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Mathematic model of rolling pressure during a semisolid shearing-rolling process 被引量:4
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作者 Ren-guo Guan Zhan-yong Zhao +2 位作者 Chao Lian Qiu-sheng Zhang Chun-ming Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第12期1121-1127,共7页
A mathematic model of rolling pressure during a novel semisolid shearing-rolling process was established. The rolling pressure in this process is higher than that in the conventional rolling. The increment of rolling ... A mathematic model of rolling pressure during a novel semisolid shearing-rolling process was established. The rolling pressure in this process is higher than that in the conventional rolling. The increment of rolling pressure in the backward slip zone is higher than that in the forward slip zone, and the neutral plane moves toward to the roll gap entrance. The maximum and the average rolling pressures increase with the decrease of strip thickness, and the effects of strip thickness on the rolling pressure is more obvious in the forward slip zone than in the backward slip zone. Meanwhile, the neutral plane moves toward the roll gap exit with the decrease of strip thickness. The maximum and average rolling pressures increase with the decrease of strip width, and the strip width affects the pressure more obviously in the backward slip zone than in the forward slip zone. At the same time, the neutral plane moves toward the roll gap entrance with the decrease of strip width. The maximum and average rolling pressures increase with increasing roll radius, and the neutral plane moves toward the roll gap exit. 展开更多
关键词 SEMISOLID rolling pressure mathematic models STRIPS magnesium alloys
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Mathematic modeling on flexible cooling system in hot strip mill 被引量:4
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作者 彭良贵 刘相华 +1 位作者 赵宪明 吴迪 《Journal of Central South University》 SCIE EI CAS 2014年第1期43-49,共7页
A novel cooling system combining ultra fast cooling rigs with laminar cooling devices was investigated.Based on the different cooling mechanisms,a serial of mathematic models were established to describe the relations... A novel cooling system combining ultra fast cooling rigs with laminar cooling devices was investigated.Based on the different cooling mechanisms,a serial of mathematic models were established to describe the relationship between water flow and spraying pressure and the relationship between water spraying heat flux and layout of nozzles installed on the top and bottom cooling headers.Model parameters were validated by measured data.Heat transfer models including air convection model,heat radiation model and water cooling capacity model were detailedly introduced.In addition,effects on cooling capacity by water temperature and different valve patterns were also presented.Finally,the comparison results from UFC used or not have been provided with respect to temperature evolution and mechanical properties of Q235B steel grade with thickness of 7.8 mm.Since online application of the sophisticated CTC process control system based on these models,run-out table cooling control system has been running stably and reliably to produce resource-saving,low-cost steels with smaller grain size. 展开更多
关键词 mathematic model ultra fast cooling laminar flow cooling variable frequency control coiling temperature control
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Mathematic model and tooth contact analysis of a new spiral non-circular bevel gear 被引量:3
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作者 HAN Xing-hui ZHANG Xuan-cheng +2 位作者 ZHENG Fang-yan XU Man TIAN Jun 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第1期157-172,共16页
A novel spiral non-circular bevel gear that could be applied to variable-speed driving in intersecting axes was proposed by combining the design principles of non-circular bevel gears and the manufacturing principles ... A novel spiral non-circular bevel gear that could be applied to variable-speed driving in intersecting axes was proposed by combining the design principles of non-circular bevel gears and the manufacturing principles of face-milling spiral bevel gears.Unlike straight non-circular bevel gears,spiral non-circular bevel gears have numerous advantages,such as a high contact ratio,high intensity,good dynamic performance,and an adjustable contact region.In addition,while manufacturing straight non-circular bevel gears is difficult,spiral non-circular bevel gears can be efficiently and precisely fabricated with a 6-axis bevel gear cutting machine.First,the generating principles of spiral non-circular bevel gears were introduced.Next,a mathematical model,including a generating tooth profile,tooth spiral,pressure angle,and generated tooth profile for this gear type was established.Then the precision of the model was verified by a tooth contact analysis using FEA,and the contact patterns and stress distributions of the spiral non-circular bevel gears were investigated. 展开更多
关键词 non circular gear spiral bevel gear mathematic model tooth contact analysis(TCA)
