Pub Date : 2020-12-30DOI: 10.24874/JSSCM.2020.14.02.02
Mohammed Zagane, A. Benouis, A. Moulgada, N. Djebbar, Abderrahmane Sahli
Cement is the weakest link in the composition of total hip prosthesis in terms of mechanical properties. The knowledge of the intensity and distribution of stresses on the cement attaching the implant to the bone is of great importance for understanding the condition of the prosthesis and its failure. In this study, the finite element method is used to analyze the magnitude and the equivalent Von Mises stress distribution induced in different components of the total hip prosthesis (THP) as well as the identification of the damage induced in the cement and between two cavities located in the polymethyl methacrylate (PMMA). The crack propagation is determined and localized using the extended element method (XFEM). The results show that the fracture stress of the cement in its proximal part is very important. These stresses increase considerably with the interaction of the cavities in this binder, causing damage to the cement and the loosening of the prosthesis.
{"title":"BIOMECHANICAL BEHAVIOUR OF THE TOTAL HIP PROSTHESIS SUBJECTED TO NORMAL GAIT CYCLE LOAD: IDENTIFICATION OF THE DAMAGE IN THE CEMENT MANTLE","authors":"Mohammed Zagane, A. Benouis, A. Moulgada, N. Djebbar, Abderrahmane Sahli","doi":"10.24874/JSSCM.2020.14.02.02","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.02","url":null,"abstract":"Cement is the weakest link in the composition of total hip prosthesis in terms of mechanical properties. The knowledge of the intensity and distribution of stresses on the cement attaching the implant to the bone is of great importance for understanding the condition of the prosthesis and its failure. In this study, the finite element method is used to analyze the magnitude and the equivalent Von Mises stress distribution induced in different components of the total hip prosthesis (THP) as well as the identification of the damage induced in the cement and between two cavities located in the polymethyl methacrylate (PMMA). The crack propagation is determined and localized using the extended element method (XFEM). The results show that the fracture stress of the cement in its proximal part is very important. These stresses increase considerably with the interaction of the cavities in this binder, causing damage to the cement and the loosening of the prosthesis.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41393463","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 : 2020-12-30DOI: 10.24874/JSSCM.2020.14.02.08
H. Laidoudi
In this paper, the governing equations of continuity and momentum subjected to suitable boundary conditions have been solved numerically to investigate the fluid flow in stirred vessel of two-bladed impeller. The numerical simulations have been carried out in three-dimensions for laminar flow. The studied fluid was considered Newtonian and incompressible. Our research studied the effects of geometrical configurations of the two-bladed impeller and its rotational speed on fluid patterns and mechanical power consumption. The innovative point in this paper is that the blades of the impeller contain three equal-sized holes of circular cross-section. The diameter of the hole (d) to the impeller diameter (D) gives the ratio d/D. the impeller speed is controlled by the Reynolds number (Re). The obtained results have been illustrated and discussed for the range of following governing parameters: d/D = 0 to 0.4 and Re = 1 to 300. The results showed that the studied parameters have significant effects on fluid flow and consumption power and the perforated blades of ratio d/D = 0.133 is more efficient than plan blades. Also, a new correlation is proposed to describe the consumption power as function of d/D and Re.
{"title":"HYDRODYNAMIC ANALYSES OF THE FLOW PATTERNS IN STIRRED VESSEL OF TWO-BLADED IMPELLER","authors":"H. Laidoudi","doi":"10.24874/JSSCM.2020.14.02.08","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.08","url":null,"abstract":"In this paper, the governing equations of continuity and momentum subjected to suitable boundary conditions have been solved numerically to investigate the fluid flow in stirred vessel of two-bladed impeller. The numerical simulations have been carried out in three-dimensions for laminar flow. The studied fluid was considered Newtonian and incompressible. Our research studied the effects of geometrical configurations of the two-bladed impeller and its rotational speed on fluid patterns and mechanical power consumption. The innovative point in this paper is that the blades of the impeller contain three equal-sized holes of circular cross-section. The diameter of the hole (d) to the impeller diameter (D) gives the ratio d/D. the impeller speed is controlled by the Reynolds number (Re). The obtained results have been illustrated and discussed for the range of following governing parameters: d/D = 0 to 0.4 and Re = 1 to 300. The results showed that the studied parameters have significant effects on fluid flow and consumption power and the perforated blades of ratio d/D = 0.133 is more efficient than plan blades. Also, a new correlation is proposed to describe the consumption power as function of d/D and Re.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47125199","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 : 2020-12-30DOI: 10.24874/JSSCM.2020.14.02.01
Mohammad Sheikh Mamoo, A. S. Goharrizi, B. Abolpour
Erosion caused by solid particles in curve pipes is one of the major concerns in the oil and gas industries. Small solid particles flow with a carrier liquid fluid and impact the inner wall of the piping, valves, and other equipment. These components face a high risk of solid particle erosion due to the constant collision, which may result in equipment malfunctioning and even failure. In this study, the two-way coupled Eulerian-Lagrangian method with the Oka erosion and Grant and Tabakoff particle-wall rebound models approach is employed to simulate the liquid-solid flow in U-bend and helical pipes using computational fluid dynamics. The effects of operating parameters (inlet fluid velocity and temperature, particle density and diameter, and mass flow rate) and design parameters (mean curvature radius/pipe diameter ratio) are investigated on the erosion of these tubes walls. It is obtained that increasing the fluid velocity and temperature, particle mass flow and particle density increase the penetration rate, particle diameter affects the rate of penetration, and increasing mean curvature radius/pipe diameter ratio decreases the rate of penetration.
