Advanced Materials Research Vols. 418-420

Abstract: A brickwork layer model was used to investigate the dielectric properties of CaCu₃Ti₄O₁₂ ceramics. It is equivalent to Debye model under the Maxwell- Wagner-type mechanism. Arrhenius relation could be obtained by the assumption that the grains in the CaCu₃Ti₄O₁₂ ceramic are of semiconductivity. The dependence of the dielectric constant on the grain size and temperature were well fitted by the model.

Abstract: In order to implement the balanced distribution in Cloud Computing system and to improve the utilization ratio of the resource as well as handling up rate of the system, the system of dynamic dispatching system based on Cloud Computing has been designed and implemented after the study on the Cloud Computing. Firstly, a layered loading balancing scheduling mode has been proposed, providing the structure of the dispatching service system. Secondly, a comprehensive service distribution algorithm has been designed and implemented in consideration of respective local service counts, each join points’ performance, current load distribution and semantic. Finally, the result of the experiment indicates that the scheduling system can improve the efficiency of dispatching service and the utilization ratio in the Cloud Computing system.

Abstract: Two experimental equipments of semi-aerobic landfill and anaerobic landfill were constructed. The total nitrogen concentrations of leachate (Recorded as CTN) that located at the bottom of equipments were determined periodically (1 or 2 times per week), the variation laws of CTN that located at the bottom of two landfill equipments with time were researched, and the reasons for the differences were also analyzed; During the period that the degradation of the landfill waste came into a relatively stable stage, the leachate that located at each sampling points of upper, middle and lower horizontal sections of the landfill equipments was collected periodically, and the CTN was determined, the CTN　data of each point of upper, middle and lower layers were processed by using Surfer software respectively, and the spacial variation characteristics and differences of two landfill equipments were also discussed. The results indicated that the CTN of each point of the semi-aerobic landfill treatment were significantly lower than the corresponding anaerobic landfill treatment, the semi-aerobic landfill treatment could achieve the effective removal of total nitrogen from the leachate, and could accelerate the process of degradation stabilization and balance of total nitrogen in leachate.

Abstract: This paper attempts to explore the influence to flexural performance of carbon fiber epoxy matrix composite circular tubes which were bonded in four different bonding Length with adhesive. Under the different bonding length, i.e. 20, 25, 35 and 40mm, the flexural performance of carbon fiber epoxy matrix composite circular tubes which were bonded were tested. It is shown that the bonding length affect the flexural properties of composite tubes. The flexural strength and elastic modulus of specimens CFRL50 increase about 18.11% and 36.95% respectively, compared to specimens CFRL20. The flexural properties of bonding composite tubes increased with the increasing length of reinforced pieces L2. Embedded bonding technology can provide a good bonding performance for composite circle tubes.

Abstract: Rubber wastes cause severe damages for the environment when unsuitably disposed in the environment and represent a challenger for mechanical recycling, because the vulcanized rubber is formed by a tridimensional network with intermolecular sulfur crosslinks. Microwave radiation can lead to the breaking of sulfur crosslinks and so enable the recycling of vulcanized rubbers. The aim of this work was to study the SBR devulcanization by microwave using inorganic salts and nitric acid. Soxhlet extraction and FTIR analyzes were carried out to evaluate the devulcanization degree and chemical modifications in the rubber structure. The results showed that the presence of carbon black in the rubber is an important factor for devulcanization and some metallic ions decrease the sulfur crosslink content. On the other hand, these ions promote the oxidation in the rubber.

Abstract: Warm rolled deformation is one of deformation technique to improve the strength of steels through the refining grain size of ferritic microstructure. In application, low carbon steel which used in structural industry need some protection against corrosion attack, cathodic protection is usually applied combining with coating. Cathodic protection creates reduction reaction which produces hydrogen, and the hydrogen atom may diffuse into the crystal lattice lead to the Hydrogen Induced Cracking. The present study is to observe the morphology of microstructure influenced by hydrogen charging as the source of hydrogen which attacks the steel surface, and observed by Optical Microscopy and Scanning Electron Microscopy. After warm rolling of 650oC and 35% deformation, ferrite grain size is smaller than bulk material and the hardness value increasing. After tensile test of hydrogen charged steel found the ductile fracture, it means the smaller the ferrite grains size, the resistance of hydrogen attack is increase.

Abstract: Aluminum alloy profile has been widely used in manufacturing industry for weight reduction. In the bending process of profile, the cross-section distortion is a common defect and also springback always happens in unloading process. In the paper, the bending process of a hollow profile with stiffener was simulated to optimize the forming parameters. Different bending radiuses and inner pressure were chosen in FEM analysis and the suitable radius and calculation equation of pressure for the given profile were obtained. The springback at different bending radiuses were studied to provide the principle of shape compensation.

Abstract: Softening behavior of deformed austenite zone of E36 ship plate in hot continuous rolling process was studied with double passes compression experiments, including cases in different deformation temperature and time span. Analyzing the influence of different factors on the softening ratio of static recrystallization. The results show that deformation temperature is the main factor to influence the recrystallization. When the deformation temperature being achieved, static recystallization ratio increases step by step with time span extending. The best time span was got and the softening ratio curve was verified through metallographic analysis, and the activation energy was obtained. Dynamic model of static recystallization was built at the end.

Abstract: Friction stir welding (FSW) of T-joints composed by 3mm thick 6061-T4 alloy was presented and the influences of process parameters on hardness profiles and tensile strength were discussed specifically. Two low hardness zones on the skin and one low hardness zone on the stringer were found. Tensile behaviors of T-joints were examined in two directions—in skin direction and in stringer direction. It was found that the tensile strength ranged from 170~180MPa for all specimens in the skin direction. And the specimens failed in heat affected zone (HAZ) corresponding to the lowest hardness. In the stringer direction, most fractures occurred in the stringer. In all the cases, the specimens welded exhibited the best tensile strength with ω/v=1541/218 in the stringer direction. The ultimate tensile strength was equal to 83% compared to base material.

Abstract: The electrochemical behavior of corrosion resistance alloys (316L SS, 2205 DSS and Inconel 625) was carried out at ambient temperature in 3.5% NaCl solution using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) techniques. Some significant characterization parameters such as E_corr, E_b, I_corr and △E in polarisation curves were analyzed and compared to reveal the corrosion resistance of corrosion resistance alloys. The ZsimpWin software was utilized to discuss the Nyquist plots of various corrosion resistance alloys. The result shows that the corrosion resistance of the corrosion resistance alloys in 3.5% NaCl solution at ambient temperature follows the sequence: Inconel 625> 2205 DSS > 316L SS.