Advanced Materials Research Vols. 560-561

Abstract: Some properties of paper sludge were analyzed, including water content, organic material content, pH value, fiber content, ash content ,C, H, S, N content and metal content of sludge in three sedimentation tanks.Besides,COD,SS, sludge concentration were analyzed and optical microscope photoes of sludge were got.The results showed that water content was high, organic material content was high, pH value of three sludges was alkalescent, metal elements were varied, lots of bacteria in wet sludge. From the first tank to the third one,COD and SS are gradually diminishing The research of sludge’s properties may be helpful to sludge treatment.

Abstract: The mechanism of CO2-CH4 reforming over supported Platinum catalyst was investigated using the B3LYP density functional method and other six methods. It was found that the reaction include two channels. There were three steps in every reaction channel, and the oxideizing material was the most important catalyst in every reaction channel. The activation energy of each step in the first reaction channel were 160.2395, 368.8722 and 195.9673 kJ•mol-1, and the enthalpy change of each step were –14.6319, –176.2305 and 17.8875 kJ•mol-1. The activation energy of each step in the second reaction channel were 129.3742, 368.8722 and 275.4919 kJ•mol-1, and the enthalpy change of each step were 97.7868, –176.2305 and –164.4861 kJ•mol-1. The rate determining step was the second step.

Abstract: The structure of benzoxazine which has bisphenol A structure as a phenolic component analyzed by tandem mass analysis. From the results, it is clear that dimethylol aniline is produced and depending on the reaction mechanism of dimethylol aniline, the final structure of oligomers are decided.

Abstract: The geometry structure, band structure and density of states of KH2PO4 (KDP) and NH4H2PO4 (ADP) single crystals were investigated by using density functional theory (DFT) method. Parameters including the phase velocity, electromechanical coupling factor and power flow angle (PFA) were calculated for KDP and ADP at X, Y, Z cuts, respectively. Our calculated data are in good agreement with the experimental results. Compared with quartz, KDP and ADP crystals are of lower phase velocities. Considering PFA, electromechanical coupling coefficients and phase velocity, it was concluded that the propagation direction of 60 of X-cut and Y-cut possess superior SAW performance for both KDP and ADP crystals.

Abstract: A zeolite pellet is formed by binding large numbers of small crystals with microporous material. The adsorption properties of a zeolite pellet depend on its micro-structure. In this paper, two physical models of a 5A zeolite pellet with the crystals dispersed or clustered are established. Mathematical models to describe nitrogen diffusion and adsorption occurred inside the pellet are proposed. The N₂ adsorption properties on pellets with different micro-structure are compared. Very detailed results regarding the effects of the crystal fraction, crystal distribution are revealed.

Abstract: Isobaric vapor-liquid equilibria (VLE) data for water + acetic acid, acetic acid + n-pentyl acetate, water + acetic acid + n-pentyl acetate systems have been measured at 101.33 k Pa using a recirculating still. The nonideality of the vapor phase caused by the association of the acetic acid has been corrected by the Hayden-O’Connellmethod. The three experimental binary data have been correlated by the NRTL and UNIQUAC models. The obtained NRTL model parameters from binary data have been used to predict ternary VLE data. The ternary predicted values obtained in this way agree well with the experimental values.

Abstract: SiC ceramics were synthesized by polymer derived method and microwave sintering processes. The as-produced SiC composites were developed by oxidizing the amorphous Si-C raw materials derived from a polymer precursor polycarbosilane. The products analyzed by X-ray diffraction (XRD), Fourier transmittance infrared spectroscopy (FTIR), and electronic microscopye consist of excess free carbon, β-SiC and SiO₂ produced by the partial oxidation of amorphous Si-C on the surface of the starting particles. The thermophysical properties of the partially oxidized SiC composites were investigated by measuring the thermal diffusivity, the specific heat and thermal conductivity. The amount of SiO₂ increased as the sintering temperature is increased, resulting in a reduction of thermal diffusivity and an increase of density due to improved liquid phase sintering of SiC particles. The thermal conductivity of samples decreased, instead of increased, as the sintering temperature was increased from 1100 °C to 1200 °C. The sample dwelled at 1200 °C, in this study, has highest density and a relatively low thermal conductivity, slightly over 0.7 W/(m·K) at room temperature.

Abstract: Given the heat transfer and force characteristics, seal ring was simplified to be equivalent to a circle. The heat transfer coefficients and temperature distribution on both rotating and stationary rings were calculated. A simplified thermal distribution model was developed for rotating and stationary rings according to the law of energy conservation and a verification method was proposed. Based on this, the deformation relationship of friction surfaces on which both heat and pressure were applied. Comparison was made between average and asymmetric thermal distributions and verified by FEM. The results showed that the deformation of stationary ring exceeds the allowed deformation amount in heat average distribution. The result of deformation is in agreement with testing results.

Abstract: The combustion stability of the self-propagating thermit reactions was analyzed, and the influence factors on combustion temperature and combustion speed were discussed in detail. Especially, a complex combustion system had an advantage in balancing the reaction heat. Through the welding experiment and result discussion, the control strategy for heat was verified in the complex combustion system of (CuO+Al)+( CuO+CaSi). The results indicated that the optimization of particle size and content rate about oxidizing agent, reducing agent and additive components had a significant effect in stable combustion, heat uniformity, beautiful forming and so on.

Abstract: In order to make adequate use of microwave to enhance extraction efficiency, the diffusion kinetics equation of microwave-assisted extraction was established on the basis of the theory of the liquid lattice model. By simplifying the diffusion kinetics equation, three simple relational expressions were obtained, which contained three experimental parameters (the extraction time, the liquid/material ratio and the particle radius, respectively). The fitting results showed that the theory curves were consentaneous to experiment results and all the related coefficient in fitting results were above 0.97 , which indicated that the kinetics model established is adaptive and appropriate in some range. Through further analyzing the fitting curves, it was indicated that the relation curves had different characteristics that one characteristic was the extraction rate obviously changed and the other was the extraction rate changed very slowly, which could provide a definite guidance for selecting the experimental parameters such as extraction duration, liquid/material ratio and particle radius in the extraction process.