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Mathematic Model of Unsteady Penetration Mass Transfer in Randomly Packed Hollow Fiber Membrane Module 被引量:2
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作者 张秀莉 张泽廷 +1 位作者 张卫东 郝欣 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第2期185-190,共6页
Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penet... Based on the membrane-based absorption experiment of CO2 into water, shell-side flow distribution and mass transfer in a randomly packed hollow fiber module have been analyzed using subchannel model and unsteady penetration mass transfer theory. The cross section of module is subdivided into many small cells which contains only one hollow-fiber. The cross sectional area distribution of these cells is presented by the normal probability density distribution function. It has been obtained that there was a most serious non-ideal flow in shell side at moderate mean packing density, and the large amount of fluid flowed and transferred mass through a small number of large voids. Thus mass transfer process is dominated by the fluid through the larger void area. The mass transfer process in each cell is described by the unsteady penetration theory. The overall mass transfer coefficient equals to the probability addition of the mean mass transfer coefficient in each cell. The comparisons of the values calculated by the model established with the empirical correlations and the experimental data of this work have been done.The predicted overall mass transfer coefficients are in good agreement with experimental data. 展开更多
关键词 hollow fiber membrane module mass transfer membrane separation mathematic model
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The mathematic model of tension straightening process of magnesium alloy and experimental validation 被引量:1
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作者 Yan Jing Zhang Ding-fei +2 位作者 Wang Xiao-hong Peng Jian Yang Lin 《Journal of Magnesium and Alloys》 SCIE EI CAS 2013年第1期76-81,共6页
The stress-strain curve of bending bar and the stress relax curve of AZ31 was obtained by a tension test using Gleeble-1500.The tension straightening process mainly consisted of the elastic loading-I and unloading sta... The stress-strain curve of bending bar and the stress relax curve of AZ31 was obtained by a tension test using Gleeble-1500.The tension straightening process mainly consisted of the elastic loading-I and unloading stage,the elastic loading-II and unloading stage,and the elastic-plastic loading stage,which were based on the stretch force change during straightening.The circular bar straightening under one-dimensional bending was investigated and assumed to be linear strain-hardening elastic-plastic material.According to the elastic-plastic mechanics theory,the mathematical displacement-force model of a tension straightening process established,on which was based,the predicted displacement of tension straightening for various original deflection was calculated.The tension straightening experiment for AZ31 magnesium was conducted under the guidance of the predicted displacement.The experiment results present good straightness when there is a stress relaxation phenomenon or the temperature of tension straightening is 25℃. 展开更多
关键词 Tension straightening mathematic model Linear strain-hardening elasticeplastic material Stress relaxation AZ31 magnesium
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MATHEMATIC MODEL FOR FORMABILITY CRITERIA OF SUPERPLASTIC AIR BULGING COMPONENTS
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作者 WANG Chunrong SONG Hailong QU Li CAO Shuzhi Institute of Metal Research,Academia Sinica,Shenyang,China WANG Chunrong Associate Professor,Institute of Metal Research,Academia Sinica Shenyang 110015,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1990年第9期217-221,共5页
A proposal for two types of press close to die,including blank coming in die and Blank cov- ering die,and four criteria for formability is put forward in the study of the superplastic air bulge forming of the metallic... A proposal for two types of press close to die,including blank coming in die and Blank cov- ering die,and four criteria for formability is put forward in the study of the superplastic air bulge forming of the metallic thin wall components.A dimensionless weigh mathematic model for the criteria of superplastic air bulge forming is developed to be: Q_w=1.56(WS)/(HF)+2.37(0-(?)π/(180)-r/(r_0)+0.19 The superior formability of components is approaching,if Q_W≥1,and the worse,if Q_W<1.It was confirmed by practice that the above mentioned model is accurate sufficiently. 展开更多
关键词 superplastic air bulge formability criteria mathematic model
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Research and Application of the Mathematic Model for the Washing Shrinkage of Woven Fabric 被引量:1
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作者 傅菊芬 白伦 《Journal of Donghua University(English Edition)》 EI CAS 2007年第2期161-164,172,共5页
