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Search Results: 1 - 10 of 1537 matches for " Fatima Riaz "
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Effects of Slip Factors and Couple Stresses for Stagnation Point Flow over a Moving Plate
Najeeb Alam Khan,Fatima Riaz
Chinese Journal of Engineering , 2013, DOI: 10.1155/2013/727826
Abstract: An investigation is presented for the two-dimensional and axisymmetric stagnation flows of a couple stress fluids intrude on a moving plate under partial slip conditions. The governing partial differential equations are converted into ordinary differential equations by a similarity transformation. The important physical parameters of skin friction coefficients of the fluid are also obtained. The homotopy analysis method (HAM) is employed to obtain the analytical solution of the problem. Also, the convergence of the solutions is established by plotting graphs of convergence control parameter. The impacts of couple stresses and slip conditions on the flow and temperature of the fluid have been observed. The numerical comparison for the considered fluid is compared with previous solutions as special case. 1. Introduction The fluids exhibiting a boundary slip are important in industrial applications, for example, the polishing of artificial heart valves, rarefied fluid problems, and flow on multiple interfaces. There are many cases where no slip condition is replaced with Navier’s partial slip condition. Partial slip condition on solid boundary occurs in many problems such as oscillatory flow channel, transient flow, some coated surfaces, some rough or porous surfaces, and heat transfer on moving plate. The flow on a moving plate is termed as a basic content for convection processes. The partial slip condition on a moving plate was considered by Wang [1]; the steady, laminar, axis-symmetric flow of a Newtonian fluid due to a stretching sheet with partial slip was studied by Ariel [2], Nadeem et al. [3] investigated steady state rotating and MHD flow of a third grade fluid past a rigid plate with slip; flow and heat transfer of a non-Newtonian fluid past a stretching sheet with partial slip are considered by Sahoo [4], and Jamil and Khan [5] considered the slip effects on fractional viscoelastic fluids; the steady boundary layer flow past a moving horizontal flat plate with a slip effect is studied by Kumaran and Pop [6]. The theory of couple stresses, introduced by Stokes [7], explain the rheological behavior of various complex non-Newtonian fluids with body stresses and body couples which cannot be illustrated by the classical theory of continuum mechanics. Due to the rotational interaction of particles, the force-stress tensor is not symmetric and flow behaviors of such fluids are not similar to the Newtonian ones. It draws the researcher’s attention with the growing applications of such fluids in engineering, biomedical, and chemical industries. The
Effect of N'-nitrosodimethylamine on red blood cell rheology and proteomic profiles of brain in male albino rats
Areeba Ahmad, Ravish Fatima, Veena Maheshwari, Riaz Ahmad
Interdisciplinary Toxicology , 2011, DOI: 10.2478/v10102-011-0020-z
Abstract: We investigated the effects of N'-nitrosodimethylamine (NDMA) induced toxicity on red blood cell rheology in male rats and identified bands in proteomic profiles of brain which can be used as novel markers. Polyacrylamide gel electrophoresis (PAGE) profiles exhibited constitutive as well as induced expression of the polypeptides. Remarkably, the molecular weight range of the polypeptides (8-150 kDa) corresponded to that of the family of heat shock proteins. Our results revealed significant changes in blood parameters and showed the presence of acanthocytes, tear drop cells, spicules and cobot rings in the treated categories. Lactate dehydrogenase and esterase zymograms displayed a shift to anaerobic metabolism generating hypoxia-like conditions. This study strongly suggests that NDMA treatment causes acute toxicity leading to cell membrane destruction and alters protein profiles in rats. It is therefore recommended that caution should be exercised in using NDMA to avoid risks, and if at all necessary strategies should be designed to combat such conditions.
