Advanced Materials Research Vols. 468-471

Abstract: An effective finite difference method (FDM) is adopted to calculate the pressure distribution of radial groove gas-lubricated face seals at slow speed condition. Some key parameters of seal performance, such as open force, gas film stiffness, and leakage rate are calculated. Effect of seal ring parameters on seal performance is also analyzed. Compared with the results of non-slip-flow condition, it is shown that the effect of slip flow should be considered when the gas seal is analyzed at slow speed

Abstract: High speed milling of hard alloy steels utilized in dies and molds is a highly demanding operation. The finite element model was developed to investigate the high speed machining of alloy cast iron which is used in auto panel dies. The modified Johnson-cook constitutive model was used to model the complex dynamic material behavior, a damage evaluation law based on Cockroft and Latham model was used to simulate the ductile fracture of alloy cast iron. The crack initiation and propagation was simulated explicitly using an explicit FEM code. Simulation results showed that the chip morphology transited from continuous to saw-tooth chip with increasing cutting speed, cutting force decreased when increasing the cutting speed, which provide a useful understanding of chip formation process in high speed machining of alloy cast iron.

Abstract: In contrast to computational aerodynamics, which has advanced to a fairly mature state, computational aeroacoustics (CAA) has only recently emerged as a separate area of study. The fluid field when air flowing through the nozzle is calculated based on the standard RNG turbulent equations. The mass flow rate is tested based on the experiment. Comparing the calculated and tested mass flow rate, there is only 0.6% error. Hence the results based on the CFD method are reliable and can be used to industrial applications. The Lighthill’s acoustic analogy method is adopted and the noise when air poured into opens space is simulated. The noise is also tested by the experiments. The result indicate that the simulated data have the same tends as experiment data. Although there are some differences between the simulated and tested data, the simulated data shows that the numerical method can be qualitatively predicting the industrial noise.

Abstract: In this paper, we consider the non-oscillatory problems of odd-dimensional system of linear delay functional differential equations. Based upon the corresponding characteristic equations, we get some criteria for non-oscillatory solutions by utilizing the matrix measures.

Abstract: A finite volume discretization method for solving the heat and mass transfer equations of drying jujubes was developed in this paper. Combined with the Labview program, development of a numerical simulation software for internal heat and mass transfer during drying of jujubes, and simulation of the drying process on the jujubes using the software. The results showed that the simulation results and experimental data were consistent.

Abstract: Cold start is a necessary function for PEMFC systems. In order to investigate the water freezing and thawing process inside PEMFC stack under subzero temperature, a 2-D transient model containing 40 cells has been developed. This model approximately estimates freezing and thawing time of each cell and shows the spatial distribution of water and ice for the purpose of analyzing the differences between single cells as well. As simulation examples, two processes under 260K ambient temperature have been studied in this paper and the results show as follows: (1)after the stack shut down, first of all, the outermost layer cell of the stack freezes before the inside cells and the freezing duration of each cells is almost the same, secondly, the freezing interval time of the outer cells is longer than the inside cells and the innermost cells almost freeze at the same time; (2) before the stack start up, heating up the membrane under two situations, one with the residual water inside and the other one has been purged after it shut down, the temperature rise of the stack with water is slower than that without water, this result indicates that the residual water would influence the cold start process.

Abstract: This paper thus applies Balanced Scorecard to construct performance measures according to the stated goals and actual results of the training program. Data collected through a questionnaire survey is analyzed using descriptive analysis, one-way ANOVA, and factor analysis to explore factors affecting the performance of the training program, differences caused by environmental and individual factors, and the causes of these differences. Finally, suggestions on the application of the proposed measures to analyze the effectiveness of human resources training are provided. These suggestions can be a basis for the future implementation or improvement of human resource training programs.

Abstract: Based on the relevant literature and research theory, this paper discusses supply chain partner relationship classification evaluation model. As an object of study, Chinese typical manufacturing enterprises were surveyed through the design questionnaire to understand the present situation of supply chain partner relationships among them. With using of cluster analysis, supply chain partner relationships are classified to explore the regulation and trend for Chinese manufacturing enterprises’ supply chain partnerships.

Abstract: Weed recognition is one of the key parts of variable rate spray system, and is the important part of precision agriculture. This paper applied the order morphology to weed recognition, and constructs the edge detection operations that fit to weed image. The corresponding simulation is also done, the result show that the operation that this paper proposed is very suit for weed edge detection.

Abstract: Target tracking algorithm is used widely in many fields, such as robot vision system, intelligent surveillance and medicine, but computational complexity and lack of dedicated embedded system for real-time processing have affected its application. This paper presents a method that combines embedded system, smart camera and mobile robot for detecting and tracking the moving targets. On the basis of particle filter algorithm, mean shift embedded particle filter algorithm is proposed and implemented on embedded platform with ARM+DSP dual core framework. At last, the whole system is optimized to improve the real-time property. The proposed method has a very powerful data processing ability, which can offer a high reliability for the navigation of a mobile robot.