Applied Mechanics and Materials Vol. 274

Abstract: Flow behavior of gas and particles is predicted by the large eddy simulation of gas-second order moment of solid model (LES-SOM model) in the simulation of flow behavior in CFB. This study shows that the simulated solid volume fractions and velocity along height using a two-dimensional model are in agreement with experiments. The second-order moments of particles are computed.

Abstract: Environmental Monitoring system has become more and more critical for biological protection recently. To get timely information from monitored environment, a timely wireless senor network routing scheme (TNRS) is proposed, which is made up of three phrases: initial setup, route discovery and establishment, data communication and route maintenance. In the first phrase, every sensor node will get the initial route table. In the second phrase, source node will find its own path with high fitness value. In the third phrase, data transmission and route maintenance are done under ACK confirmation mechanism. Simulation shows that TNRS routing scheme can decrease data miss ratio by 24.88%, and reduce average data latency by 14.85%, compared to SPEED routing scheme. So TNRS scheme can provide better real time service for environmental monitoring system.

Abstract: This study focuses on the automated essay scoring system: Teaching Resource Program (TRP) from a cross-disciplinary perspective. Different from previous research, this research emphasized the functions of Teaching Resource Program in the respect of evaluation and the capacity to enhance the writing competence. In what follows, we attempt to specify Teaching Resource Program and its contributions. We start with a brief introduction to Teaching Resource Program. Then, we provide the techniques, related theories, and computer programs used in Teaching Resource Program. We have found in this research that Teaching Resource Program and evaluations of e-writing are highly significant correlation. Based on these findings, some useful implications from this study include that automated essay scoring system: Teaching Resource Program needs to be further incorporated with the evaluations of other disciplines. We end the study with the conclusion that Teaching Resource Program contributes to evaluate e-writing pieces, consequently enhances the students' writing performance and further advances the development of writing curricula and other disciplines.

Abstract: Non-contact hydraulic seal (clearance seal) reduce the leakage by the small clearance between the seal. Non-contact hydraulic seal is the simplest form of a seal. The sealing effect depends on the size of the clearance and pressure difference, the length and parts of the sealing surface quality. Among them, the clearance size of the greatest impact on the sealing performance. The hydraulic systems sealing mathematical and CFD model are built in this paper. Studies have shown that eccentricity ratio, seal clearance and pressure are has impact to hydraulic force and leakage. It should be considered in the engineering design.

Abstract: In order to ensure the quality of marine gas turbine generation set, its speed must maintain constant. Due to rising or falling power demand, the real and reactive power balance is harmed and hence the turbine output speed gets deviated from nominal value. This necessitates the need for an intelligent fuzzy controller to generate and deliver power in an interconnected system as economically and reliably as possible while maintaining the power turbine speed within permissible limits. The design of complex parameter self-tuning fuzzy control system and efficient simulation were achieved. The models were simulated for different load conditions in order to demonstrate the effectiveness of the proposed controller. Simulation results emphasized the improved performance in comparison with fixed gain controllers. The proposed method overcomes the drawbacks of a conventional fixed gain controller and improvement was achieved in terms of settling time, oscillations and overshoot.

Abstract: As support agencies of the aviation maintenance and support system, the aviation overhaul depots undertake an important and arduous support mission, which play a pivotal role, so the science and rationality of site selection is extremely significant. This paper choose the nonlinear programming method to build a mathematic model, so as to solve the problem. For the purpose of optimizing and solving the model, a thought based on the improved particle swarm optimization which used in the model is put forward to, and an improved PSO which gained by the analyzing the standard PSO and improving the initial PSO is presented in this paper. Finally, an application example is given to analyze and summarize the model.

Abstract: In this paper, an AlN-based hot-film wind speed and direction sensor was designed through the thermal analysis of two-dimensional flow field, realized the measurement of wind speed and direction. The 2D micro structure sensor was prepared by lithography process and laser micro machining process on 0.2mm thick AlN substrate. It is composed of a heater in the middle, four temperature detectors around and a temperature sensor. The sensor has a small volume, a low power consumption, it is easily to be integrated, can be applied to a variety of portable flow meters and gas flow detectors of the complex environment.

Abstract: Design a new type of electro-hydraulic servo control system of oil film in hydrostatic center frame, regulate and control oil film thickness adopting various controllable oil chambers, build mathematical models of control system and carry on system model identification and verification. Propose a control strategy about fuzzy sliding model variable structure, and it is applied in the model achieved by identification, adopt the method of fuzzy control system approximating equivalent control and design switching controller based on fuzzy control gain dynamic regulation, which could inhabit buffeting existing in sliding model variable structure control. Simulation results show that the controller can’t only effectively inhabit buffeting and reduce steady-state error, but also has strong robustness for structure parameter uncertainty.

Abstract: Nowadays traffic accidents occur more and more frequently, as a result, intelligent vehicles develop more and more quickly. In many research directions of intelligent vehicles, vision navigation becomes the hot spot. An algorithm of the present lane left-right marking lines detection was proposed in this paper. The algorithm combines edge detection and Hough transform, firstly detects the initial lane marking lines and then tracks the final target lines. Simulation results indicated that the algorithm could recognize the present lane marking lines to make vehicle navigation precise and fast.

Abstract: In order to achieve the switching function of the force and position, the force control is executed when the hydraulic cylinder contacts with the mechanical objects, the position control is executed when the hydraulic cylinder is far away from the mechanical objects. This paper respectively established force control model and position control model. The position control adopts the PID algorithm and the force control adopts the fuzzy algorithm. In order to solve the jump and jitter of the parameters when force-position switching, this paper puts forward a fuzzy switching adaptive control strategy. Fuzzy switching ensures the smooth transition of the two control models, the results of simulations show that fuzzy switching not only ensures the system’s rapidity but also shows excellent robustness against variations of system parameters and external disturbances.