Having analyzed the relationships between washing shrinkage and weaving technique, parameters, material properties of woven fabrics and studied the shrinkage mechanism and its mathematical model of the plain fabric, r... Having analyzed the relationships between washing shrinkage and weaving technique, parameters, material properties of woven fabrics and studied the shrinkage mechanism and its mathematical model of the plain fabric, researchers set up a shrinkage model of the twills and satins and proposed a method for calculating the washing shrinkage based on weaving technique and parameters of fabrics. Shrinkage experiments of silk habotai, silk twill and silk satin fabrics were performed. The results were compared with those of the theoretical computations, and theoretical method is reliable. 展开更多
关键词 twill fabric satin fabric fabric parameter washing shrinkage mathematical model
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A Mathematic Model of Gas-diffusion Electrodes in Contact with Liquid Electrolytes
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作者 李俊 奚旦立 +1 位作者 石勇 吴锡慧 《Journal of Donghua University(English Edition)》 EI CAS 2008年第4期463-467,共5页
A mathematic model is developed which is applied to analyze the main factors that affect electrode performance and to account for the process of reaction and mass transfer in gas-diffusion electrodes in contact with l... A mathematic model is developed which is applied to analyze the main factors that affect electrode performance and to account for the process of reaction and mass transfer in gas-diffusion electrodes in contact with liquid electrolytes. Electrochemical Thiele modulus φ^2 and electrochemical effectiveness factor η are introduced to elucidate the effects of diffusion on electrochemical reaction and utilization of the gas-diffusion electrode. Profile of the reactant along axial direction is discussed, dependence of electrode potential V on current density J, are predicated by means of the newly developed mathematical model. 展开更多
关键词 fuel cell fuel cell membrane reactor liquid electrolyte gas-diffusion electrode mathematical model
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Multi-analysis with mathematic model of 3125 non-thyrogenous masses of the neck
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作者 Yong Li Ming Gao Yun Niu Liying Zhang Yang Yu Yigong Li Xiaolong Li 《The Chinese-German Journal of Clinical Oncology》 CAS 2008年第6期319-325,共7页
Objective: To systematically analyze and summarize non-thyrogenous masses of the neck (NTMN) by consideration of new areas, a large sample size and multiple-aspect analysis. Methods: Our research involved 3125 NTM... Objective: To systematically analyze and summarize non-thyrogenous masses of the neck (NTMN) by consideration of new areas, a large sample size and multiple-aspect analysis. Methods: Our research involved 3125 NTMN cases. We summarized the proportion of various NTMN and the distribution of the neck diseases based on the new international classification. The clinical traits such as sexual proportion and age, etc, were analyzed along with the unknown primary cervical metastatic carcinomas (UPCMC), and built up a mathematical model based on the data above. Results: There were 68 different diseases identified. Among all the NTMN, the percentage of metastatic carcinomas was 63.3%. The neck masses with a focus above the clavicle comprised 62.3% of the metastatic carcinomas whose focuses were clear. Moreover, other results almost supported the "rule of 80%". There was an obvious distribution of traits at every sub level. For example, there were 23 different diseases in level Ⅲ, of which the most common was lymphoma. UPCMC made up 12.3% of all metastatic carcinomas. The clinic cases could be analyzed by our model even to form a primary diagnosis which showed a high coincident rate with clinic diagnosis. Conclusion: NTMN are complex and various, with a definite distribution in each neck level. Data relating component character, sex ratio and UPCMC et al to the clinical traits of NTMN will provide vigorous support for clinical applications. The mathematical model could be an efficient method to synthetically analyze complicate data of NTMN. 展开更多
关键词 NECK non-thyrogenous mass international classification mathematical model
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MATHEMATICAL MODELING AND BIFURCATION ANALYSIS FOR A BIOLOGICAL MECHANISM OF CANCER DRUG RESISTANCE
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作者 包康博 梁桂珍 +1 位作者 田天海 张兴安 《Acta Mathematica Scientia》 SCIE CSCD 2024年第3期1165-1188,共24页
Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory ca... Drug resistance is one of the most intractable issues in targeted therapy for cancer diseases.It has also been demonstrated to be related to cancer heterogeneity,which promotes the emergence of treatment-refractory cancer cell populations.Focusing on how cancer cells develop resistance during the encounter with targeted drugs and the immune system,we propose a mathematical model for studying the dynamics of drug resistance in a conjoint heterogeneous tumor-immune setting.We analyze the local geometric properties of the equilibria of the model.Numerical simulations show that the selectively targeted removal of sensitive cancer cells may cause the initially heterogeneous population to become a more resistant population.Moreover,the decline of immune recruitment is a stronger determinant of cancer escape from immune surveillance or targeted therapy than the decay in immune predation strength.Sensitivity analysis of model parameters provides insight into the roles of the immune system combined with targeted therapy in determining treatment outcomes. 展开更多
