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Petroleum 2020年第2期6卷 182-188页

作者： Majid Mohammadi Mehdi Sedighi Meysam Hemati Department of Energy Engineering Faculty of ScienceQom University of TechnologyQomIran Division of Energy Systems Department of Chemical EngineeringUniversity of QomQomIran Center of Environmental Research University of QomQomIran Department of Management Zanjan BranchIslamic Azad UniversityZanjanIran

Asphaltenes removal enhances the quality of the oil and facilitates the *** the present work,a NiO/AlPO-5 nanocomposite using green TMG was synthesized as a particular adsorbent for asphaltenes ***/AlPO-5 was characterized using FTIR,BET,TEM,and XRD *** Response Surface Method was used to optimize three important independent operating parameters,including D/C0[(g)adsorbent/(mg/L)initial](X1),initial pH(X2)and temperature(X3),to remove asphaltenes by the NiO/AlPO-5 nanocomposites in a model oil *** a CCD,a quadratic mathematical model formula was obtained to calculate asphaltene *** results revealed that the model showed valid agreement with the experimental results,with R2=*** optimum values for D/C0,pH as well as temperature would be 0.08[g/(mg/L)],3.39 and 298 K,*** was revealed that the optimal asphaltenes removal was 83.73%at the optimum *** isothermal models of Langmuir and Freundlich represented the asphaltenes adsorption on the new adsorbent with acceptable accuracy.

关键词： Asphaltene Removal Nanocomposite Optimization Adsorption

Data-driven Self-triggered control via Trajectory Prediction

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arXiv 2022年

作者： Liu, Wenjie Sun, Jian Wang, Gang Bullo, Francesco Chen, Jie The State Key Lab of Intelligent Control and Decision of Complex Systems The School of Automation Beijing Institute of Technology Beijing100081 China The Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China The Mechanical Engineering Department The Center of Control Dynamical Systems and Computation UC Santa BarbaraCA93106-5070 United States The Department of Control Science and Engineering Tongji University Shanghai201804 China The State Key Lab of Intelligent Control and Decision of Complex Systems Beijing Institute of Technology Beijing100081 China

Self-triggered control, a well-documented technique for reducing the communication overhead while ensuring desired system performance, is gaining increasing popularity. However, existing methods for self-triggered control require explicit system models that are assumed perfectly known a priori. An end-to-end control paradigm known as data-driven control learns control laws directly from data, and offers a competing alternative to the routine system identification-then-control method. In this context, the present paper puts forth data-driven self-triggered control schemes for unknown linear systems using data collected offline. Specifically, for output feedback control systems, a data-driven model predictive control (MPC) scheme is proposed, which computes a sequence of control inputs while generating a predicted system trajectory. A data-driven self-triggering law is designed using the predicted trajectory, to determine the next triggering time once a new measurement becomes available. For state feedback control systems, instead of capitalizing on MPC to predict the trajectory, a data-fitting problem using the pre-collected input-state data is solved, whose solution is employed to construct the self-triggering mechanism. Both feasibility and stability are established for the proposed self-triggered controllers, which are validated using numerical examples. © 2022, CC BY.

关键词： Model predictive control

Atomistic Analysis on Implantation Effects of Hydrogen Ions and Copper Ions into 4h-Sic

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SSRN

SSRN 2024年

作者： Fang, Xudong Kang, Qiang Wu, Xiaoyu Fang, Ziyan Sun, Hao Wu, Chen Zhang, Zhongkai Verma, Prateek Maeda, Ryutaro Tian, Bian Kang, Chengwei State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technologies Xi’an Jiaotong University Xi’an710049 China School of Mechanical Engineering Xi'an Jiaotong University Xi’an710049 China Shandong Laboratory of Advanced Materials and Green Manufacturing Yantai Yantai264000 China Department of Chemical Engineering University of Arkansas FayettevilleAR72701 United States School of Instrument Science and Technology Xi’an Jiaotong University Xi’an710049 China

Microstructure evolution of 4H-SiC by implantation of hydron ions and copper ions is investigated by molecular dynamics (MD) simulation and experiments. MD models of single Cu2+ and H+ implanting into SiC were established, respectively. During ion implantation, lattice damage, amorphous defects, and temperature distribution etc. were analyzed. Implantation of H+ induced more amorphous atoms than Cu2+. Maximum atomic temperature (1635K) of the model with Cu2+ was significantly higher than that of the model with H+ (950K), while the volume of temperature rising region in the model with H+ was much larger. Lattice vibration caused by Cu2+ was severer than that of H+ ions. Atoms on the crystal structure were prone to move along the region where the lattice binding energy was weak. The mechanism of overlapping multiple ions implanting was studied. Ion type, initial energy, and incident angle were varied. Sputtering yield, projection range, number of amorphous atoms, and energy increment of the model with Cu2+ were each smaller than those of H+. An incident angle of 0° induced higher sputtering yield and more amorphous structure due to the channeling effect. Channeling effect of H+ model was severer than that of Cu2+ model. Experimental results supported the MD simulation analysis. © 2024, The Authors. All rights reserved.

