Advanced Materials Research Vol. 743

Abstract: Jacaranda mimosifolia of 55-year-old in Sichuan Neijiang was selected as test material. Through the observation of its growth and development by 2011 and the analysis of temperature and relative humidity, this study discussed its basic law of growth and development and the relationship between temperature and RH factor. By analysis of variance, there was no significant difference in monthly average temperature and RH between 2011 and the climate in Neijiang, the temperature and RH of 2011 could reflect the situation of Neijiang regional climatic. The results showed that the average annual growth of J. mimosifolia new shoot was 32.4cm and the average thickness was 11.2mm, and appeared thrice sprouting and twice flowering phenomenon per year. Combined the characteristics of growth and development of J. mimosifolia, the length and thickness of spring shoot, summer shoot and autumn shoot were both extremely different (P<0.01), and two florescence appeared in Spring and Autumn when the temperature was not different significantly. Therefore, temperature played an apparently predominant role in its growth and development.

Abstract: Extensive application of rigid polyurethane foam leads to a huge amount of waste after reaching their useful life. Recycling of this waste can protect the environment effectively. In this paper, mechanical recycling was employed in the preparation of the recycled insulation board. The relationship was represented between the amount of water-soluble PF and aqueous polyethylene wax used and thermal conductivity, along with the compression performance of the material. A result of better property was observed when the ratio of rubber of 15% water-soluble PF and 3% aqueous polyethylene wax was employed.

Abstract: The printed circuit boards (PCBs) are the basis of all electrical and electronic equipment (EEE) and thus are one of the most important branches of WEEE stream. Present researches mainly concentrate on the processes of reusing noble metals and copper, and a great deal of nonmetals in PCBs are disposed by combustion or filling, which may cause secondary pollution and resource-wasting. So in this paper, we study how nonmetals are used to produce recycling boards through adding different adhesives, and obtain the best formulation and working conditions. The best formulation is that the binder is Polypropylene (less than 20%), additive are methenamine (little) and stearic acid (little). Effects of working conditions on the molding results are investigated. The results show that the optimum conditions for hydraulic pressure machine are the temperatures of 160 °C, warming and pressing time of 10 minutes and the press of 30MPa.

Abstract: Based on the properties of mechanical materials, the friction noise experiment is conducted on the E-glass-reinforced nylon 6 composite gears in this paper. In the test, by combining the friction testing machine with the noise processing software DASP, the vibration noise signals of the composite gear samples with and without self-healing microcapsules at different friction temperatures were picked. Then the influence the self-healing microcapsules have on the friction noise performance of the composite gear material was analyzed by comparing the obtained signals. The results show that the noise of composite gears with self-healing microcapsules is lower than that of gears without self-healing microcapsules at both different temperatures and different frequencies, which means that the self-healing microcapsules reduce the friction noise of the composite gears.

Abstract: Fused spinning method is the most commonly used method to manufacture man-made fiber and the most important physical property of as-spun fiber is tenacity, which is affected by process parameters including spinning nozzle temperature, cooling temperature, cooling wind speed and winding speed. First, we selected the appropriate orthogonal array for the experimental plan to conduct experiments. Coupled with signal-to-noise (SN) ratio and main effect analysis, we understood the impact of process parameters on quality and confirmed the reproducibility of the experiment, and furthermore obtained the optimal combination of process parameters.

Abstract: The degradation of polylactic acid (PLA) can be divided into the hydrolysis, the degradation and metabolism. The hydrolysis reaction is caused by chain breakdown of the polymers of polylactic acid, resulting in the degradation of polylactic acid. Therefore, this study aims to improve the hydrolysis rate of PLA at the early stage of degradation process and then it increases the degradation rate of the PLA in the natural environment. We employed Taguchi method for parameter design of PLA hydrolysis, focusing on the control factors that affect the conditions of the hydrolysis rate of PLA, such as temperature, bacteria, ventilation degree, and nutrients and we also used orthogonal array to precede experiments, in conjunction with analysis of variance (ANOVA) to identify significant factors and optimal hydrolysis conditions for PLA. By analysis of variance, we know that temperature and bacteria as significant factors, and the factor of temperature contributed 96.882%. Finally, we employed confirmation Experiment to verify the reproducibility of the experiments. Our results have shown that the best condition of PLA hydrolysis rate experience with the reliability of its representatives are in compliance with the 95% of confidence interval, CI, which indicates the reliability of our study.

Abstract: An ideal anodes used for the electrochemical oxidation of organic wastewater should have excellent activity, stability and high oxygen evolution potential. In this paper the CNT (Carbon Nanotubes)-PbO₂ films electrodeposited on stainless steel were prepared. X-ray diffraction (XRD) patterns and SEM images indicated that CNT particles and PbO₂ were able to achieve co-deposit and the composite CNT-PbO₂ films were compact. The cyclic voltammograms of the CNT-PbO₂ films studied in 0.5M H₂SO₄ at a scan rate of 100 mV/s showed that the CNT-PbO₂ film has high electrochemical stability. The results of wastewater treatment indicated that the CNT-PbO₂ anodes have excellent activity in ammonia wastewater treatment.

Abstract: Gelatinization is the main transformation of the starch dough undergoing cooking. This process is very important both for the texture and the nutritional properties of the final product. Starch gelatinization process has been studied by many workers, which includes the mechanism, kinetics, and influencing factors. The kinetic models have been used by works to predict the cooking process of starch. Finite element method (FEM) is commonly used in the simulation of starch gelatinization process. The simulation results can predict the cooking process of starch, and are helpful for optimizing the cooking conditions of starch dough. The theoretical and numerical simulation research on gelatinization of starch is reviewed, and the progress and difficulties in this field are discussed.

Abstract: Cu/Al composites have the advantage of both copper and aluminum, i.e., the high electrical conductivity, high thermal conductivity, and low contact resistance of copper; the lightweight and corrosion resistant of aluminum. Roll welding is one common method to produce Cu/Al composite plates. The effects of rolling reduction ratio and annealing temperature on combined strength are analyzed by experiments. The results demonstrate that the combined strength increases with the increase of rolling reduction ratio, and at around 300°C the combined strength achieves the maximum value. The reason is then analyzed respectively. The results are helpful for understanding the Cu/Al combing mechanism, and are useful for improving the producing process of Cu/Al composite plates.

Abstract: Ultrafine-grained materials have excellent mechanical properties, which include the high strength and toughness. Equal channel angular pressing (ECAP) is one kind of severe plastic deformation method to make ultrafine-grained metals. The ECAP processes are simulated by finite element method (FEM) in this work. The effects of inner corner angle on strain distribution during the deformation process are numerically analyzed. The evolutions of effective strain on three points of different deformation are compared. The results show that the deformation becomes severe on each point when the inner corner angle is less than 90^o, which is different from the situation when the inner corner angle is equal to or greater than 90^o. The results are useful for improving the ECAP process to make the structure of metals homogenous.