关键词 mathematical model drug resistance cancer heterogeneity immune system targeted therapy
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Aggravation of Cancer,Heart Diseases and Diabetes Subsequent to COVID-19 Lockdown via Mathematical Modeling
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作者 Fatma Nese Efil Sania Qureshi +3 位作者 Nezihal Gokbulut Kamyar Hosseini Evren Hincal Amanullah Soomro 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期485-512,共28页
The global populationhas beenandwill continue to be severely impacted by theCOVID-19 epidemic.The primary objective of this research is to demonstrate the future impact of COVID-19 on those who suffer from other fatal... The global populationhas beenandwill continue to be severely impacted by theCOVID-19 epidemic.The primary objective of this research is to demonstrate the future impact of COVID-19 on those who suffer from other fatal conditions such as cancer,heart disease,and diabetes.Here,using ordinary differential equations(ODEs),two mathematical models are developed to explain the association between COVID-19 and cancer and between COVID-19 and diabetes and heart disease.After that,we highlight the stability assessments that can be applied to these models.Sensitivity analysis is used to examine how changes in certain factors impact different aspects of disease.The sensitivity analysis showed that many people are still nervous about seeing a doctor due to COVID-19,which could result in a dramatic increase in the diagnosis of various ailments in the years to come.The correlation between diabetes and cardiovascular illness is also illustrated graphically.The effects of smoking and obesity are also found to be significant in disease compartments.Model fitting is also provided for interpreting the relationship between real data and the results of thiswork.Diabetic people,in particular,need tomonitor their health conditions closely and practice heart health maintenance.People with heart diseases should undergo regular checks so that they can protect themselves from diabetes and take some precautions including suitable diets.The main purpose of this study is to emphasize the importance of regular checks,to warn people about the effects of COVID-19(including avoiding healthcare centers and doctors because of the spread of infectious diseases)and to indicate the importance of family history of cancer,heart diseases and diabetes.The provision of the recommendations requires an increase in public consciousness. 展开更多
关键词 COVID-19 mathematical modeling CANCER DIABETES heart diseases sensitivity analysis
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A Mathematical Modeling of 3D Cubical Geometry Hypothetical Reservoir under the Effect of Nanoparticles Flow Rate,Porosity,and Relative Permeability
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作者 Mudasar Zafar Hamzah Sakidin +6 位作者 Abida Hussain Loshini Thiruchelvam Mikhail Sheremet Iskandar Dzulkarnain Roslinda Nazar Abdullah Al-Yaari Rizwan Safdar 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第11期1193-1211,共19页
This study aims to formulate a steady-state mathematical model for a three-dimensional permeable enclosure(cavity)to determine the oil extraction rate using three distinct nanoparticles,SiO_(2),Al_(2)O_(3),and Fe_(2)O... This study aims to formulate a steady-state mathematical model for a three-dimensional permeable enclosure(cavity)to determine the oil extraction rate using three distinct nanoparticles,SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3),in unconventional oil reservoirs.The simulation is conducted for different parameters of volume fractions,porosities,and mass flow rates to determine the optimal oil recovery.The impact of nanoparticles on relative permeability(kr)and water is also investigated.The simulation process utilizes the finite volume ANSYS Fluent.The study results showed that when the mass flow rate at the inlet is low,oil recovery goes up.In addition,they indicated that silicon nanoparticles are better at getting oil out of the ground(i.e.,oil reservoir)than Al_(2)O_(3)and Fe_(2)O_(3).Most oil can be extracted from SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3)at a rate of 97.8%,96.5%,and 88%,respectively. 展开更多
关键词 Unconventional reservoir cubical cavity oil recovery rate reservoir engineering mathematical modeling
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Mathematical Modeling of Cell Polarity Establishment of Budding Yeast
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作者 Yue Liu Jun Xie +1 位作者 Hay-Oak Park Wing-Cheong Lo 《Communications on Applied Mathematics and Computation》 EI 2024年第1期218-235,共18页