关键词： Molecular dynamics

Enhanced Mild Hydroisomerization of N-Heptane Over Bifunctional Pd@H-Yβ Zeolite Catalysts with Synergistic Acid and Pd Nanoparticles

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SSRN

SSRN 2023年

作者： Kang, Yu-Hong Zhang, Xiao-Qi Gao, Juan Wang, Yun-Fei Liu, Guang-Hui Li, Yan-Jun Gao, Yong Bai, Jin-Jun Wang, Ai-Min Wei, Xian-Yong Lu, Cui-Ying Shaanxi Key Laboratory of Low Metamorphic Coal Clean Utilization School of Chemistry and Chemical Engineering Yulin University Yulin719000 China Key Laboratory of Coal Processing and Efficient Utilization Ministry of Education China University of Mining & Technology Xuzhou221116 China Department of Chemical Engineering Ordos Institute of Technology Ordos017000 China Yulin Institute for Drug Control Yulin719000 China

Enhancing hydroisomerization efficiency and product selectivity by exploring the bifunctional zeolite-supported metal catalysts at the nanoscale are of great important in petrochemical and coal chemical industries. Herein, we explore a simple two-step strategy for introducing intracrystalline and intercrystalline mesopores in H-Yβ by in situ compositing and loading Pd nanoparticles (NPs, ~ 2.2 nm) through an incipient wetness impregnation process followed by mild oxidation-reduction treatment. Importantly, the Pd@H-Yβ catalyst with synergistic acid sites and minimizing Pd NPs inherits the large surface area, high crystallinity and mesopore porosity, and strong thermal and hydrothermal stability. As a demonstration, Pd@H-Yβ with extremely low Pd NPs loading amount of 0.2 wt% used for hydroisomerization of n-heptane by cascade dehydrogenation and hydrogenation on Pd NPs and isomerization on accessible acid sites, and exhibits an extraordinarily selectivity of i-heptane (74.7%) compared to the conventional Pd@H-Y (48.1%), Pd@H-β (33.4%), and Pd@HZSM-5 (0.1%) at 300 oC for 3 h under 1 MPa initial hydrogen pressure. Furthermore, first-principle calculations reveal that the excellent catalytic activity of Pd@H-Yβ originates from the active hydrogen (H…H and/or H+) transfer from the facile H2 dissociation. The diffusion limitations of intermediates and secondary cracking reactions are effectively weakened due to intrinsic mesopores in Pd@H-Yβ, which still maintains high catalytic activity after 5 times recycles. These findings provide a rational design strategy of bifunctional catalysts with metal-acid sites for low-molecular reactants conversion in industrial application. © 2023, The Authors. All rights reserved.

关键词： chemical industry

Three-Dimensional Seismic Response in Complex Site Conditions: A New Approach Based on an Auxiliary-Model Method

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Journal of Earth Science 2021年第5期32卷 1152-1165页

作者： Xiaolong Zhang Xiaobo Peng Xiaojun Li Zhenghua Zhou Chong Xu Zhan Dou Bideng Liu National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China Jiangsu Earthquake Agency Nanjing 210014China College of Architecture and Civil Engineering Beijing University of TechnologyBeijing 100124China College of Transportation Science of Engineerings Nanjing Tech University Nanjing 210009China Key Laboratory of Compound and Chained Natural Hazards Dynamics(Under Construction) Ministry of Emergency Management of ChinaBeijing 100085China Department of Safety Engineering College of Mechanical and Electrical EngineeringBeijing University of Chemical TechnologyBeijing 100029China State Environmental Protection Engineering Center for City Noise and Vibration Control Beijing Municipal Institute of Labor ProtectionBeijing 100054China

In this paper, an auxiliary-model method is proposed for calculating equivalent input seismic loads in research of ground motions. This method can be used to investigate the local effect of 3 D complex sites subjected to obliquely incident SV and P waves. Using this method, we build a fictitious auxiliary model along the normal direction of the boundary of the area of interest, with the model’s localized geological features remaining the same along a vector normal to this boundary. This model is divided into five independent auxiliary models, which are then dynamically analyzed to obtain the equivalent input seismic loads. Unlike traditional methods, in this new technique, the mechanical behavior of the auxiliary model can be nonlinear, and its geometry can be arbitrary. In addition, a detailed description of the steps to calculate the equivalent input seismic loads is given. Numerical examples of incident plane-wave propagation at uniform sites with local features validate the effectiveness of this method. It is also applicable to elastic and non-elastic problems.

