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Search Results: 1 - 10 of 4659 matches for " Md. Wahiduzzaman "
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Numerical Solution of MHD Convection and Mass Transfer Flow of Viscous Incompressible Fluid about an Inclined Plate with Hall Current and Constant Heat Flux  [PDF]
Mohammad Wahiduzzaman, Runu Biswas, Md. Eaqub Ali, Md. Shakhaoath Khan, Ifsana Karim
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.312195
Abstract: The present numerically study investigates the influence of the Hall current and constant heat flux on the Magneto hydrodynamic (MHD) natural convection boundary layer viscous incompressible fluid flow in the manifestation of transverse magnetic field near an inclined vertical permeable flat plate. It is assumed that the induced magnetic field is negligible compared with the imposed magnetic field. The governing boundary layer equations have been transferred into non-similar model by implementing similarity approaches. The physical dimensionless parameter has been set up into the model as Prandtl number, Eckert number, Magnetic parameter, Schmidt number, local Grashof number and local modified Grashof number. The numerical method of Nactsheim-Swigert shooting iteration technique together with Runge-Kutta six order iteration scheme has been used to solve the system of governing non-similar equations. The physical effects of the various parameters on dimensionless primary velocity profile, secondary velocity profile, and temperature and concentration profile are discussed graphically. Moreover, the local skin friction coefficient, the local Nusselt number and Sherwood number are shown in tabular form for various values of the parameters.
Viscous Dissipation and Radiation Effects on MHD Boundary Layer Flow of a Nanofluid Past a Rotating Stretching Sheet  [PDF]
M. Wahiduzzaman, Md. Shakhaoath Khan, P. Biswas, Ifsana Karim, M. S. Uddin
Applied Mathematics (AM) , 2015, DOI: 10.4236/am.2015.63050
Abstract: Viscous dissipation and radiative heat transfer in nanofluid with the influence of magnetic field over a rotating stretching surface has been investigated numerically. The steady laminar boundary layer flow is considered in this study. The governing boundary-layer equations are formulated and transformed into nonlinear ordinary coupled differential equations by using similarity variables. The governing equations are solved numerically using the Nactsheim-Swigert Shooting iteration technique together with the Runge-Kutta six order iteration schemes with the help of a computer programming language Compaq Visual Fortran 6.6a. The simulation results are presented graphically to illustrate influence of well-known parameters on the velocity, temperature and concentration distributions as well as skin-friction coefficient, Nusselt and Sherwood number at the sheet.
Selective Extraction of Co(II) in the Presence of Mn(II), Ni(II) and Cu(II) Using Salting-out Phase Separation Method
Ahsan Habib,Md. Wahiduzzaman,Harun-Or Rashid,Anarul Islam
Pakistan Journal of Analytical and Environmental Chemistry , 2008,
Abstract: Extraction of Co(II) in the presence of Mn(II), Ni(II) and Cu(II) has been studied using the mixture of 2-propanol with water upon the addition of CaCl2 in the concentration range of 3.0 – 5.0 mol dm-3 (M). Co(II) was extracted selectively to the extent of 80% into the 2-propanol phase at 5.0 M CaCl2. The percent of extraction of other transition metal ions, for example Mn(II), Ni(II) and Cu(II) was much lower than that of Co(II), but they were stripped in the aqueous phase upon addition of CaCl2. Therefore, selective extraction of Co(II) from these metal ions was attained by using the mixture of water and 2-propanol. Co(II) was extracted as CoCl42- from the aqueous phase into the 2-propanol phase through the formation of ion pair, Ca2+ - CoCl42-. A mechanism is proposed to explain the extraction.
