Advanced Materials Research Vol. 1119

Abstract: In the dielectric heating by using microwave, both the interior and exterior of fiber materials can be evenly heated simultaneously. Especially, in case of heating the material of low thermal conduction by normal furnaces, thermal loss is great and it takes long time to finish the required treatment. However, if microwave is applied to fibrous materials, it can be treated rapidly. Also, application of microwave system has the results of remarkably enhancing productivity and improving working environment owing to no air pollution. Thus, in this study, the bonded polypropylene (PP) fibers and PP/PET nonwovens have prepared by dielectric heating with various organic solvents, and their morphological structures and debonding force have investigated with different treatment time.

Abstract: The poor corrosion resistance of magnesium alloys become the bottleneck restricting its development. Based on micro-arc oxidation (MAO) technology and the characteristics of fluorocarbon coating the surface of magnesium alloy build a high corrosion protection system, namely: Based on micro-arc oxidation coating fluorocarbon coatings. The formation of the composite coating through the resistance to ageing test through the resistance to ageing test, acid and alkali experiment and salt spray test results show the excellent corrosion resistance performance. Among them, the resistance to salt spray test time can reach 1500 h, which breaks the bottleneck of magnesium alloy corrosion resistance of 1000 h.

Abstract: During procedure and heat treatment of magnesite in shaft and rotary furnaces, a great number of fine fractions are generated. In terms of MgO content, the fractions comprises the highest quality raw material. However, the desired degrees of calcination or sintering have not been achieved. For direct heat treatment of fine particles the microfluidic furnace has been proposed. The microfluidic furnace consists of the fluidization chambers in which the technology operations are being carried out. The furnace operates on the counter-current principle. The experiments of dust magnesite and flue gas calcination from rotary and shaft furnaces were carried out in the furnaces.

Abstract: This work brings out the numerical simulation of the stir casting technique for aluminium silicon carbide Metal Matrix Composite (MMC) in a closed crucible and the effect of the blade geometry and rotational velocity on solidification of the metal matrix composite has been predictedusing Computational Fluid Dynamics (CFD) approach. The material used in the crucible is silicon carbide in aluminiummetal matrix. Geometric modelling and meshing have been carried out using ANSYS ICEM CFD. Computer simulations have been carried using the commercial CFD package, ANSYS FLUENT. The calculations used 2-D discrete phase, solidification and melting model and enthalpy method. Mushy state mixing, indicative of the solidification patterns have been studied to predict the most suitable ratio of crucible to blade dimensions and speed of stirring to obtain the most uniform type of solidification which in turn induces some enhanced mechanical properties to the casting.

Abstract: A Cellulase and amylase are important enzymes for hydrolysis of cellulose and starchy material into the glucose. The performance of the mixed cellulose-amylase immobilized on polysulfone membrane (PSF) by cross-linked with glutaraldehyde was investigated. PSF membrane consists of 1-methyl-2-pyrolidone (NMP) as a solvent and using polyvinylpyrolidone (PVP) as an additive was developed. The study highlighted in the surface structure of PSF membrane, stability of the immobilized enzyme and reusability of the immobilized enzyme. Morphology studied using FESEM analysis indicated a good distribution of the pores was formed on the surface of the PSF membrane. The immobilization process shown no effect on the membrane structure and it was stable to be used as a support in immobilization process. The optimum operating condition for enzymatic hydrolysis of mixed cellulase-amylase on PSF membrane was 50°C and pH 5. The maximum glucose produced at the optimum condition was 4.843g/ml. The study also indicated that immobilized mixed cellulase-amylase achieved a maximum rate of reaction at first recycle of reusable before the rate of reaction decreased rapidly after 5 reusable hydrolysis cycles.

