Pub Date : 2020-01-01DOI: 10.4236/mnsms.2020.101001
T. D. L. M. Ramírez, I. H. Cruz, M. D. Ruíz, N. Perrusquia, David García Bustos, M. F. Martínez
Ultra-high molecular weight polyethylene (UHMWPE) has been used in orthopedics as one of the materials for artificial joints in knee, hip and spine prostheses, most of the implanted joints are designed so that the metal of the prosthesis is articulate against a polymeric material, however the main problems is the average life time of the UHMWPE due to wear, and the particles generated by the friction of the metal on the articulation of the polymer are the most common inducer of osteolysis, generating a loosening of the implant leading to an imminent failure resulting in the total replacement of the prosthesis. In this investigation a numerical model of abrasive wear was made using the classic Archard wear equation applied to dynamic simulation of finite element analysis (FEA) of the micro-abrasion test using a subroutine written in Fortran language linked to the finite element software to predict the rate of wear. The results of the numerical model were compared with tests of abrasive wear in the laboratory, obtaining a margin of error below 5%,concluding that the numerical model is feasible for the prediction of the rate of wear and could be applied in knowing the life cycle of joint prostheses or for the tribological analysis in industrial machinery or cutting tools. The wear coefficient (K) was obtained from the grinding tests depending on the depth of stroke of the crater, which was analyzed by 3D profilometry to obtain the wear rate and the wear constant.
{"title":"Numerical Model of Ultra-High Molecular Weight Polyethylene Abrasive Wear Tests","authors":"T. D. L. M. Ramírez, I. H. Cruz, M. D. Ruíz, N. Perrusquia, David García Bustos, M. F. Martínez","doi":"10.4236/mnsms.2020.101001","DOIUrl":"https://doi.org/10.4236/mnsms.2020.101001","url":null,"abstract":"Ultra-high molecular weight polyethylene (UHMWPE) has been used in orthopedics as one of the materials for artificial joints in knee, hip and spine prostheses, most of the implanted joints are designed so that the metal of the prosthesis is articulate against a polymeric material, however the main problems is the average life time of the UHMWPE due to wear, and the particles generated by the friction of the metal on the articulation of the polymer are the most common inducer of osteolysis, generating a loosening of the implant leading to an imminent failure resulting in the total replacement of the prosthesis. In this investigation a numerical model of abrasive wear was made using the classic Archard wear equation applied to dynamic simulation of finite element analysis (FEA) of the micro-abrasion test using a subroutine written in Fortran language linked to the finite element software to predict the rate of wear. The results of the numerical model were compared with tests of abrasive wear in the laboratory, obtaining a margin of error below 5%,concluding that the numerical model is feasible for the prediction of the rate of wear and could be applied in knowing the life cycle of joint prostheses or for the tribological analysis in industrial machinery or cutting tools. The wear coefficient (K) was obtained from the grinding tests depending on the depth of stroke of the crater, which was analyzed by 3D profilometry to obtain the wear rate and the wear constant.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70497824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-30DOI: 10.4236/mnsms.2019.94005
I. Mohammed, I. Adamu, S. Barka
In this work, we presented a mathematical model for the dynamics of glucose, insulin and beta-cell mass under the influence of trauma, excitement and/or stress, the model is an improvement on the work by [1]. We defined and incorporated a parameter to represent the effectiveness of epinephrine in suppressing insulin secretion and a parameter Ge representing epinephrine induced glucose increase as the factors that affect glucose and insulin homeostasis. The model which consists of a system of three nonlinear ordinary differential equations was used to investigate the effect of epinephrine on glucose, insulin and beta-cell mass dynamics. The result of the study showed that; In the presence of epinephrine, the blood glucose increased and the blood insulin decreased due to suppression by the hormone, despite the fact that there is an increase in beta-cell mass the system remained extremely hyperglycemic. Furthermore, the result of the numerical experiment carried out indicated that frequent epinephrine secretion into the blood induced prolong and extreme hyperglycemia. Frequent epinephrine secretion increases the risk of diabetes in humans. In view of the findings of this study, we recommend that there should be massive and continuous health education, especially for communities living in the areas where the stated agents (trauma, excitement and stress) of epinephrine secretion are common.
