Chemical, Mechanical and Materials Engineering

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Authors: Pin Le Qin, Yan Lin, Ming Chen
Abstract: To improve the convergence rate of model-free learning adaptive controller (MFLAC) and decrease difficulty of parameters choice in control law, a new design method of MFLAC is presented. The controller proposed in this paper is designed based on pseudo gradient concept with solution by introducing multi-innovation method. In order to illustrate the effectiveness of the proposed method, numerical example is shown.
Authors: Rong Hui Xu, Jiu Ba Wen, Feng Zhang Ren
Abstract: Synthesis of CdS/CdCO3 Core/Shell semiconductor nanocrystals potentially used for solar cell via hydrothermal route is presented. Water-soluble crystallites with wurtzite crystal structure (CdS), hexagonal structure (CdCO3) with strong photoluminescence are prepared. The synthesis is based on the separation of the nucleation and growth stages of core and shell by controlling some crucial factors such as temperature, pH, ratio and concentration of reactant mixture. Bare wurtzite structural CdS nanocrystallites were synthesized by using cadmium acetate and thiourea as precursors. Ostwald ripening process under high temperature leads to high sample quality. Photoluminescence of nanocrystals with Core/Shell Structure and bare nanocrystals was compared and analysed. Nanocrystals with Core/Shell Structure have stabler performance of photoluminescence than CdS bare nanocrystallites because of the shell. Transmission electron microscopy and X-ray powder diffraction indicate the presence of bulk structural properties in crystallites as small as 5nm in diameter. X-ray Photoelectron Spectroscopy was used to characterize core/shell structure of as-prepared NCs. Ultra-stability and super strong photoluminescence emission of as-prepared CdS/CdCO3 Core/Shell semiconductor nanocrystallites indicates its potentially practical value in NCs solar cell.
Authors: Xing Guo Shao, Zhen Cai Zhu, Guo Hua Cao, Yi Lei Li
Abstract: This paper studies the forward kinematics of a sinking winch mechanism, which is in category of four-cable-driving parallel robot. The tension states (tautness or slackness) of cables are firstly taken into consideration in the forward kinematics model. We propose a traversal algorithm to solve the model. Both pose of platform and the tensions in cables can be solved if the lengths of four cables are given. The effectiveness of the algorithm is demonstrated by three examples. The results of this paper can be used to measure the pose of platform and the tensions of cables from the lengths of four cables.
Authors: Yi Du, Yi Lin Chi, Wu Xing
Abstract: In the traditional machinery fault diagnosis, the feature extraction leads information loss and the different information sources’ space-time registration is a difficult problem. The Probability boxes and Dempster-Shafer Structure Theory can provide a new way to solve above difficulties. This theory has a large advantage in solving uncertainties. It can be adapted for the inconstant machinery environment. In this paper, firstly the concepts of this theory are summarized and some methods of getting probability boxes are given. Secondly the method’s feasibility is discussed. Finally some promising research directions of this theory’s applications in the machinery fault diagnosis are advanced.
Authors: Bin Tang, Shuang Shou Li, Man Qiong Xu, Da Ben Zeng
Abstract: The influences of Ca addition (<1.2wt %) on structure and tensile fracture behavior of AZ91D alloy were investigated in this article. These results indicated that Ca addition can both form Al2Ca phase on interdendritic boundary and refine grain size. Ca addition evidently increases the yield strength but decreases the elongation of AZ91D alloy. The crack initiations of the AZ91D alloy and Ca-contained alloy both occur at the edges between the interdendritic eutectics and the α-Mg matrix. Failure of AZ91D alloy is brittle quasi-cleavage fracture, while Ca addition makes the failure tend to be cleavage.
Authors: Bao Hua Yu, Yan Qiu Jing, Jian Jun Liu, Huai Qi Li, Xin Hua Zhang, Xiao Ran Qu, Jin Lei, Jin Feng Zhu
Abstract: Inder order to determine Benzopyrene (BaP) in Mainstream and Sidestream Smoke, a Solid phase extraction (SPE) cartridge was used to isolate the BaP fraction from the total particulate matter of mainstream cigarette smoke and sidestream cigarette smoke and the BaP were measured by RP-HPLC with ultraviolet detection. The result showed that the recovery rate of BaP extracted is 94.5%, compared with the relative standard of 6.95%. The yields of BaP in mainstream smoke for Virginia cigarette are higher than those for blended cigarettes. The yields of BaP in sidestream smoke are much higher than those in mainstream smoke. The proposed method involves an solid phase extract and HPLC-UV analysis procedure. With this method, the BaP yields in mainstream and sidestream cigarette smoke can be measured fast, easily and precisely using readily available apparatus and instruments.
