Applied Mechanics and Materials Vol. 482

Abstract: The paper proposed a data compression method in multiresolution structure and realized multiresolution rendering of point model by traversing the KD-tree breadth-first. It established the details control of multiresolution rendering, improved the drawing efficiency of point model. And a simulation study was carried out. Results show that the method could not only reduce the geometry data volume of point models directly, but also reduce the sampling point number without debasing the numerical precision of the model geometry data, so as to further reduce data volume of point model. In addition, the mixed rendering of geometric model point and rectangle in this method overcome the shortcoming that point model set is unsuitable for large flat surface.

Abstract: This paper presents CFD analysis of shrouded diameter in aerosol sampling inlet. Different shrouded diameter for the sampling inlet will be simulated and discussed in detail. The objective of the design is to optimizing the sampling inlet flow necessary for achieving high efficiency of aerosol sampling, while minimizing disturbance to the aircraft which carries aerosol sampling inlet. The design optimization was performed with the computational fluid dynamics (CFD) code FLUENT. The shrouded diameter to minimizing flow disturbance is 150mm. A shrouded diameter understanding derived from the CFD analysis could improve shrouded design.

Abstract: The brain operates at criticality not only at resting state but also with some recognition tasks. Researches have shown that the information transmission efficiency is maximized when brain operates at criticality, however, the underlined mechanism remains some unknown. In this study, we elucidate the underlined mechanism of neuronal information transmission at criticality through a computational study. Firstly, a bifurcation analysis is conducted, by which we can obtain the Hopf bifurcation curve, responding the critical state. Secondly, we compute the autocorrelation function of the EEG (Electroencephalography) signals. The results have demonstrated that the autocorrelation function at criticality decay slowly and is much larger than other states, meaning long range dependence of the EEG signals at criticality, which reveals that the large autocorrelation function results that the information transmission efficiency is maximized at criticality.

Abstract: MEMS (Micro-electromechanical Systems) sensors have many advantages including fast response, low cost, small size and low power consumption. However, MEMS sensors suffer low accuracy and poor stability due to the limitations of the manufacturing process. the MEMS/GPS integrated navigation system based on EKF make up for these shortcomings. The system using a low-cost MEMS sensor system consists of tri-axis gyroscopes and accelerometers which also incorporates a tri-axis magnetometer, and it can provide a complete measurement of orientation relative to the direction of gravity and the earths magnetic field.Extended kalman filter is used to fuse informations from MEMS and GPSof UAV. Mathematical models of GPS and MEMS sensor system are constructed based on matlab/simulink. The experimental results indicate that the average attitude angle error obtained is less than 0.15° in simulation experiments while position error is less than 7m and the velocity error is less than 0.4m.

Abstract: The paper presents the re-entrant jet analysis of cavitating turbulent flow on a hydrofoil. Analysis was performed by OpenFOAM code. A mixture assumption and a finite rate mass transfer model were introduced. The finite volume method is used to solve the governing equations of the mixture model and the pressure-velocity coupling is handled via a Pressure Implicit with Splitting of Operators (PISO) procedure. The result of numerical simulation clearly explained the mechanism of re-entrant jet and quasi-periodic law of cavitating flow on a hydrofoil.

Abstract: Based on the KIVA-3V source program and coupling the multidimensional model of in-cylinder combustion, this thesis designs a simulation platform of the combustion and emission performances of diesel engines. Results of the test on the in-cylinder pressure change and emission of the experimental subject proves the accuracy of the platform, showing that the platform is able to objectively reflect the real working process of the subject, and that it can be used to research the combustion and emission performances of the experimental engines for a further improvement of the working performances.

Abstract: To sample wideband IF signal with large amounts of data, a high-speed data acquisition program is presented. The program focus on circuit design, issues that need attention, and high-speed sampling signal deceleration strategy. The 2.4GHz rate sampling data acquisition, reception and demux are completed with ADC083000 and Field-Programmable Gate Array (FPGA). At last, a result of sampling with the converter is offered by chipscope software. The result verified ADC083000 has an excellent performance with more than 6.5 bit ENOB and good phase coherence. In engineering practice, the design has been used and has good performance.

Abstract: Reed Solomon code is described as a theoretical decoder that corrected errors by finding the most popular message polynomial. The Verilog language is applied to descript decoding algorithm. Cyclone series FPGA EP1C6Q240C8 is adopted as a core of hardware platform and a serial port communication part is used to receive input error correction data. The results show that it can successfully correct eight errors, which is the limitation of error correction. With the RS decoder, it can ensure that the strong error correction capability and fast speed.

Abstract: Inspection work on power transmission line is an important link in the safe production of electric power, inspection staff training has always been attention of the power industry researchers. In order to improve learners training effect, we put forward a new form of teaching to inspect transmission lines with combined with simulation training. This paper analyzes the transmission line inspection requirements and the corresponding functions of the simulation system and the corresponding, then introduces the system structure, the abstract simulation training process, finally give the system application examples. Application results show that the 3D simulation training system of the power transmission line inspection can effectively guarantee training effect on the transmission line inspection technology.

Abstract: As an important raw material of chemical industry, logistics and transportation quantity of sodium cyanide is sharply increased. However, the accidents of sodium cyanide ISO-tank transportation are frequently happened, which caused huge negative impacts on the society and the environment because of its high toxicity. In order to ensure smooth transportation of the hazardous chemicals, we must strive to control the dangerous sources of transportation to eliminate and reduce accidents for the safety and property of the people. On the basis of risk analysis of ISO-tank transport of sodium cyanide, this paper studies the reasons leading to accidents on the point of people, vehicles, ISO-tanks, roads and managements in detail. At last, it focuses on the countermeasures for safety management of sodium cyanide ISO-tank transport on the view of safety assessment in order to provide some guidance for the healthy and sustainable development of this industry. Key words: sodium cyanide;transportation; safety assessment