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Airflow field simulation model building and application for aerobic compost using CFD

International Journal of Agricultural and Biological Engineering 2021年第4期14卷 245-254页

作者： Qiongyi Cheng Haibo Meng Haibin Zhou Yujun Shen Hongsheng Cheng Jingtao Ding Shihao Zhao Shance Hou Academy of Agricultural Planning and Engineering Key Laboratory of Technologies and Models for Cyclic Utilization from Agricultural ResourcesMinistry of Agriculture and Rural AffairsBeijing 100125China

Composting is a suitable low-cost strategy to transform animal waste into a stabilized end product,and the airflow field in the pile affects the fermentation *** piles in the aeration weak zone,anaerobic fermentation may happen as the lack of *** in practice,due to the extremely low speed and harsh condition,the airflow field was scarcely *** study adopted Computational Fluid Dynamics(CFD)to investigate the airflow field in the compost pile.A three-dimensional CFD model was built;the compost pile in this model was simplified as porous media;unstructured mesh was adopted to discretize the geometric model;standard k-εmodel and SIMPLE scheme were employed for numerical *** CFD model was validated with the field experiment in the cooling *** the model was applied to research the airflow field in the pile with increased pipe *** showed that it was feasible to investigate the airflow field in the pile with *** boundary conditions in the CFD model,treating the compost pile as a homogeneous porous media is *** CFD model was successfully validated by the field measurement(the average relative difference between the simulated and measured air speed was within 10%).Airflow in the existing compost pile showed nonuniform distribution with stagnation and vortex zones;the turbulence intensities were 3.57 and 1.43 for the airflow in the pile and the reactor,*** pipe diameter increased,the airflow distribution uniformity in the pile was improved *** diameter raising to 0.04 m,the turbulence intensity decreased to 1.54 and 0.42 for the airflow in the pile and the reactor,*** CFD model developed in this research can provide qualitative and quantitative analyses of the airflow field in compost piles,and can be a theoretical basis for the aeration system design.

关键词： CFD model building compost airflow field pile

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Exploiting Bivariate Dependencies to Speedup Structure Learning in Bayesian Optimization Algorithm

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Journal of Computer Science & Technology 2012年第5期27卷 1077-1090页

作者： Amin Nikanjam Adel Rahmani School of Computer Engineering Iran University of Science and Technology

Bayesian optimization algorithm （BOA） is one of the successful and widely used estimation of distribution algorithms （EDAs） which have been employed to solve different optimization problems. In EDAs, a model is learned from the selected population that encodes interactions among problem variables. New individuals are generated by sampling the model and incorporated into the population. Different probabilistic models have been used in EDAs to learn interactions. Bayesian network （BN） is a well-known graphical model which is used in BOA. Learning a propel model in EDAs and particularly in BOA is distinguished as a computationally expensive task. Different methods have been proposed in the literature to improve the complexity of model building in EDAs. This paper employs bivariate dependencies to learn accurate BNs in BOA efficiently. The proposed approach extracts the bivariate dependencies using an appropriate pairwise interaction-detection metric. Due to the static structure of the underlying problems, these dependencies are used in each generation of BOA to learn an accurate network. By using this approach, the computational cost of model building is reduced dramatically. Various optimization problems are selected to be solved by the algorithm. The experimental results show that the proposed approach successfully finds the optimum in problems with different types of interactions efficiently. Significant speedups are observed in the model building procedure as well.

