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1
Content available From waste to treat waste : exploitation of marble dust as a harmful pollutant to a green adsorbent for dyes and heavy metals from industrial wastewater
Attia H.A., Farghaly Mohamed G., Saleh A.M., Abdel Khalek M.A.
Physicochemical Problems of Mineral Processing
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2022
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Vol. 58, iss. 6
art. no. 154007
EN
The marble dust as a harmful industrial waste of marble fabrication was evaluated as aneconomical and efficient green adsorbent for Acid Red-1 dye and lead ions. The XRD, XRF, particle size, surface area and zeta-potential measurements were used to characterize the marble dust. The removal efficiency was optimized by studying several parameters such as pH, temperature, contact time, adsorbent dose and initial concentration. The optimum removal was achieved at pH 6, 20°C after 60 min in the presence of 2.5g/L marble dust. The rates of adsorption were found to follow the pseudo-second-order model. The results showed better fitting to Freundlich isotherm. The thermodynamic studies revealed that the adsorption process is spontaneous, exothermic and favorable at low temperature. The free energy (∆G°), enthalpy (∆H°), and entropy (∆S°) changes were calculated to predict the nature of adsorption.The removal efficiency was improved by calcination of the marble at 700°C. Application for textilewastewater showed high removal efficiency up to 99.9%of inorganic and organic pollutants. The product of treatment was used in the concrete and bricks manufactured, so there is nogeneration of second-order pollutants.
2
Content available On the effectiveness of variation of physical variables on steady flow between parallel plates with heat transfer in a porous medium
Attia H. A., Abdeen M, A. M.
Journal of Theoretical and Applied Mechanics
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2013
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Vol. 51 nr 1
53--61
EN
The effect of variation of physical variables on a steady flow through a porous medium with heat transfer between parallel plates is examined. The viscosity and the thermal conductivity are assumed to be temperature dependent. A constant pressure gradient is applied in the axial direction and the two plates are kept at two constant but different temperatures, while the viscous dissipation is considered in the energy equation. A numerical solution for the governing non-linear coupled equations of motion and the energy equation is determined. The effect of porosity of the medium, the variable viscosity, and the variable thermal conductivity on both the velocity and temperature distributions is reported.
PL
W pracy zbadano wpływ zmiany parametrów fizycznych na ustalony przepływ przez porowaty ośrodek przy jednoczesnym przesyle ciepła pomiędzy równoległymi płytami ograniczającym obszar ośrodka. Założono, że lepkość i współczynnik przewodnictwa cieplnego są zależne od temperatury. Do utrzymania stacjonarnego przepływu wprowadzono stały gradient ciśnienia w kierunku osiowym, a dwie płyty utrzymano w stałych, lecz różniących się temperaturach. Efekt dyssypacji wiskotycznej uwzględniono w równaniu energii. Zaprezentowano numeryczne rozwiązanie nieliniowych, sprzężonych równań ruchu oraz równania energii. Omówiono wpływ porowatości ośrodka, zmiennej lepkości i współczynnika przewodnictwa cieplnego na rozkład prędkości i temperatury w obszarze przepływu.
3
Content available remote Velocity and Temperature Distributions between Parallel Porous Plates with the Hall Effect and Variable Properties Under Exponential Decaying Pressure Gradient
Attia H. A., Abdeen M. A. M.
Engineering Transactions
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2012
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Vol. 60, iss. 2
139-139
EN
The time varying hydromagnetic flow between two infinite parallel porous plates is studied with heat transfer considering the Hall effect and temperature dependent physical properties. An exponential decaying pressure gradient is imposed in the axial direction and an external uniform magnetic field as well as a uniform suction and injection are applied perpendicular to the horizontal plates. A numerical solution for the governing non-linear coupled set of equations of motion and the energy equation is adopted. The effects of the Hall current and the temperature dependent viscosity and thermal conductivity on both the velocity and temperature distributions are investigated.
4
Content available remote Asymptotic solution for rotating disk flow in a porous medium
Attia H. A.
Mechanics and Mechanical Engineering
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2010
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Vol. 14, nr 1
119-136
EN
In this paper, we present asymptotic solution to a Navier-Stokes equation of von Karman type for the flow due to a rotating disk in a porous medium. Asymptotic solutions to a Navier-Stokes equation is given in the case of small as well as large values of the porosity parameter β whose coefficients are obtained in closed form in terms of properly scaled von Karman's similarity coordinate. Straining of coordinates is used to remove secular terms and enable to obtain expressions that can be used to determine the coefficients of the expansions to any order. A comparison of the asymptotic solution with an exact numerical solution for the governing nonlinear differential equations is presented.
