Applied Mechanics and Materials Vols. 672-674

Abstract: Several amorphous alloys (Ni-Fe-B) were synthesized using liquid phase reduction method. The influences of molar ratios n(Fe)/n(Fe+Ni) and different temperatures on phase composition, morphology and catalytic activity were investigated. The resulting products were characterized by XRD and TEM methods, and the catalytic activities were also evaluated by way of hydrogen release ability of NaBH₄ hydrolysis. The results show that the products have stable amorphous phase structures. With the increase of n(Fe)/n(Fe+Ni), the crystallizing tendency rises and the agglomeration strengthens. Under the conditions (T=333K, n(Fe)/n(Fe+Ni)=0.5), the as-prepared samples exhibit the highest catalytic activity, and the highest hydrogen generation rate is 1.70 mL/min^-1.

Abstract: Taking the physical model of a small oil-shale retorting furnace with gas heat carrier as research object, a quasi homogeneous mathematical model was established to simulate the process of heating the pebbles in the porous zone and was solved by Fluent, a commercial CFD software. We compared the calculated results of temperature with the measured data, and analyzes the cause of the deviation between them.The result showed that the calculated value is relatively close to the measured data(the relative error is 6.85%) and the model can predict accurately the actual temperature field. The research results can provide support for the process of structural design of the large oil-shale retorting furnace with gas heat carrier.

Abstract: The microwave pyrolysis is a new research method for deeply processing of coal. This paper researched the microwave pyrolysis products of low rank coal under N₂ and non-N₂ atmosphere. The results showed that, compared with non-N₂ atmosphere, the yield of liquid products increased by 4.65%, while the yield of solid bluecoke decreased by 2.95% under N₂ atmosphere. The infrared characteristics absorption peak intensity of bluecoke obtained from N₂ pyrolysis atmosphere was weaker; N₂ contributed to the transformation of heavy oil into light oil.

Abstract: The scope of this paper is focused on analyzing the chemical degradation of LSCF cathode induced from many sources by GCI technique both from theoretical and experimental sides. As you know, electrochemical reaction occurring in the SOFC cathode is the reduction of oxygen, therefore cathode materials for SOFC have to posses many properties. It is necessary to evaluate the performance and degradation of SOFC cathode since improvement of long-term stability is one of the major issues during SOFC commercialization process. This research is important toward the commercialization of SOFC because efforts are being made to clarify the mechanisms of cell performance degradation and to improve durability effectively.

Abstract: Non-precious metal Fe-C-N thin films were prepared by magnetron sputtering at different sputtering currents applied on a Fe target. The films were subsequently heated at 700 °C in N₂ atmosphere. Fe-C-N thin films were investigated as an alternative cathode catalyst for the oxygen reduction reaction (ORR) in a neutral solution. The results indicated that the catalytic activity of Fe-C-N thin films for the ORR increased with the increase of the sputtering current. When the sputtering current was 0.2 A, limiting current density was 5.50 mA cm^-2 and onset potential was-0.10 V vs. Ag/AgCl, which were comparable with those of commercial Pt/C catalysts. The current density of films was unchanged in 5000 seconds in the chronoamperometric experiment, indicating that the catalytic activity was very stable in a neutral solution for potential use in microbial fuel cells.

Abstract: Heteropolyanion substituted layered double hydroxide were synthesized and used as catalysts for oxidative desulfurization in simulated fuel oil (dibenzothiophene (DBT) in n-octane) or diesel. The catalysts are recoverable and operate with high conversion efficiency under mild conditions of atmospheric pressure and 60 °C in a biphasic system using peroxide hydrogen as oxidant and acetonitrile as extractant. Zn₉Al₃(OH)₂₄PW₁₂O₄₀(ZnAlPW), Zn₉Al₃(OH)₂₄PMo₁₂O₄₀ (ZnAlPMo) and Zn₁₂Al₄(OH)₃₂SiW₁₂O₄₀(ZnAlSiW) were identified as effective catalysts for the oxidative removal of DBT from simulated fuel oil. The order of decreasing catalytic activity is ZnAlPMo > ZnAlPW > ZnAlSiW. The results show that the best catalysts, ZnAlPMo, attained to a DBT conversion of nearly 100%. All the catalysts can be readily recycled by filtration after use. The recoverable ZnAlPMo retains nearly the same catalytic activity as the fresh. ZnAlPMo was found to exhibit an ideal catalytic activity in oxidative desulfurization of diesel with a total sulfur removal rate of 91.8%.

Abstract: The article deals with of a hydrogen pressure vessel suitable for very high pressure of approximately 100 MPa. One of the goals is to design a vessel from materials whose strength will meet mechanical requirements a calculated in numerical ways. Another objective is the simulation of the design the pressure vessel with regard to safety and weight requirements.

Abstract: An Indonesian oil sand were studied by hot water extraction and fixed bed pyrolysis for bitumen recovery. It was found that the concentration of alkali and temperature both had effects on the yield of water extraction. But the maximum yield was only 12.74wt% under the investigated condition due to its oil-wet structure. As to pyrolysis in fixed bed reactor, the influence of holding time, flow rate of gas carrier and temperature on the tar yield were considered. The maximum tar yield was 17.01wt% under 140mL/min of gas carrier, 480°C, 0.1MPa and holding for 40min. The results show that pyrolysis is more suitable for bitumen recovery of the oil sand compared with hot water extraction.

Abstract: Hydrogen is a kind of clean energy, and application is limited because the efficiency of hydrogen production was not high before. This work in the paper was to study how to advance the hydrogen production efficiency by adding rare earths in the process of electrolysis of water. The result of tests proved that the efficiency of hydrogen production of water electrolysis electrode is dramatically improved when a few of REs are added in plating bath, and La cations are more effective than Ce cations when being added in the plating bath. Besides that, this article illustrated positive impact of RE on process of plating as well as effect of RE on composition of the plating and corrosion resistance of surface of the coating. Furthermore, argumentation extended to it that RE alone and compound of La and Ce have affected on efficiency of hydrogen production by water electrolysis process. Finally the paper showed that a new mechanism had been presented in a new angle being established in effect of RE on electron state of Ni plating.

Abstract: The proton transfer impedance in the proton exchange membrane is the main impedance of PEM fuel cells. In this paper, the molecular model of the hydrated proton transfer in the Nafion117 membrane is established based on the basic principle of molecular dynamics; the effects of temperature and water content on the proton transfer are analyzed. The results reveal that the hydronium ion clusters H₅O₂⁺ is the main structure style of the hydrated proton transfer in the proton exchange membrane; with the increase of the temperature, the thermal motion of particles accelerates, which leads to the hydrated proton diffusion speed up; when the water content increases, the hydrated proton diffusion coefficient increases. The results are very helpful to understand the proton transfer in the membrane.