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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.
Effects of Thermophoresis on Unsteady MHD Free Convective Heat and Mass Transfer along an Inclined Porous Plate with Heat Generation in Presence of Magnetic Field  [PDF]
Md Alamgir Kabir, Md Abdullah Al Mahbub
Open Journal of Fluid Dynamics (OJFD) , 2012, DOI: 10.4236/ojfd.2012.24012
Abstract: An analysis of Thermophoresis effect on unsteady magneto-hydrodynamic free convection flow over an inclined porous plate with time dependent suction in presence of magnetic field with heat generation has been considered by employing Nachtsheim-Swigert shooting iteration technique along with sixth order Runge-Kutta integration scheme. Resulting non-dimensional velocity, temperature and concentration profiles are then presented graphically for different values of the parameters entering into the problem. Finally, the effects of the pertinent parameters on the skin-friction coefficient, the rate of heat transfer (Nusselt number) and wall deposition flux (Stanton number), which are of physical interest, are exhibited in tabular form.
Adverse Effects of Allelopathy from Legume Crops and Its Possible Avoidance  [PDF]
Md. Fuad Mondal, Md. Asaduzzaman, Toshiki Asao
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.66086
Abstract: Plant releases many bioactive chemicals from its various parts such as leaves, stem, root and sometimes decomposed body through different mechanism into its surrounding environment. These bioactive chemicals are often termed as allelochemicals because they interact with the surrounding environment. This interaction is either positive or negative. Effects of allelochemicals to the agricultural and biological ecosystem are well documented. In leguminosae family many species are involved in releasing of allelochemicals. Many researchers found that this allelochemicals have both positive and detrimental effects on the successive legume crops. Legume monoculture is common in many parts of the world where they cause a numbers of ecological and economic problems such as decline in crop yield due to soil sickness, regeneration failure and replant problem. These negative effects of allelochemicals open a great concern on allelopathy research. This article reviews the adverse effects of allelochemicals, their extraction and isolation, mechanism inside the plant body. These all are done to find out the possible selection methods of succeeding crops to avoid the allelopathic effects in the next crop of a monoculture farm field. The main purpose of this article is to highlight the adverse allelopathic effects of legume crops to provide ways for sustainable development in agro-ecosystem.
A Numerical Study of MHD Laminar Flow in a Rotating Curved Pipe with Circular Cross Section  [PDF]
Md. Mainul Hoque, Md. Mahmud Alam
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.52014
Abstract: The incompressible viscous steady flow through a rotating curved pipe of circular cross-section with magnetic field is investigated numerically to examine the combined effects of rotation (Coriolis force), magnetic field and curvature (centrifugal force) on the flow. The curvature of the pipe has been assumed to be small, that is, the radius of the circle in which the central line of the pipe is coiled is large in comparison with the radius of the cross section. Spectral method is applied as a main tool for the numerical technique, where Fourier series, Chebyshev polynomials, Collocation methods, and Iteration method are used as secondary tools. The flow depends on the Taylor number (Tr), Dean Number (Dn), Magnetic Parameter (M) and the dimensionless curvature of the pipe δ. When Tr > 0, the rotation is in the direction so that the Coriolis force enforces the curvature effect. When Tr < 0, the rotation is in the direction so that the Coriolis force exhibits an opposite effect to that of the curvature. The calculations are carried out for 1500 ≤ Tr ≤ 1500, Dn ≥ 1000 (large Dean number), M ≥ 0 and δ = 0.01. Due to high magnetic field four-vortex solution is observed in a rotating curved pipe system. Visualization is attained with MAPLE software.
Road Traffic Accident Scenario, Pattern and Forecasting in Bangladesh  [PDF]
Md Shakhawat Hossain, Md Omor Faruque
Journal of Data Analysis and Information Processing (JDAIP) , 2019, DOI: 10.4236/jdaip.2019.72003
Abstract: The main aim of this research work is to be aware of the road traffic accident scenario, injurious effects and pattern in Bangladesh. Moreover we are interested to forecast the magnitude of road traffic accidents for the future so that decision makers can make appropriate decision for precaution. This study also provides an assessment of road traffic accidents in Bangladesh and its impact based on data collected for the period of 1971 to 2017. In this study we have tried to pick up the main reasons of road accidents and to observe the tremendous situation. The study observed that the general trends of road traffic accident (RTA), deaths and injuries reveal that the number of RTA, deaths and injuries increased gradually with little fluctuations form 1971 to 2007 and after 2007 there is a slow decreasing trend. Although the number of RTA and deaths observed decreasing trend in recent years, the ratio of number of deaths to number of accident increased significantly. The rate of register vehicles per 10,000 people increased moderately throughout the period but a sharp increment is exhibited from 2009. Highest percentage of RTA (34%) and deaths is due to RTA (32%) in Dhaka division while the lowest percentage of RTA (4%) in Barisal and Sylhet divisions and deaths is due to RTA (3%) in Barisal division. It is noticed that the maximum number of injuries occurred between ages 21 and 30 while the maximum number of deaths occurred between ages 11 and 30. Most of the RTA and deaths due to RTA are caused by run over by vehicles and head to head collision. The severity of occurring road accident and number of deaths are higher during the festive periods because of involving higher frequency of traveling than usual. The time plot shows that the graph maintains a decreasing movement from 2012 to 2015 but increases from 2015 to 2017. In the research an additive time series model approach is applied. It included the estimation of trend, seasonal variation and random variation using triple exponential smoothing method. We performed forecasting of RTA eliminating seasonal impact for the next three consecutive years (2018-2020) with 95% confidence interval using Holt-Winters exponential technique.
