Advanced Materials Research Vol. 811

Abstract: Disc brake with the advantages of simple structure and good braking performance is widely used. But the design method of the existing brake needs a lot of calculation, test and modify repeatedly, manpower cost and long development cycle. This paper establishes a brake temperature minimum and maximum braking torque multi-objective optimization mathematical model, and then uses MATLAB optimization solution; and the finite element method (fem) is used for the transient temperature field validation. Research shows that the method is feasible, which can effectively improve the disc brake braking performance, and improve the efficiency of development.

Abstract: A small-size printed antenna is proposed for the application of mobile phones. The antennacomprisesan outer strip, an inner strip, and a common section.It not only occupies a compact area of 25 × 20 mm² butalsosupports two wide bandswithinthe resonantmodes. Prototypes of the antenna had been constructed and experimentally verified. The measured results of the antenna show the bandwidth cover the existing service bands of GSM/DCS/PCS/UMTS within 6 dB return loss specification, and also have good radiation patterns and antenna gains.This antenna is well suitable to be used for mobile phone application.

Abstract: Distinguished from the conventional discrete-point measurement, a continuous scanning measurement method of the sound field radiated from submerged structure is proposed. By rotating the structure uniformly and continuously, the pressure signals were recorded by the hydrophones array that was located in the far field. The signals were analyzed by Fourier transform respectively, and the sound field information could be obtained by the further derivation. By using the continuous scanning measurement, the spectrum broadening phenomenon was observed and analyzed. And then the point sound source field simulation and the sound power measurement experiment were carried out to prove the reliability of this method. The results show that, compared with the conventional discrete-point measurement, the continuous scanning measurement can acquire more information in less measurement time, and reduce the measurement work greatly under good measurement accuracy.

Abstract: As part of the verification of geometric specifications of manufactured parts by the conventional method "of marble and dial gauge" variability measurement deviations probing points is highlighted in several swings of the test piece.Often metrologist cannot really confirm that the part is good or bad.To overcome this problem of acceptance or rejection of the mechanical part, we offer a CAD computer program for checking the specification form for circularity following experimental study.

Abstract: The independent directional magnetic field measurement is a new technique for magnetic flux density measurement with high accuracy. This technique can reduce the limitation in term of angle that magnetic flux lines interact with Hall sensors. However, the original system limits the uniformity and symmetry of magnetic field patterns, which can cause an error for measurement system. Therefore, the aim of this research is to present the method to increase measurement accuracy of system, by improve magnetic field uniformity which can be done by using electromagnet instead of permanent magnet. The system is also improved the mechanical circle motion by using stepping motor, it is used to rotate Hall sensors in magnetic field which is generated by electromagnet. The result from experiment has shown of this method that can reduce the error percentage as 5% compare with original system. This method is shown 0.99997 of coefficient of determination, which represents to accuracy in magnetic flux density measurement range 0-1350 Gauss.

Abstract: Recently, study of transparent materials, such as thin film form, have an important field for the development of advanced electronic devices. Therefore, the need for the precision thermal property measurement techniques of transparent thin film materials becomes increasing according to the development of these material. The ideal methods for optically measurements of these properties are noncontact method. However, optically measurements are often difficult due to the transparency. So, transparent materials have not enough temperature gradient in the air layer above thin films. To solve this problem, we used the collinear deflection method which is one of the photothermal deflection methods. In the measurement process, both of the pump beam and probe beam are irradiated vertically on the transparent sample. And the probe beam is deflected by refractive index variation of samples due to the temperature gradient inside samples.The purpose of this study is to analyze the effect of thermal and optical properties analytically on the collinear deflection method for variable materials.

Abstract: The concentration of solution used in osmotic process is an important factor to dehydrate water from food, which is an effect to the rate of mass transfer. Therefore, the in line measurement and control of the concentration in osmotic process is taken into account. The density of sugar solution can be computed by volume and weight in order to determine the concentration in degree of Brix. This instrument will complete when accompanied by a statement of its uncertainty. The calibration equation established the relationship between the reading values of sensor and the values of concentration also need to clarify. The objective of this paper is to evaluate the uncertainty of predicted values of calibration equation; therefore, the uncertainty is determined in this study, and to compare the obtained results from the classical method in linear equation and the inverse method. Furthermore, the data from Monte Carlo simulations also are compared to the measured data.

Abstract: The bearings of a bridge are indispensable structural members, which support the superstructure, transfer the loads of the superstructure to the substructure and, accommodate the horizontal and vertical motions of the superstructure caused by all types of loads like traffic. Such traffic loads induce the bridge to vibrate but this energy is wasted. Therefore, a piezocomposite electricity generating element (PCGE) has been introduced in the bearing to exploit effectively this vibrational energy. The bridge bearing with built-in PCGE was seen to be effective for measuring the traffic loads and, detecting eventual overloaded or overspeeding vehicles. In a will to optimize the amount of energy generated by this bearing, this study compares experimentally the amount of electricity produced by the PCGE with respect to its position in the bridge bearing through a series of dynamic loading tests to find out the position of the PCGE providing the most efficient electricity generation.

Abstract: Many bubbles and pores are appeared on Activated Carbon Fibers (ACFs) material microscopic images. The morphology of ACFs surface image is complicated. Some widely used traditional methods are difficult to segment the object correctly. In this paper, an implicit active contour driven by local binary fitting energy is used to segment the objects for ACFs micro-images. This method is based on local image edge information to obtain optimal level set active contour model. Experimental results show that this active contour model is flexible for analyzing images with complex porous structure.

Abstract: A variable step long LMS algorithm based on Bessel function was put forward, which established the functional relationship between the step size factor and the error signal. And this algorithm would be applied to the adaptive noise canceller in order to improve the ability of the algorithm of uncorrelated noise suppression. This algorithm has a larger step-size during initial convergence stage or unknown system parameters change in order to get a faster convergence time and tracking speed. Moreover, and it adjusts small step-size to achieve a very small steady-state maladjustment noise after the convergence of the algorithm.