Kennedy Wahome Muthee, Cheikh Mbow, Geoffrey Mugo Macharia and Walter Leal-Filho
The purpose of this paper is to assess the extent to which adaptation projects have incorporated ecosystem services, as well as their redesigning options. The projects selected…
Abstract
Purpose
The purpose of this paper is to assess the extent to which adaptation projects have incorporated ecosystem services, as well as their redesigning options. The projects selected are listed under National Adaptation Programme of Action in West African region.
Design/methodology/approach
A desktop survey approach was used to review 168 projects from 13 countries across West Africa. The projects were categorized and analyzed according to their adaptation goal, thematic focus, their implementation duration and level of investment.
Findings
The adaptation initiatives are dominated by actions in the agricultural sector accounting for 32 per cent of the total. Further, they were characterized by small grants consideration with 63 per cent falling under US$1m budget, short-term implementation duration with 46 per cent having three years’ execution period. A large portion of projects (55 per cent) mentioned directly one or more ecosystem services, with provisioning services being referred to in 50 per cent of the cases.
Originality/value
Adaptation projects with ecosystem services components are more sustainable and beneficial to the community. Hence, more consideration of nature benefits during project design, more financial consideration and localizing of the projects to realize the global adaptation goal should be considered.
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Mamadou Lamine Sow, Joseph Sarr, Cheikh Mbow, Babacar Mbow, Bernard Claudet and Mamadou Mansour Kane
The purpose of this paper is to study the transient natural convection of a Newtonian fluid which develops in a closed spherical annulus delimited by two vertically eccentric…
Abstract
Purpose
The purpose of this paper is to study the transient natural convection of a Newtonian fluid which develops in a closed spherical annulus delimited by two vertically eccentric spheres by using a bispherical coordinates system. The inner sphere is heated by a heat flux of constant density and the outer one is maintained isothermal.
Design/methodology/approach
The transfer equations are written by using a bispherical coordinates system. The Navier‐Stokes equations are solved and coupled with the energy equation by using the alternating direction implicit (ADI) and the successive over relaxation (SOR) methods.
Findings
The study of the stream function and the Nusselt number shows that the convection motion is reinforced for the geometries characterized by positive values of the eccentricity with heat exchange increasing. The Nusselt number increases with the modified Rayleigh number. The heat exchange increases with the radius ratio. The results show that the steady state is reached faster when the modified Rayleigh number increases and the influence of the eccentricity is very low on the establishment of the steady state. The fluids flow depends strongly on the eccentricity and the modified Rayleigh number.
Research limitations/implications
Simulations are performed for modified Rayleigh numbers ranging from 103 to 106, for eccentricities varying between –0.6 and +0.6 and for radius ratio between 1.5 and 2.
Originality/value
The results of eccentricity and modified Rayleigh number effects in transient natural convection between vertically eccentric spheres have been displayed.
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Mohamed Naceur Borjini, Cheikh Mbow and Michel Daguenet
The effect of radiation on unsteady natural convection in a two‐dimensional participating medium between two horizontal concentric and vertically eccentric cylinders is…
Abstract
The effect of radiation on unsteady natural convection in a two‐dimensional participating medium between two horizontal concentric and vertically eccentric cylinders is investigated numerically. The equations of transfer are written by using a bicylindrical coordinates system, the stream function, and the vorticity. The finite volume radiation solution method and the control volume approach are used to discretize the coupled equations of radiative transfer, momentum, and energy. Original results are obtained for three eccentricities, Rayleigh number equal to 104, 105, and a wide range of radiation‐conduction parameter. The effects of optical thickness, wall emissivity, and scattering on flow intensity and heat transfer are discussed.
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Joseph Sarr, Mactar Sall, Mamadou Mansour Kane, Bassirou Ba and Michel Daguenet
The purpose of this paper is to compare the numerical laminar two‐dimensional unsteady natural convection in a partial sector‐shaped enclosure submitted respectively to a constant…
Abstract
The purpose of this paper is to compare the numerical laminar two‐dimensional unsteady natural convection in a partial sector‐shaped enclosure submitted respectively to a constant heat flux density q1 and a uniform temperature T1 on the inner cylindrical wall. The numerical model performed in this paper is applied more particularly for high Grashof numbers, in order to point out the advent and the development of pre‐turbulent flows. Results of numerical runs are presented. The mean Nusselt number on active walls is represented as a function of the Grashof number Gr and the aspect ratio Fr. The results may be correlated very well with an expression of the form \overlineNu = k1 Gr1k2, for technical calculations.
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The paper aims to compare the return on Mudhārabah deposits (ROMD) to the return on equity (ROE) in Islamic banks.
Abstract
Purpose
The paper aims to compare the return on Mudhārabah deposits (ROMD) to the return on equity (ROE) in Islamic banks.
Design/methodology/approach
The summary statistics of the ROMD and the ROE is used to make a comparison between them with a sample of nine Islamic banks, from seven countries, over the last five years. Regression analysis is also undertaken to unveil the variables affecting the behaviour of ROMD and ROE at Kuwait Finance House.
Findings
The results show that the ROE tend to be at least two times higher than the ROMD. In most of the investigated cases the ROMD are more correlated to the corresponding conventional interest rate than to ROE. The regression analysis suggests that the return on assets affects more significantly the ROE than the ROMD.
Originality/value
The originality of the paper resides in the size of the sample and in the design and the findings.