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Achieving high titer and yield in the bioconversion of l-threonine to 2-hydroxybutyric acid with Escherichia coli BL21

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systems Microbiology and Biomanufacturing 2024年第2期4卷 708-715页

作者： Thai Le Bassey Friday Bassey Thuan Phu Nguyen-Vo Sunghoon Park School of Energy and Chemical Engineering Ulsan National Institute of Science and TechnologyUlsan 44919Republic of Korea Department of Chemical and Biochemical Engineering North Carolina State UniversityRaleighNC 27606USA Institute of Systems Biotechnology Saarland UniversitySaarbrückenGermany

The study investigated the enhanced production of 2-hydroxybutyric acid(2-HBA)from threonine using a two-step whole-cell bioconversion by recombinant Escherichia coli BL21(DE3)overexpressing threonine dehydratase and *** address the rate-limiting step posed by NADH regeneration for the keto-reductase reaction converting 2-ketobutyric acid(2-KBA)to 2-HBA,formate dehydrogenase from Candida boidinii was overexpressed under the T7 promoter,resulting in a high titer of 1015 mM and a yield of 0.70 mol/***,the yield was improved by disrupting three enzymes responsible for the degradation of the intermediate(2-KBA),pyruvate-formate lyase(PflB),pyruvate oxidase(PoxB),and pyruvate dehydrogenase complex(PDHc),leading to an impressive yield of 0.99 mol/mol,closely approaching the theo-retical maximum of 1.00 mol/*** triple mutant,designed to prevent 2-KBA degradation,achieved a remarkable titer of 1,400 mM and volumetric productivity of 58 mmol/L/*** the best of our knowledge,this achievement represents the highest reported titer and yield for 2-HBA production to date.

关键词： 2-hydroxybutyric acid(2-HBA) Whole-cell bioconversion Threonine Degradation pathway High titer

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Effect of turbulent fluctuation on the ignition of millimeter particle:Experimental studies and numerical modelling with a new correlation of nusselt number Author links open overlay panel

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Particuology 2024年第8期91卷 168-175页

作者： Lele Feng Jie Liu Haihui Xin Liangliang Jiang Yuxin Wu Saeideh Babaee Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization China University of Mining and TechnologyXuzhou221008China School of Safety Engineering China University of Mining and TechnologyXuzhou221116China Key Laboratory of Hubei Province for Coal Conversion and New Carbon Materials Wuhan University of Science and TechnologyWuhan430000China Department of Chemical and Petroleum Engineering University of CalgaryCalgaryAlbertaCanada Department of Energy and Power Engineering Tsinghua UniversityBeijing100084China Department of Chemical and Metallurgical Engineering University of the WitwatersrandJohannesburgSouth Africa

Understanding the influencing mechanism of turbulent fluctuation on the ignition characteristics of millimeter coal particles is *** this work,to study the effect of turbulent fluctuation on ignition time,millimeter coal particles are subjected to a specific flow field,generated in a furnace with symmetric fans.A one-dimensional model with the new proposed correlation and the Ranz-Marshall(R-M)correlation for Nu(Nusselt number)is established to simulate the coal ignition *** addition,the effects of fan speed,temperature,particle diameter,particle distance and coal type on the ignition time are *** is found that an increase in fan speed from 0 to 3000 rpm leads to a particle Reynolds number Re_(p)increase from 0 to 22.5,and a turbulent particle Reynolds number Re_(t)*increase from 0 to *** a consideration of the fluctuation effect,the new correlation of Nu gives a better prediction of ignition time compared to the R-M ***,the ignition time is revealed to decrease with an increasing fan speed and an elevating *** the ignition time shows merely an initial boost with enlarging particle distance,it exhibits a linearity with the term of particle diameter dp1.3-1.7 and Reynolds numbers(Nu*/Nu)-0.6(Nu*is turbulent Nusselt number).Based on this relationship,the difference of predicted ignition time is calculated at different Re_(p)and Re_(t)*.It is shown that at low Re_(p)or high Re_(t)*values,the new correlation should substitute for the R-M correlation.

