Applied Mechanics and Materials Vols. 541-542

Abstract: The production of greenhouse has become an important means to increase the income of China's rural areas and farmers, because the environment of greenhouses is controllable and the production is efficient. The temperature and humidity are the most important environmental impacts in the production of crop. The traditional regulation of the environment in greenhouses relies on artificial sampling detection which is inefficiency. Some advanced greenhouses use field wiring to implement the environmental regulation, but the environment is complex so field wiring is also a difficult problem. Aiming at solving the problem of monitoring the temperature and humidity in greenhouses, this paper designs a on-line monitoring system of greenhouses which is based on the wireless communication technology. The system adopts the DHT11 sensors to monitor the temperature and humidity in the greenhouse, and adopts the wireless communication technology of ZigBee so as to realize the online monitoring of the temperature and humidity. By using the wireless transmission and data acquisition nodes which are placed in different greenhouses can transmit the value of the temperature and humidity in greenhouses to the central node easily, and also realized the function of the online monitoring, alarm and transmitting data from different data acquisition nodes to the central node. The system consists of a data acquisition module, a wireless communication module, an alarm module and so on. The system is advanced because of its simple structure, small volume, low cost, easy operation, wide application range, strong scalability and so on. Compared with the traditional system, it can meet the demand of acquiring the temperature and humidity value of greenhouses in China.

Abstract: A new bio-optoelectronic system, which included the behavior (aquatic organism) monitoring system and the water physiochemical factor monitoring system, was developed for the purpose of the management of accidental pollution events in water resource in Jinan, China. The system included a monitoring center and three monitoring stations. Communication between the monitoring stations and the monitoring center was mainly by the General Packet Radio Service network transmission complemented by a dial-up connection for use when this service was unavailable. The results suggested that once an accidental pollution occurred, the system would make a comprehensive evaluation based on the Self-Organising Map analysis on the monitoring data and some decision would be made based on the Emergency Management of Accidental Pollution. As a result, the new bio-optoelectronic system provided an effective approach on the management of accidental pollution events in drinking water supply.

Abstract: In the present study, the behaviour of aluminium rivets in alloy AA7278-T6 during the riveting process when used to join two aluminium plates was investigated experimentally and numerically. It was observed by Hoang et al. that a rivet in alloy AA7278-T6 may fracture in shear when undergoing high pressure during the riveting process. A damage-based failure model was adopted for studying the shear fracture behaviour of the rivet. A calibration procedure of the damage parameters was suggested based on two tests (i.e. material tension tests and rivet compression tests). The model was implemented in the finite element code LS-DYNA as a user-defined subroutine. Numerical results showed that the model seemed to be able to capture the shear fracture mode in the rivets as observed in the tests.

Abstract: Methods which are MVDR beam-forming, STMV beamforming and a method using MVDR beamforming with copy correlation are using to measure highlight of targets echoes at low frequency. Compared with conventional beam-forming, the three methods restrain noise and resist reverberation better. To reduce calculation, firstly, as the azimuth measured by using Split array cross-correlation beamforming the center, and then the neighboring area scanned using MVDR focused beamforming. Therefore, this highlight of echoes research measures have high precision and practical.

Abstract: The efficiency and accuracy could not be ensured for a long time during the numerical simulation of the process of armour-piercing bullet attacking on the target, because of some extreme conditions in it, such as the detonation of high explosive and large deformation of structures. A more effective numerical model of this process is built by the three-dimensional SPH method to study the mechanism of armour-piercing bullet attacking the target. Besides, the influences of different parameters, such as the reaching velocity and angle of bullet, are investigated. It aims at providing references for the structure optimization of armour-piercing bullet and the protective design of target structures.

Abstract: Temperature drift error usually exists in the strain-temperature measurement of continuous welded rail (CWR) temperature force. A piece of invar with low (close to zero) coefficient of thermal expansion is used to simulate the actual CWR. Then the temperature drift of the strain sensor node is measured by using a programmable temperature chamber. The temperature drift error is compensated during the monitoring of the temperature force in actual CWR. Results show that the measured temperature force vibration of the CWR is-681kN~149kN and the stress-free temperature vibration is-2.4~1.0°Cwithin a month after temperature drift error compensation. The temperature force and stress-free temperature after compensation meets the stability condition of the CWR.

