Daffodil International University

www.daffodilvarsity.edu.bd
Dhaka, Bangladesh

Daffodil International University , is a co-educational private university located in Dhanmondi, Dhaka, Bangladesh, was established on 24 January 2002 under the Private University Act, 1992.DIU is the first university in Bangladesh to have signed the UN's Commitment to Sustainable Practices of Higher Education Institutions. Wikipedia.

SEARCH FILTERS
Time filter
Source Type

Shahjahan M.,Daffodil International University
Proceedings of the International Conference on Industrial Engineering and Operations Management | Year: 2016

There is a strong association of smokeless tobacco consumption with occurrence of adverse cardiovascular disease, particularly in the low socio-economic populations. A cross-sectional study conducted among 459 representative respondents including four focus group discussions (FGDs). Descriptive and inferential analyses including binary logistic regression have done to find out the factors influencing smokeless tobacco use. Almost half of the respondents initiated SLT usage at a very young age (15-24 years), and another 22 percent respondents were smoking and using SLT concurrently. Significant association was found by gender (p<0.01), sufferings from SLT related disease (p<0.05). Males were 2.7 times more knowledgeable than females (p<0.01) about the adverse health effects of SLT usage. The respondents suffering from SLT related diseases were 3.7 times more knowledgeable than without diseases (p<0.01). On health effects of SLT use, one participant commented that "although mouth is the gateway to health, we infected our mouth by using Zarda and Gul". Again, informants opined that peer, family, curiosity and hospitality culture are influencing factors for SLT initiation. Counseling on tobacco, including SLT, health hazards have to be emphasized through mass media and there is a need for development of relevant policies and communication messages to make people aware. © IEOM Society International. © IEOM Society International.


Murad M.H.,Daffodil International University | Pant N.,Department of National Defence
Astrophysics and Space Science | Year: 2014

In this paper we have studied a particular class of exact solutions of Einstein's gravitational field equations for spherically symmetric and static perfect fluid distribution in isotropic coordinates. The Schwarzschild compactness parameter, GM/c 2 R, can attain the maximum value 0.1956 up to which the solution satisfies the elementary tests of physical relevance. The solution also found to have monotonic decreasing adiabatic sound speed from the centre to the boundary of the fluid sphere. A wide range of fluid spheres of different mass and radius for a given compactness is possible. The maximum mass of the fluid distribution is calculated by using stellar surface density as parameter. The values of different physical variables obtained for some potential strange star candidates like Her X-1, 4U 1538-52, LMC X-4, SAX J1808.4-3658 given by our analytical model demonstrate the astrophysical significance of our class of relativistic stellar models in the study of internal structure of compact star such as self-bound strange quark star. © 2013 Springer Science+Business Media Dordrecht.


Hossen M.R.,Daffodil International University | Ema S.A.,Jahangirnagar University | Mamun A.A.,Jahangirnagar University
Communications in Theoretical Physics | Year: 2014

A nonlinear propagation of cylindrical and spherical modified ion-acoustic (mIA) waves in an unmagnetized, collisionless, relativistic, degenerate multi-species plasma has been investigated theoretically. This plasma system is assumed to contain non-relativistic degenerate light ions, both non-relativistic and ultra-relativistic degenerate electron and positron fluids, and arbitrarily charged static heavy ions. The restoring force is provided by the degenerate pressures of the electrons and positrons, whereas the inertia is provided by the mass of ions. The arbitrarily charged static heavy ions participate only in maintaining the quasi-neutrality condition at equilibrium. The modified Burgers (mB) equation is derived by using reductive perturbation technique and numerically analyzed to identify the basic features of mIA shock structures. The basic characteristics of mIA shock waves are found to be significantly modified by the effects of degenerate pressures of electron, positron, and ion fluids, their number densities, and various charge state of heavy ions. The implications of our results to dense plasmas in astrophysical compact objects (e.g., non-rotating white dwarfs, neutron stars, etc.) are brieflyy discussed. © 2014 Chinese Physical Society and IOP Publishing Ltd.


Gronlund A.,Örebro University | Islam Y.M.,Daffodil International University
Information Technology for Development | Year: 2010

This paper reports a project working to improve distance education in Bangladesh by means of a low-cost, large-scale interactive learning environment using video, mobile phones, SMS- based tools administered in a learning management system, and innovative pedagogy based on the student-centered learning model. The paper addresses the question of how to use existing mobile telephony technical infrastructure to create interactive learning environments which can reach a majority of the population, be able to include thousands of students, and be sustainable from a resource perspective. This question includes challenges relating to pedagogy and teaching methods, technical tools for learning and communication, and institutional arrangements. The paper addresses these challenges by the illustrative case of the Bangladesh Virtual Interactive Classroom testing the tools and ideas in course at Bangladesh Open University. We find that our tools are feasible and usable but also that sustainability requires meeting organizational and social challenges. © 2010 Commonwealth Secretariat.


