Effects of organic and inorganic metal salts on thermogravimetric pyrolysis of biomass components

Shilin Zhao,Meng Liu,Liang Zhao,Jianhong Lu 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.12

Thermogravimetric analyzer (TGA) was employed to elucidate the catalytic effects of organic and inorganic metal salts (K2CO3, KAc, Na2CO3 and NaAc) on the pyrolysis of three biomass components (cellulose, hemicellulose and lignin). In case of cellulose, TG analysis results showed that all the four metal salts increased the yield of char products and decreased the weight loss rates of cellulose pyrolysis, which followed the order of Na2CO3>K2CO3> NaAc>KAc. In contrast to cellulose, the four organic and inorganic salts employed had no significant effects on the remaining two biomass components:, hemicellulose and lignin. However, the four metal salts led to the devolatilization reaction of hemicellulose to occur at lower temperature region, and the dehydration reaction of lignin was promoted more or less. An increase in the heating rate might augment the maximum degradation rate. Different mixing ratios had little influence on the progress of catalytic pyrolysis. Based on the observations, the potential mechanism of the catalytic pyrolysis of biomass components with metal salts was discussed.

Design optimization of vibration isolation system through minimization of vibration power flow

Shilin Xie,Siu Wing Or,Helen Lai Wa Chan,Ping Kong Choy,Peter Chou Kee Liu 국제구조공학회 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

Comparison Study of Long-haul 100-Gb/s DDO-OFDM and CO-OFDM WDM Systems

Ling Liu,Shilin Xiao,Meihua Bi,Lu Zhang 한국광학회 2016 Current Optics and Photonics Vol.20 No.5

In this paper, for the first time, the transmission performances of long-haul 100-Gb/s direct detectionoptical OFDM (DDO-OFDM) and coherent optical OFDM (CO-OFDM) wavelength division multiplexing(WDM) systems are compared by simulation. It provides specific guides for system parameter selectionto get a high-performance and cost-effective OFDM WDM system. Specifically, the comparison involvesthree aspects: launched power is investigated to achieve better system performance; laser linewidth isnumerically investigated to choose cost-effective laser; system dispersion tolerances with different laserlinewidths are analyzed to further reveal the advantages and disadvantages of these two detecting methods,direct detection and coherent detection, in long-haul OFDM WDM system.

Design optimization of vibration isolation system through minimization of vibration power flow

Xie, Shilin,Or, Siu Wing,Chan, Helen Lai Wa,Choy, Ping Kong,Liu, Peter Chou Kee Techno-Press 2008 Structural Engineering and Mechanics, An Int'l Jou Vol.28 No.6

A vibration power minimization model is developed, based on the mobility matrix method, for a vibration isolation system consisting of a vibrating source placed on an elastic support structure through multiple resilient mounts. This model is applied to investigate the design optimization of an X-Y motion stage-based vibration isolation system used in semiconductor wire-bonding equipment. By varying the stiffness coefficients of the resilient mounts while constraining the dynamic displacement amplitudes of the X-Y motion stage, the total power flow from the X-Y motion stage (the vibrating source) to the equipment table (the elastic support structure) is minimized at each frequency interval in the concerned frequency range for different stiffnesses of the equipment table. The results show that when the equipment table is relatively flexible, the optimal design based on the proposed vibration power inimization model gives significantly little power flow than that obtained using a conventional vibration force minimization model at some critical frequencies. When the equipment table is rigid enough, both models provide almost the same predictions on the total power flow.

Research of fast point cloud registration method in construction error analysis of hull blocks

Wang, Ji,Huo, Shilin,Liu, Yujun,Li, Rui,Liu, Zhongchi The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.1

The construction quality control of hull blocks is of great significance for shipbuilding. The total station device is predominantly employed in traditional applications, but suffers from long measurement time, high labor intensity and scarcity of data points. In this paper, the Terrestrial Laser Scanning (TLS) device is utilized to obtain an efficient and accurate comprehensive construction information of hull blocks. To address the registration problem which is the most important issue in comparing the measurement point cloud and the design model, an automatic registration approach is presented. Furthermore, to compare the data acquired by TLS device and sparse point sets obtained by total station device, a method for key point extraction is introduced. Experimental results indicate that the proposed approach is fast and accurate, and that applying TLS to control the construction quality of hull blocks is reliable and feasible.

Superior tribology property of zinc phosphate impregnated graphite block at high-temperature oxidative friction

Xu Yuxuan,Tu Chuanjun,Liu Yanli,Liu Ping,Chen Gang,Tan Jiao,Xiong Wei,He Yubo,Liang Shilin,Ma Qingchun 한국탄소학회 2022 Carbon Letters Vol.32 No.5

High-temperature friction performances of graphite blocks (GBs) and zinc phosphate impregnated graphite blocks (IGBs) were evaluated under various friction temperatures. The surface of IGB exhibited extremely lower average friction coefficient values, that was 0.007 at 400 °C and 0.008 at 450 °C, in comparison to that of GB (0.13 at 400 °C and 0.16 at 450 °C, respectively). The worn surface of IGB in the high-temperature friction test was smoother and more complete than that of GB. The wear under high temperature and load caused the transformation of zinc pyrophosphate to zinc metaphosphate and the formation of a continuous large-area boundary lubrication layer combined with graphite and metallic element on the wear surface. The superior tribology property of IGB could be attributed to the digestion of iron oxides by tribo-chemical reactions and passivation of the exposed dangling covalent bonds. Specifically, the layered structure generated on the IGB wear interface effectively decreased the adhesive forces and prevented the surface from serious damage.