The budding yeast Saccharomyces cerevisiae is a powerful model system for studying the cell polarity establishment.The cell polarization process is regulated by signaling molecules,which are initially distributed in t... The budding yeast Saccharomyces cerevisiae is a powerful model system for studying the cell polarity establishment.The cell polarization process is regulated by signaling molecules,which are initially distributed in the cytoplasm and then recruited to a proper location on the cell membrane in response to spatial cues or spontaneously.Polarization of these signaling molecules involves complex regulation,so the mathematical models become a useful tool to investigate the mechanism behind the process.In this review,we discuss how mathematical modeling has shed light on different regulations in the cell polarization.We also propose future applications for the mathematical modeling of cell polarization and morphogenesis. 展开更多
关键词 Budding yeast CDC42 MORPHOGENESIS SEPTIN mathematical models
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Practical Use of the Subjective Mathematical Model of Bayes and Its External Validation in Dental Medicine & Dentistry
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作者 Muyembi Muinaminayi Pierre Kayembe Mwimbi David +9 位作者 Nyimi Boshabu Fidèle Panoumvita Kapamona Junior Nsudila Mpoyi Monique Tubanza Mulongo Simplot Sekele Issouradi-Bourley Jean-Paul Mantshumba Milolo Augustin Kalala Kazadi Em Mabela Rosti Munyanga Mukongo Sylvain Dan Wang 《Open Journal of Statistics》 2024年第5期553-575,共23页
Objective: Our study aims to validate the subjective Bayes mathematical model using the mathematical model of logistic regression. Expert systems are being utilized increasingly in medical fields for the purposes of a... Objective: Our study aims to validate the subjective Bayes mathematical model using the mathematical model of logistic regression. Expert systems are being utilized increasingly in medical fields for the purposes of assisting diagnosis and treatment planning in Dentistry. Existing systems used few symptoms for dental diagnosis. In Dentistry, few symptoms are not enough for diagnosis. In this research, a conditional probability model (Bayes rule) was developed with increased number of symptoms associated with a disease for diagnosis. A test set of recurrent cases was then used to test the diagnostic capacity of the system. The generated diagnosis matched that of the human experts. The system was also tested for its capacity to handle uncommon dental diseases and the system portrayed useful potential. Method: The study used the Subjective Mathematical Bayes Model (SBM) approach and employed Logistic Regression Mathematical Model (LMR) techniques. The external validation of the subjective mathematical Bayes model (MSB) concerns the real cases of 625 patients who developed alveolar osteitis (OA). We propose strategies for reproducibility and reporting standards, outlining an updated WAMBS (when to Worry and how to Avoid the Misuse of Bayesian Statistics) checklist. Finally, we outline the impact of Bayesian analysis Logistic Regression Mathematical Model (LMR) techniques and on artificial intelligence, a major goal in the next decade. Results: The internal validation had identified seven (7) etiological factors of OA, which will be compared to the cases of MRL, for the external validation which retained six (6) etiological factors of OA. The experts in the internal validation of the MSB had generated 40 cases of OA and a COP of (0.5), which will be compared to the MRL that collected 625 real cases of OA to produce a Cop of (0.6) in the external validation, which discriminates between healthy patients (Se) and sick patients (Sp). Compared to real cases and the logistic regression model, the Bayesian model is efficient and its validity is established. 展开更多
关键词 External Validation-MSB-MRL mathematical model
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Mathematical Modeling of the Co-Infection Dynamics of HIV and Tuberculosis Incorporating Inconsistency in HIV Treatment
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作者 Sr Mary Nyambura Mwangi Virginia M. Kitetu Isaac O. Okwany 《Journal of Applied Mathematics and Physics》 2024年第5期1744-1768,共25页
A non-linear HIV-TB co-infection has been formulated and analyzed. The positivity and invariant region has been established. The disease free equilibrium and its stability has been determined. The local stability was ... A non-linear HIV-TB co-infection has been formulated and analyzed. The positivity and invariant region has been established. The disease free equilibrium and its stability has been determined. The local stability was determined and found to be stable under given conditions. The basic reproduction number was obtained and according to findings, co-infection diminishes when this number is less than unity, and persists when the number is greater than unity. The global stability of the endemic equilibrium was calculated. The impact of HIV on TB was established as well as the impact of TB on HIV. Numerical solution was also done and the findings indicate that when the rate of HIV treatment increases the latent TB increases while the co-infected population decreases. When the rate of HIV treatment decreases the latent TB population decreases and the co-infected population increases. Encouraging communities to prioritize the consistent treatment of HIV infected individuals must be emphasized in order to reduce the scourge of HIV-TB co-infection. 展开更多
