Advanced Materials Research Vols. 230-232

Abstract: There is a constant need for the reduction of operational and maintenance costs of Wind Energy Conversion System(WECS). The most efficient way of reducing these costs would be to continuously monitor the condition of these systems, which allows for early detection of the degeneration of the generator health, facilitating a proactive response, minimizing downtime, and maximizing productivity. Wind generators are also inaccessible since they are situated on extremely high towers.There are also plans to increase the number of offshore sites increasing the need for a remote means of WECS monitoring that overcomes some of the difficulties of accessibility problems. Therefore it is important of condition monitoring and fault diagnosis in WECS. The monitoring schemes of transfer its monitor status with JESS technology was put forward in this paper. A remote condition monitoring platform (RCMP) was designed and constructed in this project. And its result brings us an effective solution to deal with the WECS condition monitoring.

Abstract: Chinese Hackberry (Celtis sinensis) tree has high adaptability to environment and tolerance to water stress, and a long history of utilization and plantation in many countries. However, researches on Chinese Hackberry were mostly focused on the biomass analyses and utilizations of its wood, and lacked those to analyze the chemical components of extractives of Chinese Hackberry leaves, which was very important to recover and utilize the polluting waste Chinese Hackberry leaves. Therefore, the chemical components of benzene/ethanol extractives of Chinese Hackberry leaves were analyzed by method of GC/MS in order to identify top value-added bioactive components from waste leaves of Chinese Hackberry tree. The analytical result showed that the main components of benzene/ethanol extractives of freeze-dried Chinese Hackberry leaves by GC/MS analysis were identified 10 components (106 peaks) as: Sesquirosefuran (48.57%), Thiophene, 2-ethyltetrahydro- (20.01 %), Hexatriacontane (8.67%), Octadecane (8.60%), 1-Eicosanol Pregn-4-en-3-one, 20-hydroxy-, (20R)- (4.52%), 1-Amino-2-(hydroxymethyl)anthraquinone (3.63%), 1,3-Diphenyl-(4H)1,2,4-triazoline- (1.92%), Tricyclo[4.3.1.13,8]undecane-1-carboxylic acid (1.69%), Eucalyptol (1.60%), etc. As the first report here, our result by GC/MS showed that the benzene-methanol extractive of freeze-dried Chinese Hackberry leaves can be developed into top value-added materials of spicery, biomedicines, and biofuel.

Abstract: The extractives of C. camphora old bark were used to cure some special diseases; however, the biomedical constituents of extractives of C. camphora old bark are still not completely explained. Therefore, 350 °C-based pyrolysis- GC/MS technology was used to identify the top value-added biomedical constituents of old bark-based benzene/ethanol extractives from C. camphora trunk. 74 chemical constituents representing 99.17% were identified from 86 peaks. The main components are as: Dodecanoic acid, 1-(hydroxymethyl)-1,2-ethanediyl ester (15.717%), Octacosanoic acid, methyl ester (10.357%), Abietic acid (8.483%), Heptacosane (5.678%), Ethyl alcohol (5.282%), Hexadecanoic acid, 2-hydroxy-, methyl ester (3.365%), Hexacosanoic acid, methyl ester (2.936%), 1,2-Benzenedicarboxylic acid, butyl 2-methylpropyl ester (2.928%), 2-Methoxy-4-vinylphenol (2.692%), Hexadecanoic acid, ethyl ester (2.312%), Hexacosane (2.076%), Tetracosanoic acid, methyl ester (2.013%), etc. The analytical result showed that the 350 °C pyrolyzate of benzene/ethanol extractives from C. camphora old bark is abundant in biomedical constituents, and also contains other bioactive components, which can be used as top value-added materials of high-grade cosmetic, food, spice and chemical solvents.

Abstract: In order to explore the feasibility of large ultra-lightweight deployable optical systems, a 1.25m SiC segmented mirror is investigated. According to analysis and comparison, the mirror's material, ultra-lightweight structure pattern and support location are determined respectively. By FEM, an ultra-lightweight structure with areal density of 40kg/m² is gotten. The results show that the self-weight deformation is 4.8nm RMS/22.6nm PV under supports, and the ultra-lightweight mirror has the enough strength to bear the stress at launch. The study may provide a technical scheme to develop the large ultra-lightweight deployable optical system.

