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Proportional-Derivative (PD) Controller for Heuristic Rule-based Motorway Coordinated Ramp Meters
Rui Jiang,Jinwoo (Brian) Lee,Edward Chung 대한토목학회 2018 KSCE JOURNAL OF CIVIL ENGINEERING Vol.22 No.9
This study proposes a new control method for rule-based motorway coordinated ramp metering. Coordinated ramp metering makes use of the network-wide measurements and allows multiple meters to participate in the control action to prevent or delay the onset of congestion on motorways. An essential component is a controller to dynamically adjust the level of contribution to coordination of each participating meter. The new control method builds on the concept of proportional-integral-derivative (PID) controller. A comprehensive sensitivity analysis is carried out to formulate the controller structure and coefficients. The final structure takes the form of PD controller with P-term as the main controller and D-term as supplementary to accelerate response speed and to improve the control stability. The PD controller is embedded in a rule-based coordinated ramp metering strategy for performance evaluation. A simulation study demonstrates the effectiveness of the PD controller. The coordinated control improves the mainstream traffic condition by reducing 60% and 8.4% of average traffic delay time over the base case assuming no metering and the local metering control scenario, respectively. The overall traffic travel time also decreased by the coordinated control by 25.1% and 2.0% over the base case and local metering, respectively. The enhanced mainstream traffic flow is achieved by balanced utilization of local meters and on-ramp spaces.
Rui Jiang,Liqiang Jiang,Yi Hu,Jihong Ye,Lingyu Zhou 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.74 No.6
The fundamental period is an important parameter for seismic design and seismic risk assessment of building structures. In this paper, a simplified theoretical method to predict the fundamental period of masonry infilled reinforced concrete (RC) frame is developed based on the basic theory of engineering mechanics. The different configurations of the RC frame as well as masonry walls were taken into account in the developed method. The fundamental period of the infilled structure is calculated according to the integration of the lateral stiffness of the RC frame and masonry walls along the height. A correction coefficient is considered to control the error for the period estimation, and it is determined according to the multiple linear regression analysis. The corrected formula is verified by shaking table tests on two masonry infilled RC frame models, and the errors between the estimated and test period are 2.3% and 23.2%. Finally, a probability-based method is proposed for the corrected formula, and it allows the structural engineers to select an appropriate fundamental period with a certain safety redundancy. The proposed method can be quickly and flexibly used for prediction, and it can be hand-calculated and easily understood. Thus it would be a good choice in determining the fundamental period of RC frames infilled with masonry wall structures in engineering practice instead of the existing methods.
Li, RuiJiang,Bu, Jie 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1
Solid-phase PAMAM dendrimer was synthesized by the repetitive addition of a branching unit to silica gel. All synthesis steps were monitored by infrared spectroscopy to investigate the reaction rate. Based on the measurements of infrared spectra, which showed the ester group varied as a function of reaction time, a reaction kinetics model was proposed and simulated. FT-IR and TGA measurements suggested that a 'cross-linking' reaction occurred in amidation process and generated structural defects, which decreased the grafted amount of dendrimer on silica gel. In addition, the analysis of reaction rate constants indicated that due to the formation of an intermediate, Michael addition of methyl acrylate to diamine was probably hindered by steric crowding.
Yvonne Chow,Ruijiang Li,Jinchuan Wu,Sze Min Puah,Shu Wei New,Wei Qiang Chia,Felicia Lie,Talukder Md Mahabubur Rahman,Won Jae Choi 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4
The production of semi-synthetic beta-lactam antibiotics such as Amoxicillin may be performed enzymatically using penicillin acylase under mild conditions. However, the thermodynamically favored hydrolysis of the antibiotic product and the acyl donor substrate needs to be minimized to use the kinetically controlled route. The addition of cosolvents such as ethylene glycol and methanol (the two best solvents identified so far for semi-synthetic beta-lactam antibiotics) can achieve this to some degree, but these additives also produce enzyme inhibition and deactivation. In this study, we compared ethylene glycol and methanol under various substrate conditions. Methanol gave a better synthesis to hydrolysis ratio, although its deactivating effects adversely affected production at lower cosolvent concentrations than ethylene glycol. This effect and its dependence on substrate concentration was further modeled and optimized. A few targets of optimization such as Amoxicillin level, the synthesis to hydrolysis ratio, or a combination, were employed. While maximum levels of Amoxicillin synthesis were achievable only at high substrate concentrations, improvements derived from cosolvents were most significant at low substrate concentrations.
Jie Bu,Ruijiang Li 한국화학공학회 2004 Korean Journal of Chemical Engineering Vol.21 No.1
Solid-phase PAMAM dendrimer was synthesized by the repetitive adition of a branching unit to silicagel. All synthesis steps were monitored by infrared spectroscopy to investigate the reaction rate. Based on themeasurements of infrared spectra, which showed the ester group varied as a function of reaction time, a reaction kineticsmodel was proposed and simulated. FT-IR and TGA measurements sugested that a cros-linking reaction occuredin amidation process and generated structural defects, which decreased the grafted amount of dendrimer on silica gel.In addition, the analysis of reaction rate constants indicated that due to the formation of an intermediate, Michaeladdition of methyl acrylate to diamine was probably hindered by steric crowding.
