Rabiu Musah - Academia.edu (original) (raw)

Papers by Rabiu Musah

arXiv (Cornell University), 2012

We used a complete tight-binding band structure of graphene nanoribbon to obtain, for the first t... more We used a complete tight-binding band structure of graphene nanoribbon to obtain, for the first time, analytical techniques for observing photon assisted transport, and dynamic localization of electrons in the graphene nanoribbons. When the ribbons are subject to a multi-frequency dc-ac field, photon assisted replicas show up at rather strong drive force. The strong dependence of the photon peaks on ac amplitudes allow for high-harmonic dynamic oscillations at these amplitudes. We identified regions of positive differential conductivity where a nanoelectronic graphene device may be operated as a small signal amplifier. Our research has also reveal another quantum mechanical phenomenon, fractional photon assisted transport, when the stark factor r>1r > 1r>1.

Earthline Journal of Mathematical Sciences

The effects of fluctuating temperature on Darcy-Forchheimer flow of oil-based nanofluid with acti... more The effects of fluctuating temperature on Darcy-Forchheimer flow of oil-based nanofluid with activation energy and velocity slip has been analyzed. Similarity transformation was used to transform the governing partial differential equations into coupled nonlinear ordinary differential equations and solved numerically with the aid of the fourth order Runge-Kutta algorithm with a shooting technique. Results for the embedded parameters controlling the flow dynamics have been tabulated and illustrated graphically. The slip velocity parameter was found to enhance the Nusselt number but depleted both the skin friction coefficient and Sherwood number while the local inertial was noted to increase both the skin friction coefficient and Sherwood number but diminishes the Nusselt number. These results indicate that the velocity slip parameter and local inertial coefficient can be used to control flow characteristics in industrial and engineering systems.

American Journal of Applied Mathematics

arXiv (Cornell University), Jul 12, 2012

Engineering Transactions, 2019

The influence of thermophoretic transport of Al2O3 nanoparticles on heat and mass transfer in vis... more The influence of thermophoretic transport of Al2O3 nanoparticles on heat and mass transfer in viscoelastic flow of oil-based nanofluid past porous exponentially stretching surface with activation energy has been examined. Similarity technique was employed to transform the governing partial differential equations into a coupled fourth-order ordinary differential equations which were reduced to a system of first-order ordinary differential equations and then solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results for various controlling parameters were tabulated and graphically illustrated. It was found that the thermophoretic transport of Al2O3 nanoparticles did not affect the rate of flow and heat transfer at the surface but it affected the rate of mass transfer of the nanofluid which decayed the solutal boundary layer thickness. This study also revealed that activation energy retards the rate of mass transfer which causes a thickening of ...

arXiv: Mesoscale and Nanoscale Physics, 2016

Behaviour of hot electrons under the influence of dc field in carbon nanotubes is theoretically c... more Behaviour of hot electrons under the influence of dc field in carbon nanotubes is theoretically considered. The study was done semi-classically by solving Boltzmann transport equation with the presence of the hot electrons source to derive the current densities. Plots of the normalized axial current density versus electric field strength of the chiral CNTs reveal a negative differential conductivity (NDC). Unlike achiral CNTs, the NDC occurs at a low field about mathrm6kV/cm\mathrm{6\ kV/cm}mathrm6kV/cm for chiral CNT. We further observed that the switch from NDC to PDC occurs at lower dc field in chiral CNTs than achiral counterparts. Hence the suppression of the unwanted domain instability usually associated with NDC and a potential generation of terahertz radiations occurs at low electric field for chiral CNTs.

Physica E: Low-dimensional Systems and Nanostructures, 2021

Abstract The radius dependence of the electrical conductivity of metallic and semiconducting zigz... more Abstract The radius dependence of the electrical conductivity of metallic and semiconducting zigzag carbon nanotubes (CNTs) is theoretically studied. The investigation was done semiclassically by solving the Boltzmann transport equation to derive current density as a function of a homogenous axial dc field and radius of the tube. The analysis was numerically carried out by varying the radius of the materials at a constant temperature. Plots of the normalized current density versus dc field applied along the axis of both materials are presented. We observed that in the case of the metallic zigzag CNTs as the radius increases, the electrical conductivity decreases. On the other hand, in the semiconducting zigzag CNT there was an increase as radius increases. This research shows that thinner metallic zigzag CNTs and thicker semiconducting zigzag CNTs are better conductors of electricity. This investigation therefore offers way of obtaining higher electrical conductivity in both materials without doping. This study therefore shows applications in the development of current conducting nano-devices for scientific systems.