关键词： seismic-wave input topography effect oblique incidence equivalent input seismic load free field motion

Mn, N co-doped carbon nanospheres for efficient capture of uranium (VI) via capacitive deionization

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Chemosphere 2023年 342卷 140190页

作者： Jin, Meiyue Huang, Xinhua Wang, Zhirou Chan, Vincent Hu, Jinsong Wu, Ai Hu, Guangzhi School of Materials Science and Engineering Anhui University of Science and Technology Huainan232001 China Department of Biomedical Engineering Khalifa University of Science and Technology Abu Dhabi United Arab Emirates School of Chemical Engineering Anhui University of Science and Technology Huainan232001 China Institute of Energy Hefei Comprehensive National Science Center Hefei230031 China Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental Science Yunnan University Kunming650504 China

Heteroatom doping, involving the introduction of atoms with distinct electronegativity into carbon materials, has emerged as an effective approach to optimize their charge distribution. In this study, we designed a strategy to synthesize in-situ Mn, N co-doped carbon nanospheres (Mn-NC) through the polycondensation of 2,6-diaminopyridine and formaldehyde in synchronization with Mn2+ chelation to form Mn-polytriazine precursor, followed by calcination to form carbonaceous solid. Then Mn-NC was fabricated into a capacitive deionization (CDI) electrode for the selective removal of uranium ions (U (VI)), which is commonly found in radioactive water. Interestingly, Mn-NC exhibited good selectivity for UO22+ capture with a demonstrated adsorption capacity of approximately 194 mg/g @1.8 V. The systematic analysis of the adsorption mechanism of UO22+ revealed that N dopants within Mn-NC can coordinate with the U (VI) ions, thereby facilitating the removal process. Our study presents a straightforward and convenient strategy for removing UO22+ ions by harnessing the coordination effect, eliminating the requirement for pore size control. © 2023 Elsevier Ltd

关键词： Ions

Coincidence analysis of Stackelberg and Nash equilibria in three-player leader-follower security games

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arXiv 2022年

作者： Xu, Gehui Chen, Guanpu Cheng, Zhaoyang Hong, Yiguang Qi, Hongsheng Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Beijing China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing China JD Explore Academy Beijing China Department of Control Science and Engineering Shanghai Research Institute for Intelligent Autonomous Systems Tongji University Shanghai China The Key Laboratory of Systems and Control Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

There has been significant recent interest in leader-follower security games, where the leader dominates the decision process with the Stackelberg equilibrium (SE) strategy. However, such a leader-follower scheme may become invalid in practice due to subjective or objective factors, and then the Nash equilibrium (NE) strategy may be an alternative option. In this case, the leader may face a dilemma of choosing an SE strategy or an NE strategy. In this paper, we focus on a unified three-player leader-follower security game and study the coincidence between SE and NE. We first explore a necessary and sufficient condition for the case that each SE is an NE, which can be further presented concisely when the SE is unique. This condition not only provides access to seek a satisfactory SE strategy but also makes a criterion to verify an obtained SE strategy. Then we provide another appropriate condition for the case that at least one SE is an NE. Moreover, since the coincidence condition may not always be satisfied, we describe the closeness between SE and NE, and give an upper bound of their deviation. Finally, we show the applicability of the obtained theoretical results in several practical security cases, including the secure transmission problem and the cybersecurity defense. Copyright © 2022, The Authors. All rights reserved.

关键词： Game theory

Meta-Reinforcement Learning for the Tuning of PI controllers: An Offline Approach

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arXiv 2022年

作者： McClement, Daniel G. Lawrence, Nathan P. Backström, Johan U. Loewen, Philip D. Forbes, Michael G. Gopaluni, R. Bhushan Department of Chemical and Biological Engineering University of British Columbia VancouverBC Canada Department of Mathematics University of British Columbia VancouverBC Canada Backstrom Systems Engineering Ltd. Honeywell Process Solutions North Vancouver BC Canada Canada

Meta-learning is a branch of machine learning which trains neural network models to synthesize a wide variety of data in order to rapidly solve new problems. In process control, many systems have similar and well-understood dynamics, which suggests it is feasible to create a generalizable controller through meta-learning. In this work, we formulate a meta reinforcement learning (meta-RL) control strategy that can be used to tune proportional-integral controllers. Our meta-RL agent has a recurrent structure that accumulates "context" to learn a system's dynamics through a hidden state variable in closed-loop. This architecture enables the agent to automatically adapt to changes in the process dynamics. In tests reported here, the meta-RL agent was trained entirely offline on first order plus time delay systems, and produced excellent results on novel systems drawn from the same distribution of process dynamics used for training. A key design element is the ability to leverage model-based information offline during training in simulated environments while maintaining a model-free policy structure for interacting with novel processes where there is uncertainty regarding the true process dynamics. Meta-learning is a promising approach for constructing sample-efficient intelligent controllers. © 2022, CC BY.

