifolia oil were observed. Stage II of the X. sorbifolia oil could be described by the Avramic- Erofeev equation 20 (n=4). The average activation energy of X. sorbifolia oil was 353 kJ mol-1

Abstract: This paper presents the influence of the appropriate polypropylene fibers on the performance of cement concrete pavement. The experimental results show that the fibers can obviously reduce cracks and improve the mechanical performance and durability of concrete. When the content of polypropylene fiber is 0.8 kg/m3, the time of the first crack appearance is 45min and 2h 17min later than that of the concrete samples with 0.4 kg/m3 polypropylene fiber and plain concrete. Comparing with the concrete samples with 0.4 kg/m3 polypropylene fiber and plain concrete, the indexes of average crack area, numbers of cracks per area, and total crack area per area of concrete with 0.8 kg/m3 polypropylene fiber reduce 16.2%, 33.0%, 44.3% and 26.9%, 48.1%, 62.2% respectively. Comparing with plain concrete, the 7d and 28d compressive strength of concrete with 0.4 kg/m3 and 0.8 kg/m3 polypropylene fiber enhances 3%, 4% and 4%, 2%, the 90d tensile splitting strength enhances 7% and 10%, and the impact resistance performance of concrete enhances 130% and 250% respectively.

Abstract: Based on the extensive research and analysis of actual condition of top culvert of high embankment, a calculation theory for the earth pressure of top culvert was presented. The theory could optimize the structure design for culverts, and reduce the waste of resource. First, based on the simplified assumption of the stress of soil on the top culvert and the analysis of single unit of the load on the top culvert, the calculation formula of earth pressure on different position of top culvert was presented by theoretical derivation. Then, to verified the results by using scaled test model and ABAQUS finite element software. Through the comparison with the traditional calculation theory and finite element simulation, we could prove that the calculation theory is more tallies with the actual situation of the earth pressure on the top culvert.

Abstract: At present, our country is in large-scale capital period, the construction scale of is increasing year by year, and the high rate of accident is becoming one of the hot issues in the society. The safety training is the fundamental means and effective way to improve the safety management level, only through scientific and effective training can improve the workers’ safety awareness and skill, and to ensure safe production and the implementation of all the work. Based on analysis of the main defects and reasons of training in Hebei province, the safety training content combined with the characteristics of highway and waterway construction, and used PDCA cycle model in total quality management for reference, the training system of three categories of staff for safety production perfected. Proposed and used a new training method that combined kinds of advanced devices, make the training an continuous improvement system, obtained a good reputation and result. The most important guidance provided in the study is to enhance the training effect and ensure safety training to develop sustained and healthily.