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Search Results: 1 - 10 of 325373 matches for " S. Noreen "
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Stability Analysis of Electromagnetic Ordinary and Extraordinary Modes  [PDF]
N. Noreen, S. Zaheer, H. A. Shah
Journal of Modern Physics (JMP) , 2016, DOI: 10.4236/jmp.2016.710101
Abstract: By using kinetic theory, we derived the general dispersion relations for ordinary mode (O-mode) and Extra-ordinary mode (X-mode) in anisotropic magnetized plasma. The effects of energy anisotropy, magnetic field to density ratio (\"\") and the plasma beta \"\" on the propagation characteristics, have been analyzed. The stability analysis and the growth rates have been presented. The marginal threshold condition for oscillatory and purely growing mode has been obtained for higher harmonics and we have also calculated their growth rates in terms of plasma beta \"\" and energy anisotropy \"\". The X-mode satisfies the instability condition according to difference of geometry with the O-Mode. These modes are important for spherical tokamaks, and their coupling leads to the generation of the Bernstein mode, which causes the heating effects.
Falkner-Skan Flow of a Maxwell Fluid with Heat Transfer and Magnetic Field
M. Qasim,S. Noreen
International Journal of Engineering Mathematics , 2013, DOI: 10.1155/2013/692827
Abstract: This investigation deals with the Falkner-Skan flow of a Maxwell fluid in the presence of nonuniform applied magnetic fi?eld with heat transfer. Governing problems of flow and heat transfer are solved analytically by employing the homotopy analysis method (HAM). Effects of the involved parameters, namely, the Deborah number, Hartman number, and the Prandtl number, are examined carefully. A comparative study is made with the known numerical solution in a limiting sense and an excellent agreement is noted. 1. Introduction The Falkner-Skan problem under various aspects has attracted the attention of several researchers [1]. This problem under various aspects has been discussed extensively for viscous fluid. The interested readers may consult the studies in [2–11] for detailed information in viscous fluids. There are several materials which do not obey the Newton's law of viscosity, for example, biological products like blood and vaccines, foodstuffs like honey, ketchup, butter, and mayonnaise, certain paints, cosmetic products, pharmaceutical chemicals and so forth. These fluids are characterized as the non-Newtonian fluids. Investigation of such fluids is very useful in industrial, engineering, and biological applications. However, such fluids cannot be studied by employing a single constitutive relationship. This is due to diverse properties of non-Newtonian fluids in nature. These non-Newtonian fluid models are discussed in view of three main categories, namely, the differential, the rate, and the integral types. The simplest subclass of rate type fluids is called Maxwell. The Maxwell fluid allows for the relaxation effects which cannot be predicted in differential type fluids, namely, second, third, and fourth grades. Recently, there has been an increasing interest in the theory of rate type fluids and, in particular, a Maxwell fluid model has been accorded much attention. The Falkner-Skan wedge flow of a non-Newtonian fluid was firstly investigated by Rajagopal et al. [12]. Massoudi and Ramezan [13] discussed the effect of injection or suction on the Falkner-Skan flows of second grade fluids. The Falkner-Skan wedge flow of power-law fluids embedded in a porous medium is investigated by Kim [14]. Olagunju [15] studied this flow problem for viscoelastic fluid. In [10–15], the attention has been given to the differential type fluids. To the best of our knowledge, no one investigated the Falkner-Skan flow problem for rate type fluids. In [10], Yao has examined the Falkner-Skan wedge flow. He established series solution for the velocity and temperature by
Onset of Linear Instability in a Complex Plasma with Cairns Distributed Electrons  [PDF]
I. Habumugisha, S. K. Anguma, E. Jurua, N. Noreen
International Journal of Astronomy and Astrophysics (IJAA) , 2016, DOI: 10.4236/ijaa.2016.61001
Abstract: A rigorous theoretical investigation of linear dust ion acoustic (DIA) solitary waves in an unmagnetized complex plasma consisting of ion and ion beam fluids, nonthermal electrons that are Cairns distributed and immobile dust particles were undertaken. It was found out that, for large beam speeds, three stable modes propagated as solitary waves in the beam plasma. These were the “Fast”, “Slow” and “Ion-acoustic” modes. For two stream instability to occur between ion and ion beam, it is shown that \"\" or when \"\".
Peristaltic flow of a micropolar fluid with nano particles in small intestine
Noreen Sher Akbar,S. Nadeem
Applied Nanoscience , 2013, DOI: 10.1007/s13204-012-0160-2
Abstract: The present article analyzed the peristaltic flow of a nanofluid in a uniform tube for micropolar fluid. The governing equations for proposed model are developed in cylindrical coordinates system. The flow is discussed in a wave frame of reference moving with velocity of the wave c. Under the assumptions of longwave length the reduced coupled nonlinear differential equations of momentum, energy, and concentrations are solved by Homotopy perturbation method is used to get the solutions for velocity, temperature, nano particle, microrotation component. The solutions consists Brownian motion number N b, thermophoresis number N t, local temperature Grashof number B r and local nano particle Grashof number G r . The effects of various parameters involved in the problem are investigated for pressure rise, pressure gradient, temperature and concentration profile. Five different waves are taken into account for analysis. Streamlines have been plotted at the end of the article.
Simulation of the Second Grade Fluid Model for Blood Flow through a Tapered Artery with a Stenosis

S Nadeem,Noreen Sher Akbar,

中国物理快报 , 2010,
Abstract: We analyze the blood flow through a tapered artery, assuming the blood to be a second order fluid model. The resulting nonlinear implicit system of partial differential equations is solved by the perturbation method. The expressions for shear stress, velocity, flow rate, wall shear stress and longitudinal impedance are obtained. The physical behavior of different parameters is also discussed, as are trapping phenomena.
