scispace - formally typeset
Search or ask a question
Author

Abdullah Al-Mamun

Bio: Abdullah Al-Mamun is an academic researcher from Khulna University. The author has contributed to research in topics: Nanofluid & Streamlines, streaklines, and pathlines. The author has an hindex of 7, co-authored 11 publications receiving 180 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: Trace element contamination assessment, using different environmental contamination indices, reveals that As, Sb, Th and U are low to moderately contaminated while Cd is moderately to severely contaminated in the sediments of this area.

95 citations

Journal ArticleDOI
TL;DR: In this paper, the heat and mass transfer characteristics of naturally convective hydromagnetic flow of fourth-grade radiative fluid resulting from vertical porous plate are analyzed, where coupled fundamental equations are transformed into a dimensionless arrangement by implementing finite difference scheme explicitly.

58 citations

Journal ArticleDOI
TL;DR: In this article, a finite-difference computational approach is used to evaluate the mathematical model followed by a stability and convergence analysis, and the nanofluid blood velocity characteristics, temperature, concentration, and microorganisms are discussed following the diagrams.
Abstract: As blood flow patterns are employed in the diagnosis of circulatory disorders such as arteriosclerotic disease, bioengineers and medical scientists are interested in blood flow identification via the circulatory system. Researchers used non-Newtonian fluid models to measure blood flow cardiovascular system (e.g., hyperbolic tangent fluid, Powell Erying fluid, Casson fluid, Williamson fluid, etc.) as these fluids provide a rheological representation of blood with a more detailed thinning component. In this study, blood is taken as Williamson's fluid, and flow velocity is unsteady towards the stretching/shrinking surface in consonance with exothermic/endothermic function. The theology of gyrotactic microorganisms (GM) is addressed to nanofluid to stabilise nanoparticles due to bioconvection. A finite-difference computational approach evaluates the mathematical model followed by a stability and convergence analysis. The nanofluid blood velocity characteristics, temperature, concentration, and microorganisms are discussed following the diagrams. The skin friction, Nusselt number, Sherwood number and the microorganisms density are evaluated and clarified in detail. Besides, iso-concentrations and iso-microorganisms are configured for various factors to assess the nanofluid blood flows' boundary line thickness. The present analysis may be useful for many hyperthermia therapies, such as cancer treatment, tumour therapy and cardiac surgery, and applications in microbial fuel cells, microfluidic systems, and heat transfer contrivances.

38 citations

Journal ArticleDOI
03 Feb 2021
TL;DR: In this article, the authors have characterized a Casson type of non-Newtonian fluid flow through heat as well as mass conduction towards a stretching surface with thermophoresis and radiation absorption impacts in association with periodic hydromagnetic effect.
Abstract: The perspective of this paper is to characterize a Casson type of Non-Newtonian fluid flow through heat as well as mass conduction towards a stretching surface with thermophoresis and radiation absorption impacts in association with periodic hydromagnetic effect. Here heat absorption is also integrated with the heat absorbing parameter. A time dependent fundamental set of equations, i.e. momentum, energy and concentration have been established to discuss the fluid flow system. Explicit finite difference technique is occupied here by executing a procedure in Compaq Visual Fortran 6.6a to elucidate the mathematical model of liquid flow. The stability and convergence inspection has been accomplished. It has observed that the present work converged at, Pr ≥ 0.447 indicates the value of Prandtl number and Le ≥ 0.163 indicates the value of Lewis number. Impact of useful physical parameters has been illustrated graphically on various flow fields. It has inspected that the periodic magnetic field has helped to increase the interaction of the nanoparticles in the velocity field significantly. The field has been depicted in a vibrating form which is also done newly in this work. Subsequently, the Lorentz force has also represented a great impact in the updated visualization (streamlines and isotherms) of the flow field. The respective fields appeared with more wave for the larger values of magnetic parameter. These results help to visualize a theoretical idea of the effect of modern electromagnetic induction use in industry instead of traditional energy sources. Moreover, it has a great application in lung and prostate cancer therapy.

