Browsing by Author "Kabir, Md. Humaun"

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Analysis of magnetohydrodynamic mixed convection nanofluid flow in a lid-driven porous rectangular cavity with three square heating blocks
(Department of Mathematics, 2019-09-28) Kabir, Md. Humaun; Parveen, Dr. Nazma
Analyses of magnetohydrodynamic mixed convection nanofluid flow in a lid-driven porous rectangular cavity with three square heating blocks are carried out. The current geometry are analyzed numerically by finite element method using Galerkins weighted residual approach. The physical problem is represented mathematically by the governing equation along with the corresponding boundary conditions. Two-dimensional steady state Navier-Stokes equations, energy equation and continuity equation are modified to account for the presence of thermal buoyancy and heat generation effects. With proper choice of the dimensionless variables, the equations are transformed to non-dimensional form. Comparisons with previously published works are performed and the results are found to be an excellent agreement. The left and right walls are cold upward and downward lid-directions respectively. Three different cases have been studied based on the location of the square blocks. A set of graphical result is presented in terms of streamlines, isotherms, velocity profiles and the variation of the average Nusselt number and average fluid temperature. It is observed that Darcy number is a good control parameter for heat transfer in fluid flow through porous medium in enclosure. The simulation results indicate that there is an optimal volume fraction of the nanoparticles for each Rayleigh number and Darcy number at which the maximum heat transfer rate occurs. Numerical calculation is carried out for different parameters namely, Darcy Number (1e^(-5)≤Da≤1e^(-2)), Hartmann Number (0≤Ha≤150), Solid volume fraction (0≤φ≤0.1), Richardson Number (0.1≤Ri≤10). Various characteristics such as streamlines, isotherms and heat transfer rate in terms of the average Nusselt Number and average fluid temperature are presented for the aforesaid parameters.
Congestion Avoidance and Synchronized Rate Control in Data Center Network
(Department of Computer Science and Engineering (CSE), Islamic University of Technology (IUT), Board Bazar, Gazipur-1704, Bangladesh, 2013-11-15) Billah, Mustakim; Kabir, Md. Humaun
TCP Incast, also known as TCP throughput collapse, is a term used to de- scribe a link capacity under-utilization phenomenon in certain many-to-one communication patterns, typically in many datacenter applications. The main root cause of TCP Incast analyzed by prior works is attributed to packet drops at the congestion switch that result in TCP timeout. Conges- tion control algorithms have been developed to reduce or eliminate packet drops at the congestion switch. In this paper, the performance of Quantized Congestion Noti?cation (QCN) with respect to the TCP incast problem dur- ing data access from clustered servers in datacenters are investigated. QCN can e ectively control link rates very rapidly in a datacenter environment. However, it performs poorly when TCP Incast is observed. To explain this low link utilization, we examine the rate ?uctuation of di erent ?ows within one synchronous reading request, and ?nd that the poor performance of TCP throughput with QCN is due to the rate unfairness of di erent ?ows. There- fore, an enhanced QCN congestion control algorithm, called fair Quantized Congestion Noti?cation (FQCN), is proposed to improve fairness of multiple ?ows sharing one bottleneck link. We evaluate the performance of FQCN as compared to that of QCN in terms of fairness and convergence with four simultaneous and eight staggered source ?ows. As compared to QCN, fair- ness is improved greatly and the queue length at the bottleneck link con- verges to the equilibrium queue length very fast. The e ects of FQCN to TCP throughput collapse are also investigated. Simulation results show that FQCN signi?cantly enhances TCP throughput performance in a TCP Incast setup
DISSEMINATING THE BIOMEDICAL WASTE GENERATION SCENARIO DURING COVID-19
(AMERICAN INTERNATIONAL JOURNAL OF NURSING EDUCATION AND PRACTICE, 2021) Muhib, Md. Iftakharul; Akter, Rifat; Kabir, Md. Humaun; Rayhan, Md. Shamim; Khan, Md. Shawkut Ali
This study investigates the present COVID-19-related medical waste generation scenario and suggests a way forward from the perspective of lower-middle-income countries like Bangladesh. Bangladesh is a densely populated vulnerable country in the perspective of the COVID-19 induced biomedical waste management field. The pandemic COVID-19 has already created enormous instability in healthcare waste handling and subsequent recycling around the world. The medical waste management sector in Bangladesh is struggling and COVID-19 makes the situation even more complicated. A rigorous timeseries calculation was done to determine the facemask and medical waste load during COVID-19 in Bangladesh from March 8, 2020, to September 13, 2021 period. Results showed that about 1,58,10,400 pieces of facemask are disposed of alone in different urban areas which is equivalent to 517 tons of solid waste while extra 5,203 tons of biomedical waste is added every day to regular waste streams during this pandemic. The findings of this study suggest that these extra tons of hazardous waste threaten the aquaculture of the country and promote the risk of contagious diseases to the waste workers especially women and as well as at the community level. The findings also reveal that this pandemic has already created a hindrance to achieving the country’s SDGs by 2020.