Advanced Materials Research Vols. 156-157

Abstract: The effects of MA packaging on nutritional value and quality of honey pomelo have been investigated during storage at 8 . Results show that 25μm-thick PE films maintained more suitable headspace gas concentrations for preservation of pomelo than 50μm-thick PE films and microperforated 25μm-thick PE films (control). The 25μm -thick PE films have the highest value on quality parameters, which were 12.2%, 0.9%, 47.1mg/100g and 44.8mg/100g for total soluble solid, titratable acidity, vitamin C and total phenolic content after 150 days of storage, respectively. This study suggests that MA packaging with 25μm-thick PE films show the best effects in maintaining the quality of honey pomelo during storage at 8 .

Abstract: The change of H/O mixture ratio has affect on the combustion of H/O mixed gas in the micro combustor, and the temperature distribution of the micro combustor wall are researched in this paper, when the mixed gas flux is different in the combustor of the micro thermophotovoltaic system. The result of the test indicates that H/O mixed gas can combust stably in the micro combustor. As mixed gas flux is 3.92g/h and H/O mixture ratio is 2, the temperature of the micro combustor wall is about to 1100K, which matches work requirement of the micro thermophotovoltaic system.

Abstract: A classical Demerit control chart is used to monitor the process through which various types of defects in complex products, such as automobiles, computers, mobile phones, etc. are found in general. As a technique for rapidly detecting small shifts of the process mean in the control chart, the EWMA(exponentially weighted moving average) technique is very effective. This study suggested the Demerit-GWMA control chart, combining the GWMA(generally weighted moving average) technique, which shows better performance than EWMA technique in detecting small shifts of process mean, into the classical Demerit control chart, and evaluated its performance. Through the evaluation of its performance, it was found that the Demerit-GWMA control chart is more sensitive than both the classical Demerit control chart and the Demerit-EWMA control chart in detecting small shifts of process mean.

Abstract: In this paper, the micro pits were fabricated on 316L stainless steel surface, and the influence of pits topography on the platelets adhesion was investigated. For initial steel, large platelets agglomeration and long pseudopodia are observed. It is found that the pits on stainless steel surface can effectively prevent pseudopodia spreading; as a result the aggregation of platelets is fully restrained. The resistance of platelets adhesion increase with the coverage rate of pits area () on total steel surface.

Abstract: The characteristics of heat transfer enhancement and deterioration in supercritical water reactor core is essential to the reactor efficiency and security. At present, there exists deficiency in the study of core enhanced channels. Two different fins arrangements of the enhanced channels are designed in present paper, which are long-strip fins and equal-distance short fins. At the conditions of the supercritical pressure of 25MPa, the inlet temperature of 350°C and different inlet velocities, the heat transfer enhancement and deterioration characteristics of water flowing in the two different fins arrangements of the enhanced channels were studied and comparatively analyzed. The results show that the heat transfer is enhanced in the channels with fins. The heat transfer enhancement is better in the channel with equal-distance short fins when lower input velocity, better in the channel with long-strip fins when high input velocity. The surface heat transfer coefficients increase with the velocity increases; the surface heat transfer coefficients in equal-distance short fins is two to three times than that in the channel without fins. There exists heat transfer deterioration when the input velocity is lower in the channel without fins and with long-strip fins, no deterioration occurs in the channel with equal-distance short fins. The channel with equal-distance short fins is a relatively reasonable of the three channels.

Abstract: The electrochemical reaction in the cathode plays an important role on the performance and application of PEM fuel cell. In this paper, mechanism of oxygen reduction reaction in the cathode of PEM fuel cell is simulated based on molecule dynamics and quantum mechanics. The most probable electrochemical reaction process in the cathode is obtained by analyzing transition state and free energy of oxygen reduction reaction with the catalysis of Pt. Simulation results show that 2e reaction mechanism is more applicable to oxygen reduction reaction in the cathode than 4e reaction mechanism; according to the potential energy barrier, the process from hydrogen peroxide to water is the controlling process of oxygen reduction; comparison with the total free energy, when the fuel cell temperature is 353K, the thermodynamics potential of PEM fuel cell is the highest. Simulation results are very helpful to understanding reaction mechanism in the cathode of PEM fuel cell and optimizing its performance.

Abstract: In modern life, factories and household electricity consume the largest amount of electric power, especially in summer. The continuous operation of air-conditioning system increases the heat in the environment and speeds up energy consumption as well. Therefore, in order to promote ecological balance, reduce carbon dioxide emission, and establish no pollution living environment, this study used green energy power generation technology, rainwater collection system, automatic light sensor-controlled curtain, infrared-controlled light, temperature sensor-controlled air-conditioning system, anti-theft system, and smoke-sensing device as effective devices for utilization of green energy. The rainfall collection system can increase the utilization of water resource. The curtain with light sensors, illumination system, and air-conditioning system can effectively save energy. The anti-theft system and smoke sensing device can both ensure the safety of living environment and achieve the objective of energy saving and carbon reduction, which can make the future living environment become more comfortable, energy-saving, and environmental-friendly. In addition, the devices above can also make contribution environmental protection of the earth and preserve a clean, beautiful, and sustainable environment for future generations.

Abstract: A proprietary in situ chemical vapor deposition (CVD) process was developed to grow a layer of pyrocarbon on carbon paper preform for proton exchange membrane fuel cells (PEMFC). The carbon paper preform is continuously manufactured by dry method. The characteristics of the carbon paper such as surface morphology, polarized light characteristics, and cross-section morphology were characterized using electron microscope, polarized light microscope, respectively. Fuel cell performance of the carbon paper was evaluated using single cell with hydrogen/air at various relative humidity (RH) conditions. The carbon paper with in situ growth of pyrocarbon showed significant improvement in lowering in-plane electrical resistance as well as fuel cell performance at dry condition. The carbon paper as seen under scanning electron microscope showed excellent surface morphology with pyrocarbon connecting carbon fibers tightly by CVD process.

Abstract: To represent curves and surfaces unified, many commercial soft-wares adopt non-uniform rational B-spline (NURBS) as the method. The NURBS method includes Bézier, B-spline and so forth. In surfaces smoothing Class A surfaces of auto-body are a kind of surfaces that have high desire. While different representing methods can fit curves and surfaces with prodigiously different qualities and efficiency. So the representing methods and degree selection of curves and surfaces for auto-body are fundamental issues that auto-body engineers must be solved. Based on analyzing the character of Bézier and B-spline representing methods, Bézier method is adopted to represent Class A surfaces of auto-body according to the desire of auto-body surfaces. At the same time, the degree of curves and surfaces for auto-body is limited between 2nd-7th according to the oscillation of high degree curves and surfaces and continuity desire. The example verified that the Bézier method can improve the quality and efficiency.

Abstract: Damping capacity and stiffness loss must be considered together in the design of integral damping composite structures. In the present paper, a discrete layer beam finite element is used to model and analyze a damped composite I-beam embedded with viscoelastic layers. Two multi-objective optimization models are developed with maximum natural frequency and modal loss factor. In the first model, only one damping layer is embedded in each flange of the I-beam. Design variables consist of damping layer thickness and its inserting location. In the second model, multiple damping layers of equal thickness are embedded in the flanges. Design variables included the number of damping layers and their inserting locations. Multi-objective genetic algorithm is used to solve optimization problems. It is showed that the analysis method has acceptable accuracy for composite damped I-beams, and it is convenient for optimization design of integral damping composite structures, especially for the cases embedded with multiple damping layers.