Dynamic Analysis of Rotating Pendulum by Hamiltonian Approach
Najeeb Alam Khan,Nadeem Alam Khan,Fatima Riaz
Chinese Journal of Mathematics , 2013, DOI: 10.1155/2013/237370
Abstract: A conservative system always admits Hamiltonian invariant, which is kept unchanged during oscillation. This property is used to obtain the approximate frequency-amplitude relationship of the governing equation with sinusoidal nonlinearity. Here, we applied Hamiltonian approach to obtain natural frequency of the nonlinear rotating pendulum. The problem has been solved without series approximation and other restrictive assumptions. Numerical simulations are then conducted to prove the efficiency of the suggested technique. 1. Introduction The rotational pendulum equation [1, 2] arises in a number of models describing the phenomenon in engineering. This equation has been described in the wind-excited vibration absorber [3] and mechanical and civil structure [4, 5] and has received much attention recently. To improve the understanding of dynamical systems, it is important to seek their exact solution. Most dynamical systems can not be solved exactly; numerical or approximate methods must be used. Numerical methods are often costly and time consuming to get a complete dynamics of the problem. Little progress was made on the integrability of the rotational pendulum by Lai et al. [6]. Lai and his colleagues used Taylor’s series and Chebyshev’s polynomials to convert the trigonometric nonlinearity to algebraic nonlinearity. They used Mickens iteration method [7] and found the approximate explicit formulas. Various alternative approaches have been proposed for solving nonlinear dynamical system, parameter-expanding method [8], frequency-amplitude formulation [9], max-min approach [10], harmonic balance method [11], variational approach [12], homotopy perturbation method [13–15], Lindstedt-Poincare method [16], and Hamiltonian approach [17–19]. 2. Governing Equation of a Rotational Pendulum Let us consider a pendulum revolving about a vertical axis and swinging horizontally as shown in Figure 1. The rotational pendulum is assumed to have a length and a lumped mass and turn at constant speed . The kinetic energy and potential energy are where is the angular displacement of the pendulum in the vertical direction. The equation of rotational pendulum can be derived using the Lagrange equation. From the Lagrange equation of motion where . ?We have The second-order differential equation of the rotational pendulum system with initial conditions is where , . Figure 1: Rotational pendulum at a constant speed. According to (1), we have Consequently the rotational pendulum equation has a conservative behavior and a periodic solution. The variational principle for (4) can be
Parameters Approach Applied on Nonlinear Oscillators
Najeeb Alam Khan,Fatima Riaz,Nadeem Alam Khan
Shock and Vibration , 2014, DOI: 10.1155/2014/624147
Abstract: We applied an approach to obtain the natural frequency of the generalized Duffing oscillator and a nonlinear oscillator with a restoring force which is the function of a noninteger power exponent of deflection . This approach is based on involved parameters, initial conditions, and collocation points. For any arbitrary power of , the approximate frequency analysis is carried out between the natural frequency and amplitude. The solution procedure is simple, and the results obtained are valid for the whole solution domain. 1. Introduction Although a large amount of the efforts on dynamical systems are related to second-order differential equations, some dynamical systems can be described by nonlinear (second-order) differential equations. Attention in nonlinear oscillator equations involving the second temporal derivative of displacement has recently been focused on the existence of periodic solutions. The study of nonlinear periodic oscillator is of interest to many researchers and various methods of solution have been suggested. Several approaches have been proposed to deal with different kinds of oscillator equations, for example, [1–7]. He in [8] used Hamiltonian method to calculate the analytical approximate periodic solutions of nonlinear oscillator equations. The approximations to the periodic solution and the angular frequency obtained by He were not accurate enough. Yildirim et al. [9] and Khan et al. [10], respectively, applied a higher order Hamiltonian formulation combined with parameters for nonlinear oscillators. Our concern in this work is the derivation of amplitude-frequency relationship for the nonlinear oscillator equations and . The attention here has been restricted primarily to odd positive integer power for the first equation and rational powers greater than unity for the second equation. There are examples of systems, however, for which these exponents can be of noninteger order, for instance, the flexible elements of vibration isolators made of wire-mesh and felt materials, cable isolators, and radially loaded rubber cylinder. In the present work, the mentioned parameters are the undetermined values in the assumed solution. In the parameters technique, the motion has been assumed as where , , and are the angular frequency of motion and Fourier coefficients, respectively. The method in this approach to obtain the parameters is quite different from the method in He’s Hamiltonian technique. Hence, the present technique is not similar to He’s Hamiltonian technique. Finally, the paper provides some accurate results for the angular
