Advanced Materials Research Vols. 148-149

Abstract: This paper explores the grey model based PSO (particle swarm optimization) algorithm for fatigue strength prognosis of concrete. First, depending on concrete’s testing status, fatigue life is studied. Then, one GM(1,1) based PSO algorithm is used in fatigue strength prognosis of concrete. One important advantage of the proposed algorithm is that only fewer data is in need for fatigue strength prognosis. Finally, a case study is given to illustrate effectiveness and efficiency of the proposed approach.

Abstract: A mathematical model to predict oxygen, carbon dioxide, and water vapour exchanges in non-perforated and micro-perforated modified atmosphere packaging films has successfully been proposed.

Abstract: As the operation performances and reliability of semiconductor devices are tightly related to its operating temperature, the research on the heat transfer characteristic and thermal modeling do a significant meaning to extend services lifetime and improve application reliability of the IGBT modules. The physical structure and the conception, RC component network of thermal resistance, test principle and platform of the transient thermal impedance of IGBT module and three modeling methods are briefly introduced. The parameters of Cauer RC thermal network of a certain type IGBT is derived based on transmission line method. The junction-case thermal resistance can be deduced by Finite Element Method in the numerical simulator ANSYS and the transient thermal impedance curve. Thermal compact model can also be deduced from the numerical simulation and experimental results. An excellent agreement is obtained between experimental results derived by the transient thermal impedance curve and numerical simulation results based on FEM. The thermal compact model and experimental results could be helpful for modeling of thermal model and heat sink design for such electronic devices.

Abstract: The superplasticity of fine-grained 1420 Al-Li alloy which was prepared by two-stage aging and turning rolling process was studied by constant-strain-rate tensile test. The results showed that: good superplasticity was attained at temperature range of 460°C~520°C and deformation strain rate 1×10-4s-1~5×10-3s-1. An elongation of 650% was obtained at the temperature of 650°C and strain rate of 1×10-4s-1. Furthermore, the microstructures of material before and after deformation were examined using OM and TEM. Equiaxed grains were still kept, and the second-phase particles and dislocations were observed in the deformed samples.

Abstract: In this study, effects of Modified Atmosphere (MA) packaging on the quality of rice after a long term storage at room temperature have been investigated. PVC films with different thicknesses and woven bag were used as the package materials for rice samples. Results showed that MA packaging had a significant effect on the quality of the rice. After an extended period of storage, the rice in woven bag showed most severe quality deterioration compared to those stored in PVC packages. Rice packed in 0.05 mm PVC film package has the lowest value of total acid among all samples. The increase of fatty acid content in rice packed in 0.03 mm film, 0.05 mm film, 0.08 mm film and 0.12 mm film was 38.58 mg KOH/100g, 18.96 mg KOH/100g, 26.83 mg KOH/100g and 32.64 mg KOH/100g, respectively. The volatile aldehyde components accumulated in the stored rice are mainly acetaldehyde, valeraldehyde and hexanal. Small package with a MA has obvious benefits in regulating the metabolism and accumulation of volatile aldehyde components in the rice. Rice samples stored in a package of 0.05mm film had the lowest value of volatile aldehyde, while those in 0.03mm film had the highest value. This study suggests that MA packaging with a PVC film of 0.05 mm shows the best effects in maintaining the quality of rice after an extended period of storage (3 to 5 years).

Abstract: A transparent hard coating of silicon oxide (SiOx) deposited by using plasma enhanced chemical vapour deposition (PECVD) can protect the surfaces of plastics and metals. This coating has good adhesion, good wear-resistance and environmental resistance. Our work is to optimize this protective organosilicon film in an industry manufacturing process for the metal cover of mobile phones and plastic lenses. Investigation of the failures of the film and analysis of the defect in deposited films by means of the optical microscope and atomic force microscope (AFM) shows that mechanism of the micro defect with Newton color rings.

Abstract: In order to solve the interlayer channeling in the process of oil and gas production, the forming agent of agglomerated cake and mud cake modifier based on Mud Cake to Agglomerated Cake (MTA) method are developed. The evaluation results in laboratory show that the bond strength of cement-formation interface (BSCFI) with the new materials increases significantly with curing time by comparison with those without new materials. The analysis shows that the mechanism of new materials includes three steps. Firstly, the forming agent of agglomerated cake modifies and treats the surface of mud cake and it reacts primarily with the mud cake modifier. Secondly, the cement generates in agglomerated cake. Lastly, the compact agglomerated cake forms. Field applications show that the high quality rate and qualified rate of well cementing with the new materials increased by 13.01 percent points and 1.15 percent points respectively, and the proportion of isolation section length whose Bond Index is greater or equal to 0.8 with the new materials increased by 15.92 percent points compared with other wells in the same block.

Abstract: The gating system is usually made up of the sprue, the runner, the gate and the slag well. It is an important component of the mold. On the basis of relationship among runner’s geometry, the pressure fall of plastic melt flowing in runner, flow rate and material properties, we can use the UDF library features and Pro / Toolkit functions in PRO / E software to do the second development of PRO / E software. As a result, we can establish the CAD module of gating system for the injection mold. The module has the perfect function and good generality and can help the designer for cost reduction. It may be used whenever you want to use. The PRO / E software has a powerful function to design mold. Taking these as a base, it is very convenient for the module to design the gating system of injection mold.

Abstract: Al-Si alloy casting used in high-voltage switch is of various types, small quantities and high quality, so it is difficult to meet the quality requirement to adopt general production technique in practice. Inclinable-pour technique of no-bake resin sand mould is realized successfully by means of inclinable-pour auxiliary means designed in the paper. This method not only can shorten the processing cycle and decrease the manufacture cost of casting die, but also can improve obviously mechanical characters and quality standards in total of Al-Si Alloy casting.

Abstract: This Using same cementitious materials and mix parameters, effects of aggregate variety on volume deformation of concrete are analyzed and essential causes are explored. Results shown that given the aggregate content, linear expansion coefficient of concrete increase with that of aggregate; aggregate variety has significant impact on autogenous volume deformation of concrete primarily caused by different water absorption of aggregate over long time, which was confirmed by qualitative and quantitative analysis. Paper looks forward to providing technical support for anti-cracking study of dam concrete.