{"title":"Mathematical Model for the Dynamics of Glucose, Insulin and β-Cell Mass under the Effect of Trauma, Excitement and Stress","authors":"I. Mohammed, I. Adamu, S. Barka","doi":"10.4236/mnsms.2019.94005","DOIUrl":"https://doi.org/10.4236/mnsms.2019.94005","url":null,"abstract":"In this work, we presented a mathematical model for the dynamics of glucose, insulin and beta-cell mass under the influence of trauma, excitement and/or stress, the model is an improvement on the work by [1]. We defined and incorporated a parameter to represent the effectiveness of epinephrine in suppressing insulin secretion and a parameter Ge representing epinephrine induced glucose increase as the factors that affect glucose and insulin homeostasis. The model which consists of a system of three nonlinear ordinary differential equations was used to investigate the effect of epinephrine on glucose, insulin and beta-cell mass dynamics. The result of the study showed that; In the presence of epinephrine, the blood glucose increased and the blood insulin decreased due to suppression by the hormone, despite the fact that there is an increase in beta-cell mass the system remained extremely hyperglycemic. Furthermore, the result of the numerical experiment carried out indicated that frequent epinephrine secretion into the blood induced prolong and extreme hyperglycemia. Frequent epinephrine secretion increases the risk of diabetes in humans. In view of the findings of this study, we recommend that there should be massive and continuous health education, especially for communities living in the areas where the stated agents (trauma, excitement and stress) of epinephrine secretion are common.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42725498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-29DOI: 10.4236/mnsms.2019.94006
A. Coulibaly, Sampson Oladapo Oyedele, N’guessan Raymond Kre, B. Aka
In recent years, there has been an unprecedented rise in the performance of metal halide perovskite solar cells. The lead-free perovskite solar cells (PSCs) have drawn much research interest due to the Pb toxicity of the lead halide perovskite. CH3NH3SnI3 is a viable alternative to CH3NH3PbX3. In this work, we designed a tin-based perovskite simulated model with the novel architecture of (TCO)/buffer (TiO2)/absorber (Perovskite)/hole transport material (HTM) and analyzed using the solar cell capacitance simulator (SCAPS-1D), which is well adapted to study the photovoltaic architectures. In the paper, we studied the influences of perovskite thickness and the doping concentration on the solar cell performance through theoretical analysis and device simulation. The results are indicating that the lead-free CH3NH3SnI3 is having the greatpotential to be an absorber layer with suitable inorganic hole transport materials like CuI (PCE: 23.25%), Cu2O (PCE: 19.17%), organic hole transport materials like spiro-OMETAD (PCE: 23.76%) and PTAA (PCE: 23.74%) to achieve high efficiency. This simulation model will become a good guide for the fabrication of high efficiency tin-based perovskite solar. The results show that the lead-free CH3NH3SnI3 is a potential environmentally friendly solar cells with high efficiency.
{"title":"Comparative Study of Lead-Free Perovskite Solar Cells Using Different Hole Transporter Materials","authors":"A. Coulibaly, Sampson Oladapo Oyedele, N’guessan Raymond Kre, B. Aka","doi":"10.4236/mnsms.2019.94006","DOIUrl":"https://doi.org/10.4236/mnsms.2019.94006","url":null,"abstract":"In recent years, there has been an unprecedented rise in the performance of metal halide perovskite solar cells. The lead-free perovskite solar cells (PSCs) have drawn much research interest due to the Pb toxicity of the lead halide perovskite. CH3NH3SnI3 is a viable alternative to CH3NH3PbX3. In this work, we designed a tin-based perovskite simulated model with the novel architecture of (TCO)/buffer (TiO2)/absorber (Perovskite)/hole transport material (HTM) and analyzed using the solar cell capacitance simulator (SCAPS-1D), which is well adapted to study the photovoltaic architectures. In the paper, we studied the influences of perovskite thickness and the doping concentration on the solar cell performance through theoretical analysis and device simulation. The results are indicating that the lead-free CH3NH3SnI3 is having the greatpotential to be an absorber layer with suitable inorganic hole transport materials like CuI (PCE: 23.25%), Cu2O (PCE: 19.17%), organic hole transport materials like spiro-OMETAD (PCE: 23.76%) and PTAA (PCE: 23.74%) to achieve high efficiency. This simulation model will become a good guide for the fabrication of high efficiency tin-based perovskite solar. The results show that the lead-free CH3NH3SnI3 is a potential environmentally friendly solar cells with high efficiency.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47718738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-07-22DOI: 10.4236/MNSMS.2019.93004
J. Hemanth
The present investigation aims at developing copper chilled aluminum alloy (LM-13) reinforced with beryl using stir casting method. Matrix alloy was melted in a composite making furnace to a temperature of about 700°C to which preheated reinforcement particles was added (3 wt.% to 12 wt.% in steps of 3 wt.%), stirred well and finally poured in to an AFS standard mold containing copper end chills of different thickness (10, 15, 20 and 25 mm) placed judiciously for directional solidification. The resulting chilled composites were subjected to microstructural, XRD, mechanical properties (strength and hardness) and tribological behavior.Results of the microstructural and XRD analysis indicate that the chilled castings were sound with good distribution and presence of all the particles. The bonding between beryl reinforcement and Al alloy matrix (LM-13) leads to excellent isotropic properties without any shrinkage or microporosity. Mechanical characterization indicates that both strength and hardness were maximum in the case of copper chilled MMC containing 9 wt.% and 12 wt.% reinforcement respectively. Strength and hardness of chilled MMC are found to increase by 9.88% and 16.66% as compared against the matrix alloy. It is observed that because of the ceramic (beryl) reinforcement in aluminum alloy, the wear resistance of the chilled composite developed has increased with increase in reinforcement content. At lower load, chilled MMCs exhibited mild wear regime with high coefficient of friction and at higher loads they exhibited severe wear with better wear resistance compared to un-chilled composite. It is observed that the increase in mechanical properties and wear resistance are due to incorporation of beryl reinforcement, the effect of chilling that has resulted in grain refined microstructure with good bonding of the matrix and the reinforcement.