Computed Tomography Image Enhancement Using Cuckoo Search: A Log Transform Based Approach  [PDF]
Amira S. Ashour, Sourav Samanta, Nilanjan Dey, Noreen Kausar, Wahiba Ben Abdessalemkaraa, Aboul Ella Hassanien
Journal of Signal and Information Processing (JSIP) , 2015, DOI: 10.4236/jsip.2015.63023
Abstract: Medical image enhancement is an essential process for superior disease diagnosis as well as for detection of pathological lesion accurately. Computed Tomography (CT) is considered a vital medical imaging modality to evaluate numerous diseases such as tumors and vascular lesions. However, speckle noise corrupts the CT images and makes the clinical data analysis ambiguous. Therefore, for accurate diagnosis, medical image enhancement is a must for noise removal and sharp/clear images. In this work, a medical image enhancement algorithm has been proposed using log transform in an optimization framework. In order to achieve optimization, a well-known meta-heuristic algorithm, namely: Cuckoo search (CS) algorithm is used to determine the optimal parameter settings for log transform. The performance of the proposed technique is studied on a low contrast CT image dataset. Besides this, the results clearly show that the CS based approach has superior convergence and fitness values compared to PSO as the CS converge faster that proves the efficacy of the CS based technique. Finally, Image Quality Analysis (IQA) justifies the robustness of the proposed enhancement technique.
Non-Linear Ion-Acoustic Solitary Waves in Electron-Positron-Ion Plasma with Non-Thermal Electrons  [PDF]
S. K. Anguma, I. Habumugisha, L. Nazziwa, E. Jurua, N. Noreen
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.86055
Abstract: Ion-acoustic solitary (IAS) waves in electron-positron-ion (e-p-i) plasma have been of interest to many researchers probably due to their relevance in understanding the Universe. However, the study of non-linear ion-acoustic waves in e-p-i plasma with non-thermal electrons has not been adequately studied. A theoretical investigation on non-linear IAS waves in e-p-i plasma comprising of warm inertial adiabatic fluid ions and electrons that are kappa distributed, and Boltzman distributed positron is presented here using the Sagdeev potential technique. It was found that existence domains of finite amplitude IAS waves were confined within the limits of minimum and maximum Mach numbers with varying k values. For lower values of k, the amplitude of the solitary electrostatic potential structures increased as the width decreased, while for high values, the potential amplitude decreased as the width of the solitary structure increased.
Evaluation of Co-Inhibition Characteristics of caffeine-Zn2+ system in preventing Carbon Steel Corrosion.
Noreen Antony,,H.Benita Sherine,S. Rajendran
International Journal of Engineering Science and Technology , 2010,
Abstract: The inhibition efficiency of Caffeine-Zn2+ system in controlling the corrosion of carbon steel in 120 ppm chloride solution has been evaluated by mass – los method, potentiodynamic polarization study and AC impedance spectra. A formulation consisting of 200ppm of caffeine and 75 ppm of Zn2+ has inhibition efficiency (IE) of 75% at pH7. However IE decreases sharply at low and high pH. Polarization studies show that the caffeine - Zn2+ system functions as a mixed inhibitor. AC impedance spectra and AFM studies reveal the formation of a protective film on the metal surface. FTIR spectrum shows the presence of Fe2+- caffeine complex and Zn(OH)2 in the film.
Pakistan Veterinary Journal , 2007,
Abstract: Growth performance and feed conversion ratio (FCR) of hybrid (Labeo rohita x Catla catla) fingerlings fed for six weeks on soybean meal, maize gluten 30% and feather meal were evaluated. The feed trails were replicated for each of the ingredients. The feed was supplied at the rate of 4% of wet body weight of fingerlings twice a day. The hybrid (Labeo rohita x Catla catla) fingerlings gained highest body weight (2.07 ± 0.01g) on maize gluten 30%, followed by feather meal (1.88 ± 0.04g) and soybean meal (1.66 ± 0.01g) and these values were significantly different from each other (p<0.05). The growth measured in terms of total length was significantly higher on maize gluten 30% (6.85 ± 0.04 cm) than feather meal (6.20 ± 0.05 cm) and soybean meal (6.15 ± 0.04 cm). The difference between the latter two groups was, however, non significant. FCR calculated for three ingredients was lower (better) on maize gluten 30% (1.90 ± 0.06), followed by feather meal (1.97 ± 0.04) and soybean meal (2.06 ± 0.08). The FCR value on maize gluten 30% was significantly better than soybean meal but non significantly different from feather meal. It was concluded that maize gluten 30% could be included in the feed formulation for fingerling hybrids.
A Comparison of Direct and Indirect Solvers for Linear Systems of Equations
Noreen Jameel
International Journal of Emerging Sciences , 2012,
Abstract: In this paper, various methods are compared for solving linear systems of equations. Both direct and indirect methods are considered. Direct and Indirect methods are widely used for solving large sparse and dense problems. In direct methods, two methods will be considered: Gaussian Elimination and LU-Factorization methods. Jacobi, Gauss-Seidel ,SOR, CG and GMRES Methods will be discussed as an iterative method. The results show that the GMRES method is more efficient than the other iterative and direct methods. The criteria considered are time to converge, number of iterations, memory requirements and accuracy.
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