Bias process for heteroepitaxial diamond nucleation on Ir substrates

Wang Weihua,Yang Shilin,Liu Benjian,Hao Xiaobin,Han Jiecai,Dai Bing,Zhu Jiaqi 한국탄소학회 2023 Carbon Letters Vol.33 No.2

Heteroepitaxy is a better method of enlarging SCD wafer size than homoepitaxy. In this work, several aspects of the bias process for heteroepitaxial diamond nucleation are studied experimentally. First, with increasing bias time, the diamond-nucleation pathway is found to transform from “isolated-crystal nucleation” to “typical domain-nucleation” and back to “isolated-crystal nucleation.” An interdependent relationship between bias voltage and bias time is proposed: the higher the bias voltage, the shorter the bias time. Second, a correlation exists between the threshold bias voltage and reactor-chamber pressure: a higher reactor chamber pressure usually requires a higher threshold bias voltage to realize “typical domain nucleation.” Third, diamond bias-enhanced nucleation and growth is observed at a high CH4 content, where the dynamic equilibrium between amorphous-carbon-layer deposition and atomic-hydrogen etching is broken. Finally, epitaxial nucleation is obtained on a substrate with ∅30 mm in a home-made MPCVD setup.

Research of fast point cloud registration method in construction error analysis of hull blocks

Wang, Ji,Huo, Shilin,Liu, Yujun,Li, Rui,Liu, Zhongchi The Society of Naval Architects of Korea 2020 International Journal of Naval Architecture and Oc Vol.12 No.-

The construction quality control of hull blocks is of great significance for shipbuilding. The total station device is predominantly employed in traditional applications, but suffers from long measurement time, high labor intensity and scarcity of data points. In this paper, the Terrestrial Laser Scanning (TLS) device is utilized to obtain an efficient and accurate comprehensive construction information of hull blocks. To address the registration problem which is the most important issue in comparing the measurement point cloud and the design model, an automatic registration approach is presented. Furthermore, to compare the data acquired by TLS device and sparse point sets obtained by total station device, a method for key point extraction is introduced. Experimental results indicate that the proposed approach is fast and accurate, and that applying TLS to control the construction quality of hull blocks is reliable and feasible.

Bagasse as functional fillers to improve and control biodegradability of soy oil-based rigid polyurethane foams

Zengcheng Yu,Yuqin Xiao,Huafeng Tian,Shilin Liu,Jian Zeng,Xiaogang Luo 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.10

Using agricultural wastes (bagasse) and polyol derived from soy oil as raw materials to develop biodegradable rigid polyurethane foams (RPUFs) is beneficial to reduce the dependence on petroleum resources and promote the sustainable socioeconomic and environmental development. This study focuses on bagasse as a functional filler to improve and control the mechanical properties and biodegradability of the RPUFs. With the increasing levels of bagasse content, the density and mechanical properties of RPUFs increase. The biodegradation of RPUFs has a greater enhancement compared to the foam without bagasse, and all bio-foams have excellent thermal insulation properties. All changes in foam performance are due to the fact that the active hydroxyl groups on bagasse react with excess isocyanate to form urethane, which affects the structure of RPUFs. In this study, scientific design and molecular regulation theory were applied to improve the utilization value of bagasse and develop high-performance biodegradable RPUFs for thermal insulation materials

TCSC Nonlinear Adaptive Damping Controller Design Based on RBF Neural Network to Enhance Power System Stability

Yao, Wei,Fang, Jiakun,Zhao, Ping,Liu, Shilin,Wen, Jinyu,Wang, Shaorong The Korean Institute of Electrical Engineers 2013 Journal of Electrical Engineering & Technology Vol.8 No.2

In this paper, a nonlinear adaptive damping controller based on radial basis function neural network (RBFNN), which can infinitely approximate to nonlinear system, is proposed for thyristor controlled series capacitor (TCSC). The proposed TCSC adaptive damping controller can not only have the characteristics of the conventional PID, but adjust the parameters of PID controller online using identified Jacobian information from RBFNN. Hence, it has strong adaptability to the variation of the system operating condition. The effectiveness of the proposed controller is tested on a two-machine five-bus power system and a four-machine two-area power system under different operating conditions in comparison with the lead-lag damping controller tuned by evolutionary algorithm (EA). Simulation results show that the proposed damping controller achieves good robust performance for damping the low frequency oscillations under different operating conditions and is superior to the lead-lag damping controller tuned by EA.