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Particuology 2024年第2期85卷 280-295页

作者： Fei Zhang Youyu Lu Shaoyan Zhu Funian Han Guanghua Wen Ping Tang Zibing Hou College of Materials Science and Engineering Chongqing UniversityChongqing400044China Guizhou Academy of Testing and Analysis Guizhou Academy of SciencesGuiyang550014China

In this work,the formation mechanism of the droplet-to-granule was investigated in detail based on mold powder manufacturing.A specific mathematical model of two-stage spray drying was established to describe droplet and granule motion,heat and mass transfer,and granule morphology during spray ***,the relationships between spray drying parameters(inlet temperature,atomization pres-sure,slurry mass flow rate)and the properties of the drying tower(temperature and velocity fields)and mold powder granules(temperature,evaporation rates,moisture content,and diameter)were simulated and calculated using ANSYS/Fluent *** ensure that the granule size of mold powder was controlled within the ideal range(0.2-0.6 mm)for producing granules with appropriate mechanical and metallurgical properties,the following optimum spray drying parameters were chosen based on the results of the numerical simulation:inlet temperatures,873 K;slurry atomization pressure,1.8 MPa;slurry mass flow rate,0.05 kg *** these parameters,the slurry mass flow rate has the most significant effect on granule size.

关键词： Mold powder slurry Spray drying parameters mathematical model Numerical simulation Granule sizes

Improving mathematical model of burden distribution and correcting chute angle to cope with fluctuation of stock line

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Journal of Iron and Steel Research International 2024年第2期31卷 342-356页

作者： Jian-sheng Chen Wen-guo Liu Hao Guo Wang Ding Qing-guo Xue Jing-song Wang Hai-bin Zuo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China MCC Capital Engineering&Research Incorporation Limited Beijing100176China Hunan Valin Xiangtan Iron and Steel Co. Ltd.Xiangtan411101HunanChina

Accurate evaluations of the burden distribution are of critical importance to stabilize the operation of blast *** mathematical model and discrete element method(DEM)are two attractive methods for predicting burden *** on DEM,the initial velocities of the pellet,sinter,and coke were calculated,and the velocity attenuations of the above three particles between the burden and the chute were *** initial velocity and velocity attenuation were applied to a mathematical model for improving the ***,based on the improved model,a scheme for rectifying the chute angles was proposed to address the fluctuation of the stock line and maintain a stable burden *** validity of the scheme was confirmed via a stable burden distribution under different stock *** mathematical model has been successfully applied to evaluate the online burden distribution and cope with the fluctuation of the stock line.

关键词： Burden distribution mathematical model Discrete element method Velocity attenuation Stock line fluctuation

A methodology for laser tool setters calibration and its precise mathematical model

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Chinese Journal of Aeronautics 2024年第7期37卷 564-581页

作者： Tao FANG Zixi FANG Ze Zhong CHEN Zhiyong CHANG School of Mechanical Engineering Northwestern Polytechnical UniversityXi’an 710072China Gina Cody School of Engineering and Computer Science Concordia UniversityMontrealQuebec H3G 1M8Canada Changsha Optimum CNC Corporation Changsha 410221China Institute for Aero-engine Smart Assembly of Shaanxi Province Xi’an 710072China

On-machine tool setting is a pivotal approach in achieving intelligent manufacturing,and laser tool setters have become a crucial component of smart machine *** tool setters play a crucial role in precisely measuring the dimensions of cutting tools during the part machining process,focusing on tool length and *** a measuring instrument,the positions of the laser axis of the laser tool setter need to be accurately calibrated before ***,in actual calibration scenarios,traditional calibration methods face challenges due to installation errors in the tool setter and geometric errors in the measuring *** address this issue,this study proposes a novel calibration ***,the calibration mechanism of the laser beam axis is *** on the accurate mathematical model of the laser beam and the measuring rod,and using the polygon clipping algorithm,the mathematical mechanism of the laser tool setter’s work is ***,a novel method is introduced to calculate the compensation distance between the laser beam reference point and the rod bottom center point at each moment during ***,by utilizing the kinematic chain of the tool setter calibration system,a new calibration method is developed to accurately calibrate the position of the laser beam axis in the machine tool coordinate ***,the accuracy of the calibration method is verified through simulation experiments and calibration *** method improves the calibration accuracy of the tool setter,and the mathematical model of the laser tool setter can be extended to the measurement of tools,thereby improving the precision of tool *** research significantly improves the efficient production performance of smart machine tools.