关键词 Co-Infection modeling HIV-TB Co-Infection mathematical modeling Reproduction Number Inconsistent Treatment
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Mathematical Modeling of HIV Investigating the Effect of Inconsistent Treatment
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作者 Sr Mary Nyambura Mwangi Virginia M. Kitetu Isaac O. Okwany 《Journal of Applied Mathematics and Physics》 2024年第4期1063-1078,共16页
HIV is a retrovirus that infects and impairs the cells and functions of the immune system. It has caused a great challenge to global public health systems and leads to Acquired Immunodeficiency Syndrome (AIDS), if not... HIV is a retrovirus that infects and impairs the cells and functions of the immune system. It has caused a great challenge to global public health systems and leads to Acquired Immunodeficiency Syndrome (AIDS), if not attended to in good time. Antiretroviral therapy is used for managing the virus in a patient’s lifetime. Some of the symptoms of the disease include lean body mass and many opportunistic infections. This study has developed a SIAT mathematical model to investigate the impact of inconsistency in treatment of the disease. The arising non-linear differential equations have been obtained and analyzed. The DFE and its stability have been obtained and the study found that it is locally asymptotically stable when the basic reproduction number is less than unity. The endemic equilibrium has been obtained and found to be globally asymptotically stable when the basic reproduction number is greater than unity. Numerical solutions have been obtained and analyzed to give the trends in the spread dynamics. The inconsistency in treatment uptake has been analyzed through the numerical solutions. The study found that when the treatment rate of those infected increases, it leads to an increase in treatment population, which slows down the spread of HIV and vice versa. An increase in the rate of treatment of those with AIDS leads to a decrease in the AIDS population, the reverse happens when this rate decreases. The study recommends that the community involvement in advocating for consistent treatment of HIV to curb the spread of the disease. 展开更多
关键词 HIV modeling mathematical modeling Reproduction Number Inconsistent Treatment
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A dynamic soil freezing characteristic curve model for frozen soil 被引量:1
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作者 Xiaokang Li Xu Li Jiankun Liu 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第8期3339-3352,共14页
The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen soil.This study proposes a dynamic model to uniformly express SFCCs ami... The soil freezing characteristic curve(SFCC)plays a fundamental role in comprehending thermohydraulic behavior and numerical simulation of frozen soil.This study proposes a dynamic model to uniformly express SFCCs amidst varying total water contents throughout the freezing-thawing process.Firstly,a general model is proposed,wherein the unfrozen water content at arbitrary temperature is determined as the lesser of the current total water content and the reference value derived from saturated SFCC.The dynamic performance of this model is verified through test data.Subsequently,in accordance with electric double layer(EDL)theory,the theoretical residual and minimum temperatures in SFCC are calculated to be-14.5℃to-20℃for clay particles and-260℃,respectively.To ensure that the SFCC curve ends at minimum temperature,a correction function is introduced into the general model.Furthermore,a simplified dynamic model is proposed and investigated,necessitating only three parameters inherited from the general model.Additionally,both general and simplified models are evaluated based on a test database and proven to fit the test data exactly across the entire temperature range.Typical recommended parameter values for various types of soils are summarized.Overall,this study provides not only a theoretical basis for most empirical equations but also proposes a new and more general equation to describe the SFCC. 展开更多
关键词 Frozen soils Unsaturated soils Soil freezing characteristic curve(SFCC) mathematic models
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Refined mathematical model for the breaching of concrete-face sand-gravel dams due to overtopping failure
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作者 QIU Wen LI Yan-long +2 位作者 WEN Li-feng WANG Jing YIN Qiao-gang 《Journal of Mountain Science》 SCIE CSCD 2023年第3期670-687,共18页
