Advanced Materials Research Vols. 403-408

Abstract: On the basis of optimization-based design goals, design variables, constraints, the Offset slider-crank mechanism mathematical model of optimization is established, its parameters are designed by MATLAB Optimization Toolbox and achieve the best. The closed-loop vector equation of the Offset slider-crank mechanism is established based on the vector method, using MATALB/Simulink for simulation of kinematics to get the slider's motion curve. The method improves the efficiency and quality of design and motion analysis, the result shows that the method is efficient and useful in the design and kinematics analysis of mechanism.

Abstract: Ring die is key component in feed granulator; this document analyze current design method of the ring die, purposed a new design method is proposed. This method starts design of ring die from the pellet product property, and then gives concise analyses to the concept design and optimization design of ring die; by this design method, the porosity of the ring die and the pellets productivity of this ring die are increased. Using Shrimp feed granulator of 1.8mm pellet diameter as an example to verify this design method.

Abstract: The equation of large deflection of functionally graded beam subjected to arbitrary loading condition is derived. In this work assumed that the elastic modulus varies by power function in longitudinal direction. The nonlinear derived equation has not exact solution so shooting method has been proposed to solve the nonlinear equation of large deflection. Results of shooting method are validated with finite element solutions. The method will be useful toward the design of compliant mechanisms driven by smart actuators. Finally the effect of different elastic modulus functions and loading conditions are investigated and discussed.

Abstract: This paper presents an impact-based frequency increased electromagnetic vibration energy harvester to scavenge energy in a low frequency environment. To realize the novel impact based frequency up-conversion mechanism, a coil has been elastically anchored with a platform on which four permanent magnets are arranged in such a way that a strong closed magnetic flux path, linking the coil, is formed. The proposed scavenger has two dynamics of motion. The first phase is a low frequency oscillation to absorb energy from ambient vibration during which both the coil and magnet act as proof mass and move collectively. The increased proof mass ensures maximization of absorbed energy. After crossing a certain clearance, the platform containing magnetic setup rigidly and supporting the coil elastically, collides with a rigid stopper and bounces back. As a result of this mechanical impact a high frequency oscillation is setup in the coil relative to the magnets during which energy is transferred to electrical domain by electromagnetic induction. A macro-prototype has been build to prove the proposed concept. Initial test results show that the proposed harvester generates a peak voltage of 1 volt across a load of 220 Ω at an excitation frequency of 5 Hz which corresponds to a peak power of 4.5 mW and average power of 660 µW.

Abstract: The prototype of the silicon micro gyroscope is introduced. Temperature is the key factor that affects the performance of the gyroscope. In this paper, temperature dependent characteristics of silicon micro gyroscope drive mode is analyzed. The theoretical results show that temperature coefficient of the Young’s modulus is the most critical factor that affects temperature characteristics of the silicon micro gyroscope’s drive modal frequency and the frequency is proportional to the temperature. The results are verified by finite element simulations. The silicon micro gyroscopes are experimented in a high accurate thermostat. The drive modal frequency and temperature are measured and sampled. These experimental results show that the temperature coefficient of Young’s modulus is the key factor and the frequency is proportional to the temperature. The theoretic analyses are also validated by the experiments.

Abstract: The presented work focuses on the design, fabrication and frequency characteristics of a multi-mass MEMS vibrating ring gyroscope. After modal and harmonic simulation in ANSYS, the first 12 modes’ resonant frequencies and impacts on the sense-axis displacement are obtained. This gyroscope is fabricated through the silicon-on-glass process and deep etching bulk silicon MEMS technology. With a view to obtain the frequency characteristics, the authors attempt set of frequency sweeping experiment, whose record agrees well with ANSYS simulation results. The preliminary experimental data present the relationship between drive voltage and resonant characteristics and indicate that the structural design of vibrating ring and multi-mass can effectively depart the operational modes away from the interfering modes with a higher Q of sense axis at atmospheric pressure.

Abstract: A program of digital phase locked loop (DPLL) drive is proposed to supply the gaps including debugging complex, easiness of interference and poor flexibility in the traditional analog drive loop of the silicon micro-machined gyroscope (SMG). The program, i.e. field programmable gate array (FPGA) is utilized to process the drive sensitive signal of the SMG after the analog to digital (A/D) processing of high-precision, has been utilized to achieve phase and amplitude closed-loop of the SMG’s drive mode. The simulation and test results show that the program has a great advantage to reduce the requirements on quality factor compared with the original program. When the gyroscope with a low quality factor is not easy to vibrate by the analog self-excited drive circuit, the program is adopted to reach drive mode’s frequency stability of 18ppm.

Abstract: This paper reports a micro-pulsating heat pipe (micro-PHP) fabricated in a silicon wafer that consists of trapezoidal microchannels with a hydraulic diameter of 394μm for electronic cooling applications. Electronic liquid FC-72 was used as the working fluid. To evaluate the maximum temperature reduction of the evaporator wall, experimental results of the vertical and horizontal-located micro-PHP at filling ratios ranging from 47% to 62% were compared with those measured from the empty micro-PHP (0% filling ratio). Results show that incorporating a micro-PHP as an integral part of silicon wafer could significantly decrease the maximum wafer temperatures and reduce the intensity of localized hot spots. At a power input of 6.0W, reductions in the evaporator wall temperature of about 32.3°C and 24.4°Cwere obtained for the micro-PHP at vertical and horizontal orientations, respectively. In addition, a CCD camera was employed to record the fluid movement inside microchannels and affirmed the existence of nucleation boiling and bulk circulation flow in the micro-PHP.

Abstract: The work presented uses multiwavelet because of its inherent property to resolve the signal better than all single wavelets. Multiwavelets are based on more than one scaling function. The proposed methodology utilizes an enhanced resolving capability of multiwavelet to recognize power system disturbances. The disturbance classification schema is performed with multiwavelet neural network (MWNN). It performs a feature extraction and a classification algorithm composed of a multiwavelet feature extractor based on norm entropy and a classifier based on a multi-layer perceptron. The performance of this classifier is evaluated by using total 1000 PQ disturbance signals which are generated the based model. The classification performance of different PQ disturbance using proposed algorithm is tested. The rate of average correct classification is about 99.65% for the different PQ disturbance signals and noisy disturbances.

Abstract: The recent progress in modern electronic technology has enabled the implementation of complex information processing systems and created a big push towards the development of various kinds of application specific embedded and high performance systems. Design is a task that requires knowledge and creativity which are two human attributes normally considered too complex to be automated. Researchers in Artificial Intelligence have devoted a lot of work towards automating different aspects of design, but most of the current results consist of complex and expensive programs that can be easily outperformed by experienced human designers. The main goal of this review reported in this paper is to develop logic circuits which are not only fully functional, but also optimum according to some metrics. In this review, four important areas are considered. They are fpga based reconfigurable computing systems, soft computing techniques, pipelining concept and financial analysis as an application.