关键词： evolutionary computation Bayesian optimization algorithm Bayesian network model building bivariate interaction

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Full mode flight dynamics modelling and control of stopped-rotor UAV

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Chinese Journal of Aeronautics 2022年第10期35卷 95-105页

作者： Ao HE Honggang GAO Shanshan ZHANG Zhenghong GAO Bodi MA Lulu CHEN Wei DAI School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China

The Stopped-Rotor(SR)UAV combines the advantages of vertical take-off and landing of helicopter and high-speed cruise of fixed-wing *** the same time,it also has a unique aerodynamic layout,which leads to great differences in the control and aerodynamic characteristics of various flight modes,and brings great challenges to the flight dynamics modelling and control in full-mode *** this paper,the flight dynamics modelling and control method of SR UAV in full-mode flight is ***,based on the typical flight profile of SR UAV when performing missions,using the theory and method of fuzzy mathematics,the T-S flight dynamics model of SR UAV in full-mode flight is established by synthesizing the flight dynamics model of each flight ***,an explicit model tracking and parameter adjusting control system based on fuzzy theory is designed to enhance the stability of the inner loop of SR UAV in full-mode flight,which effectively reduces the coupling between axes and improves the control quality of the ***,the outer loop control system is designed by using classical control method,and the control law of SR UAV in full-mode automatic flight is *** simulation results show that the proposed control system design method is feasible and effective,which lays a solid foundation for the subsequent engineering implementation of the SR UAV.

关键词： Full-mode control High-speed helicopter model building Stopped-rotor aircraft Variable parameter stabilization

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Optimal Design and Dynamic Simulation of Mountain Bike with Rear Suspension

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 21-26页

作者： BU Yan XIANG Zhongxia HUANG Tian ZHANG Xu WANG Xinghua School of Mechanical Engineering Tianjin University Tianjin 300072 China Tianjin Entry-exit Inspection and Quarantine Bureau Tianjin 300211 China

This paper investigates the dynamic design methodology of mountain bikes with rear suspension. Firstly, a multi-rigid body dynamic model of rider and mountain bike coupled system is constructed. The rider model includes 19 skeletons, 18 joints and 118 main muscles. Secondly, to validate the feasibility of the model, an experiment test is designed to reflect the real cycling status. Finally, aiming at enhancing the performance of the rider vibration comfort, the scale parameters of rear suspension are optimized with computer simulation and uniform design. The mathematical model in the vibration performance and the design variables is constructed with regression analysis. The result shows that when the length of side link is 90 mm, the length of connected rod is 336.115 1 mm and the included angle between absorber and side link is 60°, the mountain bike has better vibration comfort. This study and relevant conclusions are of practical importance to the design of the mountain bike＇s rear suspension system.

关键词： mountain bike model building dynamic simulation experiment test vibrant comfort optimal design

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Unsteady RANS simulation of wind flow around a building shape obstacle

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building Simulation 2022年第2期15卷 291-312页

作者： Sheikh Hassan Md.Mamun Molla Preetom Nag Nasrin Akhter Amirul Khan Department of Mathematics&Physics North South UniversityDhaka 1229Bangladesh Department of Mathematics Dhaka University of Engineering&TechnologyGazipur 1708Bangladesh School of Civil Engineering University of LeedsLeeds LS29JTUK

This work aims to find the origin and connection of the surface,near-wake,and far-wake structures in the flow encompassing a high-rise building for a high Reynolds *** origin and interconnection of the stream-wise tip vortices,with the other components of the wake,is analysed in this study for the current *** Unsteady Reynolds Averaged Navier-Stokes equations(URANS)together with the realizable k-εturbulence model have been used in this investigation to study the turbulent wake flow following a ground-surface-attached square shape building.A moderately big obstacle aspect ratio of 4,a Reynolds number of 12,000,and a thin evolving boundary layer thickness have been used in the flow *** designed flow addresses the reversed-flows at the outlet during computation to improve the accuracy of the realizable k-e *** Reynolds stress components are retrieved using the Boussinesq *** wake’s principal compositions,including span-wise-side eddies and area of high stream-wise vorticity in the uppermost portion of the wake,are illustrated by both three-dimensional(3D)representations and planner projections of the mean flow distributions.A braided vortex formation,composed of asymmetric hairpin vortexes,is witnessed in the far-wake *** association of the near-wake vortex structures with the far-wake and near-wall flow,which is associated with the flow strengths,is also *** this investigation,few areas of large stream-wise vorticity magnitude,like tip vortexes,are correlated to the 3D curving of the fluid motion,and tip vortices did not continuously reach to the free end part of the *** 3D fluid motion interpretation,which combined several measurements of the flow distribution encompassing the cylinder,shows that the time-averaged near-wake structures are formed of two segments of distinct source and section of ***,addressing reversed-flow during computation shows notable improvement in the results.