Urban Green Spaces and an Integrative Approach to Sustainable Environment  [PDF]
Shah Md. Atiqul Haq
Journal of Environmental Protection (JEP) , 2011, DOI: 10.4236/jep.2011.25069
Abstract: This paper explains the benefits and challenges of urban green spaces based on the critical discussion of study results from different studies in different cities. The important roles played by green spaces are social, economic, cultural and environmental aspects of sustainable development. Urban green spaces can be a comprehensive tool for long term protection of environmental sustainability through improving the quality of life and air quality, increasing property value due to their amenity and aesthetic characteristics, and reducing the energy costs of cooling buildings. Urban green spaces also can provide ecosystem services in which the recreation and relaxation facilities are especially available to urban dwellers and tourists too. To confirm the multiple roles played by green spaces, certain level of qualitative improvements and distribution of green spaces within the urban area should be considered and incorporated effectively into the environmental sustainability agenda. To do this, an integrated approach regarding the planning, monitoring, designing and maintaining of urban green spaces is required for improving the environmental sustainability in cities in different countries.
In Vitro Organogenesis of Colocasia esculenta cv. Antiquorum L.  [PDF]
Md. Jahangir Hossain
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.36085
Abstract: In vitro organogenesis of an upland species of Colocasia esculenta cv. antiquorum L. was examined in relation to different explants like meristem and parenchymatous storage tissues with or without anthocyanin layer, four levels of each of Kn, 2,4-D, NAA and BAP and four incubation environments such as: 1) 16 h 3 Kl light intensity + 24°C ± 2°C; 2) 24 h dark + 24°C ± 2°C; 3) 24 h dark + 30°C ± 3°C and 4) 12 h diffuse light + 30°C ± 3°C. Only meristems showed proliferation with various degree of intensity both at 16 h 3 Kl light + 24°C ± 2°C and 24 h dark + 24°C ± 2°C conditions and poor response with different levels of Kn + NAA either in light or in the dark. Cultures with NAA + BAP were proliferated very quickly with very high degree of intensity. The cultures under dark did not proliferate for 20 days which upon transfer to light showed high degree of proliferation. Cultures with NAA + BAP formed calluses more pronouncedly at dark than that occurred in the light. Parenchymatous tissues with or without anthocyanin did not proliferate but the tissues with anthocyanin lost pigmentation after 25 - 30 days and turned to grey colour after 50 days while tissues without anthocyanin turned to green colour with shinny pimples indicating that protocorm may be developed. No culture under high temperature environment (30°C ± 3°C) neither survived nor proliferated. The meristems in culture were died within 15 - 20 days while others within 25-30 days. In conclusion, a combination of NAA (0.5 - 3.0 mg/l) and BAP (0.5 - 2.0 mg/l) and an incubation photoperiod of 16 h coupled with temperature of 24°C ± 2°C were found most suitable for in vitro culture of Colocasia esculenta cv. antiquorum L.
Some Classes of Operators Related to p-Hyponormal Operator  [PDF]
Md. Ilyas, Reyaz Ahmad
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.26063
Abstract: We introduce a new family of classes of operators termed as *p-paranormal operator, classes *A(p,p); p > 0 and *A(p,q); p, q > 0, parallel to p-paranormal operator and classes A(p,p); p> 0 and A(p,q); p, q > 0 introduced by M. Fujii, D. Jung, S. H. Lee, M. Y. Lee and R. Nakamoto [1]. We present a necessary and sufficient condition for p-hyponormal operator T∈B(H)to be *p-paranormal and the monotonicity of *A(p,q). We also present an alternative proof of a result of M. Fujii, et al. [1, Theorem 3.4].
Living with Stigma and Managing Sexual Identity: A Case Study on the Kotis in Dhaka  [PDF]
Md. Azmeary Ferdoush
Sociology Mind (SM) , 2013, DOI: 10.4236/sm.2013.34034
Abstract:

Identity as a koti in Dhaka as well as in Bangladesh has always been a stigmatized one. The study aims to explore how the kotis in Dhaka manage their sexual identity and stigma attached with it. To do so eighteen kotis were selected from two areas of Dhaka and unstructured face to face in-depth interviews were conducted. The results show that the kotis in Dhaka have to face numbers of difficulties if their sexual identity is disclosed and knowing or unknowingly they have adopted the stigma management strategies identified by Goffman.

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