Defect and Diffusion Forum, 2021

Heat transport processes through radiation in a dissipative flow of Al2O3 and CuO oil-based nanof... more Heat transport processes through radiation in a dissipative flow of Al2O3 and CuO oil-based nanofluids has been discussed. The equations modeling the flow has been transformed using similarity variables into coupled nonlinear higher order ordinary differential equations. These equations are solved by employing the fourth order Runge-Kutta algorithm and a shooting technique. The results for the embedded parameters were tabulated and depicted graphically. The study revealed that oil-based nanofluid of CuO has a better rate of heat transfer than Al2O3 oil-based nanofluid with increased radiation. Thus, the study concluded that CuO oil-based nanofluid has a superior heat transfer characteristic and thus preferred for radiation hardening.

Journal of Nanofluids, 2021

In this current paper, an investigation has been conducted on the magnetohydrodynamic boundary la... more In this current paper, an investigation has been conducted on the magnetohydrodynamic boundary layer flow of non-Newtonian Casson fluids on magnetized sheet with an exponentially stretching sheet. The similarity approach has been used to transform the governing models for Casson fluid to ordinary differential equations. We presented numerical results for momentum, energy and concentration equation parameters. Effects of the magnetized sheet and varying all the emerged parameters on the flow of Casson fluid with respect to the friction between the fluid and the surface, temperature and concentration are presented in tables. As a result of the induced magnetization of the sheet, the thickness of the thermal boundary layer has been enhanced. This behaviour brings a considerable reduction to the heat transfer. The induced magnetized sheet has a similar influence on the skin friction, Nusselt number and the Sherwood number. We however proposed incorporation of magnetized surfaces in MHD ...

Defect and Diffusion Forum, 2018

The effect of variable heat source on viscoelastic fluid of CuO-oil based nanofluid over a porous... more The effect of variable heat source on viscoelastic fluid of CuO-oil based nanofluid over a porous nonlinear stretching surface is analyzed. The problem was modelled in the form of partial differential equations and transformed into a coupled fourth order ordinary differential equations by similarity techniques. It was further reduced to a system of first order ordinary differential equations and solved numerically using the fourth order Runge-Kutta algorithm with a shooting method. The results for various controlling parameters have been tabulated and the flow profiles graphically illustrated. The study revealed that the viscoelastic parameter has a decreasing effect on the magnitude of both the skin friction coefficient and the rate of heat transfer from the surface. It enhanced the momentum boundary layer thickness whilst adversely affecting the thermal boundary layer thickness.

Diffusion Foundations, 2018

: The combined effect of variable viscosity and thermal conductivity on dissipative flow of oil-b... more : The combined effect of variable viscosity and thermal conductivity on dissipative flow of oil-based nanofluid over a permeable vertical plate with suction has been studied. The governing partial differential equations have been transformed into a coupled third-order ordinary differential equations using similarity techniques. The resulting third-order ordinary differential equations were then reduced into a system of first-order ordinary differential equations and solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results revealed that both viscosity and thermal conductivities of CuO oil-based nanofluid enhances the intensity of the skin friction coefficient and the rate of heat transfer at the surface of the plate. Furthermore, the thermal boundary layer thickness is weakened by the viscosity of CuO oil-based nanofluid, the Prandtl number, the suction parameter, the permeability of the medium and the thermal Grashof number

Diffusion Foundations, 2017

The combined effect of suction and thermal conductivity on the boundary layer flow of oil–based n... more The combined effect of suction and thermal conductivity on the boundary layer flow of oil–based nanofluid over a porous stretching surface has been investigated. Similarity techniques were employed in transforming the governing partial differential equations into a coupled third order ordinary differential equations. The higher third order ordinary differential equations were then reduced into a system of first order ordinary differential equations and solved numerically using the fourth order Runge-Kutta algorithm with a shooting method. The results were presented in tabular and graphically forms for various controlling parameters. It was found that increasing the thermal conductivities of the base fluid (oil) and nanoparticle size (CuO) of the nanofluid did not affect the velocity boundary layer thickness but depreciates with suction and permeability. The suction parameter and thermal conductivity of the base fluid also made the thermal boundary layer thinner.