Abstract: The energy analysis of hydrogen production from the methanol reforming and oxidation under atmospheric (ATM) pressure and supercritical water (SCW) conditions was performed. The equilibrium hydrogen was investigated by the minimization of the Gibbs free energy based on Peng-Robinson equation of state for high pressure and ideal gas equation for atmospheric pressure. An objective of this study was to obtain the optimum operating conditions to maximize the net hydrogen yield, defined as the hydrogen yield taking into account also the methanol consumed by combustion to generate heat. This was done by investigating the effect of operating parameters over the following ranges: temperatures between 773 and 1273 K, pressures between 0.1 and 25.0 MPa, water-to-methanol (H₂O:MeOH) ratios between 1 and 5, and oxygen-to-methanol (O₂:MeOH) ratios between 0 and 1.05. At ATM pressure, it was found that the equilibrium hydrogen yield increases with increasing H₂O:MeOH ratio but the peak of equilibrium H₂ yield is at 973 K for higher H₂O:MeOH ratio than 1:1. Additionally, the total heat load increases significantly as the reaction temperature and the water amount increase. Therefore, the optimum net H₂ yield is at the H₂O:MeOH ratio of 2:1 and the reaction temperature at 973 K. Under SCW conditions, an increase of temperature and water amount in the system constantly increases the equilibrium H₂ yield. It means that the high H₂O:MeOH ratio and temperature are required in SCW. The presence of oxygen in hydrogen production was investigated that an increase of O₂:MeOH ratio constantly decreases the H₂ yield and also the net H₂ yield for reaction at ATM pressure whereas under SCW conditions, the equilibrium H₂ yield and the net H₂ yield increase with increasing oxygen up to 0.42 and 0.84, respectively.

Abstract: In this study, a series of composite proton exchange membranes are prepared from sulfonated polydivinyl benzene (sPDVB) microspheres and sulfonated polyphenyl ether (SPPO). The PDVB microsphers and PPO are functionalized by direct sulfonation. The synthesis products are characterized by Fourier Transform Infrared Spectroscopy technique (FT-IR), thermogravimetry analysis (TGA), scanning electron microscope (SEM). The incorporation of sPDVB decreases the water uptake and proton exchange capacity, so the proton conductivity is lower than that of blank SPPO membrane. But the composite membranes still have the excellent conductivity range from 4.88×10^-2 to 6.99×10^-2 Scm^-1.

Abstract: The residue sulfate ions (SO₄^2-) occurs in an adsorption and complex salt manner which are significant influence the electrochemical properties of LiNi_1/3Co_1/3Mn_1/3O₂ as cathodes materials for lithium-ion batteries. Compare with different SO₄^2- concentration electrochemical performance reveals that low SO₄^2- concentration (0.28%) demonstrated a better charge/discharge cycle performance than the high SO₄^2- concentration (0.48%) of LiNi_1/3Co_1/3Mn_1/3O₂, it maintains a capacity of 148.9 mAh·g⁻¹ with a coulomb efficient of 91 % after 100 cycles which superior to the SO₄^2- concentration (0.48%) circulation coulomb efficient of 87%, respectively.

Abstract: Lost circulation is one of the most troublesome problems encountered in drilling due to uncontrolled flow of drilling mud into the formation that likely to happen due to ineffective filter cake. The smaller particles of drilling mud are able to break through into the larger void spaces in the formation which lead to lost circulation. Hence, fibrous materials in apple skin being identified to be used as lost circulation material (LCM) in drilling mud to prevent loss of circulation. Mud rheology tests and API filter press test are performed on the apple skin in drilling mud to find out the potential of fiber in apple skin to be used as LCM. From the mud rheology test, it was found that the specific gravity does not affected by the increasing concentration of apple skin and only a slight reduction in pH value to the acidic condition of the apple skin. As for API filter press test, the additions of apple skin in mud reduced the mud filtrate and increase the mud cake formation thickness. Apple skin fibers have a potential to be used as LCM in drilling mud due to the ability in reducing the mud filtrate and increasing the mud cake thickness that will prevents mud lost circulation problem to happen.

Abstract: Effect of comprehensive alloying system (W, Ta, Nb, Mo, V, Hf, Ti, Zr, Ni) and impurity N on cohesive properties of the bulk and the special high-angle grain boundary (GB) Σ5 (210)[100] in Cr-base alloys, as well as segregation behavior of impurities at the GB and the (210) free surface are studied by first principles calculations. The analysis of the data obtained allows us to single out W, Ta as the best and nitrogen as the worst interatomic bond strengthening elements for both the bulk and GB in Cr-base alloys. To verify these theoretical results by means of experiment, we investigated an influence of W (up to 10 wt. %), and (Ta, Nb, Hf and Zr) on mechanical properties of Cr-base alloy. We observed an increasing of the strength properties due to W addition and increasing of the plasticity as a result of (Ta, Nb, Hf, Zr) adding.