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AWells-Riley/based COVID-19 infectiousrisk assessment model combining both short rangeandroom scale effects

Building Simulation 2024年第1期17卷 93-111页

作者： Yinshuai feng Yifan Fan Xiaoyu Luo Jian ge College of Civil Engineering and Architecture Zhejiang UniversityHangzhouChina Center for Balance Architecture Zhejiang UniversityHangzhouChina International Research Center for Green Building and Low-Carbon City International CampusZhejiang UniversityHainingChina

There is growing evidence of the high transmission potential of COVID-19 through virus-laden *** aerosols are inhaled in various concentrations,an overall assessment of transmission risks at different indoor scales is ***,a comprehensive risk assessment method that evaluates the direct link between short-range and room-scale zones is stl *** this paper,a risk assessment model combining both short-range and room-scale effects is developed to obtain effective reproduction number in confined indoor environments,called Turbulent Jet Wells Riley(TJWR)*** with the viral load data and aerosol generation data of different human respiratory activities,the Monte Carlo simulation method is applied to calculate the quanta emission rate,which further provides the input parameters of the TJWR *** known outbreaks(Hangzhou banquet hall X,Guangzhou restaurant Y,and Hong Kong restaurant Z,China)are chosen to validate the TJWR *** show that the TJWR model is more efficient than the original Wells-Riley *** average relative error of the TJWR model ranges between 9%and 44%,while for the Wells-Riley model,it ranges between 57%and 78%.The TJWR model also proves that infection risk assessments using the well-mixed assumption can systematically underestimate the transmission risk for those close to the ***,there is a significant positive linear correlation between the total number of exposed individuals at the short-range and the effective reproduction *** newly developed TJWR model has great potential for rapid and real-time overall airborne transmission risk assessment in buildings and cities.

关键词： COVID-19 airborne transmission infection risk Wells-Riley model Monte Carlo simulation

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Constructal design of a rectangular parallel phase change microchannel in a three-dimensional electronic device

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Science China(Technological Sciences) 2024年第5期67卷 1381-1390页

作者： ZHANG JiWen feng HuiJun CHEN Lingen ge YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan430205China College of Power Engineering Naval University of EngineeringWuhan430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan430205China

Based on constructal theory,a rectangular parallel phase change microchannel model in a three-dimensional electronic device(TDED)is established with R134a as the cooling *** on the minimization of a complex function(CF)composed of linear weighting sum of maximum temperature difference and pumping power consumption,constructal design of the TDED is conducted first;and then,maximum temperature difference and pumping power consumption are minimized by non-dominated sorting genetic algorithm-II *** results reveal that there exist an optimal mass flow rate(0.0012.kg/s)and a quadratic optimal aspect ratio(AR)(0.39)of the microchannel which lead to quadratic minimum CF(0.817).Compared with the original value,the CF after optimization is reduced by 18.34%.Reducing the inlet temperature of cooling fluid and microchannel number appropriately can help to enhance the overall performance of *** using the artificial neural network and genetic algorithms in the toolboxes of Matlab software,the optimal AR gained in the Pareto solution set is located between 0.2.*** smallest deviation index among three discussed strategies is 0.346,and the corresponding optimal AR is 0.413,which is selected as the optimal design strategy of the microchannel in the TDED under multiple *** findings in this study can serve as theoretical guides for thermal designs of electronic devices.