{"title":"CFD SIMULATION OF EROSION BY PARTICLE COLLISION IN U-BEND AND HELICAL TYPE PIPES","authors":"Mohammad Sheikh Mamoo, A. S. Goharrizi, B. Abolpour","doi":"10.24874/JSSCM.2020.14.02.01","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.01","url":null,"abstract":"Erosion caused by solid particles in curve pipes is one of the major concerns in the oil and gas industries. Small solid particles flow with a carrier liquid fluid and impact the inner wall of the piping, valves, and other equipment. These components face a high risk of solid particle erosion due to the constant collision, which may result in equipment malfunctioning and even failure. In this study, the two-way coupled Eulerian-Lagrangian method with the Oka erosion and Grant and Tabakoff particle-wall rebound models approach is employed to simulate the liquid-solid flow in U-bend and helical pipes using computational fluid dynamics. The effects of operating parameters (inlet fluid velocity and temperature, particle density and diameter, and mass flow rate) and design parameters (mean curvature radius/pipe diameter ratio) are investigated on the erosion of these tubes walls. It is obtained that increasing the fluid velocity and temperature, particle mass flow and particle density increase the penetration rate, particle diameter affects the rate of penetration, and increasing mean curvature radius/pipe diameter ratio decreases the rate of penetration.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43356327","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 : 2020-12-30DOI: 10.24874/JSSCM.2020.14.02.09
S. Posavljak, G. Tošić, K. Maksimovic
This paper deals with jet engines compressor disks which have dovetail joints with blades. A compressor disk with reduced fatigue resistance was taken as an example. Two simplified conceptual solutions of the dovetail joint with blades were devised. Based on the low cycle fatigue theory, the crack initiation life of their critical parts with newly-proposed transition rounding at the bottom of dovetail grooves was estimated. Two different flank angles in the dovetail grooves (60° in the critical part that belongs to the first dovetail joint conceptual solution and 55° in the critical part that belongs to the second dovetail joint conceptual solution), two different aviation steels selected for workmanship (13H11N2V2MF and AISI 304 steel) and two load histories (load history LH1 and load history LH2), were taken into account. By load history LH2 an overload of the critical parts was simulated. The results of crack initiation life estimation of the critical parts in the dovetail joint conceptual solutions show that there is a possibility for the crack initiation life extension of the observed compressor disk. In all analyzed variants, it has been shown that the critical part in the second dovetail joint conceptual solution has longer crack initiation life than the critical part in the first dovetail joint conceptual solution. For example, the critical part in the second dovetail joint conceptual solution made of AISI 304 steel, in the case of load history LH1 has 141.55% longer crack initiation life than the critical part in the first dovetail joint conceptual solution made of 13H11N2V2MF steel. In the case of load history LH2 (an overload case) that percent is greater and amounts to 173.15%.
