Advanced Materials Research Vols. 479-481

Abstract: This paper aims at investigating the influence of solidification condition on the processing of calcined kaolin geopolymeric powder. This is a new process developed using the geopolymerization process. Geopolymer slurry was prepared from calcined kaolin and activating solution (mixture of NaOH and Na₂SiO₃). This slurry was allowed to solidify in oven and then crushed and grounded to fixed particle size. Compressive testing and SEM analysis were performed in this study. The results showed that the solidification condition at 80 °C for 4 hours was the best to synthesize the geopolymeric powder where this solidification condition results in geopolymeric powder which can produce higher strength resulted geopolymer paste. The microstructure showed more intervening gel phase which indicates that the geopolymerization process continued to react after the addition of water to the calcined kaolin geopolymeric powder.

Abstract: The dynamic stability of fluid conveying piping system under different supporting conditions, considering the fluid structures interaction, was investigated. The expression of vertical vibration mode-function of commonly supported piping system was derived from its boundary condition of the similar beam. Firstly, considering the effects of Kelvin-Voigt visco-elastic coefficient of pipe, fluid pressure and axially sectional force of pipe, the motion equation of the piping system was established. Secondly, the equation was discretized by Galerkin method according with its similar supporting conditions of beam. Thirdly, the expression of critically instable flow velocity was obtained. Lastly, the stability of the piping system was analyzed by using the dynamical simulation methods. The numerical results showed that the critically instable flow velocity is proportional conversely to supported linear spring coefficients, but is proportional to restrained torsion spring coefficients.

Abstract: In this study, the antioxidant activity and browning intensity of thermal products of half-fin anchovy pepsin hydrolysate (HAHp) were investigated. Thermal treatment, in particular at 121 °C, increased the 1, 1-diphenyl-2-picrylhydrazayl (DPPH) radical scavenging rates. The browning intensity ranging from 0.082 to 0.372 displayed a linear correlation (R2=0.9343) with their corresponding scavenging DPPH radical rates. During 12 days of storage at 4 °C, the antioxidant activity of ground beef meat with addition of heated HAHp (HAHp-H, 121°C for 30 min) was determined using the following assays: a pH assay, a DPPH assay and a malondialdehyde (MDA) assay. The results showed that the HAHp-H treatment significantly inhibited the pH value changes compared with the control or HAHp treatments (P < 0.05). The HAHp-H treatment remained unaffected or slightly decreased activity on scavenging DPPH radicals throughout storage. By comparison, the DPPH radical scavenging rates of control and HAHp treatments greatly decreased upon storage. The increase of MDA values of all treatments indicated that the lipid oxidation of beef meat increased with storage time, whereas, the HAHp-H treatment still had significantly lower MDA value (0.433 nmol/mg prot) than the control (1.141nmol/mg prot) and HAHp treatments (0.884 nmol/mg prot) after 12 days of storage (P < 0.05). Overall, HAHp-H could be a potent antioxidant in minimizing beef meat oxidation stored at 4 °C.

Abstract: Spherical plain bearing was applied widely in industry. In the paper, with the finite element code Abaqus, a sequentially coupled, 3D, and thermal-mechanical finite element analysis model of the bearing system was built up based on the theories of heat transfer, tribology and composite material mechanics. The paper focused on effects of the mean sliding velocity and the load. In the end, the paper mentioned a simulation method of computing wear.

Abstract: In this paper, an evaluation indicator system of green supply chain in electronics manufacturers is established, including five areas: financial level, business implementation, customer service level, development ability and green degrees. This paper uses the analytic hierarchy process to determine the subjective weights, uses the data envelopment analysis to determine the objective weights, uses fuzzy comprehensive evaluation method (FCE) to evaluate the performance of green supply chain in electronics manufacturers, and has an empirical research.

Abstract: In this paper, the optimization of conditions for calcium lactate nano-particle production by chemical precipitation by the orthogonal method was reported. The optimal conditions for enhancing yield and purity of calcium lactate were determined as: mixture ratio between lactic acid and Ca(OH)₂ 1.35:1, Ca(OH)₂ 0.46 mol•L^-1, lactic acid 6 mol•L^-1, reaction temperature 50 °C,reaction time 30 min, reaction mixing speed 500 r•min^-1, mixture ratio between the volume of alcohol addition and total reaction 1:1. This optimization strategy lead to an calcium lactate nano-particle yield of 85% and the purity of 98%, which was considerably higher than that obtained in preliminary studied. The TEM images shown that the width of the calcium lactate was about 100 nm.

Abstract: The 3003/4004 clad slabs are prepared by direct chill continuous casting. The microstructures on the interface are investigated by optical and scanning electron microscopes, chemical composition distributions across the interface are detected by EPMA, and tensile strengths are evaluated by MTS NEW-810 Materials Test System. The results show that 3003 alloy and 4004 alloy are metallurgical bonding on the interface on the interface, which is results from fusion and diffusion bonding. The thickness of diffusion layers is about 30 μm on average. The tensile strengths of the top, center and bottom regions of the bimetal slab tend to be uniform. The tensile properties of the interface for 3003/4004 clad slab are better than that of 3003 alloy.

Abstract: The corrosion behavior of low carbon bainitic steel with Cu-P alloying in the environment simulating coastal industrial atmosphere was investigated by using dry-wet cycling corrosion test. 09CuPCrNi steel and low carbon bainitic steel without Cu-P alloying were used as comparative steels. The corrosion kinetics and electrochemical impedance spectra of the steels were measured, respectively. The morphologies of rust layers were observed by SEM and the phase constitutes of the rust layers were analyzed by XRD. Low carbon bainitic steel with Cu-P alloying behaves the lowest corrosion rate and the highest resistance of rust layer. Bainite microstructure is responsible for the uniform corrosion and the formation of dense rust layer. Cu-P alloying accelerates the transformation of gamma-FeOOH and Fe₃O₄ to thermodynamic stable phase alpha-FeOOH, which improves the protective effect of the rust layer.

Abstract: According to compressive test date, relationship between flow stress, temperature, strain rate and strain is studied through single and multiple regression, and constitutive equation is researched. The results show the relationship between flow stress and stain is applied to hyperbolic sine equation in the hot compressive deformation of Ti-6Al-4V-rare earth titanium alloy. Relationship between logarithmic hyperbolic sine of its flow stress and reciprocal of absolute temperatures is liner, and hot compressive deformation is controlled by activation energy.

Abstract: In this study, we report a straightforward route for the synthesis of silver nanoparticles by chitosan under moderate thermal treatment. Chitosan acted as both a reducing agent and a capping agent. The synthesized nanocomposites could function as effective catalysts for the reduction of 4-nitrophenol in the presence of sodium borohydride.