Abstract: In terms of manufacture, operation and other aspects, many investigations, tests and analysis on microcomputer-based protection and monitoring device are made to overcome the problems brought by low temperature when installing the protection and monitoring device. This study reveals that ambient temperature has made an influence on protection devices components and display device and proposes the proper range of temperature and solutions. Also, the study solves the difficulties on the device installed locally at low temperature.

Abstract: In this paper, it is put forward a new kind of gyroscope and Theoretical analysis and simulation for it. it is based on the latest proposed a kind of MEMS gyroscope, the micro machine rotor of the liquid floated gyroscope in the thermal field has carried on the stress analysis and simulation. The magnetic field is a kind of drive, Gyroscope lumen is composed of stator and detecting electrode plates,it is filled with 2 # industrial white oil in the inner cavity body,2 # industrial white oil support this gyroscope of rotor . The measuring accuracy of the rotor is very high, and the rotor's drift stability is also greatly improved. But the rotor is governed by thermal field, it is still mentioned the main reason for the precision. For the generation of thermal field mainly comes from two parts: heat field and eddy heat. Comsol software is presented in this paper, the thermal field of the rotor were analyzed, and the current in the magnetic field to join 280 mA, 580 mA, 780 mA and 1800 mA, the temperature distribution for the magnetic field, the rotor's blow plate of temperature is less than the up plate of temperature; The rotor side wall is the highest temperature and its the lining is greater than the outer wall temperature; Around the rotor 2 # industrial white oil to join as the speed of 2500 rmp, 3500 rmp, 5500 rmp, 8000 rmp, because of the large flow rate, the eddy current is big, so the temperature increased. Two physical field coupling together to produce energy losses, affect the material performance, at the same time bring local vibration,this phenomenon results in the decrease of accuracy of measurement. Therefore, we need to change the rotor structure and materials to reduce the influence on measurement accuracy. At the same time for the next step, the stress analysis of rotor under the confined space for experiment platform test provide simulation data and the theoretical analysis.The sidewalls of the rotor machining into the radian of 0.05 mm.

Abstract: The Unmanned Ariel Vehicle Model is Mounted in the Wind Tunnel. where its Longitudinal Motion of Electric Propeller was Developed and Simulated as a Free Aircraft Flight. the Numerical Values of the Aerodynamic Stability and Control Derivatives are Evaluated via the Digital Tornado Algorithm. this Evaluation is Carried out Based on the Geometric Parameters of the Airplane, Aircraft Center of Gravity and Mass Moment of Inertia. the Stability and Response of the Linearized Longitudinal Model of the Considered Aircraft are Tested and Investigated. the Onboard Computer is Implemented Based on a Microcontroller Pic16f877a, where the Pitch Angle and Speed of the Considered Free Flight Vehicle are Read Respectively by an Gyroscope and Pressure Sensors. and the Microcontroller Read these Signals via Analog to Digital Converter which are in Turns as a Serial Digital Data by Using of Universal Synchronous Asynchronous Receive Transmit. Apply the Personal Computer to Receive the Serial Signal through the PC RS232 Standard as Serial Data. where in the PC, the Visual Basic Algorithm is Written as well in Order to Display and Plot the Pitch Angle Airspeed Responses on the Screen. Finally, the Experimental Results of Aircraft Free Flight in Real Time are Obtained by Carrying out the Simulation in the Wind Tunnel.

Abstract: In order to reduce the error, restore the real surface reflectance, in this work, FLAASH (Fast Line-of-sight Atmospheric Analysis of Spectral Hypercubes) model and 6S (Second Simulation of a Satellite Signal in the Solar Spectrum) code model were used to conduct the atmospheric correction for Terra/MODIS data of Akita prefecture in northeast of Japan. From the results of snow cover detection, the accuracy of without atmospheric correction is only 46%, with FLAASH model for atmospheric correction is 86% and the accuracy of with 6S code model for atmospheric correction is 92%. As experimental results show, compared to the snow cover detection without atmospheric correction, the snow cover detection accuracy was improved by 40% and 46% with FLAASH model and 6S code model for atmospheric correction respectively. In addition, the accuracy with 6S code model is higher about 6% than FLAASH model.