Multidrug-Resistant Tuberculosis in Admitted Patients at a Tertiary Referral Hospital of Bangladesh
Sayera Banu, Asif Mujtaba Mahmud, Md. Toufiq Rahman, Arman Hossain, Mohammad Khaja Mafij Uddin, Tahmeed Ahmed, Razia Khatun, Wahiduzzaman Akhanda, Roland Brosch
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040545
Abstract: Background This study was set out to investigate the magnitude, patterns and molecular characterization of drug-resistant Mycobacterium tuberculosis strains at a tertiary referral hospital in Bangladesh. Methods Pulmonary tuberculosis (TB) patients admitted at National Institute of Diseases of the Chest and Hospital from February 2002 to September 2005 with or without previous history of TB and/or other complications were randomly interviewed. Among 265 participants enrolled, M. tuberculosis isolates from 189 patients were finally tested for susceptibility to rifampicin (RMP), isoniazid (INH), ethambutol (ETM) and streptomycin (STM). Genotyping of M. tuberculosis was done using deletion analysis and spoligotyping. Results Eighty-eight percent (n = 167) of the patients had history of previous anti-TB treatment while the remaining 12% were new TB cases. Of the 189 isolates, 9% were fully susceptible to the first line anti-TB drugs and 73.5% were multi-drug resistant TB. Other susceptibility results showed 79.4%, 77.2%, 76.7% and 78.8% resistance to INH, RMP, ETM and STM respectively. Multi-drug resistance was significantly higher among the 130 (78%) patients with previous history of anti-tuberculosis treatment (95% confidence interval, p = 0.001). Among the 189 analyzed isolates, 69% were classified as “modern” M. tuberculosis strains (i.e. TbD1- strains, lacking the M. tuberculosis-deletion region TbD1), whereas the remaining 31% were found to belong to the “ancestal” TbD1+ M. tuberculosis lineages. One hundred and five different spoligotype patterns were identified in which 16 clusters contained 100 strains and 89 strains had unique pattern. Strains with a spoligotype characteristic for the “Beijing” cluster were predominant (19%) and most of these strains (75%) were multi-drug resistant (MDR). Conclusions A high level of drug resistance observed among the re-treatment patients poses a threat of transmission of resistant strains to susceptible persons in the community. Proper counseling of patients and attention towards the completion of the anti-TB treatment is needed.
MHD Free Convection and Mass Transfer Flow from a Vertical Plate in the Presence of Hall and Ion-Slip Current
Koushik Dash,Mahmud Alam,Mohammad Wahiduzzaman
Advances in Mechanical Engineering , 2012, DOI: 10.1155/2012/851957
Abstract: MHD free convection and mass transfer flow over a continuously moving vertical porous plate under the action of strong magnetic field is investigated. In this analysis the hall and ion-slip current in the momentum equation are considered for high speed fluid flows and the level of concentration of foreign mass have been taken very high. The governing equations of the problem contain a system of partial differential equations. The coupled partial differential equations are solved numerically by explicit finite difference method. The results of this investigation are discussed for the different values of the well-known parameters with different time steps. Finally, the obtained finite difference solutions are compared with analytical solution by the graphical representation.
Hydrogen adsorption in metal-organic frameworks: the role of nuclear quantum effects
Mohammad Wahiduzzaman,Christian F. J. Walther,Thomas Heine
Physics , 2014, DOI: 10.1063/1.4892670
Abstract: The role of nuclear quantum effects on the adsorption of molecular hydrogen in metal-organic frameworks (MOFs) has been investigated on grounds of Grand-Canonical Quantized Liquid Density-Functional Theory (GC-QLDFT) calculations. For this purpose, we have carefully validated classical H2 -host interaction potentials that are obtained by fitting Born-Oppenheimer ab initio reference data. The hydrogen adsorption has first been assessed classically using Liquid Density-Functional Theory (LDFT) and the Grand-Canonical Monte Carlo (GCMC) methods. The results have been compared against the semi-classical treatment of quantum effects by applying the Feynman-Hibbs correction to the Born-Oppenheimer-derived potentials, and by explicit treatment within the Grand-Canonical Quantized Liquid Density-Functional Theory (GC-QLDFT). The results are compared with experimental data and indicate pronounced quantum and possibly many-particle effects. After validation calculations have been carried out for IRMOF-1 (MOF-5), GC-QLDFT is applied to study the adsorption of H2 in a series of MOFs, including IRMOF-4, -6, -8, -9, -10, -12, -14, -16, -18 and MOF-177. Finally, we discuss the evolution of the H2 quantum fluid with increasing pressure and lowering temperature.
