Advanced Materials Research Vols. 156-157

Abstract: The carbothermal reduction of alumina in a vacuum was investigated by XRD and thermodynamic analysis. Experiments on mixtures of alumina and graphite in a vacuum furnace at 1743-1843K proved that the residues consisted of Al2O3and C, and the deposits formed on the upper wall of the crucible contained Al4O4C, C, Al4C3 and Al2O3. Thermodynamic analysis indicated that alumina should react with carbon to form gaseous Al2O and Al above 1671K and 1713K at 100Pa respectively, Al2O and Al react back with CO to form Al4O4C, C, Al4C3 and Al2O3, which constitute deposits.

Abstract: Based on the analysis and research about comprehensive training bed for medical rehabilitation, the design method of the training bed is obtained. The analysis of humanized design and practice for the bed are presented, the design of the bed need to consider the physiological and psychological needs of users in order to create a comfortable space and relieve their physical and psychological pain as can as possible. The bed should not only fit physiological needs of the user but also to meet the spiritual needs. So the rational functions and humanized design of the comprehensive training bed should combine to reflect the caring for humanity to the disadvantaged groups.

Abstract: According to the characteristics of the soft soil subgrade reinforced by geosynthetic and piles, the deformation of geosynthetic was modeled as circular arc and the arching effect in embankments and the interaction of piles and soil are both considered in the calculation. The interaction mechanism of geosynthetic, pile and soil under the embankment load was analyzed. The method presented in this paper was validated by comparing with the testing results and three current design methods in the literature. The results show that the analytical solutions have agreement with the measured data and can be applied in engineering practice. Finally, four important parameter (the differential settlement, the diameter of pile, the width of pile cap, the height of equal settlement plane) were investigated.

Abstract: How to predict the relationship among particle size and among product size, to establish the relationship between the granularity and working parameters in the process of grinding and to determine the optimum operating parameters. With proposing BS squeeze crush model by L. Bass and the idea of roll surface division as the material uneven extrusion force are adopted. Based on field experiments the experimental data is analyzed, the select function and the breakage functions are fitted with MATLAB software, and obtaining their model. The comminution model is determined by the roller division. We obtain the model parameter through the experimental data. Through model analysis shows: the relationship between particle breakage and energy absorption, namely the smaller size of the same power, the lower broken; the breakage diminishes with the decrease of particle size ratio and it will be tending to a small constant when the smaller particle size ratio. The breakage functions rapidly decrease within ratio of between 0.2-0.7. This shows: the energy consumption will rapidly increase when the particle size of less than 0.2 in broken; the selection diminish with the decrease of particle size. Pressure (8-9MPa) should be the most appropriate value.

Abstract: Relative high carbon steel bearing Cr and Mo with microstructure consisting of nanoscaled bainitic laths and certain amount of retained austenite was produced through the combination of rolling and isothermal/multi-step heat treatment at low temperatures. The effect of the heat treatment temperature, time and path on the volume fraction of retained austenite and the width of bainitic lath was investigated. Nanoindentation was applied to inspect the separate hardness of the tiny bainite and retained austenite for different heat treatment parameters. The results showed that bainitic lath treatedt at 250°C was much thinner than that at 300°C and the volume fraction of retained austenite changed with different heat treatment temperatures, time and paths. The nanohardness of the baintic lath and retained austenite also changed with the processing of both carbon partitioning and displacive transformation for different heat treatment paths.

Abstract: Intragranular porous aluminum titanate ceramics were prepared by using graphite powder as pore-forming agent and magnesium-doped aluminum titanate powder as starting material. FESEM was employed to observe the microstructure. In order to investigate the expansion behavior and mechanical property, the dilatometric curve and three-point flexural strength of the prepared aluminum titanate ceramics were measured respectively. The results demonstrate that because of the formation of the intragranular pores, the aluminum titanate ceramics are of low thermal expansion and high strength simultaneously.

Abstract: Aiming at reducing cost and time of repair, condition-based shaft faults diagnosis is considered an efficient strategy for machine tool community. While the shaft with faults is operating, its vibration signals normally indicate nonlinear and non-stationary characteristics but Fourier-based approaches have shown limitations for handling this kind of signals. The methodology proposed in this research is to extract the features from shaft faults related vibration signals, from which the corresponding fault condition is then effectively identified. With an incorporation of empirical mode decomposition (EMD) method, the model applied in this research embraces some characteristics, like zero-crossing rate and energy, of intrinsic mode functions (IMFs) to represent the feature of the shaft condition.

Abstract: We review the fabrication and properties of highly ordered TiO2 nanotube arrays made by anodic oxidation of titanium in fluoride-based electrolytes. The N-doped TiO2 nanotubes were prepared by changing the composition of electrolyte. TiO2 nanotubes and N-doped TiO2 nanotubes characterized by various analytical methods, such as scanning electron microscope (SEM) and X-ray photoelectron emission spectroscopy (XPS). The photocatalytic efficiency was evaluated by the photodegradation of Methyl orange solution under UV irradiation. It has been confirmed that the recombination rate of electron-hole pairs declined significantly. The higher visible light activity is due to the codoping of nitrogen.

Abstract: This article is to apply Taguchi method to optimize the process parameters for MWCNT/Natural rubber composite as vibration isolator. The objectives of well-known Taguchi method for robust parameter design are to find out the best combination of design parameters and reduce the variation for quality from minimum number of experiments, and thereby optimize the quality of products. This paper investigates the effect of control parameters, such as, wt. % of carbon nanotube, sonicating method, and the time of sonication, which is related to the force reduction in transmissibility of vibration isolator under various fabricating conditions. It has been found that MWCNT/NR isolator fabricated by this methodology can obtain a higher damping ratio and better vibration isolation compared to pure natural rubber isolator. Therefore, the presented MWCNT/NR composite can be considered a substitute for rubber vibration isolator.