5
Content available remote On the Effectiveness of Heat Generation/Absorption on Heat Transfer in a Stagnation Point Flow of a Micropolar Fluid over a Stretching Surface
Attia H. A.
Mechanics and Mechanical Engineering
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2009
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Vol. 13, nr 1
79-84
EN
The heat transfer in a steady laminar stagnation point flow of an incompressible non-Newtonian micropolar fluid impinging on a permeable stretching surface with heat generation or absorption is investigated. Numerical solution for the governing nonlinear momentum and energy equations is obtained. The effect of the characteristics of the non-Newtonian fluid, the surface stretching velocity, and the heat generation/absorption coefficient on the heat transfer is presented.
6
Content available remote Effect of Porosity on Unsteady Couette Flow with Heat Transfer in the Presence of Uniform Suction and Injection
Attia H. A.
Mechanics and Mechanical Engineering
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2009
|
Vol. 13, nr 1
85-90
EN
The unsteady Couette flow through a porous medium of a viscous, incompressible fluid bounded by two parallel porous plates is studied with heat transfer. A uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to a constant pressure gradient. The two plates are kept at different but constant temperatures while the viscous dissipation is included in the energy equation. The effect of the porosity of the medium and the uniform suction and injection on both the velocity and temperature distributions is examined.
7
Content available remote Circular Pipe Flow of a Dusty Casson Fluid Considering the Hall Effect
Attia H. A.
Mechanics and Mechanical Engineering
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2009
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Vol. 13, nr 2
69-79
EN
In this paper, the transient flow of a dusty viscous incompressible electrically conducting non-Newtonian Casson fluid through a circular pipe is studied taking the Hall effect into consideration. A constant pressure gradient in the axial direction and an uniform magnetic field directed perpendicular to the flow direction are applied. The particle-phase is assumed to behave as a viscous fluid. A numerical solution is obtained for the governing nonlinear equations using finite differences.
8
Content available remote Unsteady MHD Couette Flow with Heat Transfer in the Presence of Uniform Suction and Injection
Attia H. A.
Mechanics and Mechanical Engineering
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2008
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Vol. 12, nr 2
165-170
EN
The unsteady Couette flow of an electrically conducting, viscous, incompressible fluid bounded by two parallel non-conducting porous plates is studied with heat transfer. An external uniform magnetic field and a uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to a constant pressure gradient. The two plates are kept at different but constant temperatures while the Joule and viscous dissipations are included in the energy equation. The effect of the magnetic field and the uniform suction and injection on both the velocity and temperature distributions is examined.
9
Content available remote Unsteady MHD Flow in a Circular Pipe of a Dusty Non-Newtonian Fluid
Attia H. A., Ahmed M. E. S.
Mechanics and Mechanical Engineering
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2007
|
Vol. 11, nr 1
113-127
EN
In this paper, the unsteady magnetohydrodynamic flow of a dusty viscous incompressible electrically conducting non-Newtonian Casson fluid through a circular pipe is investigated. A constant pressure gradient in the axial direction and a uniform magnetic field directed perpendicular to the flow direction are applied. The particle-phase is assumed to behave as a viscous fluid. A numerical solution is obtained for the governing nonlinear momentum equations using finite differences. The effect of the magnetic field, the non-Newtonian fluid characteristics, and the particle-phase viscosity on the transient behavior of the velocity, volumetric flow rates, and skin friction coeffcients of both fluid and particle-phases are studied. It is found that all the flow parameters for both phases decrease as the magnetic field increases or the flow index decreases. On the other hand, increasing the particle-phase viscosity increases the skin friction of the particle phase, but decreases the other flow parameters.
10
Content available remote Recursive Formulation For The Dynamic Simulation of Multibody Systems
Attia H. A.
Mechanics and Mechanical Engineering
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2007
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Vol. 11, nr 1
5-19
EN
In this paper, recursive dynamic formulation for the dynamic simulation of multibody systems are presented. The method uses the concepts of linear and angular momentums to generate the rigid body equations of motion in terms of the Cartesian coordinates of a dynamically equivalent constrained system of particles, without introducing any rotational coordinates and the corresponding rotational transformation matrix. For the open-chain system, the equations of motion are generated recursively along the serial chains. Closed-chain system is transformed to open-chain by cutting suitable kinematic joints and introducing cut-joint constraints. An example is chosen to demonstrate the generality and simplicity of the developed formulation.