关键词： Turbulent fluctuation Particle heat transfer Empirical correlation Coal ignition

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Neural Dynamics for Cooperative Motion control of Omnidirectional Mobile Manipulators in the Presence of Noises: A Distributed Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1605-1620页

作者： Yufeng Lian Xingtian Xiao Jiliang Zhang Long Jin Junzhi Yu Zhongbo Sun the Department of Control Engineering Changchun University of TechnologyChangchun 130012China IEEE the College of Information Science and Engineering Northeastern UniversityShenyang 110819 the National Mobile Communications Research Laboratory Southeast UniversityNanjing 210096China the School of Information Science and Engineering Lanzhou UniversityLanzhou 730000China the State Key Laboratory for Turbulence and Complex Systems Department of Advanced Manufacturing and RoboticsCollege of EngineeringPeking UniversityBeijing 100871China

This paper presents a distributed scheme with limited communications, aiming to achieve cooperative motion control for multiple omnidirectional mobile manipulators(MOMMs).The proposed scheme extends the existing single-agent motion control to cater to scenarios involving the cooperative operation of MOMMs. Specifically, squeeze-free cooperative load transportation is achieved for the end-effectors of MOMMs by incorporating cooperative repetitive motion planning(CRMP), while guiding each individual to desired poses. Then, the distributed scheme is formulated as a time-varying quadratic programming(QP) and solved online utilizing a noise-tolerant zeroing neural network(NTZNN). Theoretical analysis shows that the NTZNN model converges globally to the optimal solution of QP in the presence of noise. Finally, the effectiveness of the control design is demonstrated by numerical simulations and physical platform experiments.

关键词： Cooperative motion control noise-tolerant zeroing neural network(NTZNN) omnidirectional mobile manipulator(OMM) repetitive motion planning

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Hierarchically Distributed Optimization with a Flexible and Complexity-Reducing Algorithm

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Journal of systems Science & Complexity 2024年第6期37卷 2530-2555页

作者： LIANG Shu ZHANG Lei WEI Yiheng LIU Yemo Department of Control Science and Engineering Tongji UniversityShanghai 200092China Shanghai Research Institute for Intelligent Autonomous Systems Shanghai 200092China School of Mathematics Southeast UniversityNanjing 211189China Beijing Aerospace Automatic Control Institute Beijing 100854China

In this paper,the authors consider distributed convex optimization over hierarchical *** authors exploit the hierarchical architecture to design specialized distributed algorithms so that the complexity can be reduced compared with that of non-hierarchically distributed *** this end,the authors use local agents to process local functions in the same manner as other distributed algorithms that take advantage of multiple agents'computing ***,the authors use pseudocenters to directly integrate lower-level agents'computation results in each iteration step and then share the outcomes through the higher-level network formed by *** authors prove that the complexity of the proposed algorithm exponentially decreases with respect to the total number of *** support the proposed decomposition-composition method for agents and pseudocenters,the authors develop a class of *** operators are generalizations of the widely-used subgradient based operator and the proximal operator and can be used in distributed convex ***,these operators are closed with respect to the addition and composition operations;thus,they are suitable to guide hierarchically distributed design and ***,these operators make the algorithm flexible since agents with different local functions can adopt suitable operators to simplify their ***,numerical examples also illustrate the effectiveness of the method.

关键词： Complexity convergence convex optimization distributed algorithm hierarchical network

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Optimal and Robust control Design for Educational Magnetic Levitation System 16

Optimal and Robust Control Design for Educational Magnetic L...