Overtopping is one of the main reasons for the breaching of concrete-face sand-gravel dams(CFSGDs).In this study,a refined mathematical model was established based on the characteristics of the overtopping breaching o... Overtopping is one of the main reasons for the breaching of concrete-face sand-gravel dams(CFSGDs).In this study,a refined mathematical model was established based on the characteristics of the overtopping breaching of CFSGDs.The model characteristics were as follows:(1)Based on the Renormailzation Group(RNG)k-εturbulence theory and volume of fluid(VOF)method,the turbulent characteristics of the dam-break flow were simulated,and the erosion surface of the water and soil was tracked;(2)In consideration of the influence of the change in the sediment content on the dam-break flow,the dam material transport equation,which could reflect the characteristics of particle settlement and entrainment motion,was used to simulate the erosion process of the sand gravels;(3)Based on the bending moment balance method,a failure equation of the concrete face slab under dead weight and water load was established.The proposed model was verified through a case study on the failure of the Gouhou CFSGD.The results showed that the proposed model could well simulate the erosion mode of the special vortex flow of the CFSGD scouring the support body of the concrete face slab inward and reflect the mutual coupling relationship between the dam-break flow,sand gravels,and concrete face slabs.Compared with the measured values,the relative errors of the peak discharge,final breach average width,dam breaching duration,and maximum failure length of the face slab calculated using the proposed model were all less than 12%,thus verifying the rationality of the model.The proposed model was demonstrated to perform better and provide more detailed results than three selected parametric models and three simplified mathematical models.The study results can aid in establishing the risk level and devising early warning strategies for CFSGDs. 展开更多
关键词 Concrete-face sand-gravel dam OVERTOPPING Dam-break flow Concrete face slab failure Refined mathematical model
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Tight gas charging and accumulation mechanisms and mathematical model
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作者 ZHOU Nengwu LU Shuangfang +11 位作者 ZHANG Pengfei LIN Zizhi XIAO Dianshi LU Jiamin ZHU Yingkang LIU Yancheng LIN Liming WANG Min JIANG Xinyu LIU Yang WANG Ziyi LI Wenbiao 《Petroleum Exploration and Development》 SCIE 2023年第6期1411-1425,共15页
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 q... 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. 展开更多
关键词 tight gas charging and accumulation mechanism mathematical model Xujiaweizi fault depression Songliao Basin Linxing-Huangfu area Ordos Basin
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Quantification of Ride Comfort Using Musculoskeletal Mathematical Model Considering Vehicle Behavior
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作者 Junya Tanehashi Szuchi Chang +4 位作者 Takahiro Hirosei Masaki Izawa Aman Goyal Ayumi Takahashi Kazuhito Misaji 《Computer Modeling in Engineering & Sciences》 SCIE EI 2023年第6期2287-2306,共20页
This research aims to quantify driver ride comfort due to changes in damper characteristics between comfort mode and sport mode,considering the vehicle’s inertial behavior.The comfort of riding in an automobile has b... This research aims to quantify driver ride comfort due to changes in damper characteristics between comfort mode and sport mode,considering the vehicle’s inertial behavior.The comfort of riding in an automobile has been evaluated in recent years on the basis of a subjective sensory evaluation given by the driver.However,reflecting driving sensations in design work to improve ride comfort is abstract in nature and difficult to express theoretically.Therefore,we evaluated the human body’s effects while driving scientifically by quantifying the driver’s behavior while operating the steering wheel and the behavior of the automobile while in motion using physical quantities.To this end,we collected driver and vehicle data using amotion capture system and vehicle CAN and IMU sensors.We also constructed a three-dimensional musculoskeletal mathematical model to simulate driver movements and calculate the power and amount of energy per unit of time used for driving the joints and muscles of the human body.Here,we used comfort mode and sport mode to compare damper characteristics in terms of hardness.In comfort mode,damper characteristics are soft and steering stability is mild,but vibration from the road is not easily transmitted to the driver making for a lighter load on the driver.In sport mode,on the other hand,damper characteristics are hard and steering stability is comparatively better.Still,vibration from the road is easily transmitted to the driver,whichmakes it easy for a load to be placed on the driver.As a result of this comparison,it was found that a load was most likely to be applied to the driver’s neck.This result in relation to the neck joint can therefore be treated as an objective measure for quantifying ride comfort. 展开更多
关键词 Human engineering BIOMECHANICS driver’s sense of fatigue double lane change musculoskeletal mathematical model
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