Advanced Materials Research Vols. 160-162

Abstract: The influence of HRT , oxidic time and anoxidic time on the carbon and nitrogen removal of integrated oxidation ditch with continuous flow and intermittent aeration was studied by cross experiment method. The results show that the anoxidic time has the most distinct influence on removal ratio of BOD5 and TN in the system and the oxidic time has a distinct influence on BOD5 as well .When HRT , oxidic time and anoxidic time of the system is 8h , 2 h and 2 h respectively , the effluent quality and the removal ratio for BOD5 are <20 mg/ l and 85. 2 % and for TN are < 20 mg/ l and 55. 5 % respectively.

Abstract: Strontium hydroxyapatite powders was prepared by the hydrothermal method using Sr(NO3)2 and (NH4)2HPO4 as reagents. Fourier transform infrared spectroscopy, X-ray diffraction, Transmission electron microscope, Energy dispersive X-ray, and Thermogravimetric-differential thermal analysis were employed to investigate the crystalline phase, chemical composition, morphology, and thermal stability of the Strontium hydroxyapatite. And the cytotoxicity of Strontium hydroxyapatite was analyzed through MTT assay. Results showed that Strontium hydroxyapatite prepared by hydrothermal Method has excellent crystal structure, good dispersion, high purity, and rod-like morphology with dimensions 200-500 nm in length and 20 nm in diameter. Meanwhile, the apatite has poor thermal stability. However, the apatite is cytocompatible and may have better biocompatibility, which can serve as strontium source incorporation into calcium phosphate cement and for bone repair.

Abstract: Stamping speed is an important parameter in sheet metal forming especially in hot forming. In this study, hot forming of a U-shaped part made of ultra high strength boron steel (22MnB5) sheet is simulated with solid elements. The mechanical properties of 22MnB5 steel sheet and the key process parameters are introduced in detail. Emphasis is laid on the forming response of the boron steel sheet to stamping speeds of 3.25m/s, 0.325m/s and 0.0325m/s. The mechanism of stamping speed acting on hot formability and temperature field of the stamped part is analyzed. It is demonstrated that stamping speed affects both formability and the heat transferred from blank to tools and to environment during hot forming. And the coupling effect of material properties, the heat produced during plastic deformation and heat boundary condition decides the formability and temperature field. An appropriate stamping speed is more important for hot forming than that for common cold forming.

Abstract: The total content of heavy metal in solid waster is usually used to forecast heavy metal’s potential harm for environment.This work was to study the potential harm for environment of ancient pyrometallurgical slag.The heavy metal content in ancient pyrometallurgical slag is high and the average content of heavy metal (zinc plus plumbum) is up to 6.97%.But the leachable quantity of Zn,Pb,Cr and Cd are all very low.It shows that the total content of heavy metal could not represent the harm for environment. Meanwhile,leaching behavior of heavy metal in pyrometallurgical slag was discussed through extraction toxicity test in different pH. The results showed that in neutral condition,the leachable quantity of Zn,Pb,Cr and Cd is at the lowest level and their migration ability were weak.

Abstract: With static and dynamic load for the research background, this paper conducted a four-phase composite model for concrete damage test simulation of micro-mechanics. The two kinds of three-point bending beam load ware studied in case of failure process. The study found that the location of the main crack in the most disadvantaged section of beam shear in the vicinity. Crack is always along the aggregate and the mortar bond zone be extended. The main crack extension direction is always toward the load point. The main crack is showing a tortuous shape. Dynamic load and static load the stress - strain curve is basically similar shape, but basically the same as the starting point of the initial fracture. Stress wave in the sample after multiple visits, is the main reason leading to the breakdown of the sample. Dynamic load cases, the concrete elastic modulus higher than the static modulus of elasticity, numerical simulation results agree well with the experimental results.

Abstract: The related single phases, composites of TiB2/Cu and doped with Fe or Mo series were calculated by the density function and discrete variational method (DFT-DVM) to study the relation among electronic structure, chemical bond and properties. When Fe or Mo is doped into composite, the ionic and covalent bond become stronger, and the interaction between Cu and TiB2 phases also becomes stronger. The influence of doping Mo is more obvious than that of doping Fe. The results are consistent with the experiment that additives of Mo and Fe can improve preparation of TiB2/Cu composite, and effect of additive of Mo is more obvious than that of Fe.

Abstract: The frame beam end uses the carbon fiber cloth restraint, then uses the steel stranded wire assembly,which is a new assembly architecture structure. This thesis studies deeply the crack development characteristics, failure pattern, hysteresis curve and the displacement ductility of prestressed precast reinforced concrete frame, by analyzing one prestressed precast reinforced concrete frame under low reversed cyclic load test. We build a model using finite element analysis software to the test piece model analysis, the analysis result agree well with the experimental results. Experimental studies indicate that assembly of prestressed reinforced concrete frame structure has a good seismic performance. This prestressed precast reinforced concrete frame is a new kind of structural system complying with the development of architectural industrialization, which is worthy of popularization and application in the earthquake area.

Abstract: The fluid flow of Q235 molten steel in 700mm×700mm billet mold has been numerically simulated by a software FLUENT. By comparing the influence of submerged entry nozzle with different immersed depths, different number of holes and different opening angles on the distribution of fluid field, the structure of mold and the involved process parameters are optimized. With the application of the optimized structure and process parameters, the stability of fluid field is increased and the thickness uniformity of steel shell is improved, so that the quality of continuous casting billet is ameliorated, which provides a theoretical basis for engineering application.

Abstract: At annealing temperature, Al-Mg alloys have grain boundary and surface magnesium segregation and their strength are also impossibly enhanced by heat treatment. Friction and wear properties of cold-rolled 5052 aluminum alloy annealed at different temperature were studied in this paper. X-ray diffract analysis(XRD) indicates that metallurgical phase has no obvious transformation with different annealing temperature. Auger electron (AE) fines that magnesium segregation and oxide layer thickness of surface are different along the plate thickness direction at different annealing temperatures. Results show that the higher oxide layer of the surface, the smaller wear can be got. Friction and wear testing shows that 5052 aluminum alloy annealed at different temperatures almost have the same coefficient of friction under the same experimental condition , but the coefficient friction of the same sample will increase while temperature rises.

Abstract: The ability of Cr-bentonite prepared using synthetic wastewater containing chromium was investigated for adsorptive removal of 4-aminophenol and 4-chlorophenol from aqueous solution in a batch system at 25 °C. The physic-chemical parameters including pH value of solution and contact time were studied. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of sorption. The equilibrium sorption data for 4-aminophenol and 4-chlorophenol were well fitted to Langmuir adsorption isotherm and the monolayer sorption capacity was found to be 26.53 and 23.81 mg/g at 25 °C, respectively. The sorption energy calculated from Dubinin-Redushkevich (D-R) isotherm are 8.31 and 8.20 kJ/mol for the uptake of 4-aminophenol and 4-chlorophenol respectively which indicates that both the sorption processes are chemical in nature. The kinetic data were analyzed using pseudo-first order, pseudo-second order kinetic equation and intraparticle diffusion model. The experimental data fit very well the pseudo-second order kinetic model. Intraparticle diffusion affects 4-aminophenol and 4-chlorophenol uptake. Sorption studies carried out using industrial wastewater samples containing phenolic compounds show that there is significant potential for Cr-bentonite as an adsorbent material for phenollic compounds removal from aqueous solutions.