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16th International Conference on Developments in esystems engineering, DeSE 2023

作者： Hadi, Musadaq A. Ali, Hazem I. University of Technology-Iraq Control and Systems Engineering Department Baghdad Iraq

ISBN: (纸本)9798350381344

In this study, a novel, robust, and optimal control algorithm is introduced for the Magnetic Levitation (MagLev) system. Initially, a model for the MagLev system that inheriting instability and featuring a non-affine property, is developed. Subsequently, the system is analyzed using the Lyapunov Quadratic Function (LQF) to formulate a suitable controller capable of achieving stable system performance. To further enhance the control algorithm, the Most Valuable Player Algorithm (MVPA) is employed and its performance is compared to that of the Genetic Algorithm (GA) for the optimization of the controller's parameters. The effectiveness of our proposed control algorithm in compensating the MagLev system's problems is demonstrated by the outcomes. Additionally, a comparative analysis is conducted to elucidate the distinctions in performance between MVPA and GA. Finally, the controller is applied to a laboratory magnetic levitation device to validate the proposed control algorithm. © 2023 IEEE.

关键词： Genetic algorithms

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Image Semantic Segmentation Used in Automatics 17

Image Semantic Segmentation Used in Automatics

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17th International Conference on engineering of Modern Electric systems, EMES 2023

作者： Spoiala, Viorica University of Oradea Control Systems Engineering and Management Department Oradea Romania

ISBN: (纸本)9798350310634

This paper presents the importance of segmentation methods used in the object analysis in computer vision and image proccessing field, in the automated processes. Image segmentation is a crucial stage of image processing in the context of industrial automation. The detection of objects is one of the main purposes of image segmentation, and in order to do this, it is necessary to perform the segmentation and extraction of the image's significant elements in advance. Putting pixels into semantic classifications is the foundation of semantic segmentation, this being a deep learning method. In order to apply segmentation in computer vision of automated processes the first step could be to label the objects and then to train a neural network to apply this labels to all the similar objects detected in similar images. In this paper some images were segmented by using labels and deep learning methods. After the theoretical aspects are presented, then some examples are made in Matlab environment. © 2023 IEEE.

关键词： Automation

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A Model-Based Unmatched Disturbance Rejection control Approach for Speed Regulation of a Converter-Driven DC Motor Using Output-Feedback

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IEEE/CAA Journal of Automatica Sinica 2022年第2期9卷 365-376页

作者： Lu Zhang Jun Yang Shihua Li School of Automation Southeast UniversityKey Laboratory of Measurement and Control of Complex Systems of EngineeringMinistry of Education IEEE Department of Aeronautical and Automotive Engineering Loughborough University

The speed regulation problem with only speed measurement is investigated in this paper for a permanent magnet direct current(DC)motor driven by a buck *** lumping all unknown matched/unmatched disturbances and uncertainties together,the traditional active disturbance rejection control(ADRC)approach provides an intuitive solution for the problem under ***,for such a higher-order disturbed system,the increase of poles for the extended state observer(ESO)therein will lead to drastically growth of observer gains,which causes severe noise *** paper aims to propose a new model-based disturbance rejection controller for the converter-driven DC motor system using *** of estimating lumped disturbances directly,a new observer is constructed to estimate the desired steady state of control signal as well as errors between the real states and their desired steady-state ***,a controller with only speed measurement is proposed by utilizing the *** performance of the proposed method is tested through experiments on *** is further shown via numerical calculations and experimental results that the poles of the observer within the proposed control approach can be largely increased without significantly increasing magnitude of the observer gains.

关键词： Bandwidth widening converter-driven direct current(DC)motor disturbance observer model-based disturbance rejection speed regulation

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Design and Implementation of an 80-160 kV High Voltage Power Supply

Design and Implementation of an 80-160 kV High Voltage Power...

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2024 Energy Conversion Congress and Expo Europe, ECCE Europe 2024

作者： Bilicioglu, Muhammed Faruk Bodur, Haci Aselsan Inc. Department of Power and Control Systems Design Engineering Ankara Turkey Yildiz Technical University Department of Electrical Engineering Istanbul Turkey

ISBN: (纸本)9798350364446

In this study, an 80-160 kV, 200 W high voltage power supply is designed and implemented. To overcome the insulation restrictions of the transformer used in the high voltage power supply, a resonant converter and a voltage multiplier circuit were used consecutively for the voltage boosting process. To utilize the parasitic capacitor of transformer becoming dominant due to the high turn ratio, an LCC type series-parallel resonant converter is used as the resonant converter. An optimization algorithm that optimizes efficiency and power density is developed to determine the resonant tank parameters. Bipolar Cockcroft-Walton Voltage Multiplier as the voltage multiplier is preferred due to the advantages of less secondary winding and lower voltage drop. The high voltage power supply design is verified with simulations and experimental results. © 2024 IEEE.