关键词： turbulent wake vortex shedding flow structures tip vortexes model building URANS turbulent boundary layer

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Spatiotemporal modeling of Monthly Precipitation in the Upper Shiyang River Watershed in West Central Gansu,Northwest China

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Advances in Atmospheric Sciences 2010年第1期27卷 185-194页

作者：张存杰 C.P.-A.BOURQUE 孙兰东 Q.K.HASSAN Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou Regional Climate Centre Faculty of Forestry and Environmental Management University of New Brunswick28 Dineen DriveFrederictonNew BrunswickE3B 6C2Canada Department of Geomatics Engineering Schulich School of EngineeringUniversity of Calgary2500 University Drive NWCalgaryAlbertaT2N 1N4Canada

This paper outlines a methodology to estimate monthly precipitation surfaces at 1-kin resolution for the Upper Shiyang River watershed （USRW） in northwest China. Generation of precipitation maps is based on the application of a four-variable genetic algorithm （GA） trained on 10 years of weather and ancillary data, i.e., surface air temperature, relative humidity, Digital Elevation model-derived estimates of elevation, and time of year collected at 29 weather stations in west-central Gansu and northern Qinghai province. An observed-to-GA predicted data comparison of 10 years of precipitation collected at the 29 weather stations showed that about 84% of the variability in observed values could be explained by the trained GA, including variability in two independent datasets. Point-comparisons of observed and modeled precipitation along an elevation-rainfall gradient demonstrated near-similar spatiotemporal patterns. A precipitation surface for USRW for July, 2005, was developed with the trained GA and input surfaces of surface air temperature and relative humidity generated from Moderate Resolution Imaging Spectroradiometer sensor （MODIS） products of land surface temperature. Spatial tendencies in predicted maximum and minimum values of surface air temperature, relative humidity, and precipitation within a 2-kin radius circle around selected weather stations were in close agreement with the values measured at the weather stations.

关键词： genetic algorithms model building MODIS products principal component analysis watershed delineation

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A model with flavor-dependent gauged U(1)B-L1×U(1)B-L2-L3 symmetry

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Chinese Physics C 2018年第12期42卷 44-52页

作者： Linping Mu niroshi Okada Chao-Qiang Gen School of Physics and Information Engineering Shanxi Normal UniversityLinfen 041004 physics Division National Center for Theoretical SciencesHsinchuTaipei 300 Asia Pacific Center for Theoretical Physics PohangGeyoengbuk 790-784 Department of Physics National Tsing Hun UniversityHsinchuTaipei 300

We propose a new model with flavor-dependent gauged U(1)B-L1×U(1)B-L2-L3symmetry in addition to the flavor-blind symmetry in the Standard model. The model contains three right-handed neutrinos to cancel gauge anomalies and several Higgs bosons to construct the measured fermion masses. We show the generic features of the model and explore its phenomenology. In particular, we discuss the current bounds on the extra gauge bosons from the K and B meson mixings as well as the LEP and LHC data, and focus on their contributions to the lepton flavor violating processes of ?i+1→?iγ(i=1,2).

关键词： flavor-dependent gauged Abelian symmetries model building numerical analysis of gauge boson masses and coupling

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Radiomics for predicting perineural invasion status in rectal cancer

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World Journal of Gastroenterology 2021年第33期27卷 5610-5621页

作者： Mou Li Yu-Mei Jin Yong-Chang Zhang Ya-Li Zhao Chen-Cui Huang Sheng-Mei Liu Bin Song Department of Radiology West China Hospital of Sichuan UniversityChengdu 610041Sichuan ProvinceChina Department of Radiology Chengdu Seventh People’s HospitalChengdu 610213Sichuan ProvinceChina Department of Research Collaboration R&D CenterBeijing Deepwise&League of PHD Technology Co.LtdBeijing 100080China