Authors: Yan Qiu Jing, Guang Liang Li, Jian Jun Liu, Hai Tang Huang, Hong Min Hu, Hong Li Zhang, Xiao Hui Xie, Jin Feng Zhu
Abstract: In order to study the effects of filter ventilation on flavor constituents in cigarette smoke, the deliveries of 20 added flavor constituents (showed in table 2) and routine components (including TPM, nicotine, tar, carbon monoxide and water) in cigarette mainstream smoke were studied when filter ventilation were 0, 10%, 30%, 50% and 70% respectively. The flavor substance test was done by addition of standard samples. The flavor constituents were identified and determined quantitatively by gas chromatopraphy -mass spectrometry (GC/MS) and capillary gas chromatography (GC) and their condensate were separated by simultaneous distillation-extraction (SDE) and GC. The deliveries of routine components in mainstream smoke were determined according to international standard methods. It was found that the flavor constituents and routine components in mainstream smoke decreased in different proportions as the filter ventilation increased. Carbon monoxide and tar decreased more than nicotine. The flavor constituents with lower boiling points and molecular weights decreased more than those with higher. With the increase of filter ventilation, not only is the amount of smoke components reduced and the smoke taste weakened, but also the composition of smoke is modified and the quality of aroma changed slightly. Therefore, when low-tar cigarettes are made through the use of ventilation technology, different constituents and their changes should be taken into account in order to determine appropriate leaf group blending and flavoring.
Authors: Yan Qiu Jing, Jian Jun Liu, Guang Liang Li, Yang Hong, Xin Hua Zhang, Li Xin Xue, Xiao Hui Xie, Jin Le
Abstract: A Reversed-Phase High Performance Liquid Chromatographic method was developed for determining free Amino Acids in Burley Tobacco. The test was done by OPA/3-mercaptopropionic Acid as the pre-column derivatising reagent. Chromatographic column was Elitte C18 column (4.6mm×250mm i.d., 5um). Mobile phase A was 18mmol/L NaAc (PH=7.2) including 0.002% (v/v) triethylamine and 0.3% (v/v) furanidine. Mobile phase B was 100 mmol/L NaAc (PH=7.2) -Acetonitrile- methanol (v/v=1:2:2). The column temperature was 40°C and the flow rate was 1.0ml/min. The fluorescence detector was used with 350nm excitation wave length and 450nm emission wave length. The average recoveries of the method ranged 95.3% to 100.7% with the relative standard deviation of 2.32%~9.24%. The method is simple, accurate and has good repeatability. The results of the determination of seventeen kinds of free amino acids in burley leaves which were produced by way of different ratio of cake fertilizer and inorganic fertilizer. The results show that aspartic acid has the highest content however ratio of cake fertilizer and inorganic fertilizer. The most contents of free amino acids are increased and then gradually decreased with the increase of organic manure. The most contents of free amino acids are very close at the ratio of 15%:85% ratio and 30%:70% between cake fertilizer and inorganic fertilizer. The total content of free amino acids is the highest at the ratio of 30%: 70% between cake fertilizer and inorganic fertilizer. Considering comprehensively, the quality of burley leaves is the best at the ratio of 30%:70% between cake fertilizer and inorganic fertilizer.
Authors: Hong Li Li, Yan Wang
Abstract: The aim of this paper was to analyze the biomethanization process of cattle manure with four different total solid percentages (15%, 20%, 25%, 30% TS) and three different stirring frequency. The experimental procedure was programmed to select the initial performance parameter and the operational parameter in a lab-reactor. The values of VFAs indicated that all the reactors showed no destabilization and at the end of the experiment the VFAs were consumed completely. The best performance for cattle manure biodegradation and methane generation was the reactor with 20% TS, with the biogas yield of 0.22 L/g VS and the methane yield of 0.11 LCH4/g VS. Furthermore, the better operational parameter of stirring frequency was stirring once every two days.

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