Ehsanul Azim - Academia.edu (original) (raw)

Papers by Ehsanul Azim

Research paper thumbnail of Pressure induced tuning of the physical properties of SnZrO3 and SnHfO3: A first principle study

AIP Advances

Structural, electronic, optical, and mechanical properties of cubic SnZrO3 and SnHfO3 have been s... more Structural, electronic, optical, and mechanical properties of cubic SnZrO3 and SnHfO3 have been studied under different hydrostatic pressures within the framework of density functional theory. A strong atomic interaction resulting from a considerable drop in the lattice parameter and bond length was observed. The Sn–O and Hf/Zr–O showed strong ionic and weak covalent characteristics, respectively, and the bond strengths are found to enhance under the applied pressure. Poisson’s ratio of these compounds also supports the bonding nature. The external pressure remarkably changed the optical absorption and conductivity of the materials to a higher value in the UV region of the solar spectrum and the direct bandgap of Sn(Zr/Hf)O3 significantly reduced, thereby enhancing the conductivity. Likewise, in other optical parameters, the elastic properties exhibited some noticeable changes: the stiffness, ductility, anisotropy, hardness, and machinability of these materials were significantly in...

Research paper thumbnail of Poster Presentation on Investigating Variation of Dynamic Frictional Effect of Different Textile Fabrics Against Dry and Wet Human Skin Condition At A Fixed Load

Research paper thumbnail of Investigating Variation of Dynamic Frictional Effect of Different Textile Fabrics Against Dry and Wet Human Skin Condition at a Fixed Load

Proceedings of International Exchange and Innovation Conference on Engineering & Sciences (IEICES), 2021

The principal focus of this experiment was to investigate the dynamic friction properties of diff... more The principal focus of this experiment was to investigate the dynamic friction properties of different fabric samples at dry and wet skin conditions for a fixed load. The experiment was done by a simple setup with fabric sliding mechanism over human skin for four separate fabric samples of two different categories. Friction forces between different fabrics and human skin were measured through the experimental procedure and afterwards friction coefficient was calculated using Capstan formula from the obtained value of force. It was observed that the friction coefficient of Garment fabrics is lower than that of Special fabrics in dry condition. Wet condition resulted in higher frictional effects than dry condition of the skin providing perfect matching of natural frictional characteristics of any surface. Besides, the wetness of skin, as well as wettability of fabrics, also have a significant influence on the friction coefficient.

Research paper thumbnail of Investigation on conjugate mixed convection inside a square cavity with heat generating rotating circular cylinder

Proceedings of the 13th International Conference on Mechanical Engineering (ICME2019), 2021

This paper displays the execution of a numerical investigation of conjugate pure mixed convection... more This paper displays the execution of a numerical investigation of conjugate pure mixed convection heat transfer inside a square cavity with a circular rotating cylinder placed at the center of the cavity. Both top and bottom walls of the cavity are considered to be insulated, whereas the vertical walls are kept isothermally cooled. Besides, the rotating cylinder plays the simultaneous role of both heat conducting element and heat generating source. The numerical simulation is performed to solve the governing Navier-Stokes and energy equations using Galerkin finite element method. Both counterclockwise and clockwise rotations of the cylinder are taken into account along with the simultaneous variation of Reynolds and Grashof numbers, and the change of diameter of the cylinder. The analysis has been accomplished in terms of streamline and isotherm plots, the distribution of average Nusselt number of the heated cylinder surface and average temperature of the cavity. The findings of the present study reveal that variations of governing parameters and the size of the cylinder significantly contribute towards the thermal performance through drastically change of flow pattern and thermal field. However, the direction of rotation of the cylinder has insignificant effect on the characteristics of pure mixed convection heat transfer inside the cavity.

Research paper thumbnail of Effect of Parameters of Rotating Cylinders on the Heat Transfer Advancement

Journal of Heat Transfer, 2022

Conjugate pure mixed convection in a differentially heated square cavity with two vertically plac... more Conjugate pure mixed convection in a differentially heated square cavity with two vertically placed heat conductive revolving cylinders has been analyzed in a computational approach applying the finite element method. This analysis has been implemented considering the upper and lower wall as insulated simultaneously and the left vertical wall as heated maintaining constant temperature (i.e., isothermally heated) and the right vertical wall as isothermally cooled. The outcomes of this study have been examined concerning streamlines, isotherms, average Nusselt number (Nu) which unveils a noteworthy fact that both the rotating cylinders' inclination patterns and Reynolds number (Re) have a vital role upon the average Nusselt number (Nu), flow pattern, and isotherms. From that perspective, best heat transfer phenomena have been observed for counterclockwise circulation of both cylinders so that the condition for these cases has been assessed from a distance variation between the two...