26 citations

Journal ArticleDOI
TL;DR: In this article, the stability and convergence analysis (SCA) have been analyzed for the Prandtl number (Pr) and Lewis number (Le) to obtain the non-similar equation, the boundary layer governing equations including continuity, momentum, energy and concentration balance were nondimensionalized by usual transformation.
Abstract: This study numerically investigates Magnetohydrodynamic (MHD) convective and chemically reactive unsteady micropolar fluid flow with nanoparticles through the vertical porous plate with mass diffusion, thermal radiation, radiation absorption and heat source. A flow model is established by employing the well-known boundary layer approximations. To obtain the non-similar equation, the boundary layer governing equations including continuity, momentum, energy and concentration balance were nondimensionalised by usual transformation. A non-similar approach is applied to the flow model. To optimize the parametric values, the stability and convergence analysis (SCA) have been analysed for the Prandtl number (Pr) and Lewis number (Le). It is observed that with initial boundary conditions, U =V =T = C= 0 and for Delta tau = 0.005, Delta X = 0.20 and Delta Y = 0.25, the system converged at Prandtl number, P-r >= 0.356 and Lewis number, L-e >= 0.16. The coupled non-linear partial differential equations are solved by explicit finite difference method (EFDM) and the numerical results have been calculated by Compaq Visual FORTRAN 6.6a. Evaluation of the thermal and momentum boundary layer thickness with isotherms and streamlines analysis of boundary layer flows have been shown for the thermal radiation parameter (R). The effects of various parameters entering the problem on velocity, angular velocity, temperature and concentration are shown graphically.

25 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this paper, a novel mathematical computing analysis for steady magnetohydrodynamic convective flows of radiative Casson fluids moving over a nonlinearly elongating elastic sheet with a nonuniform thickness is established successfully in this numerical exploration.
Abstract: A novel mathematical computing analysis for steady magnetohydrodynamic convective flows of radiative Casson fluids moving over a nonlinearly elongating elastic sheet with a nonuniform thickness is established successfully in this numerical exploration. Also, the significance of an externally applied magnetic field with space-dependent strength on the development of MHD convective flows of Casson viscoplastic fluids is evaluated thoroughly by including the momentous influence of linear thermal radiation along with the temperature-dependent viscosity and thermal conductivity effects. By combining the assumption of the low-inducing magnetic field with the boundary layer approximations, the governing partial differential equations monitoring the current flow model are transmuted accordingly into a set of nonlinear coupled ordinary differential equations by invoking appropriate similarity transformations. Moreover, these derived differential equations are resolved numerically by utilizing a new innovative GDQLLM algorithm integrating the local linearization technique with the generalized differential quadrature method. On the other hand, the behaviours of velocity and temperature fields are deliberated properly through various graphical illustrations and different sets of flow parameters. However, the accurate datasets generated for the skin friction coefficient and local Nusselt number are presented separately in tabular displays, whose physical insights are discussed comprehensively via the slope linear regression method (SLRM). As main results, it is demonstrated that the higher values of the Casson viscoplastic parameter reduce significantly the fluid velocity within the boundary layer region, while a partial reverse tendency is observed near the stretching sheet as long as the wall thickness parameter is increased. Besides the previously mentioned hydrodynamical features, it is also depicted that the thermal field throughout the medium is enhanced considerably with the elevating values of these parameters.

100 citations

Journal ArticleDOI
TL;DR: In this article, the main economic sectors and activities in and around the coastal wetlands and their catchments exert multiple pressures that affect the state of the wetlands and the delivery of valuable ecosystem services.
Abstract: :Coastal wetlands, such as saltmarshes and mangroves, that fringe transitional waters deliver important ecosystem services that support human development. Coastal wetlands are complex social-ecological systems that occur at all latitudes, from polar regions to the tropics. This overview covers wetlands in five continents. The wetlands are of varying size, catchment size, human population and human development. Economic sectors and activities in and around the coastal wetlands and their catchments exert multiple pressures that affect the state of the wetlands and the delivery of valuable ecosystem services. All the coastal wetlands were found to be affected in some ways, irrespective of the conservation status. The main economic sectors were identified as agriculture, animal rearing including aquaculture, fisheries, tourism, urbanisation, shipping, industrial development and mining. Specific human activities include land reclamation, damming, draining and water extraction, construction of ponds for aquaculture and salt extraction, construction of ports and marinas, dredging, discharge of effluents from urban and industrial areas and logging, in the case of mangroves. The main pressures were loss of wetland habitat, changes in connectivity affecting hydrology and sedimentology, as well as contamination and pollution. These pressures lead to changes in environmental state, such as erosion, subsidence and hypoxia that threaten the sustainabilty of the wetlands. There are also changes in the state of the ecology, such as loss of saltmarsh plants and seagrasses, and mangrove trees, in tropical wetlands. These changes in the structure and function of the wetland ecosystems affect the delivery of important ecosystem services that are often underestimated. The loss of ecosystem services impacts human welfare as well as the regulation of climate change by coastal wetlands. These impacts are likely to be further aggravated by climate change..

