Advanced Materials Research Vols. 482-484

Abstract: It was most effective and practical that using computational fluid dynamics simulation to analyze the distribution of flow field in gob for studying optimal layout scheme of the working face ventilation system. In this paper, numerical simulation was applied for studying the migration laws and high concentration of gas gathering area of N1201 working face in Tunliu Coal Mine; the gob of robbing working surface gas migration laws and high concentration of gas gathering area was obtained; the optimum arrangement of ventilation system for the working face was given. The conclusions had a certain theoretical value and practical significance for controlling the working face gas.

Abstract: With CaF2 and CaCO3 as sintering additives, AlN-Mo composite was prepared using hot pressed sintering technique. The phase composition and morphology of AlN-Mo composite ceramics were analyzed using XRD and SEM, respectively. The experimental results show that when CaF2 and CaCO3 additives is in a range of 1~3wt%, the thermal conductivity AlN-Mo composites increases with increasing of the CaF2 content; With the increasing of CaCO3 content, first increases and then decreases. Sintering additives in a certain type and content, the thermal conductivity of AlN-Mo composite ceramics with 20 vol% Mo is higher than containing 18 vol% Mo. The dielectrical property of AlN-Mo composite ceramics was also discussed. The addition of CaF2 can decrease the dielectric constant of AlN-Mo composite ceramics.

Abstract: Application experiments have been done to research the strand quality of high carbon steel 65Mn under the condition of electromagnetic stirring. The experimental results show that the effect of electromagnetic stirring with stirring rollers in side-side disposition mode is better than that in face-face disposition mode. The effect of electromagnetic stirring is also increased with the increasing of current intensity, and the continuous stirring is better than alternating stirring. Thus, conclusion could be arrived that the strand inner quality is improved obviously by the adoption of electromagnetic stirring due to 32% increase of equiaxed zone ratio in the strand and the decrease from B0.5 to C1.0 of the center segregation grade.

Abstract: The minerals of zirconolite doping simulated radioactive incineration ash were fabricated by solid reaction, using zirconium dioxide, titanium dioxide, calcium carbonate or CaTiO₃ as raw materials. The phase assemblage was tested by X-ray diffractometer. TG-DSC was tested by SDT-Q600. Compared to carbonate preparation method, using intermediate products (CaTiO₃) preparation method to synthesis CaZrTi₂O₇ is more energy saving.

Abstract: This paper introduces the structural composition and the working principle of the support installation vehicle. The 3D model of the support installation vehicle is established in SolidWorks and imported into ADAMS. Then the virtual prototyping model of the support installation vehicle is established with ADAMS software. The dynamically leveling angle curve of the leveling mechanism is obtained by the simulation analysis. Curves of cylinders’ driving force and the joint force are also derived. The results of simulation analysis contribute to the finite element analysis of working unit and the designs of cylinders of the support installation vehicle.

Abstract: The changes of the tensile properties of the full lamellar TiAl alloy under pre-compression were studied by means of pre-compression damage tests and tensile tests. The study indicated that：The changes of the tensile property of the damaged alloy at room temperature were different from that of high temperature. The mechanical property of the TiAl alloy degrades because of the present of the cracks, which decrease the load area of the alloy.

Abstract: The thermal stresses at the extreme temperatures in bridge deck pavements (BDP) was analyzed in the paper. The sample bridge deck and asphalt concrete pavements were analyzed. The maximum principal and shear stresses in the BDP at the wide range of temperatures were calculated using 3D finite element method. The compared results showed a strong linear correlation between the BDP maximum principal stress and the elastic modulus. This linear relationship also existed between the shear stress and the elastic modulus. From the finite element analysis, it is found that the BDP elastic modulus affects the thermal stress more than the thickness of BDP. With the consideration of thermal stresses of BDP, the thickness of BDP from 6 to 12 cm is recommended for the BDP construction.

Abstract: Telemetering power supply and distribution system is an important part of the telemetry system. Arming at a telemetering power supply and distribution system, this paper adopts digital multimeter and multiplex switch based on PXI bus to realize 32-channel power supply and distribution DC voltage signal acquisition, storage, real-time monitoring and analysis, and also automatic data interpretation. The system consists of PXI host, multiplex switch, digital multimeter, interface unit, a control software and so on, which has the advantages of high precision, high efficiency, easy to operate, and has been used successfully in the test of a telemetry system.

Abstract: The problems of robust fault-tolerant control for T-S fuzzy system with actuator failure are studied. A new sufficient condition for the existence of robust fault-tolerant controller is given. Under the condition, the designed controller can provide the asymptotical stability of the closed-loop system. The non strict LMIs for the system are transformed into strict ones by means of the matrix decomposition. In this way the solutions to the controller can be given via the LMI toolbox. An illustrative example is given to show the feasibility and validity of the proposed approach.

Abstract: Water supply system is a complex system. Aimed at the puzzle of being very heavy in energy consumption of system control and being not better in water supply quality resulted from being inappropriate in control strategy, The paper researched on the energy conservation strategy and control mechanism of water supply system. It discussed the cybernetics characteristic of water supply process, proposed the intelligence based fusion control strategy and the energy conservation executing strategy, and analyzed the control model of water supply purifying process and the control algorithm of constant pressure control system. Based on the comparative study of simulation experiment, the display of response curve demonstrated that the intelligence based control strategy would be better than conventional PID control method. The simulation results show that the proposed strategy combined intelligence based fusion control with speed control by frequency variation has better application prospect in water supply system.