Research paper thumbnail of Pressure induced tuning of the physical properties of SnZrO3 and SnHfO3: A first principle study

AIP Advances

Structural, electronic, optical, and mechanical properties of cubic SnZrO3 and SnHfO3 have been s... more Structural, electronic, optical, and mechanical properties of cubic SnZrO3 and SnHfO3 have been studied under different hydrostatic pressures within the framework of density functional theory. A strong atomic interaction resulting from a considerable drop in the lattice parameter and bond length was observed. The Sn–O and Hf/Zr–O showed strong ionic and weak covalent characteristics, respectively, and the bond strengths are found to enhance under the applied pressure. Poisson’s ratio of these compounds also supports the bonding nature. The external pressure remarkably changed the optical absorption and conductivity of the materials to a higher value in the UV region of the solar spectrum and the direct bandgap of Sn(Zr/Hf)O3 significantly reduced, thereby enhancing the conductivity. Likewise, in other optical parameters, the elastic properties exhibited some noticeable changes: the stiffness, ductility, anisotropy, hardness, and machinability of these materials were significantly in...

Research paper thumbnail of Poster Presentation on Investigating Variation of Dynamic Frictional Effect of Different Textile Fabrics Against Dry and Wet Human Skin Condition At A Fixed Load

Research paper thumbnail of Investigating Variation of Dynamic Frictional Effect of Different Textile Fabrics Against Dry and Wet Human Skin Condition at a Fixed Load

Proceedings of International Exchange and Innovation Conference on Engineering & Sciences (IEICES), 2021

The principal focus of this experiment was to investigate the dynamic friction properties of diff... more The principal focus of this experiment was to investigate the dynamic friction properties of different fabric samples at dry and wet skin conditions for a fixed load. The experiment was done by a simple setup with fabric sliding mechanism over human skin for four separate fabric samples of two different categories. Friction forces between different fabrics and human skin were measured through the experimental procedure and afterwards friction coefficient was calculated using Capstan formula from the obtained value of force. It was observed that the friction coefficient of Garment fabrics is lower than that of Special fabrics in dry condition. Wet condition resulted in higher frictional effects than dry condition of the skin providing perfect matching of natural frictional characteristics of any surface. Besides, the wetness of skin, as well as wettability of fabrics, also have a significant influence on the friction coefficient.

Research paper thumbnail of Investigation on conjugate mixed convection inside a square cavity with heat generating rotating circular cylinder

Proceedings of the 13th International Conference on Mechanical Engineering (ICME2019), 2021

This paper displays the execution of a numerical investigation of conjugate pure mixed convection... more This paper displays the execution of a numerical investigation of conjugate pure mixed convection heat transfer inside a square cavity with a circular rotating cylinder placed at the center of the cavity. Both top and bottom walls of the cavity are considered to be insulated, whereas the vertical walls are kept isothermally cooled. Besides, the rotating cylinder plays the simultaneous role of both heat conducting element and heat generating source. The numerical simulation is performed to solve the governing Navier-Stokes and energy equations using Galerkin finite element method. Both counterclockwise and clockwise rotations of the cylinder are taken into account along with the simultaneous variation of Reynolds and Grashof numbers, and the change of diameter of the cylinder. The analysis has been accomplished in terms of streamline and isotherm plots, the distribution of average Nusselt number of the heated cylinder surface and average temperature of the cavity. The findings of the present study reveal that variations of governing parameters and the size of the cylinder significantly contribute towards the thermal performance through drastically change of flow pattern and thermal field. However, the direction of rotation of the cylinder has insignificant effect on the characteristics of pure mixed convection heat transfer inside the cavity.

Research paper thumbnail of Effect of Parameters of Rotating Cylinders on the Heat Transfer Advancement

Journal of Heat Transfer, 2022

Conjugate pure mixed convection in a differentially heated square cavity with two vertically plac... more Conjugate pure mixed convection in a differentially heated square cavity with two vertically placed heat conductive revolving cylinders has been analyzed in a computational approach applying the finite element method. This analysis has been implemented considering the upper and lower wall as insulated simultaneously and the left vertical wall as heated maintaining constant temperature (i.e., isothermally heated) and the right vertical wall as isothermally cooled. The outcomes of this study have been examined concerning streamlines, isotherms, average Nusselt number (Nu) which unveils a noteworthy fact that both the rotating cylinders' inclination patterns and Reynolds number (Re) have a vital role upon the average Nusselt number (Nu), flow pattern, and isotherms. From that perspective, best heat transfer phenomena have been observed for counterclockwise circulation of both cylinders so that the condition for these cases has been assessed from a distance variation between the two...