关键词： Reinforcement learning

Chemist-X: Large Language Model-empowered Agent for Reaction Condition Recommendation in chemical Synthesis

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arXiv 2023年

作者： Chen, Kexin Lu, Jiamin Li, Junyou Yang, Xiaoran Du, Yuyang Wang, Kunyi Shi, Qiannuan Yu, Jiahui Li, Lanqing Qiu, Jiezhong Pan, Jianzhang Huang, Yi Fang, Qun Heng, Pheng Ann Chen, Guangyong Department of Computer Science and Engineering The Chinese University of Hong Kong Hong Kong Institute of Intelligent Chemical Manufacturing and iChemFoundry Platform ZJU-Hangzhou Global Scientific and Technological Innovation Center Hangzhou China Institute of Microanalytical Systems Department of Chemistry Zhejiang University Hangzhou China Zhejiang Lab Hangzhou China Department of Information Engineering The Chinese University of Hong Kong Hong Kong

Recent AI research plots a promising future of automatic chemical reactions within the chemistry society. This study proposes Chemist-X, a comprehensive AI agent that automates the reaction condition optimization (RCO) task in chemical synthesis with retrieval-augmented generation (RAG) technology and AI-controlled wet-lab experiment executions. To begin with, as an emulation on how chemical experts solve the RCO task, Chemist-X utilizes a novel RAG scheme to interrogate available molecular and literature databases to narrow the searching space for later processing. The agent then leverages a computer-aided design (CAD) tool we have developed through a large language model (LLM) supervised programming interface. With updated chemical knowledge obtained via RAG, as well as the ability in using CAD tools, our agent significantly outperforms conventional RCO AIs confined to the fixed knowledge within its training data. Finally, Chemist-X interacts with the physical world through an automated robotic system, which can validate the suggested chemical reaction condition without human interventions. The control of the robotic system was achieved with a novel algorithm we have developed for the equipment, which relies on LLMs for reliable script generation. Results of our automatic wet-lab experiments, achieved by fully LLM-supervised end-to-end operation with no human in the lope, prove Chemist-X’s ability in self-driving laboratories. Copyright © 2023, The Authors. All rights reserved.

关键词： Biosynthesis

The effect of cylinder wall cooling and vortex finder (tapered in-out) geometry on temperature, heat rate, and flow field to increase cyclone performance using CFD

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Case Studies in chemical and Environmental engineering 2023年 7卷

作者： Yohana, Eflita Tauviqirrahman, Mohammad Ismail, Rifky Muliyawan, Anggi Carles, Henry Dwinanda, M. Farkhan H. Ariyanto, H.D. Yulianto, M.E. Choi, Kwang-Hwan Department of Mechanical Engineering Diponegoro University Semarang 50275 Indonesia Departemen of Energy Conservation & Loss Control Engineering Development RU V Balikpapan PT Kilang Pertamina International Indonesia Diploma III Programme of Chemical Engineering Diponegoro University Indonesia College of Engineering Pukyong National University 365 Sinseon-ro Nam-gu Busan 608-739 South Korea

The results of testing the effect of temperature, flow field, heat transfer, and performance by simulating the tapered in-out shape with and without cylinder wall cooling (17 °C). The tapered in-out height variations used in this study are 0.5, 0.75, 1, and 1.25D with diameters De 74 and Dc 148. The fluid flow simulation used the RSM turbulence model. The particle movement approach is predicted using Eulerian-Lagrangian. The DPM method was applied to track the flow trajectories of individual particles. A model with cooling is applied to the cyclone body assuming constant temperature. The validation results of experimental and CFD simulation show the same trend with an error of 5.5%. Simulation results show that changing the shape of the vortex finder from the conventional cyclone (V0) to tapered in-out (V1) results in a significant improvement in performance: particle efficiency of 18.11% and pressure drop of 59.46%. The tapered in-out with cylinder wall cooling (V1C) slightly affects the performance: 1.9% increase in particle efficiency and 8.23% increase in pressure drop compared to the tapered in-out (V1). The change in height of V1 to V4 and V1C to V4C causes the performance on particle efficiency to decrease by 31.41% and 30.67% pressure drop decreases with increasing height of tapered in-out. © 2023

关键词： Cooling Heat transfer Particle efficiency Pressure drop Temperature Vortex finder