关键词： Resonant converters

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Continuous flow pyrolysis of virgin and waste polyolefins:a comparative study,process optimization and product characterization

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Frontiers of chemical Science and engineering 2024年第6期18卷 133-149页

作者： Ecrin Ekici Güray Yildiz Magdalena Joka Yildiz Monika Kalinowska ErolŞeker Jiawei Wang Karlsruhe Institute of Technology Institute of Catalysis Research and TechnologyEggenstein-Leopoldshafen 76344Germany Izmir Institute of Technology Faculty of EngineeringDepartment of Energy Systems EngineeringIzmir 35430Türkiye Department of Materials Engineering and Production Faculty of Mechanical EngineeringBialystok University of TechnologyBialystok 15-351Poland Department of Agricultural and Food Engineering and Environmental Development Institute of Civil Engineering and EnergeticsFaculty of Civil Engineering and Environmental SciencesBialystok University of Technology15-351 BialystokPoland Department of Chemistry Biology and BiotechnologyInstitute of Civil Engineering and EnergeticsFaculty of Civil Engineering and Environmental SciencesBialystok University of TechnologyBialystok 15-351Poland Izmir Institute of Technology Faculty of EngineeringDepartment of Chemical EngineeringIzmir 35430Türkiye Energy and Bioproducts Research Institute(EBRI) Aston UniversityBirmingham B47ETUnited Kingdom

Under optimal process conditions,pyrolysis of polyolefins can yield ca.90 wt%of liquid product,i.e.,combination of light oil fraction and heavier *** this work,the experimental findings reported in a selected group of publications concerning the non-catalytic pyrolysis of polyolefins were collected,reviewed,and compared with the ones obtained in a continuously operated bench-scale pyrolysis *** process parameters were used for the pyrolysis of waste and virgin counterparts of high-density polyethylene,low-density polyethylene,polypropylene and a defined mixture of those(i.e.,25:25:50 wt%,respectively).To mitigate temperature drops and enhance heat transfer,an increased feed intake is employed to create a hot melt plastic *** 1.5 g·min^(-1) feed intake,1.1 L·min^(-1) nitrogen flow rate,and a moderate pyrolysis temperature of 450℃,the formation of light hydrocarbons was favored,while wax formation was limited for polypropylene-rich *** of virgin plastics yielded more liquid(maximum 73.3 wt%)than that of waste plastics(maximum 66 wt%).Blending polyethylenes with polypropylene favored the production of liquids and increased the formation of gasoline-range *** products were mainly composed of C3 hydrocarbons,and no hydrogen production was detected due to moderate pyrolysis temperature.

关键词： waste plastics polyolefins chemical recycling pyrolysis alternative fuels waste-to-energy

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Vertical velocity of a small sphere in a sheared granular bed

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Physical Review Research 2024年第2期6卷 L022015-L022015页

作者： Song Gao (高颂) Julio M. Ottino Richard M. Lueptow Paul B. Umbanhowar Department of Mechanical Engineering Northwestern University Evanston Illinois 60208 USA Department of Chemical and Biological Engineering Northwestern University Evanston Illinois 60208 USA Northwestern Institute on Complex Systems (NICO) Northwestern University Evanston Illinois 60208 USA

Small particles fall through sheared beds of larger particles in settings ranging from geophysics to industry, but the study of large-to-small size ratios R, spanning the trapping threshold Rt, has been neglected. In simulations of noncohesive spheres for RRt, vp is constant at low γ̇, but again decreases at high γ̇. We model these behaviors and discuss analogies with electron transport in solids.

关键词： Granular flows Granular segregation Granular materials

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