{"title":"INVESTIGATING POSSIBILITIES OF CRACK INITIATION LIFE EXTENSION IN JET ENGINES COMPRESSOR DISKS","authors":"S. Posavljak, G. Tošić, K. Maksimovic","doi":"10.24874/JSSCM.2020.14.02.09","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.09","url":null,"abstract":"This paper deals with jet engines compressor disks which have dovetail joints with blades. A compressor disk with reduced fatigue resistance was taken as an example. Two simplified conceptual solutions of the dovetail joint with blades were devised. Based on the low cycle fatigue theory, the crack initiation life of their critical parts with newly-proposed transition rounding at the bottom of dovetail grooves was estimated. Two different flank angles in the dovetail grooves (60° in the critical part that belongs to the first dovetail joint conceptual solution and 55° in the critical part that belongs to the second dovetail joint conceptual solution), two different aviation steels selected for workmanship (13H11N2V2MF and AISI 304 steel) and two load histories (load history LH1 and load history LH2), were taken into account. By load history LH2 an overload of the critical parts was simulated. The results of crack initiation life estimation of the critical parts in the dovetail joint conceptual solutions show that there is a possibility for the crack initiation life extension of the observed compressor disk. In all analyzed variants, it has been shown that the critical part in the second dovetail joint conceptual solution has longer crack initiation life than the critical part in the first dovetail joint conceptual solution. For example, the critical part in the second dovetail joint conceptual solution made of AISI 304 steel, in the case of load history LH1 has 141.55% longer crack initiation life than the critical part in the first dovetail joint conceptual solution made of 13H11N2V2MF steel. In the case of load history LH2 (an overload case) that percent is greater and amounts to 173.15%.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48490876","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 : 2020-12-30DOI: 10.24874/JSSCM.2020.14.02.07
M. Atashafrooz, Mohsen Shafie
In this research, analysis of entropy generation for mixed convection fluid flow in a trapezoidal enclosure is numerically investigated. To achieve this goal, the influences of Grashof number, Reynolds number and inclination angle of enclosure side walls on the distributions of the velocity and temperature fields and the values of entropy generation and Bejan numbers are examined with full details. The Boussinesq approximation is used to calculate the buoyancy force. Also, the entropy generation numbers are calculated according to the second law of thermodynamics. In addition, the modified blocked region method is applied to accurately simulate the diagonal walls of the trapezoidal enclosure. The results of numerical solution show that the maximum values of the flow irreversibility in the whole computational domain of the enclosure are related to the case with the highest values of Grashof number, Reynolds number and inclination angle of side walls.
{"title":"ANALYSIS OF ENTROPY GENERATION FOR MIXED CONVECTION FLUID FLOW IN A TRAPEZOIDAL ENCLOSURE USING THE MODIFIED BLOCKED REGION METHOD","authors":"M. Atashafrooz, Mohsen Shafie","doi":"10.24874/JSSCM.2020.14.02.07","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.07","url":null,"abstract":"In this research, analysis of entropy generation for mixed convection fluid flow in a trapezoidal enclosure is numerically investigated. To achieve this goal, the influences of Grashof number, Reynolds number and inclination angle of enclosure side walls on the distributions of the velocity and temperature fields and the values of entropy generation and Bejan numbers are examined with full details. The Boussinesq approximation is used to calculate the buoyancy force. Also, the entropy generation numbers are calculated according to the second law of thermodynamics. In addition, the modified blocked region method is applied to accurately simulate the diagonal walls of the trapezoidal enclosure. The results of numerical solution show that the maximum values of the flow irreversibility in the whole computational domain of the enclosure are related to the case with the highest values of Grashof number, Reynolds number and inclination angle of side walls.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46771094","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}
In this work, the influence of entropy generation analysis for an electrically conducting Casson fluid flow with convective boundary conditions has been numerically studied. The governing equations are analyzed numerically using weighted residual methods. Subsequently, the residuals were minimized using two different approaches of weighted residual method namely collocation weighted residual method (CWRM) and Galerkin weighted residual method (GWRM) and computed numerically using MATHEMATICAL software. The impacts of governing parameters on Casson flow velocity, temperature profile, local skin friction, and Nusselt number were analysed. The obtained solutions were used to determine the heat transfer irreversibility and bejan number of the model. The results of the computation show that the effect of thermophysical properties such as thermal radiation parameter, suction/injection parameter, magnetic field parameter, radiation parameter, and Eckert number has a significant influence on Skin friction coefficient (Cf) and local Nusselt number (Nu) when compared to the Newtonian fluid. The findings from this study are relevant to advances in viscoelasticity and enhanced oil recovery.