79 citations

Journal ArticleDOI
TL;DR: This study showed that effluents from both industries demonstrated high levels of TSS, TDS, EC, and heavy metals, which will be useful for identifying pollutants emanating from the two industries and will guide future industrial aquatic studies where multiple industrial runoffs are concerned.
Abstract: Industrial effluents are one of the foremost concerns relating to the anthropogenic environmental pollution. The effluents from the tanning and textile industries in Dhaka, Bangladesh, were characterized chemically and physicochemically with multivariate statistical techniques. The concentrations of heavy metals viz., Pb, Cd, Cr, Mn, Fe, Ni, Cu, and Zn were determined by atomic absorption spectrometer while concentrations of anions viz., F−, Cl−, NO2−, NO3−, and SO42− were measured by ion chromatograph. The physicochemical parameters viz., temperature, pH, electrical conductivity (EC), salinity, turbidity, dissolved oxygen (DO), and biological oxygen demand (BOD) were measured by a multiparameter meter while total suspended solids (TSS) and total dissolved solids (TDS) were measured gravimetrically. This study showed that effluents from both industries demonstrated high levels of TSS, TDS, EC, and heavy metals. Tannery effluents have lower pH and DO, and higher BOD, Cl−, SO42−, and Cr concentrations while textile dyeing effluents have higher pH, NO2−, and NO3− concentrations, compared to the standard limits promulgated by the Bangladesh government. Multivariate statistical techniques such as cluster analysis and principal component analysis along with the correlation matrices showed significant association among the measured parameters and identified pollution sources as well as effluent types in the study area which could be linked to the processes used in textile dying and tanning industries. This study will be useful for identifying pollutants emanating from the two industries and will guide future industrial aquatic studies where multiple industrial runoffs are concerned.

74 citations

Journal ArticleDOI
TL;DR: Evaluating the environmental and ecological pollution of Jazmurian playa revealed moderately to strongly pollution levels of Pb, Ni and Al, while Dy, PB, Y, Yb, Sm, Te, U, Cu, Mn, Sc represented moderate pollution.
Abstract: Jazmurian playa was an ephemeral lake with a large catchment in southeast Iran, which dried up over the last 10 years as a result of prolonged drought. As the lake was recipient of incoming industrial water with trace metals deposited to the sediment, the dust is the cause of environmental concern of the region and requires evaluation and better management. The aim of this study was to evaluate the environmental and ecological pollution of Jazmurian playa. Hence, 24 collected surface sedimentary samples were analyzed with ICP-OES. The environmental pollution indices including degree of contamination (Cd), geoaccumulation index (Igeo), enrichment factor (EF), pollution load index (PLI) and potential ecological risk (PER) were determined. The study revealed moderately to strongly pollution levels of Pb, Ni and Al, while Dy, Pb, Y, Yb, Sm, Te, U, Cu, Mn, Sc represented moderate pollution. The EF values indicated four sites were highly enriched with Dy, Pb and Ni. The PER results showed high risk for four sites and considerable risk for others. Cluster analysis illustrated interconnection between the contaminants and the sites with major pollution at six sites. Obviously, climate change has considerable complex environmental impacts through transformation of local water and sediment pollution problem.

73 citations

Journal ArticleDOI
TL;DR: In this article, the authors conducted an extensive survey to understand the current situation and propose possible remedial measures to mitigate heavy metal pollution in sediment, which is a serious concern particularly in developing nations.

67 citations