关键词： constructal theory parallel microchannel evaporation phase change three-dimensional electronic device multi-objective optimization artificial neural network

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Constructal design of a rectangular porous fin considering minimization of maximum temperature difference and pumping power consumption

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Science China(Technological Sciences) 2024年第3期67卷 919-929页

作者： LIU XiaoYe feng HuiJun CHEN Lingen ge YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

A heat dissipation model of a rectangular porous fin is established based on constructal theory. First, the constructal design of rectangular porous fin is conducted by selecting a complex function minimization, which composed of linear weighting sum of maximum temperature difference and pumping power consumption, as optimization objective. Effects of gap height, air inlet velocity, total porous fin volume and porosity on the optimal constructs are investigated, respectively. The findings show that the complex function can attain its double minimum at a value of 0.802.when the fin length and number are optimized, and the corresponding optimal fin length and number are 8.01 mm and 10, respectively. In comparison to original design, the complex function and maximum temperature difference after twice optimization are decreased by 19.80% and 66.31%, ***, the comprehensive performance of porous fin is improved by simultaneously optimizing the fin length and number. The artificial neural network is applied to predict the fin performances, which is used to conduct multi-objective optimization based on NSGA-II algorithm. Optimal structure of porous fin for multiple requirements is gained by LINMAP and TOPSIS decisionmaking strategies. The findings in this study can serve as theoretical guides for fin thermal designs of electronic devices.

关键词： constructal theory rectangular porous fin pumping power consumption maximum temperature difference complex function multi-objective optimization

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Energy and exergy analyses and optimizations for two-stage TEC driven by two-stage TEG with Thomson effect

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Science China(Technological Sciences) 2024年第4期67卷 1077-1093页

作者： CHEN Lingen ge YanLin {2. HuiJun REN TingTing Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China

Based on the non-equilibrium thermodynamics and energy and exergy analyses,a thermodynamic model of two-stage thermoelectric(TE)cooler(TTEC)driven by two-stage TE generator(TTEG)(TTEG-TTEC)combined TE device is established with involving Thomson effect by fitting method of variable physical parameters of TE *** total number of TE elements as constraint,influences of number distributions of TE elements on three device performance indictors,that is,cooling load,maximum COP and maximum exergetic efficiency,are *** number distributions of TE elements are optimized with three maximum performance indictors as the objectives,*** of hot-junction temperature of TTEG and coldjunction temperature of TTEC on optimization results are analyzed,and difference between optimization results corresponding to three performance indicators are *** performance intervals and optimal variable intervals are *** of Thomson effect on three general performance indicators,three optimal performance indicators and optimal variables are comparatively *** effect reduces three general performance indicators and three optimal performance indicators of *** hot-and cold-junction temperatures of TTEG and TTEC are 450,305,32. and 2.5 K,respectively,Thomson effect reduced maximum cooling load,maximum COP and maximum exergetic efficiency from 9.52. W,9.043×10^(-2.and2.552.to 6.651 W,6.2.6×10^(-2.and 1.752.,respectively.

关键词： non-equilibrium thermodynamics cooling load COP exergetic efficiency combined thermoelectric device performance optimization

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A class of natural pinus koraiensis population system with time delay and diffusion term

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International Journal of Biomathematics 2024年第2期17卷 233-262页

作者： Guo-feng feng Jiaqi Chen Bin {2. School of Mathematical Sciences Harbin Engineering University Harbin 150001 P.R.China

In this paper,we consider the long-term sustainability of the northeast Korean *** propose a class of natural Korean pine population system with time delay and diffusion ***,by analyzing the roots distribution of the characteristic equation,we study the stability of the model system with diffusion terms and prove the occurrence of Hopf ***,we introduce lactation time delay into a population model with a diffusion term,based on stability theory of ordinary differential equation,norm form methods and center manifold theorem,the stability of bifurcating periodic solutions and the relevant formula for the direction of Hopf bifurcation are ***,some numerical simulations are given.