{"title":"NUMERICAL SIMULATION OF ENTROPY GENERATION FOR CASSON FLUID FLOW THROUGH PERMEABLE WALLS AND CONVECTIVE HEATING WITH THERMAL RADIATION EFFECT","authors":"Obalalu Adebowale Martins, K. Issa, A. Abdulraheem, Ajala Olusegun Adebayo, Adeosun Adeshina Taofeeq, Oluwaseyi Aliu, Adebayo Lawal Lanre, Wahaab Adisa Fatai","doi":"10.24874/JSSCM.2020.14.02.10","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.02.10","url":null,"abstract":"In this work, the influence of entropy generation analysis for an electrically conducting Casson fluid flow with convective boundary conditions has been numerically studied. The governing equations are analyzed numerically using weighted residual methods. Subsequently, the residuals were minimized using two different approaches of weighted residual method namely collocation weighted residual method (CWRM) and Galerkin weighted residual method (GWRM) and computed numerically using MATHEMATICAL software. The impacts of governing parameters on Casson flow velocity, temperature profile, local skin friction, and Nusselt number were analysed. The obtained solutions were used to determine the heat transfer irreversibility and bejan number of the model. The results of the computation show that the effect of thermophysical properties such as thermal radiation parameter, suction/injection parameter, magnetic field parameter, radiation parameter, and Eckert number has a significant influence on Skin friction coefficient (Cf) and local Nusselt number (Nu) when compared to the Newtonian fluid. The findings from this study are relevant to advances in viscoelasticity and enhanced oil recovery.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47464568","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 : 2020-06-30DOI: 10.24874/JSSCM.2020.14.01.01
M. Kojic
The lungs are the pair of organs where very complex internal microstructure provides gas exchange as the vital process of living organisms. This exchange in humans occurs within only 300g of tissue but on the surface of millions of alveoli with the total surface area of around 130m2. The extremely complex microstructure consists of micron-size interconnected channels and alveoli, which significantly change the size during breathing and remain open. These conditions are maintained due to existence of two mechanical systems – one external and the other internal, which act in the opposite sense, so that the lung behaves as a tensegrity system. Many computational models, with various degrees of simplifications and sophistication have been introduced. However, this task remains a challenge. We here introduce a 3D multi-scale composite FE for mechanics of lung tissue (MSCL). The model can be further used in generating computational models for mechanics for the entire lung and coupling to airflow.
{"title":"MULTISCALE COMPOSITE 3D FINITE ELEMENT FOR LUNG MECHANICS","authors":"M. Kojic","doi":"10.24874/JSSCM.2020.14.01.01","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.01.01","url":null,"abstract":"The lungs are the pair of organs where very complex internal microstructure provides gas exchange as the vital process of living organisms. This exchange in humans occurs within only 300g of tissue but on the surface of millions of alveoli with the total surface area of around 130m2. The extremely complex microstructure consists of micron-size interconnected channels and alveoli, which significantly change the size during breathing and remain open. These conditions are maintained due to existence of two mechanical systems – one external and the other internal, which act in the opposite sense, so that the lung behaves as a tensegrity system. Many computational models, with various degrees of simplifications and sophistication have been introduced. However, this task remains a challenge. We here introduce a 3D multi-scale composite FE for mechanics of lung tissue (MSCL). The model can be further used in generating computational models for mechanics for the entire lung and coupling to airflow.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47011501","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 : 2020-06-30DOI: 10.24874/JSSCM.2020.14.01.03
R. Yahiaoui, R. Noureddine, B. Saadi
Predicting crack initiation life (CIL) of a mechanical component or a structure in service remains difficult since the crack formation process is of stochastic nature. To ensure a high level of safety and reliability, it is essential to have an appropriate probability distribution law of the CIL to ensure that cracks can be detected before reaching a critical length. In the present study, a stochastic model is used to predict the number of cycles corresponding to the formation of a crack 500 μm long resulted from the nucleation, growth, and coalescence of multiple microcracks. The model is applied in the case of a 316L austenitic stainless steel for different plastic strain ranges.
{"title":"A STOCHASTIC MODEL FOR CRACK INITIATION LIFE PREDICTION OF AN AUSTENITIC STAINLESS STEEL UNDER CONSTANT AMPLITUDE LOADING","authors":"R. Yahiaoui, R. Noureddine, B. Saadi","doi":"10.24874/JSSCM.2020.14.01.03","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.01.03","url":null,"abstract":"Predicting crack initiation life (CIL) of a mechanical component or a structure in service remains difficult since the crack formation process is of stochastic nature. To ensure a high level of safety and reliability, it is essential to have an appropriate probability distribution law of the CIL to ensure that cracks can be detected before reaching a critical length. In the present study, a stochastic model is used to predict the number of cycles corresponding to the formation of a crack 500 μm long resulted from the nucleation, growth, and coalescence of multiple microcracks. The model is applied in the case of a 316L austenitic stainless steel for different plastic strain ranges.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48669704","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 : 2020-06-30DOI: 10.24874/JSSCM.2020.14.01.02
B. P. Reddy
Numerical investigation is undertaken to study the effects of thermo-diffusion and Hall current on unsteady magneto-hydrodynamic convective flow of a viscous, incompressible, electrically conducting, radiating and heat absorbing fluid past an exponentially accelerated infinite vertical porous plate with ramped temperature in the presence of chemical reaction. A uniform magnetic field is applied transversely in the direction of the flow. The governing system of partial differential equations along with initial and boundary conditions is transformed to dimensionless form and then solved by employing finite element method. The impact of various flow parameters on the primary and secondary fluid velocities, fluid temperature and fluid concentration as well as shear stress, rate of heat and mass transfer at the plate are displayed through the graphs and tables. It can be observed that the temperature profiles are slower in case of ramped temperature plate than that of isothermal plate.