BACKGROUND Perineural invasion(PNI),as a key pathological feature of tumor spread,has emerged as an independent prognostic factor in patients with rectal cancer(RC).The preoperative stratification of RC patients according to PNI status is beneficial for individualized treatment and improved ***,the preoperative evaluation of PNI status is still *** To establish a radiomics model for evaluating PNI status preoperatively in RC *** This retrospective study enrolled 303 RC patients in a single institution from March 2018 to October *** patients were classified as the training cohort(n=242)and validation cohort(n=61)at a ratio of 8:2.A large number of intraand peritumoral radiomics features were extracted from portal venous phase images of computed tomography(CT).After deleting redundant features,we tested different feature selection(n=6)and machine-learning(n=14)methods to form 84 *** best performing classifier was then selected to establish ***,the clinicoradiological model(combined model)was developed by combining Rad-score with clinical *** models for predicting PNI were compared using receiver operating characteristic curve(ROC)analysis and area under the ROC curve(AUC).RESULTS One hundred and forty-four of the 303 patients were eventually found to be *** factors including CT-reported T stage(cT),N stage(cN),and carcinoembryonic antigen(CEA)level were independent risk factors for predicting PNI *** established Rad-score by logistic regression analysis after selecting features with the L1-based *** combined model was developed by combining Rad-score with cT,cN,and *** combined model showed good performance to predict PNI status,with an AUC of 0.828[95%confidence interval(CI):0.774-0.873]in the training cohort and 0.801(95%CI:0.679-0.892)in the validation *** comparison of the models,the combined model achieved a higher AUC than the clinic

关键词： Radiomics Perineural invasion Rectal cancer Computed tomography Preoperative prediction model building

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System Dynamics and Airlines' Economic Operation model

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Systems Science and Systems Engineering 2000年第1期10卷 46-55页

作者： WU Tong\|shui\+1,\ QIN Jing\+2,\ NING Xuan\|xi\+2 1.Civil Aviation University of China, Tianjin 300300, China 2.Business And Management College, NUAA Nanjing 210016, China

The paper is an analysis of applicability of system dynamics to description of airlines′ economic operation. It is the first attempt to use the theory and approaches of system dynamics to build a dynamic economic operation model for airlines. The paper introduces modeling design, basic model structure and content. A computer simulation of benefit analysis is given in the case of a given airline of China. Whereupon the outcome proves that it is successful using system dynamics theory and approaches to describe non linear, multivariable, dynamic, multiple\|feedback, complex economic systems, as in airlines. The model offers a powerful support to decision makers, greatly upgrading the systematicness and foreseeability of enterprise management. The theory and approaches, advanced in the paper, is also applicable to enterprises in other sectors.

关键词： simulation model building decision support system forecasting

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Advances in Research on Synthetic Microbial Communities

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Advances in Bioscience and Biotechnology 2024年第10期15卷 602-620页

作者： Lin Yang Honghao Zhang Jaixin Liu Guotao Hang Yong Yang Yanyan Li Haibo Xiang College of Life Sciences Hubei University Wuhan China State Key Laboratory of Biocatalysis and Enzyme Engineering College of Life Sciences Hubei University Wuhan China Tobacco Research Institute of Hubei Province Wuhan China

The synthetic microbial community is a synthetic microbial system co-cultured with multiple species, which has the characteristics of clear composition and strong controllability. Compared with a single colony, it can achieve more complex functions and adapt to the changing environment more easily, so as to meet a wide range of needs. In this paper, the contents and concepts of microbial community and synthetic microbial community are briefly introduced, the principles that should be followed in the construction of microbial community are expounded, the methods and mathematical models used in the construction of synthetic microbial community are introduced, and the applications of synthetic microbial community in various fields are summarized. Finally, the challenges in the research of synthetic microbial communities are briefly described.

关键词： Microorganism Synthetic Microbial Community model building

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