{"title":"Tribological Behavior of Copper Chilled Aluminum Alloy (LM-13) Reinforced with Beryl Metal Matrix Composites","authors":"J. Hemanth","doi":"10.4236/MNSMS.2019.93004","DOIUrl":"https://doi.org/10.4236/MNSMS.2019.93004","url":null,"abstract":"The present investigation aims at developing copper chilled aluminum alloy (LM-13) reinforced with beryl using stir casting method. Matrix alloy was melted in a composite making furnace to a temperature of about 700°C to which preheated reinforcement particles was added (3 wt.% to 12 wt.% in steps of 3 wt.%), stirred well and finally poured in to an AFS standard mold containing copper end chills of different thickness (10, 15, 20 and 25 mm) placed judiciously for directional solidification. The resulting chilled composites were subjected to microstructural, XRD, mechanical properties (strength and hardness) and tribological behavior.Results of the microstructural and XRD analysis indicate that the chilled castings were sound with good distribution and presence of all the particles. The bonding between beryl reinforcement and Al alloy matrix (LM-13) leads to excellent isotropic properties without any shrinkage or microporosity. Mechanical characterization indicates that both strength and hardness were maximum in the case of copper chilled MMC containing 9 wt.% and 12 wt.% reinforcement respectively. Strength and hardness of chilled MMC are found to increase by 9.88% and 16.66% as compared against the matrix alloy. It is observed that because of the ceramic (beryl) reinforcement in aluminum alloy, the wear resistance of the chilled composite developed has increased with increase in reinforcement content. At lower load, chilled MMCs exhibited mild wear regime with high coefficient of friction and at higher loads they exhibited severe wear with better wear resistance compared to un-chilled composite. It is observed that the increase in mechanical properties and wear resistance are due to incorporation of beryl reinforcement, the effect of chilling that has resulted in grain refined microstructure with good bonding of the matrix and the reinforcement.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47832207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-04-11DOI: 10.4236/MNSMS.2019.92002
Claude Lincourt, J. Lanteigne, M. Krishnadev, C. Blais
The intent of this paper is to propose an engineering approach to estimate the stress intensity factor of a micro crack emerging from an inclusion in relation with the morphology of the inclusion and its relative stiffness with the matrix. A micromechanical model, based on the FEA (finite element analysis) of the behavior of cracks initiated at micro structural features such as inclusions, has been developed using LEFM (Linear Elastic Fracture Mechanics) to predict the stress intensity factor of a micro crack emerging from an inclusion. Morphology of inclusions has important connotations in the development of the analysis. Stress intensity factor has been estimated from the FEA model for different crack geometries. Metallographic analysis of inclusions has been carried out to evaluate the typical inclusion geometry. It also suggests that micro cracks less than 1 μm behave differently than larger cracks.