Abstract: This paper presents an investigation on laser direct metal deposition of tool steel on copper alloy substrate both directly and using high nickel stainless steel as buffer layer. The bond strength between the clad and the substrate has been investigated. Tensile testing was employed to measure the bond strength. The characteristics of the fracture surfaces have also been analyzed. Bond strength measurement revealed that the ultimate tensile strength of the substrate material was higher compared to the bond strength between the clad and the substrate. In addition, the experimental result revealed that use of high nickel stainless steel reduced the bond strength with substrate. However, the bond strength measured in this experiment between laser cladded tool steel and copper alloy substrate was much higher compared to the bond strength between these two metals coated using other techniques.

Abstract: Laser cladding is a thermal process for depositing a metallic alloy on to a parent metal to repair corrosion, erosion, wear or other physical damage. The present work studies the effects of the laser cladding process on the integrity of metal substrates and the bond between the cladding layer and the base metal. It also evaluates some physical characteristics of the cladding layer, in this case grade 420 stainless steel. The research compares the work with Tungsten Inert Gas (TIG) welding and concludes that, due to the small size of the heat-affected zone, this laser cladding process does not adversely affect the physical properties of the metallic substrates.

Abstract: Previous researches on oil price volatility have been done with parametric models of GARCH types. In this work, we model volatility of crude oil price based on GARCH(p,q) by using Neural Network which is one of powerful classes of nonparametric models. The empirical analysis based on crude oil prices in US and China show that the proposed models significantly generate improved forecasting accuracy than the parametric model of normal GARCH(p,q). Among nine different combinations of hybrid models (for p = 1,2,3 and q = 1,2,3), it is found that NN-GARCH(1,1) and NN-GARCH(2,2) perform better than the others in US market whereas, NN-GARCH(1,1) and NN-GARCH(3,1) outperform in Chinese case.

Abstract: The recent development in advanced packaging and MEMS applications has created a need for high aspect ratio lithography processes, ultrasonic spray coating is a very appropriate method to meet this requirement, the parameters of atomization are greatly affected the spray quality. By using a laser-phase Doppler analyzer (PDA), an experimental study was conducted of the atomization characteristics of the ultrasonic spray nozzle, water was used as the liquid to be atomized instead of photoresist and air was used as the auxiliary gas instead of nitrogen, the parameters of atomization characteristics under different operating conditions were measured, such as mean diameter D₁₀ and diameter distribution of atomized droplet particles etc. The experimental measurement results indicate that the flow rate of atomized liquid and auxiliary gas have a significant impact on the spray characteristics, the nozzle can achieve a comparatively good atomization state under the condition of a relatively small flow rate of atomized liquid or a relatively high flow rate of auxiliary gas, the mean diameter D₁₀ of droplets can be 18.39μm. The research findings can provide an underlying basis for the application of the ultrasonic spray nozzle.

Abstract: By optimizing design and reasonable matching, internal combustion engine can operate under the condition of high efficiency to improve fuel efficiency and reduce exhaust emissions. This paper use reverse energy flow simulation method, transmission of speed and torque as the main line, based on the establishing of engine, motor, battery and other models, analyzing HEV parameter and the request of driving force, motor and battery. Regarding one kind of Hybrid Electric Vehicle as the research object, the mathematics model of power and economic performance was established. A PHEV performance simulation software was developed by using MATLAB/ SIMULINK. The demand of Hybrid Electric Vehicle to the power of motor and battery were analyzed on the given Driving Cycle.

Abstract: In reverse engineering, in order to analyze the accuracy of formed work-piece, the shape error between the formed work-piece and its CAD model need to be calculated. In this paper, a matching method on the basis of triangle mesh is proposed. This matching method includes three parts: pre-positioning, rough registration and fine registration. Firstly, the maximum projective plane of cloud data is designed to parallel to the xy plane through translation and rotation, and cloud data is translated by a vector which can be obtained with the point with the maximum z coordinate and the origin of coordinates. Secondly, cloud data is gradually rotated 360 degree around z axis confirm the angle making the error minimum. In this way, an initial value of ICP algorithm can be obtained, which can avoid the local convergence in the algorithm. Finally, ICP algorithm can be applied to calculate the surface error further. After matching, the error between work-piece and the CAD model can be calculated by interpolation based on triangle mesh. The results show that the matching method can obtain the higher matching accuracy.