Combined Age and Segregated Kinetic Model for Industrial-scale Penicillin Fed-batch Cultivation

Jingqi Yuan,Zhifeng Wang,Maarten J. C. Lauwerijssen 한국생물공학회 2005 Biotechnology and Bioprocess Engineering Vol.10 No.2

This paper proposes a cell age model for Penicillium chrysogenum fed-batch cultivation to supply a qualitative insight into morphology-associated dynamics. The average ages of the segregated cell populations, such as growing cells, non-growing cells and intact productive cells, were estimated by this model. A combined model was obtained by incorporating the average ages of the cell sub-populations into a known but modified segregated kinetic model from literature. For simulations, no additional effort was needed for parameter identification since the cell age model has no internal parameters. Validation of the combined model was performed by 20 charges of industrial-scale penicillin cultivation. Meanwhile, only two charge-dependent parameters were required in the combined model among approximately 20 parameters in total. The model is thus easily transformed into an adaptive model for a further application in on-line state variables prediction and optimal scheduling.

Disturbance observer based adaptive sliding mode control for power tracking of PWRs

Hui, Jiuwu,Yuan, Jingqi Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.11

It is well known that the model of nuclear reactors features natural nonlinearity, and variable parameters during power tracking operation. In this paper, a disturbance observer-based adaptive sliding mode control (DOB-ASMC) strategy is proposed for power tracking of the pressurized-water reactor (PWR) in the presence of lumped disturbances. The nuclear reactor model is firstly established based on point-reactor kinetics equations with six delayed neutron groups. Then, a new sliding mode disturbance observer is designed to estimate the lumped disturbance, and its stability is discussed. On the basis of the developed DOB, an adaptive sliding mode control scheme is proposed, which is a combination of backstepping technique and integral sliding mode control approach. In addition, an adaptive law is introduced to enhance the robustness of a PWR with disturbances. The asymptotic stability of the overall control system is verified by Lyapunov stability theory. Simulation results are provided to demonstrate that the proposed DOB-ASMC strategy has better power tracking performance than conventional sliding mode controller and PID control method as well as conventional backstepping controller.

Disturbance observer-based robust backstepping load-following control for MHTGRs with actuator saturation and disturbances

Hui, Jiuwu,Yuan, Jingqi Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.11

This paper presents a disturbance observer-based robust backstepping load-following control (DO-RBLFC) scheme for modular high-temperature gas-cooled reactors (MHTGRs) in the presence of actuator saturation and disturbances. Based on reactor kinetics and temperature reactivity feedback, the mathematical model of the MHTGR is first established. After that, a DO is constructed to estimate the unknown compound disturbances including model uncertainties, external disturbances, and unmeasured states. Besides, the actuator saturation is compensated by employing an auxiliary function in this paper. With the help of the DO, a robust load-following controller is developed via the backstepping technique to improve the load-following performance of the MHTGR subject to disturbances. At last, simulation and comparison results verify that the proposed DO-RBLFC scheme offers higher load-following accuracy, better disturbances rejection capability, and lower control rod speed than a PID controller, a conventional backstepping controller, and a disturbance observer-based adaptive sliding mode controller.

Adaptive second-order nonsingular terminal sliding mode power-level control for nuclear power plants

Jiuwu Hui,Jingqi Yuan 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

This paper focuses on the power-level control of nuclear power plants (NPPs) in the presence of lumpeddisturbances. An adaptive second-order nonsingular terminal sliding mode control (ASONTSMC) schemeis proposed by resorting to the second-order nonsingular terminal sliding mode. The pre-existingmathematical model of the nuclear reactor system is firstly described based on point-reactor kineticsequations with six delayed neutron groups. Then, a second-order sliding mode control approach isproposed by integrating a proportional-derivative sliding mode (PDSM) manifold with a nonsingularterminal sliding mode (NTSM) manifold. An adaptive mechanism is designed to estimate the unknownupper bound of a lumped uncertain term that is composed of lumped disturbances and system statesreal-timely. The estimated values are then added to the controller, resulting in the control system capableof compensating the adverse effects of the lumped disturbances efficiently. Since the sign function iscontained in the first time derivative of the real control law, the continuous input signal is obtained afterintegration so that the chattering effects of the conventional sliding mode control are suppressed. Therobust stability of the overall control system is demonstrated through Lyapunov stability theory. Finally,the proposed control scheme is validated through simulations and comparisons with a proportionalintegral-derivative (PID) controller, a super twisting sliding mode controller (STSMC), and a disturbance observer-based adaptive sliding mode controller (DO-ASMC)