关键词： Pinus koraiensis populations delay diffusion term Hopf bifurcation periodic solution

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Multi-objective constructal design for quadrilateral heat generation body based on thermal-entransy theory and NSGA-Ⅱ

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Science China(Technological Sciences) 2024年第9期67卷 2777-2786页

作者： CHEN Lingen ZHU HongWei ge YanLin SHI ShuangShuang {2. HuiJun Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical Electrical EngineeringWuhan Institute of TechnologyWuhan 430205China

Based on thermal-entransy theory, the multi-objective constructal design of quadrilateral heat generation body(HGB) with similar shapes of leaves is studied further. The relationship between the aspect ratio of quadrilateral HGB and average temperature difference based on thermal-entransy dissipation is compared with that between the aspect ratio of quadrilateral HGB and the maximum temperature difference(MTD). The relationship between a composite function, consisting of linear weighting sum of the average temperature difference and MTD, and aspect ratio is obtained, and the optimal aspect ratios under minimum composite function with different weighting coefficients are obtained. Using the NSGA-Ⅱ algorithm, the Pareto frontier containing a series of compromise results of average temperature difference and MTD is obtained, and optimization results are compared using the deviation index. There is no aspect ratio to make both MTD and average temperature difference reach the minimum, and the optimal aspect ratio under the minimum MTD is smaller than that under the minimum average temperature difference. The optimal aspect ratio is obtained by making the composite function reach the minimum, and the optimal aspect ratios obtained by minimizing the composite function with different weighting coefficients are different. Compared with the construct of the initial design, the value of the composite function with optimal construct decreases by 1.9%, and the aspect ratio of the quadrilateral HGB decreases by 9.1%. The average temperature difference with the optimal construct increases by 2.1%, and the MTD with the optimal construct decreases by 5.6%. The deviation index under multi-objective optimization is smaller than that under single-objective optimization, and the obtained construct has better comprehensive thermal conductivity. Compared with TOPSIS and LINMAP decision-making methods, the average temperature difference with composite function optimization increases by 0.5

关键词： thermal-entransy theory constructal theory heat conduction quadrilateral heat generation body composite function NSGA-Ⅱ

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Constructal design of printed circuit recuperator for S-CO_(2.cycle via multi-objective optimization algorithm

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Science China(Technological Sciences) 2024年第1期67卷 285-294页

作者： DAN ZhiSong feng HuiJun CHEN Lingen LIAO NaiBing ge YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China Hubei Provincial Engineering Technology Research Center of Green Chemical Equipment Wuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China AECC Hunan Aviation Powerplant Research Institute Zhuzhou 412002China

Based on a constructal theory,the structure design of a printed circuit recuperator with a semicircular heat transfer channel for supercritical CO_(2.cycle is carried ***,a complex function composed of weighted sum of the reciprocal of total heat transfer rate and total pumping power consumption is regarded as an optimization objective,and total volumes of the recuperator and heat transfer channel are regarded as *** optimal heat transfer channel radius and minimum complex function of the recuperator are *** turns out that heat transfer rate,pumping power consumption,and complex function under the optimal construct of recuperator are reduced by 15.10%,82.44%,and 32.33%,*** exists the optimal single plate channel number which results in the double minimum complex ***,for the purpose of minimizing the reciprocal of heat transfer rate and pumping power consumption,NSGA-II algorithm is used to achieve multi-objective optimization,and the minimum deviation index derived by the decision-making methods is 0.076,which can be taken as multi-objective optimal design scheme for printed circuit recuperator with semicircular heat transfer *** findings presented here can serve as theoretical recommendations for the structure design of printed circuit recuperator.

关键词： constructal theory supercritical CO_(2.cycle printed circuit heat exchanger heat transfer rate pumping power consumption multi-objective optimization

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Robot-Oriented 6G Satellite-UAV Networks: Requirements, Paradigm Shifts, and Case Studies

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China Communications 2024年第2期21卷 74-84页

作者： Peng Wei Wei feng Yunfei Chen Ning ge Wei Xiang Department of Electronic Engineering Tsinghua UniversityBeijing 100084China Department of Engineering University of DurhamDH13LEDurhamUK School of Computing Engineering and Mathematical SciencesLa Trobe UniversityMelbourneVIC 3086Australia

