Applied Mechanics and Materials Vols. 157-158

Abstract: A novel wireless sensor networks is designed with integrating sensors, embedded operating systems and wireless networking technology. The temperature, humidity, light strength and pressure around the sensor could be measured accurately. The collected data by sensor networks are analysed and treated in PC computer via USB interface. LEACH communication protocol was introduced to ZigBee networks in this paper. The node programs were exploited based on IAR System platform to accomplish data collection.

Abstract: In an optical fiber manufacturing process, glass fibers drawn from the heated silica preform in the furnace should be sufficiently cooled down close to ambient temperature. As the fiber drawing speed continues to increase for better manufacturing productivity, the glass fiber cooling becomes more difficult and the use of helium injection into the glass fiber cooling unit is required to greatly enhance the fiber cooling effectiveness. The present study numerically simulates the flowfield and heat transfer phenomena on the glass fiber cooling in order to investigate the effects of helium injection and fiber drawing speed on the fiber cooling effectiveness of glass cooling unit. The results found that the amount of air entrainment at the unit inlet is the significant factor that decides the cooling effectiveness by significantly lowering the helium purity in cooling gas. Also, at a given fiber drawing speed, there exists a critical helium injection rate and the fiber cooling does not improve any more, even if the helium injection rate increases above this critical value.

Abstract: Stress corrosion test of pressure vessels and piping in H2S environment has been explored extensively, but experimental research closed to the actual stress state of pipelines and the actual operating conditions, especially considered the combined effect of various factors is not common. Stress corrosion test simulated the actual operating conditions is taken in this paper. Four in-service pipes are researched as specimens and complex stress field is built by a specially designed loading device. Specimens are immersed in three different H2S concentration environments. The appearance and expansion of crack is observed regularly and the sensitivity of pipeline on stress corrosion is evaluated by metallographic examination. The result shows that: Intergranular corrosion, transgranular corrosion or micro-crack is not found in H2S corrosive solution (500×10-6, 800×10-6mg/L) after 2160 hours or in saturated H2S corrosive solution (greater than 2000×10-6mg/L) after 360 hours. A surface crack is found in H2S corrosive solution (500×10-6mg/L) after 720 hours and the expression for expansion rate of the crack during 2160 hours is a=16.835e0.0002h.

Abstract: Mammogram registration is an important step in the processing of automatic detection of breast cancer. It provides aid to better visualization correspondence on temporal pairs of mammograms. This paper presents a novel algorithm based on SIFT feature and Graph Transformation methods for mammogram registration. First, features are extracted from the mammogram images by scale invariant feature transform (SIFT) method. Second, we use graph transformation matching (GTM) approach to obtain more accurate image information. At last, we registered a pair of mammograms using Thin-Plate spline (TPS) interpolation based on corresponding points on the two breasts, and acquire the mammogram registration image. Performance of the proposed algorithm is evaluated by three criterions. The experimental results show that our method is accurate and closely to the source images.

Abstract: In this paper, we present the results of a study of TiN thin films which are deposited by a Physical Vapour Deposition (PVD) and Ion Beam Assisted Deposition (IBAD). In the present investigation the subsequent ion implantation was provided with N2+ ions. The ion implantation was applied to enhance the mechanical properties of surface. The thin film deposition process exerts a number of effects such as crystallographic orientation, morphology, topography, densification of the films.. A variety of analytic techniques were used for characterization, such as scratch test, calo test, Scanning electron microscopy (SEM), Atomic Force Microscope (AFM), X-ray diffraction (XRD) and Energy Dispersive X-ray analysis (EDAX).

Abstract: Removed at authors request.

Abstract: A novel technical finding is proposed based on the analytical study of the underlying conservative system of a small mass nonlinear vibration absorber coupled with a main structure. For the system with linear damping under impulsive excitation, a result is obtained that the initial energy for inducing maximum dissipation of energy in the nonlinear attachment is inversely proportional to the cubic stiffness. The technical point coincides with massive numerical simulations precisely. This relationship between the cubic stiffness and the initial conditions facilitates the tuning of a nonlinear vibration absorber for realizing optimal targeted energy transfer.

Abstract: Reliable tracking of multiple people in cluttered or complex situations is a challenging visual surveillance problem since the high density of objects results in occlusion. In order to deal with this problem, multiple synchronized cameras were mounted at various heights in our experiment. To ensure the existence of the homography, it is necessary to assume that different views share a common dominant ground plane. Thus, corresponding people have to be located within the multi-camera surveillance system, accurate multi-people localizing is an important prerequisite to reliable tracking. In this paper, we present a novel approach to fusing foreground information on planes of different height from multiple views to increase accurateness of localization. Our method does not require fully camera calibration. First we obtain the foreground likelihood maps in each view by modeling the background using codebook algorithm. Then we compute homographies induced by multiple planes and obtain the localization of multiple people at multiple planes. Finally, we adopt an algorithm of feature-based using Kalman filter motion to handle multiple objects tracking at multiple plane. The experimental results show that our method is valid and has nice robustness to the occlusion in crowed environments.

Abstract: In order to solve time synchronization problem of wireless sensor network, combined with the broadcast characteristics of wireless transmission and bi-directional message mechanism and the characteristics of clustering network, this paper presents an improved time synchronization algorithm HLTN based on clustering network and the simulation experiment by NS-2 simulation platform and analyzed the results.

Abstract: This paper proposed an audio watermark algorithm with synchronization in wavelet domain based on support vector machine. The synchronization code and encrypted digital watermark are embedded into the low frequency coefficients in DWT domain by using quantization modulation, the image watermark and the synchronization code are extracted through SVM possessing two-class problem. The experimental results show that the audio watermarking scheme is inaudible, but also robust against noise adding, filtering, random cropping attacks.