关键词： On-machine tool setting Smart machine tools mathematical model Calibration method Laser tool sette

mathematical model of burden distribution in bell-less top blast furnace

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Journal of Iron and Steel Research International 2023年第2期30卷 216-226页

作者： Jian-sheng Chen Hai-bin Zuo Jing-xiu Wang Qing-guo Xue Jing-song Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

The burden distribution in the shaft of blast furnace is known to affect the gas distribution,heat transfer,and chemical reactions inside the ***,the internal layer structure of burden in the shaft cannot be directly ***,a mathematical model for evaluating burden profile and layer structure was established.A sensitivity analysis based on the model was implemented to elucidate the effect of some factors on the burden distribution,including the stockline height and the mass of central *** results show that the width of funnel zone widens with the increase in stockline height,and the mass percentage of ore to coke in this zone slightly ***,the mass of central coke shows a significant influence on the width of coke channel,and 2%of batch mass of coke is recommended to implement central coke charging *** model has been indirectly verified by the gas temperature in operating blast furnace and successfully applied to online evaluate burden distribution.

关键词： Blast furnace Burden distribution mathematical model Stockline height Central coke

mathematical model for predicting fungal growth and decomposition rates based on improved Logistic equations

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International Journal of Agricultural and Biological Engineering 2023年第1期16卷 60-65页

作者： Jiayong Pan Wenxin Le Zi’ao Wang Jian Chen College of Engineering China Agricultural UniversityBeijing 100083China Shenzhen Key Laboratory of Intelligent Microsatellite Constellation Shenzhen 518107GuangdongChina Key Laboratory of Spatial-temporal Big Data Analysis and Application of Natural Resources in Megacities MNRShanghai 200063China Key Laboratory of Urban Land Resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen 518000GuangdongChina Jiangsu Province and Education Ministry Co-sponsored Synergistic Innovation Center of Modern Agricultural Equipment Jiangsu UniversityZhenjiang 212013China Key Laboratory of Smart Agricultural Technology in Tropical South China Ministry of Agriculture and Rural AffairsGuangzhou 510642China State Key Laboratory of Virtual Reality Technology and Systems Beihang UniversityBeijing 100191China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou 310013China

As the function of the decomposition of fungi has been clearly researched in the global carbon cycle,it is obviously of value to explore the decomposition rate of fungal *** study analyzed the relationship between environmental factors and biodiversity step by *** order to explore the interaction between the fungi and the relationship between the decomposition rate of fungi with time,the model based on the Logistic model was built and the Lotka-Volterra model was employed in the condition of two kinds of fungi existing in an environment with limited *** changing trend of population number and decomposition rate of several fungi under different environmental conditions can be predicted through the *** illustrate the applicability of the model,Laetiporus conifericola and Hyphoderma setigerum were applied as *** results showed that the higher the degree of population diversity,the greater the decomposition rate,and the higher the decomposition efficiency of the *** rich species diversity is conducive to accelerating the decomposition of litter,lignocellulose,and the circulation of the entire *** on the above model and using the data from measuring the mycelial elongation rate of each isolate at 10℃,16℃,and 22℃ under standardized laboratory conditions,the growth patterns of the five fungi combinations were *** results revealed a general increase in growth rate with increasing temperature,which verifies the accuracy of the ***,it also revealed that the total decomposition rate after fungal incorporation was negatively correlated with the decomposition rate of a fungal single *** on the above model,predictions can be made for fungal growth in different environments,and suitable environments for fungal growth can be *** the future,the model can be further optimized,and lignin and cellulose decomposition factors can be added to fit the decomposition of *** application

关键词： Logistic equations fungal decomposition mathematical model

Three-dimensional flow field mathematical model inside the pilot stage of the deflector jet servo valve

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2022年第10期23卷 795-806页

作者： Shuang-lu LI Yao-bao YIN Jiang-yang YUAN Sheng-rong GUO School of Mechanical Engineering Tongji UniversityShanghai 201804China Aviation Key Laboratory of Science and Technology on Aero Electromechanical System Integration Aviation Industry Corporation of ChinaNanjing 210061China

A new flow field mathematical model is proposed to describe accurately the flow field structure and calculate the static characteristics of the pilot stage in a deflector jet servo valve(DJSV). The flow field is divided into five regions, a 3D turbulent jet is adopted to describe the free jet region, and a velocity distribution expression of the jet is proposed. The jet entrainment model is put forward in the pressure recovery region to describe the coupling relationship between the pressure in the receiving chamber and the jet flow. The static characteristics, including pressure-flow characteristics, pressure characteristics,and flow characteristics of the pilot stage are obtained. The flow field structure and the static characteristics are verified by finite element analysis(FEA) and experiment, respectively, and the mathematical model results are in good agreement with the experimental and simulation results.