Networked robots can perceive their surroundings, interact with each other or humans,and make decisions to accomplish specified tasks in remote/hazardous/complex environments. Satelliteunmanned aerial vehicle(UAV) networks can support such robots by providing on-demand communication services. However, under traditional open-loop communication paradigm, the network resources are usually divided into user-wise mostly-independent links,via ignoring the task-level dependency of robot collaboration. Thus, it is imperative to develop a new communication paradigm, taking into account the highlevel content and values behind, to facilitate multirobot operation. Inspired by Wiener’s Cybernetics theory, this article explores a closed-loop communication paradigm for the robot-oriented satellite-UAV network. This paradigm turns to handle group-wise structured links, so as to allocate resources in a taskoriented manner. It could also exploit the mobility of robots to liberate the network from full coverage,enabling new orchestration between network serving and positive mobility control of robots. Moreover,the integration of sensing, communications, computing and control would enlarge the benefit of this new paradigm. We present a case study for joint mobile edge computing(MEC) offloading and mobility control of robots, and finally outline potential challenges and open issues.

关键词： closed-loop communication mobility control satellite-UAV network structured resource allocation

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Influence of ammonium sulfate on the corrosion behavior of AZ31 magnesium alloy in chloride environment

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Journal of Magnesium and Alloys 2024年第3期12卷 1082-1101页

作者： feng ge Zhongyu Cui Yue Liu Li Lei Xin Wang Hongzhi Cui School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Beijing National Innovation Institute of Lightweight Ltd.Beijing 101499China

Electrochemical corrosion of AZ31 magnesium alloy in the NH_(4)^(+)-SO_(4)2.-Cl−environment is *** of NH_(4)^(+)overshadows that of Cl−as the(NH_(4))_(2.SO_(4) concentration is 0.005 M or higher,yielding an evolution from localized corrosion to uniform *** effect of NH_(4)^(+)can be attributed to that(i)NH_(4)^(+)dissolves the inner MgO and hinders the precipitation of Mg(OH)_(2. and(ii)the buffering ability of NH_(4)^(+)provides H+,enhances the hydrogen evolution,and expedites the corrosion *** latter is demonstrated as the dominant factor with the results in unbuffered and buffered *** severe corrosion and hydrogen process in NH_(4)^(+)-containing solution results in a high Hads coverage and yields an inductive loop within the low ***,SO_(4)^(2.)is helpful in generating cracked but partially protective corrosion products,while Cl−could broaden the corrosion area beneath the corrosion product.

关键词： Magnesium alloy Ammonium corrosion Electrochemical kinetic parameter Anodic dissolution.

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Co-Harvest Phase-Change Enthalpy and Isomerization Energy for High-Energy Heat Output by Controlling Crystallization of Alkyl-Grafted Azobenzene Molecules

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Energy & Environmental Materials 2024年第3期7卷 415-424页

作者： Jian Gao Yiyu feng Wenyu Fang Hui Wang Jing ge Xiaoyu Yang Huitao Yu Mengmeng Qin Wei feng School of Materials Science and Engineering Tianjin UniversityTianjin 300350China Key Laboratory of Materials Processing and Mold Ministry of EducationZhengzhou UniversityZhengzhou 450002China

Photoisomerization-induced phase change are important for co-harvesting the latent heat and isomerization energy of azobenzene *** optimizing heat output and energy delivery at alternating temperatures are challenging because of the differences in crystallizability and *** article reports two series of asymmetrically alkyl-grafted azobenzene(Azo-g),with and without a methyl group,that have an optically triggered phase *** exothermic modes were designed to utilize crystallization enthalpy(△H_(c))and photothermal(isomerization)energy(△H_(p))at different temperatures determined by the ***-g has high heat output(2.5-303 J g^(-1))by synchronously releasing△H_(c)and△H_(p)over a wide temperature range(-79℃to 2.℃).We fabricated a new distributed energy utilization and delivery system to realize a temperature increase of 6.6℃at a temperature of-8℃.The findings offer insight into selective utilization of latent heat and isomerization energy by molecular optimization of crystallization and isomerization processes.

关键词： crystallizability distributed energy utilization system energy density exothermic modes isomerization

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