Study on Variable Parameter Helical Milling of TC4 Titanium Alloy Tube

Anyuan Jiao,Jingqi Yuan,Yue Zhang,Jialong Zhang,Yongxin Miao,Guojun Liu 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.11

Titanium alloy was widely used in various tubing systems due to the excellent performance, and tubes were usually used as a connection channel for conveying media with holes. However, the stability and dependability of media transmission in the tubing system would be directly impacted by the quality of the holes. This study primarily focused on TC4 titanium alloy tubes to investigate variable parameter helical milling holes to enhance the quality of tube connection holes. The finite element method simulation and response surface method were used to examine the relationship between each process parameter and the accuracy of the holes. Thus, a better combination of process parameters was projected. And based on this, a variable parameter hole-making scheme was proposed to lower the burrs at the entrance and exit of holes and enhance the quality of the wall of holes. The results showed that the aperture of 5.015 mm after processing the titanium alloy tube using the better process parameters met the requirements of H8. Additionally, the burrs at the hole entrance were 1.4 μm, the burrs at the hole exit were not noticeable, and the surface roughness Rz and Ra were 1.459 μm and 0.232 μm, respectively, met the requirements of process technology. The variable parameter helical milling technique used in this study could significantly raise the quality of holes produced in titanium alloy tubes and serve as a valuable benchmark for tubes of other materials.

Combined Age and Segregated Kinetic Model for Industrial-scale Penicillin Fed-batch Cultivation

Wang Zhifeng,Lauwerijssen Maarten J. C.,Yuan Jingqi The Korean Society for Biotechnology and Bioengine 2005 Biotechnology and Bioprocess Engineering Vol.10 No.2

This paper proposes a cell age model for Penicillium chrysogenum fed-batch cultivation to supply a qualitative insight into morphology-associated dynamics. The average ages of the segregated cell populations, such as growing cells, non-growing cells and intact productive cells, were estimated by this model. A combined model was obtained by incorporating the aver-age ages of the cell sub-populations into a known but modified segregated kinetic model from literature. For simulations, no additional effort was needed for parameter identification since the cell age model has no internal parameters. Validation of the combined model was per-formed by 20 charges of industrial-scale penicillin cultivation. Meanwhile, only two charge-dependent parameters were required in the combined model among approximately 20 parameters in total. The model is thus easily transformed into an adaptive model for a further application in on-line state variables prediction and optimal scheduling.

Macrokinetic Model for Gluconobacter oxydans in 2-keto-L-gulonic Acid Mixed Culture

Zhixiong Zhang,Xinjie Zhu,Ping Xie,Junwei Sun,Jingqi Yuan 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.5

A set of kinetic models have been developed for the production of 2-keto-L-gulonic acid from L-sorbose by a mixed culture of Gluconobacter oxydans and Bacillus megaterium. A metabolic pathway is proposed for Gluconobacter oxydans, and a macrokinetic model has been developed for Gluconobacter oxydans, where the balances of some key metabolites, ATP and NADH are taken into account. An unstructured model is proposed for concomitant bacterium Bacillus megaterium. In the macrokinetic model and unstructured model, the mechanism of interaction between Gluconobacter oxydans and Bacillus megaterium is investigated and modeled. The specific substrate uptake rate and the specific growth rate obtained from the macrokinetic model are then coupled into a bioreactor model such that the relationship between the substrate feeding rate and the main state variables, such as the medium volume, the biomass concentrations, the substrate,and the is set up. A closed loop regulator model is introduced to approximate the induction of enzyme pool during lag phase after inoculation. Experimental results demonstrate that the model is able to describe 2-keto-Lgulonic acid fermentation process with reasonable accuracy.