Innovation and Validation of Neuropsychopharmacological Testing Methods for the Assessment of Memory, Attention and Cognition in Human Participants  [PDF]
Md. Sahab Uddin, Md. Asaduzzaman
Neuroscience & Medicine (NM) , 2016, DOI: 10.4236/nm.2016.73010
Abstract: To meet the challenges of time searching for the new method for neuropsychopharmacology is still an ongoing process. In this experiment, we proposed and validated three neuropsychopharmacological testing methods, which are Matching Capacity (MC), Dissimilarity Identification (DI) and Sense Making (SM) tests for the estimation of memory, attention and cognition respectively in healthy aged human participants. The purpose of this experiment was to generate more effective testing methods for the determination of memory, attention and cognition in human. To endorse proposed methods a randomized double blind placebo controlled clinical trial was conducted among healthy aged human participants between the period of December 2015 and February 2016. The experiment was conducted at Gazipur Sadar, Gazipur-1703, Dhaka, Bangladesh and the experiment center was the Department of Pharmacy, Southeast University, Dhaka-1213, Bangladesh. In this experiment, 60 healthy male participants between the age of 42 to 50 years were selected and divided into 4 groups with 15 participants in each by simple randomization process. Ginkgo biloba standardized extract’s capsule (Giloba?) and Bacopa monnieri standardized extract’s syrup (Monera?) were used as standard. Psyllium seed husk (i.e., seed of the Plantago ovata) was incorporated in the hard gelatin capsule shell (size 0) to prepare capsule and used as a placebo control of the capsule (PCC). Excipients of oral liquid preparation of vitamin were used to prepare syrup and used as a placebo control of the syrup (PCS). The treatment procedure for group 1 was Ginkgo biloba standardized extract’s capsule (120 mg/capsule), 3 times daily for 21 days; group 2 was treated with Bacopa monnieri standardized extract’s syrup (1.21 g/5 ml), 2 teaspoonfuls, 3 times daily for 21 days. Psyllium seed husk’s capsule and excipients of oral liquid vitamin’s syrup were used as placebo control (PC) for group 3 and group 4 and administered in the similar manner of group 1 and group 2, respectively. Administration of Ginkgo biloba (GB) and Bacopa monnieri (BM) standardized extracts for successive days significantly increased the memory, attention and cognition of the participants with respect to PC groups. In the MC test, treatment with GB extract markedly (P < 0.05) increased the memory of the participants on 21st day with respect to PCC group. On the other hand administration of BM extract remarkably (P < 0.01)
A Comparative Study between Arbitration and Judicial Settlement as Means of Maritime Boundary Dispute Settlement  [PDF]
Md. Monjur Hasan, Md. Arifuzzaman
Beijing Law Review (BLR) , 2018, DOI: 10.4236/blr.2018.91006
Abstract: This paper makes an effort to draw a comparative study between judicial process and arbitration as the method of maritime boundary dispute settlement. Currently, maritime boundary dispute between states is a much talked issue all over the World. The United Nations Convention on the Law of the Sea refers four means of maritime dispute settlement. Arbitration and Judicial processes are mainly two of them. According to the Convention every state has the right to choose one of the four means to settle their dispute. Practices show that Arbitration and Judicial settlement are more popular than any other methods of maritime boundary dispute settlement. Most of the previous maritime boundary disputes have been settled either by judicial process or by Arbitration. The present paper attempts to compare between arbitration and Judicial process as the means of maritime boundary dispute. In addition, many of the concepts mentioned in this paper may use to understand about the peaceful settlement of maritime boundary dispute.
Heat Generation Effects on MHD Natural Convection Flow along a Vertical Wavy Surface with Variable Thermal Conductivity  [PDF]
Md Abdul Alim, Md Rezaul Karim, Md Miraj Akand
American Journal of Computational Mathematics (AJCM) , 2012, DOI: 10.4236/ajcm.2012.21005
Abstract: The heat generation effects on magnetohydrodynamic(MHD) natural convection flow along a vertical wavy surface with variable thermal conductivity have been investigated. The governing boundary layer equations are first transformed into a non-dimensional form using suitable set of dimensionless variables. The resulting nonlinear system of partial differential equations are mapped into the domain of a vertical flat plate and then solved numerically employing the implicit finite difference method, known as Keller-box scheme. The numerical results of the surface shear stress in terms of skin friction coefficient and the rate of heat transfer in terms of local Nusselt number, the stream lines as well as the isotherms are shown graphically for a selection of parameters set consisting of thermal conductivity variation parameter, heat generation parameter Q, magnetic parameter M and Prandtl number Pr. Comparison of numerical results of present work with other published data has been shown in table.
Quality Study of Rice Husk Ash (RHA) Brick Using Neutron Radiography Technique  [PDF]
Md. Khurshed Alam, Md. Moniruz Zaman, Md. Al Amin
Journal of Building Construction and Planning Research (JBCPR) , 2015, DOI: 10.4236/jbcpr.2015.33013
Abstract: A powerful non-destructive testing (NDT) technique is adopted to study the quality of RHA brick-1 and RHA brick-2. In that case, rice husk ash has been utilized for the preparation of bricks in full replacement of clay. In these studies, homogeneity of elemental distribution, water absorption and size and shape of the pores have been observed. From the studies, it was observed that elemental distribution is very good at various level, large number of porosity is presented with little bit size, initial rate of absorption (IRA) due to first five minutes immersion of water is higher compared to other immersion time (>5 minute), incremental water intrusion area increases very slowly with the increasing immersion time and the water absorption for RHA brick-2 becomes saturated very early than that of the RHA brick-1.
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