11
Content available remote MHD flow and heat transfer of a Bingham fluid in an eccentric annulus with the Hall effect
Sayed-Ahmed M. E., Attia H. A.
Computer Assisted Mechanics and Engineering Sciences
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2007
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Vol. 14, No. 1
25-42
EN
The steady laminar flow and heat transfer of an incompressible, electrically conducting, non-Newtonian Bingham fluid in an eccentric annulus are studied in the presence of an external uniform magnetic field. The inner cylinder is subject to a constant heat flux while the outer cylinder is adiabatic and, the viscous and Joule dissipations are taken into consideration. The governing momentum and energy equations are solved numerically using the finite difference approximations. The velocity, the temperature, the volumetric flow rate and the average Nusselt number are computed for various values of the physical parameters.
12
Hydromagnetic flow of a dusty fluid between parallel porous plates, considering the ion slip
Attia H. A.
Journal of Technical Physics
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2006
|
Vol. 47, no 3
131-147
EN
In the present study, the transient hydromagnetic flow between parallel porous plates of a dusty viscous, incompressible, electrically conducting fluid under the influence of a constant pressure gradient is studied, considering the ion slip. The parallel plates are assumed to be porous and subjected to uniform suction from above and injection from below, while the fluid is acted upon by an external uniform magnetic field applied perpendicular to the plates. The equations of motion are solved analytically to yield the velocity distributions for both the fluid and dust particles as functions of time and space.
13
Content available remote Unsteady Couette-Poiseulle Flow with Variable Physical Properties in the Presence of a Uniform Magnetic Field
Attia H. A.
Mechanics and Mechanical Engineering
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2005
|
Vol. 9, nr 2
5--13
EN
The unsteady hydromagnetic Couette-Poiseulle flow and heat transfer of an electrically conducting fluid is studied in the presence of a transverse uniform magnetic field with variable physical properties. The viscosity and thermal conductivity of the fluid are assumed to vary with temperature. The fluid is subjected to a constant pressure gradient and an external uniform magnetic field perpendicular to the plates which are kept at different but constant temperatures. The effect of the magnetic field, the temperature dependent viscosity and thermal conductivity on both the velocity and temperature fields is reported.
14
Content available remote Equations of motion of serial chains in spatial motion using a recursive algorithm
Attia H. A.
Computer Assisted Mechanics and Engineering Sciences
|
2004
|
Vol. 11, No. 1
35-46
EN
In the present study, a recursive algorithm for generating the equations of motion of serial chains that undergo spatial motion is presented. The method is based on treating each rigid body as a collection of constrained particles. Then, the force and moment equations are used to generate the rigid body equations of motion in terms of the Cartesian coordinates of the dynamically equivalent constrained system of particles, without introducing any rotational coordinates and the corresponding rotation matrices. For the open loop case, the equations of motion are generated recursively along the serial chains. Closed loop systems are transformed to open loop systems by cutting suitable kinematic joints and introducing cut-joint constraints. The method is simple and suitable for computer implementation. An example is chosen to demonstrate the generality and simplicity of the developed formulation.
15
Content available remote A recursive method for the dynamic analysis of a system of rigid bodies in plane motion
Attia H. A.
Computer Assisted Mechanics and Engineering Sciences
|
2001
|
Vol. 8, No. 4
557-566
EN
In this study, a recursive method for generating the equations of motion of a system of rigid bodies with all common types of kinematic joints in plane motion is presented. The method rests upon the idea of replacing the rigid body by a dynamically equivalent system of particles with added geometric constraints that fix the distance between the particles. Some kinematic constraints due to common types of kinematic joints are automatically eliminated. The concepts of linear and angular momentums are used to generate the rigid body equations of motion without either introducing any rotational coordinates or distributing the external forces and moments over the particles. For the open loop case, the equations of motion are generated recursively along the open chains. For the closed loop case, the system is transformed to open loops by cutting suitable kinematic joints with the addition of cut-joints kinematic constraints. An example of a multi-branch closed-loop system is chosen to demonstrate the generality and simplicity of the proposed method.
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