Advanced Materials Research Vols. 468-471

Abstract: Feature selection for modeling the high dimensional data, such as the near-infrared spectrum (NIR) is very important. A novel modeling approach combined the adaptive genetic algorithm-kernel partial least squares (AGA-KPLS) is proposed. The KPLS algorithm is used to construct nonlinear models with the popular kernel based modeling technology. The AGA is used to select the optimal feature sub-set from the original high dimensional data, which also used to select the kernel parameters of the KPLS algorithm simultaneously. The experimental results based on the vibration frequency spectrum show that the proposed approach has better prediction performance than the normal GA-PLS method.

Abstract: This study was conducted using the data collected at the mouth of Canon River to investigate and analyze zinc (Zn) contained in the sediments, and to evaluate the accumulation of Zn and the degree of its potential risk. The results show that samples collected at all monitoring stations near the mouth of Canon River contain 358–3,365 mg/kg of Zn with average of 1,878±1,015 mg/kg. The spatial distribution of Zn reveals that the Zn concentration is relatively high in the river mouth region, and gradually diminishes toward the harbor region. This indicates that upstream industrial and municipal wastewater discharges along the river bank are major sources of pollution. The enrichment factor (EF) and geo-accumulation index (Igeo) indicate that the sedimentation at Canon River mouth has the moderately severe to extremely severe degree accumulation and moderate to very strongly accumulation of Zn. However, the potential ecological risk index indicates that the sedimentation at Canon River mouth has the low to moderate ecological potential risk.

Abstract: Rock strength is a key factor in the tunneling efficiency of TBM construction. An issue needing special attention on the work site is how to determine rapidly and accurately the strength of the surrounding rock which makes a crucial reference for the choice of TBM tunneling parameters and corresponding support measures. In the study conducted on the TBM construction site of Zhongtianshan Tunnel, point load test (PLT) of rocks is adopted to measure the rock strength and the data is compared with those of the uniaxial compressive strength (UCS). Finally, the correlation between the two is revealed through regression analysis method.

Abstract: This paper presents a fast panoramic mosaic algorithm from a video sequence with parallax scene taken by a PTZ camera. A new approach that uses a four-step automatic imaging mosaic, based on interest points, is proposed. The four steps are extraction of interest points, finding corresponding points in the stitching images, deriving the spatial transform matrix then image mosaic. In order to reduce the cost of searching best match of feature points, we employ SIFT-16 descriptor and the LMPs descriptor as index . Our method preserves the efficiency and accuracy of image mosaic.

Abstract: The spatial fluid model in diesel engine was built, and multiphase flow transient numerical simulation of working process of diesel engine was done based on computational fluid dynamics. The visualized result of simulation shows the distribution of flow field, press and particle trajectory which can hardly tested direct under the actual working condition. Swirl formed during the intake process and accompanied the whole working process of diesel engine. Keywords: Diesel engine; Numerical simulation; Flow field; Particle trajectory

Abstract: The growth of Chinese economy originates from the progress of the private enterprises. The entrepreneurship orientation, such as innovativeness, pro-activeness and risk-taking, contributes to the performance, defined as a compound measure dimension of growth as well as financial achievement. The case of the Mao Lixiang implies that economies with stronger entrepreneurial cultures from his family’s business tradition, are more tolerant and understanding of business failure and do not perceive this as a barrier to entry, but as an opportunity to learn. The ambition to change the present situation urges him to have the adaptability to political institutions and the regulation of entry, and find the business opportunities as well. The business history of Mao exhibits the Chinese continuous spirit of entrepreneurship.

Abstract: In this paper, experimental performance comparison of shell heat transfer is made between shell and tube heat exchangers (STHXs) with segmental baffles and non-continuous helical baffles. The helical angles contain 7°, 13°, 25°, which are smaller than the experiment made before. The experiment is carried out in the large-scale experimental equipment with the inner shell diameter, 500 mm and effective tube length, 6 m., which is larger than the previous experimental setup in the scale. The results indicate that the shell side heat transfer rate per unit pressure drop of non-continuous helical baffles is higher than that of traditional segmental baffles at the same volume rate. It is found that with the helical angle increasing, the shell side heat transfer rate decreases.

Abstract: Power performance tests of natural gas engine were carried out using a self-dependent developed electronic injection system and ignition system, and a comparative analysis between the natural gas engine and original gasoline engine was conducted. The result shows that if the gasoline engine is fueled with NG torque of the engine decreases and with the throttle opening increases, the decrease amplitude increases. Developing a suitable electronic ignition system can recover engine torque to some extent. Under the conditions that both throttle opening and rotation speed of the engine are constant, MBT angle increases with the decrease of mixture concentration.

Abstract: The binding energies, formation energies and DOS (density of state) of several carbides(Fe₃C, Fe₂C, Fe₅C₂, NbC) in Nb micro-alloyed steels are investigated using the first-principle pseudo potential plane-wave method. The results show that the structure type with the strongest alloying ability and the highest structure stability is NbC with fcc structure. After compared the DOS of these different structure types, the results show that the discrepancy in structural stability of carbides can be attributed to the difference in the bonding electron numbers at Feimi level. The less the valence electrons at Feimi level are, the better the structural stability of carbides. Therefore, the theory predicts that the existence form of Nb in medium and high carbon steels are the same as low carbon steels. Nb is still the effective alloying element in medium and high carbon steels.

Abstract: The oscillating motion occurring in an oscillating heat pipe (OHP) can enhance heat transfer. The fluid flow of liquid plugs trapped between the vapor bubbles play a key role in an OHP. Understanding the flow field of liquid plug moving in a capillary tube will provide an insight into the oscillating motion occurring in an OHP. An experimental setup of a liquid plug moving in a capillary tube was established to determine the flow field of a liquid plug using the microscale particle image velocimetry (µPIV) system. The motion of liquid plug was controlled by a computer-controlled system, which can produce a velocity ranging from 0.5 mm/s to 9 mm/s. The diameter of the capillary tube investigated herein is 1mm with a liquid plug length from 1.0 mm to 5.0 mm. The µPIV data clearly indicates the complex nature of liquid plug flow in a capillary tube trapped between two gas bubbles. Experimental results show that there exist circulations near the contact line. The circulation strength in a liquid plug depends on the liquid plug length and velocity of the liquid plug.