Ema S.A.,Jahangirnagar University | Hossen M.R.,Daffodil International University | Mamun A.A.,Jahangirnagar University
Contributions to Plasma Physics | Year: 2015

The nonlinear propagation of modified electron-acoustic (mEA) shock waves in an unmagnetized, collisionless, relativistic, degenerate quantum plasma (containing non-relativistic degenerate inertial cold electrons, both nonrelativistic and ultra-relativistic degenerate hot electron and inertial positron fluids, and positively charged static ions) has been investigated theoretically. The well-known Burgers type equation has been derived for both planar and nonplanar geometry by employing the reductive perturbation method. The shock wave solution has also been obtained and numerically analyzed. It has been observed that the mEA shock waves are significantly modified due to the effects of degenerate pressure and other plasma parameters arised in this investigation. The properties of planar Burgers shocks are quite different from those of nonplanar Burgers shocks. The basic features and the underlying physics of shock waves, which are relevant to some astrophysical compact objects (viz. non-rotating white dwarfs, neutron stars, etc.), are briefly discussed. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Hossen M.R.,Daffodil International University | Mamun A.A.,Jahangirnagar University
Plasma Science and Technology | Year: 2015

A theoretical study on the nonlinear propagation of nonplanar (cylindrical and spherical) electrostatic modified ion-acoustic (mIA) shock structures has been carried out in an unmagnetized, collisionless four component degenerate plasma system (containing degenerate electron fluids, inertial positively as well as negatively charged light ions, and positively charged static heavy ions). This investigation is valid for both non-relativistic and ultra-relativistic limits. The modified Burgers (mB) equation has been derived by employing the reductive perturbation method, and used to numerically analyze the basic features of shock structures. It has been found that the effects of degenerate pressure and number density of electron and inertial positively as well as negatively charged light ion fluids, and various charging state of positively charged static heavy ions significantly modify the basic features of mIA shock structures. The implications of our results to dense plasmas in astrophysical compact objects (e.g., non-rotating white dwarfs, neutron stars, etc.) are briefly discussed. © 2015, IOP. All rights reserved.


Fatema S.,Daffodil International University | Murad M.H.,Daffodil International University
International Journal of Theoretical Physics | Year: 2013

This paper presents a family of two-parametric interior solutions of Einstein-Maxwell field equations in general relativity for a static spherically symmetric distribution of a charged perfect fluid with particular choice of charge distribution and the metric component g 00. This family gives us wide range of parameters, n and K, for which the solutions are regular and acceptable on physical grounds and hence suitable for modeling of charged compact star. The maximum allowable mass and corresponding radius, for this family of solutions with the particular form of charge distribution, is determined to be 2.48M ⊙ and 10.56 km respectively by assuming the stellar "surface" density equal to strange (quark) matter density at zero pressure. It is hoped that our investigation may be of some importance in connection with the study of internal structure of electrically charged strange (quark) star. © 2013 Springer Science+Business Media New York.


Murad M.H.,Daffodil International University | Fatema S.,Daffodil International University
International Journal of Theoretical Physics | Year: 2013

In continuation of recent work done by the present authors (Int. J. Theor. Phys. 2013, doi:10.1007/s10773-013-1538-y, hereafter paper I) some new exact families of static spherically symmetric perfect fluid solution of Einstein-Maxwell gravitational field equations are presented. These solutions and the corresponding equations of state, presented in parametric form, may be astrophysically significant in constructing relativistic stellar models of electrically charged self-bound stars. © 2013 Springer Science+Business Media New York.


Murad M.H.,Daffodil International University
Astrophysics and Space Science | Year: 2013

The paper presents a new class of parametric interior solutions of Einstein-Maxwell field equations in general relativity for a static spherically symmetric distribution of a charged perfect fluid with a particular form of electric field intensity. This solution gives us wide range of parameter, K (0. 69≤K≤7. 1), for which the solution is well behaved hence, suitable for modeling of superdense star. For this solution the gravitational mass of a superdense object is maximized with all degree of suitability by assuming the surface density of the star equal to the normal nuclear density ρnm=2. 5×1017kg m-3. By this model we obtain the mass of the Crab pulsar MCrab=1. 401M⊙ and the radius, RCrab=12. 98 km constraining the moment of inertia INS,38>1. 61 for the conservative estimate of Crab nebula mass 2M⊙ and MCrab=2. 0156M⊙ with radius, RCrab=14. 07 km constraining the moment of inertia INS,38>3. 04 for the newest estimate of Crab nebula mass 4. 6M⊙ which are quite well in agreement with the possible values of mass and radius of Crab pulsar. Besides this, our model yields the moments of inertia for PSR J0737-3039A and PSR J0737-3039B are IA,38=1. 4624 and IB,38=1. 2689 respectively. It has been observed that under well behaved conditions this class of parametric solution gives us the maximum gravitational mass of causal superdense object 2. 8020M⊙ with radius 14. 49 km, surface redshift zR=0. 4319, charge Q=4. 67×1020C, and central density ρc=2. 68ρnm. © 2012 Springer Science+Business Media Dordrecht.


Murad M.H.,Brac University | Fatema S.,Daffodil International University
European Physical Journal C | Year: 2015

In this work some families of relativistic anisotropic charged fluid spheres have been obtained by solving the Einstein–Maxwell field equations with a preferred form of one of the metric potentials, and suitable forms of electric charge distribution and pressure anisotropy functions. The resulting equation of state (EOS) of the matter distribution has been obtained. Physical analysis shows that the relativistic stellar structure for the matter distribution considered in this work may reasonably model an electrically charged compact star whose energy density associated with the electric fields is on the same order of magnitude as the energy density of fluid matter itself (e.g., electrically charged bare strange stars). Furthermore these models permit a simple method of systematically fixing bounds on the maximum possible mass of cold compact electrically charged self-bound stars. It has been demonstrated, numerically, that the maximum compactness and mass increase in the presence of an electric field and anisotropic pressures. Based on the analytic models developed in this present work, the values of some relevant physical quantities have been calculated by assuming the estimated masses and radii of some well-known potential strange star candidates like PSR J1614-2230, PSR J1903+327, Vela X-1, and 4U 1820-30. © 2015, The Author(s).

Loading Daffodil International University collaborators
Loading Daffodil International University collaborators