Chow, Yvonne,Li, Ruijiang,Wu, Jinchuan,Puah, Sze Min,New, Shu Wei,Chia, Wei Qiang,Lie, Felicia,Rahman, Talukder Md Mahabubur,Choi, Won-Jae Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.4
The production of semi-synthetic beta-Iactam antibiotics such as Amoxicillin may be performed enzymatically using penicillin acylase under mild conditions. However, the thermodynamically favored hydrolysis of the antibiotic product and the acyl donor substrate needs to be minimized to use the kinetically controlled route. The addition of cosolvents such as ethylene glycol and methanol (the two best solvents identified so far for semi-synthetic beta-lactam antibiotics) can achieve this to some degree, but these additives also produce enzyme inhibition and deactivation. In this study, we compared ethylene glycol and methanol under various substrate conditions. Methanol gave a better synthesis to hydrolysis ratio, although its deactivating effects adversely affected production at lower cosolvent concentrations than ethylene glycol. This effect and its dependence on substrate concentration was further modeled and optimized. A few targets of optimization such as Amoxicillin level, the synthesis to hydrolysis ratio, or a combination, were employed. While maximum levels of Amoxicillin synthesis were achievable only at high substrate concentrations, improvements derived from cosolvents were most significant at low substrate concentrations.
( Zhixiang Lv ),( Qingmei Yu ),( Zhou Wang ),( Ruijiang Liu ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.6
Magnetic Ni<sub>0.7</sub>Co<sub>0.3</sub>Fe<sub>2</sub>O<sub>4</sub> nanoparticles that were prepared via the rapid combustion process were functionalized and modified to obtain magnetic Ni<sub>0.7</sub>Co<sub>0.3</sub>Fe2O<sub>4</sub>@SiO<sub>2</sub>-CHO nanocomposites, on which penicillin G acylase (PGA) was covalently immobilized. Selections of immobilization concentration and time of fixation were explored. Catalytic performance of immobilized PGA was characterized. The free PGA had greatest activity at pH 8.0 and 45 ℃ while immobilized PGA’s a ctivities p eaked at p H 7.5 and 4 5 ℃. Immobilized PGA had better thermal stability than free PGA at the range of 30-50 ℃ for different time intervals. The activity of free PGA would be 0 and that of immobilized PGA still retained some activities at 60 ℃ after 2 h. V<sub>max</sub> and K<sub>m</sub> of immobilized PGA were 1.55 mol/min and 0.15 mol/l, respectively. Free PGA’s V<sub>max</sub> and K<sub>m</sub> separately were 0.74 mol/min and 0.028 mol/l. Immobilized PGA displayed more than 50% activity after 10 successive cycles. We concluded that immobilized PGA with magnetic Ni<sub>0.7</sub>Co<sub>0.3</sub>Fe<sub>2</sub>O<sub>4</sub>@SiO<sub>2</sub>-CHO nanocomposites could become a novel example for the immobilization of other amidohydrolases.
Preparation and Characterization of A Semi-interpenetrating Network Alkaline Anion Exchange Membrane
Yifu Wang,Heting Wan,Dan Wang,Jilin Wang,Lulu Wang,Ruijiang Feng 한국섬유공학회 2018 Fibers and polymers Vol.19 No.1
A series of semi-interpenetrating network (semi-IPN) anion exchange membranes (QCS/St-G8-2-8, Quaternized chitosan/styrene-[maleic alkylene group diethyl bis (octyl dimethyl chloro/bromide), abbreviated as G8-2-8] were prepared via in-situ polymerization by Styrene (St) and G8-2-8 in QCS casting solution. During the process of in-situ polymerization, linearblock polymers (St-G8-2-8) of Styrene and G8-2-8 was constructed, then was mixed with QCS casting solution, followed crosslinking the QCS by glutaraldehyde (GA). With the increasing content of linear block polymer, water uptake and swelling ratio of the composite membrane decreased; This kind of linear structure makes an order arrangement of quaternaryammonium groups which improves the OH− migration efficiency. At 70 oC, the M-30 composite membrane performs a high OH− conductivity of 8.20×10-2 S·cm-1, the methanol permeability is 3.23×10-6 cm-2·s-1 which is still lower than Nafion 115 of 2.42×10-6 cm-2·s-1, but M-30 shows a higher selectivity of 25.3 than Nafion 115 of 11.6. Furthermore, the membranes exhibited excellent thermal stability (≥150 oC), the tensile strength of the composite membrane is in the range of 14-25 MPa and elongation at break is in the range of 16-37 % at room temperature, as well as superior chemical stability in 1.0 M KOH solution for 250 h.