{"title":"THERMO—DIFFUSION AND HALL EFFECT ON RADIATING AND REACTING MHD CONVECTIVE HEAT ABSORBING FLUID PAST AN EXPONENTIALLY ACCELERATED VERTICAL POROUS PLATE WITH RAMPED TEMPERATURE","authors":"B. P. Reddy","doi":"10.24874/JSSCM.2020.14.01.02","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.14.01.02","url":null,"abstract":"Numerical investigation is undertaken to study the effects of thermo-diffusion and Hall current on unsteady magneto-hydrodynamic convective flow of a viscous, incompressible, electrically conducting, radiating and heat absorbing fluid past an exponentially accelerated infinite vertical porous plate with ramped temperature in the presence of chemical reaction. A uniform magnetic field is applied transversely in the direction of the flow. The governing system of partial differential equations along with initial and boundary conditions is transformed to dimensionless form and then solved by employing finite element method. The impact of various flow parameters on the primary and secondary fluid velocities, fluid temperature and fluid concentration as well as shear stress, rate of heat and mass transfer at the plate are displayed through the graphs and tables. It can be observed that the temperature profiles are slower in case of ramped temperature plate than that of isothermal plate.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43176360","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 : 2020-06-01DOI: 10.24874/JSSCM.2020.01.08
D. Milenković, J. Đorović, Edina H. Avdović, Žiko B. Milanović, M. Antonijević
In the present paper, M05-2X/6-311+G(d,p) level of theory was used to investigate antiradical activity of cyanidin towards highly damaging radical species (.OH, .OCH3, .OOH and .OOCH3). The applied method successfully reproduces the values of reaction enthalpies (ΔHBDE, ΔHIP, and ΔHPA). These parameters are important to determine which of the mechanisms are preferred. Reaction enthalpies related to the antioxidant mechanisms of the investigated species were calculated in water and DMSO. The enthalpies of reactions indicate the preferred radical scavenging mechanisms in polar (water) and polar aprotic (DMSO) solvents. Single- electron transfer followed by proton transfer (SET-PT) is not a favorable reaction pathway under any conditions. Both remaining mechanisms, HAT and SPLET, are suitable for the reaction of cyanidin with •OH and •OCH3 in all solvents under investigation. On the other hand, in the reaction of cyanidin with •OOH and •OOCH3, the SPLET mechanism is possible in both solvents. Simulation of the reaction of the cyanidin anion with the hydroxy radical confirmed that position 3` of Cy‒O- is the most suitable for reaction with •OH through electron transfer mechanism (ET) in both solvents.
{"title":"THERMODYNAMIC AND KINETIC INVESTIGATION OF ANTIRADICAL POTENTIAL OF CYANIDIN","authors":"D. Milenković, J. Đorović, Edina H. Avdović, Žiko B. Milanović, M. Antonijević","doi":"10.24874/JSSCM.2020.01.08","DOIUrl":"https://doi.org/10.24874/JSSCM.2020.01.08","url":null,"abstract":"In the present paper, M05-2X/6-311+G(d,p) level of theory was used to investigate antiradical activity of cyanidin towards highly damaging radical species (.OH, .OCH3, .OOH and .OOCH3). The applied method successfully reproduces the values of reaction enthalpies (ΔHBDE, ΔHIP, and ΔHPA). These parameters are important to determine which of the mechanisms are preferred. Reaction enthalpies related to the antioxidant mechanisms of the investigated species were calculated in water and DMSO. The enthalpies of reactions indicate the preferred radical scavenging mechanisms in polar (water) and polar aprotic (DMSO) solvents. Single- electron transfer followed by proton transfer (SET-PT) is not a favorable reaction pathway under any conditions. Both remaining mechanisms, HAT and SPLET, are suitable for the reaction of cyanidin with •OH and •OCH3 in all solvents under investigation. On the other hand, in the reaction of cyanidin with •OOH and •OOCH3, the SPLET mechanism is possible in both solvents. Simulation of the reaction of the cyanidin anion with the hydroxy radical confirmed that position 3` of Cy‒O- is the most suitable for reaction with •OH through electron transfer mechanism (ET) in both solvents.","PeriodicalId":42945,"journal":{"name":"Journal of the Serbian Society for Computational Mechanics","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47041719","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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