Department of Mathematics and Natural Sciences (MNS)
http://hdl.handle.net/10361/106
20161211T04:11:41Z

Isolation of yeasts from raisins and Palmjuice and ethanol production in molasses medium
http://hdl.handle.net/10361/7163
Isolation of yeasts from raisins and Palmjuice and ethanol production in molasses medium
Rahman, Shafkat Shamim; Islam, Sarkar Mohammad Khairul; Rafiqul, Islam Mohammad; Khaled, Hossain; Kamrun, Nahar; Kumar, Roy Chapol; Uddin, Md Ekhlas; Choudhury, Naiyyum
The alternative fuels are expected to satisfy the progressive demand for energy on the wake of the negative effects of fossil fuel on the atmosphere and resultant universal warming. In this study two ethanol fermenting Saccharomyces cerevisae were isolated from Palm juice and Raisins. Method/Statistical Analysis: Both isolates were grown in Yeast extract Peptone Dextrose (YEPD) medium and characterized for alcoholic fermentation using molasses medium and optimized for pH, thermo, osmo, ethanol tolerance and sugar concentration. Findings: Results showed for ethanol fermentation, 31°C temperature, 6.01 pH and 6.50% sugar concentration is the prime condition. Raisinisolate emerged as highly thermophilic and stress tolerant in nature. Under optimized conditions, S. cerevisae isolated from Palmjuice produced 9.85% of ethanol in the medium. Application/Improvements: Creation of ethanol through fermentation appears to be a potential other fossil fuel and can be used as exclusive fuel in vehicles with dedicated engines or in fuel blends.
This article was published in the Indian Journal of Science and Technology [© 2016 Indian Society for Education and Environment ] and the definite version is available at : http://doi.org/10.17485/ijst/2016/v9i12/85509
The Journal's website is at: http://www.indjst.org/index.php/indjst/article/view/85509
20160101T00:00:00Z

A class of relativistic anisotropic charged stellar models in isotropic coordinates
http://hdl.handle.net/10361/7156
A class of relativistic anisotropic charged stellar models in isotropic coordinates
Pant, Neeraj; Pradhan, Nirakar; Murad, Mohammad Hassan
In this present paper, we present a class of static, spherically symmetric charged anisotropic fluid models of super dense stars in isotropic coordinates by considering a particular type of metric potential, a specific choice of electric field intensity E and pressure anisotropy factor Δ which involve parameters K (charge) and α (anisotropy) respectively. The solutions so obtained are utilized to construct the models for superdense stars like neutron stars and strange quark stars. Our solutions are well behaved within the following ranges of different constant parameters: 4<n≤21.6, 0<K<0.2499, 0≤α≤0.068 and Schwarzschild parameter, 0≤u=GM/c2R≤0.334. With Δ=0 we rediscover the isotropic model of Pant et al. (Astrophys. Space Sci. 352:135, 2014) and with α=0 and K=0 we rediscover the isotropic neutral model of Murad and Pant (Astrophys. Space Sci. 350:349, 2014). It has been observed that with the increase of α maximum mass decreases. We also present models of super dense star like neutron and quark star based on the particular solution taking n=4.35, α=0.002, K=0.2062 for which u has maximum value umax=0.306. By assuming surface density ρb=4.6888×1014 g cm−3 the resulting well behaved solution has a maximum quark star mass M=2.02 M⊙ and radius R=9.78 km; and the choice ρb=2.7×1014 g cm−3 results charged fluid ball of maximum mass M=2.66 M⊙ and radius R=12.89 km.
This article was published in the Journal of Astrophysics and Space Science [© 2014, Springer Science+Business Media Dordrecht.] and the definite version is available at : http://dx.doi.org/10.1007/s1050901421568. The Journal's website is at: http://link.springer.com/article/10.1007%2Fs1050901421568
20140101T00:00:00Z

A class of super dense stars models using charged analogues of HajjBoutros type relativistic fluid solutions
http://hdl.handle.net/10361/7152
A class of super dense stars models using charged analogues of HajjBoutros type relativistic fluid solutions
Pant, Neeraj; Pradhan, Nirakar; Murad, Mohammad Hassan
We present a spherically symmetric solution of the general relativistic field equations in isotropic coordinates for perfect charged fluid, compatible with a super dense star modeling. The solution is well behaved for all the values of Schwarzschild parameter u lying in the range 0 < u < 0.1727 for the maximum value of charge parameter K = 0.08163. The maximum mass of the fluid distribution is calculated by using stellar surface density as ρb = 4.6888×1014g cm−3. Corresponding to K = 0.08 and umax = 0.1732, the resulting well behaved solution has a maximum mass M = 0.9324M⊙ and radius R = 8.00 and by assuming ρb = 2×1014g cm−3 the solution results a stellar configuration with maximum mass M = 1.43M⊙ and radius Rb = 12.25 km. The maximum mass is found increasing with increasing K up to 0.08. The well behaved class of relativistic stellar models obtained in this work might has astrophysical significance in the study of internal structure of compact star such as neutron star or selfbound strange quark star like Her X1.
This article was published in the International Journal of Theoretical Physics [© 2014, Springer Science+Business Media New Yor] and the definite version is available at : http://dx.doi.org/10.1007/s1077301421470. The Journal's website is at: http://link.springer.com/article/10.1007%2Fs1077301421470
20141001T00:00:00Z

Anisotropic charged stellar models in Generalized Tolman IV spacetime
http://hdl.handle.net/10361/7149
Anisotropic charged stellar models in Generalized Tolman IV spacetime
Murad, Mohammad Hassan; Fatema, Saba
With the presence of electric charge and pressure anisotropy some anisotropic stellar models have been developed. An algorithm recently presented by Herrera et al. (Phys. Rev. D 77, 027502 (2008)) to generate static spherically symmetric anisotropic solutions of Einstein's equations has been used to derive relativistic anisotropic charged fluid spheres. In the absence of pressure anisotropy the fluid spheres reduce to some wellknown Generalized Tolman IV exact metrics. The astrophysical significance of the resulting equations of state (EOS) for a particular case (WymanLeibovitzAdler) for the anisotropic charged matter distribution has been discussed. Physical analysis shows that the relativistic stellar structure obtained 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 like electrically charged bare strange quark stars.
This article was published in the Journal of European Physical Journal Plus [© 2015, Società Italiana di Fisica and SpringerVerlag Berlin Heidelberg.] and the definite version is available at : http://dx.doi.org/10.1140/epjp/i201515003y. The Journal's website is at: http://link.springer.com/article/10.1140%2Fepjp%2Fi201515003y
20150101T00:00:00Z