关键词： Deflector jet servo valve(DJSV) Pilot stage Three-dimensional jets Jets entrainment Static characteristics mathematical model

The mathematical model for Streptococcus suis Infection in Pig-Human Population with Humidity Effect

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Computers, Materials & Continua 2022年第5期71卷 2981-2998页

作者： Inthira Chaiya Kamonchat Trachoo Kamsing Nonlaopon Din Prathumwan Department of Mathematics Faculty of ScienceMahasarakham UniversityMahasarakham44150Thailand Department of Mathematics Faculty of ScienceKhon Kaen UniversityKhon Kaen40002Thailand

In this paper,we developed a mathematical model for Streptococcus suis,which is an epidemic by considering the moisture that affects the *** disease is caused by Streptococcus suis infection found in pigs which can be transmitted to *** patients of Streptococcus suis were generally found in adults males and the elderly who contacted pigs or who ate uncooked *** human cases,the infection can cause a severe illness and *** disease has an impact to the financial losses in the swine *** the development of models for this disease,we have divided the population into 7 related groups which are susceptible pig compartment,infected pig compartment,quarantined pig compartment,recovered pig compartment,susceptible human compartment,infected human compartment,and recovered human *** that,we use this model and a quarantine strategy to analyze the spread of the *** addition,the basic reproduction number R0 is determined by using the next-generation matrix which can analyze the stability of the *** numerical simulations of the proposed model are illustrated to confirm the results from *** results showed that there is an effect from moisture to the disease *** the moisture increases the disease infection also increases.

关键词： Streptococcus suis mathematical model stability analysis infectious disease reproduction number

Tuberculosis screening among children and adolescents in China:insights from a mathematical model

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Intelligent Medicine 2023年第3期3卷 157-163页

作者： Janne Estill Yangqin Xu Shouyuan Wu Lidong Hu Nan Yang Shu Yang Yaolong Chen Guobao Li Evidence-Based Medicine Center School of Basic Medical SciencesLanzhou UniversityLanzhouGansu 730000China Institute of Global Health University of GenevaGenevaSwitzerland School of Public Health Lanzhou UniversityLanzhouGansu 730000China Department of Rheumatology and Immunology The First Medical CenterChinese PLA General HospitalBejing 100853China College of Medical Information Engineering Chengdu University of Traditional Chinese MedicineChengduSichuan 610000China Research Unit of Evidence-Based Evaluation and Guidelines Chinese Academy of Medical Sciences(2021RU017)School of Basic Medical SciencesLanzhou UniversityLanzhouGansu 730000China Lanzhou University Institute of Health Data Science LanzhouGansu 730000China WHO Collaborating Centre for Guideline Implementation and Knowledge Translation LanzhouGansu 730000China Department of Lung Disease Shenzhen Third People's HospitalThe Second Affiliated HospitalSouthern University of Science and TechnologyShenzhen Guangdong 518112China

Background Tuberculosis(TB)continues to be prevalent in China also among children and adolescents in *** built a dynamic mathematical model for TB transmission in China,and applied it to compare the epidemic trends 2021–2030 under a range of screening interventions focusing on children and *** We developed a dynamic mathematical model with a flexible *** model can be applied either stochastically or deterministically,and can encompass arbitrary age structure and resistance *** the present version,we used the deterministic version excluding resistance but including age structure with six groups:0–5,6–11,12–14,15–17,18–64,and 65 years and *** parameterized the model by literature data and fitting it to case and death estimates provided by the World Health *** compared the new TB cases and TB-related deaths in each age group over the period 2021–2030 in 10 scenarios that involved intensified screening of particular age groups of children,adolescents,or young adults,or decreased or increased diagnostic accuracy of the *** Screening the entire age class of 18-year-old persons would prevent 517,000 TB cases and 14,600 TB-related deaths between years 2021 and 2030,corresponding to 6.6%and 5.5%decrease from the standard of care projection,*** screening of children aged 6–11 and,to a lesser extent,0–5 years,also reduced TB incidence and mortality,particularly among children of the respective ages but also in other age *** contrast,intensified screening of adolescents did not have a major *** with a simpler and less accurate method resulted in worsened outcomes,which could not be offset by more intensive *** accurate screening and better sensitivity to detect latent TB could prevent 2.3 million TB cases and 68,500 TB deaths in the coming 10 *** Routine screening in schools can efficiently reduce the burden of TB in *** should be intensifie