{"title":"Calculation of the Stress Intensity Factor in an Inclusion-Containing Matrix","authors":"Claude Lincourt, J. Lanteigne, M. Krishnadev, C. Blais","doi":"10.4236/MNSMS.2019.92002","DOIUrl":"https://doi.org/10.4236/MNSMS.2019.92002","url":null,"abstract":"The intent of this paper is to propose an engineering approach to estimate the stress intensity factor of a micro crack emerging from an inclusion in relation with the morphology of the inclusion and its relative stiffness with the matrix. A micromechanical model, based on the FEA (finite element analysis) of the behavior of cracks initiated at micro structural features such as inclusions, has been developed using LEFM (Linear Elastic Fracture Mechanics) to predict the stress intensity factor of a micro crack emerging from an inclusion. Morphology of inclusions has important connotations in the development of the analysis. Stress intensity factor has been estimated from the FEA model for different crack geometries. Metallographic analysis of inclusions has been carried out to evaluate the typical inclusion geometry. It also suggests that micro cracks less than 1 μm behave differently than larger cracks.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46355457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The chemical oxygen demand (COD) is selected as the index in this paper. The system dynamics method is used to analyze the emission right price of medical sewage, the boundary of the emission right price system is determined, and the system dynamics model of the initial emission right of medical sewage is constructed, in which the system is divided into water resources subsystem, population subsystem, economic subsystem and social subsystem. It is expected to expand the theory of the system modeling of the initial discharge right of medical sewage, and to provide the basis for the relevant decision of the environmental management authorities.
{"title":"Study on Dynamic Model of Initial Emission Rights for Medical Sewage System","authors":"Lina Wang, Yongqiang Pan, Linjiao Yang, Yitong Wang, Fulin Li, Jiaqi Wang, Shanwei Wang, Na Zuo","doi":"10.4236/MNSMS.2019.92003","DOIUrl":"https://doi.org/10.4236/MNSMS.2019.92003","url":null,"abstract":"The chemical oxygen demand (COD) is selected as the index in this paper. The system dynamics method is used to analyze the emission right price of medical sewage, the boundary of the emission right price system is determined, and the system dynamics model of the initial emission right of medical sewage is constructed, in which the system is divided into water resources subsystem, population subsystem, economic subsystem and social subsystem. It is expected to expand the theory of the system modeling of the initial discharge right of medical sewage, and to provide the basis for the relevant decision of the environmental management authorities.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49331853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-31DOI: 10.4236/MNSMS.2019.91001
C. Ozigagu, A. Duben
The Soave-Redlich-Kwong (SRK-EOS) and Peng-Robinson (PR-EOS) equations of state are used often to describe the behavior of pure substances and mixtures despite difficulties in handling substances, like water, with high polarity and hydrogen bonding. They were employed in studying the binary vapor-liquid equilibria (VLE) of methane + methanol, monoethylene glycol (MEG), and triethylene glycol (TEG). These liquids are used to inhibit the formation of gas hydrates. The investigation focused on the conditions at which methane-water clathrates can form 283.89 K to 323.56 K and 5.01 MPa to 18.48 MPa. The pressure of methane in methanol is overestimated by a factor of two by either the SRK-EOS or the PR-EOS. In the methane + MEG system, the predicted pressures for both equations of state are generally less than experimental pressure except for the highest concentration of methane in MEG calculated by the SRK-EOS. In the methane + TEG system, the predictions of both models are close and trend similarly. Because of the comparative lack of extensive experimental methane + TEG data, the similarity of the methane + TEG computed results can be used as a basis for further study of this system experimentally.
{"title":"Sensitivity Analysis of Computations of the Vapor-Liquid Equilibria of Methane + Methanol or Glycols at Gas Hydrate Formation Conditions","authors":"C. Ozigagu, A. Duben","doi":"10.4236/MNSMS.2019.91001","DOIUrl":"https://doi.org/10.4236/MNSMS.2019.91001","url":null,"abstract":"The Soave-Redlich-Kwong (SRK-EOS) and Peng-Robinson (PR-EOS) equations of state are used often to describe the behavior of pure substances and mixtures despite difficulties in handling substances, like water, with high polarity and hydrogen bonding. They were employed in studying the binary vapor-liquid equilibria (VLE) of methane + methanol, monoethylene glycol (MEG), and triethylene glycol (TEG). These liquids are used to inhibit the formation of gas hydrates. The investigation focused on the conditions at which methane-water clathrates can form 283.89 K to 323.56 K and 5.01 MPa to 18.48 MPa. The pressure of methane in methanol is overestimated by a factor of two by either the SRK-EOS or the PR-EOS. In the methane + MEG system, the predicted pressures for both equations of state are generally less than experimental pressure except for the highest concentration of methane in MEG calculated by the SRK-EOS. In the methane + TEG system, the predictions of both models are close and trend similarly. Because of the comparative lack of extensive experimental methane + TEG data, the similarity of the methane + TEG computed results can be used as a basis for further study of this system experimentally.","PeriodicalId":60895,"journal":{"name":"材料科学建模与数值模拟(英文)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44728071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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