关键词： Tuberculosis China Children and adolescents mathematical model Screening

Spread and control of COVID-19:A mathematical model

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International Journal of modeling, Simulation, and Scientific Computing 2022年第3期13卷 121-148页

作者： O.P.Misra Omprakash Singh Sisodiya School of Mathematics and Allied Sciences Jiwaji University Gwalior 474011Madhya PradeshIndia

A mathematical model is proposed in this paper to study the transmission and control of *** mathematical model is formulated using system of nonlinear ordinary differential *** model includes disease-related parameters such as contact rate,disease-induced death rates,immigration rate and transition rates along with parameters for control measures such as implementation of social distancing practices,isolation and quarantine *** the stability analysis of the model,it is shown that if the social distancing is practiced by the large number of susceptible population,then the disease will not spread,and it may eventually die ***,it is derived from the analysis of the model that if most of the infected populations are isolated or quarantined,then the spread of the disease can be eventually ***,from the analysis of the model,it is observed that if there is constant immigration of asymptomatic infected persons,then the disease will continue to spread and will remain *** controlling the disease,two more parameters,that is,vaccination and testing rates,are introduced in the original mathematical model and from the numerical analysis of this model,it has been shown that the control strategy involving vaccination and testing in combination can have synergistic effect for minimizing the COVID-19 infected cases.

关键词： COVID-19 social distancing isolation quarantine immigration mathematical model

Tight gas charging and accumulation mechanisms and mathematical model

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Petroleum Exploration and Development 2023年第6期50卷 1411-1425页

作者： ZHOU Nengwu LU Shuangfang ZHANG Pengfei LIN Zizhi XIAO Dianshi LU Jiamin ZHU Yingkang LIU Yancheng LIN Liming WANG Min JIANG Xinyu LIU Yang WANG Ziyi LI Wenbiao Sanya Offshore Oil&Gas Research Institute Northeast Petroleum UniversitySanya 572025China Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development Ministry of EducationNortheast Petroleum UniversityDaqing 163318China School of Geosciences China University of Petroleum(East China)Qingdao 266580China College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Exploration and Development Research Institute PetroChina Daqing Oilfield Company LimitedDaqing 163712China China United Coalbed Methane Co. Ltd.Beijing 100083China

The gas-water distribution and production heterogeneity of tight gas reservoirs have been summarized from experimental and geological observations, but the charging and accumulation mechanisms have not been examined quantitatively by mathematical model. The tight gas charging and accumulation mechanisms were revealed from a combination of physical simulation of nuclear magnetic resonance coupling displacement, numerical simulation considering material and mechanical equilibria, as well as actual geological observation. The results show that gas migrates into tight rocks to preferentially form a gas saturation stabilization zone near the source-reservoir interface. When the gas source is insufficient, gas saturation reduction zone and uncharged zone are formed in sequence from the source-reservoir interface. The better the source rock conditions with more gas expulsion volume and higher overpressure, the thicker the gas saturation stabilization and reduction zones, and the higher the overall gas saturation. When the source rock conditions are limited, the better the tight reservoir conditions with higher porosity and permeability as well as larger pore throat, the thinner the gas saturation stabilization and reduction zones, but the gas saturation is high. The sweet spot of tight gas is developed in the high-quality reservoir near the source rock, which often corresponds to the gas saturation stabilization zone. The numerical simulation results by mathematical model agree well with the physical simulation results by nuclear magnetic resonance coupling displacement, and reasonably explain the gas-water distribution and production pattern of deep reservoirs in the Xujiaweizi fault depression of the Songliao Basin and tight gas reservoirs in the Linxing-Huangfu area of the Ordos Basin.

关键词： tight gas charging and accumulation mechanism mathematical model Xujiaweizi fault depression Songliao Basin Linxing-Huangfu area Ordos Basin