A rare association of crossed fused renal ectopia
Riaz Ahmad
BMC Nephrology , 2007, DOI: 10.1186/1471-2369-8-5
Abstract: A 24 years old female with Thrombocytopenia and absent radius syndrome admitted with pelvic fracture was investigated for recurrent urinary tract infections. Abdominal ultrasonography could not visualise the kidney on right side. Further extensive investigations in the form of intravenous urography (IVU), Magnetic resonance imaging (MRI) and renal isotope scans revealed a crossed fused renal ectopia.This report describes the new finding of a crossed fused renal ectopia associated with TAR syndrome that has not been reported before in the literature. Ectopic kidneys have increased susceptibility to develop complications like urinary infections, urolithiasis, and abdominal mass. There is a reported case of TAR syndrome with renal anomaly that developed Wilm's tumor. Finding of crossed fused renal ectopia warrants complete urologic investigation to rule out surgically correctable pathology in the urinary tract.TAR syndrome is an autosomal recessive disorder with constant findings of thrombocytopenia and bilateral absence of radii with presence of thumbs (Figure 1). Many of the congenital anomalies have been described such as ulnar hypoplasia, malformed humeri, leucocytosis, tetralogy of fallot, atrial septal defect, ventricular septal defect and milk protein allergy [1].There are only three reports of renal anomalies associated with TAR syndrome.Bradshaw et al. [2] reported a patient with TAR syndrome and horse shoe kidney, Chappel [3] reported TAR syndrome with penoscrotal transposition, i.e., insertion of penis below scrotum , Fivush et al. [4] reported TAR syndrome with bilateral hypoplastic kidneys and poor renal function. Crossed fused renal ectopia is a very rare anomaly in which both kidneys are located on the same side and are fused. The autopsy incidence of renal ectopia is 5.9%.We report the first patient of TAR syndrome associated with crossed fused renal ectopia and discuss the pathogenetic explanation for crossed fused renal ectopia.A 24 years old female w
Constructing Outraged Communities and State Responses:The Taslima Nasreen Saga in 1994 and 2007
Ali Riaz
South Asia Multidisciplinary Academic Journal , 2008,
Abstract: Taslima Nasreen, the exiled Bangladeshi author, was forced to leave India, her adopted homeland, in March 2008 after being under ‘security protection’ for months following street agitation against her writings in Kolkata. The events between August 2007, when she was physically attacked in Hyderabad, and March 2008, when she left the country, were reminiscent of those in Bangladesh in 1994 which led to her departure from there. In both instances, the states’ responses were her forced removal from the country to placate the agitators. In this paper I analyze the events on the ground and the responses of the states. I argue that these events demonstrate how ‘outraged communities’ are constructed, and symbols are invented to mobilize the community. The role of state has received little attention in the extant discussions while I contend that states bear a significant responsibility in engendering the controversy.
Hepatitis - misconceptions
Riaz A
theHealth , 2011,
Dengue Fever: prevention most recommended
Riaz A
theHealth , 2011,
Pharmaceuticals: Drug or poison
Riaz A
theHealth , 2012,
Riaz Ahmad
The Professional Medical Journal , 1997,
Abstract: This observational study was conducted on right and left normal calcanei obtained from anatomy departmentQuaid-e-Azam Medical College Bahawalpur. Mean weight of right male calcaneus was 52.54gms and thatof the left male calcaneus was 47.88 gms (Range: 31.1-64.51 gms and 31-68.13 gms respectively) with astandard deviation of 9.12 and 8.26, and calculated rage of 25.18-79.9 and 23.1-72.66 respectively. Therewas statistically significant difference between the mean weights of bones of two sides. The mean weightof right and left female calcaneus was 35.28gms and 35.03gms, standard deviation of 1.63 and 1.48, actualrange of 32.1-37.6gms and calculated range of 30.39-40 .17gms and 30.59-39.47gms respectively. Nostatistically significant difference was noted between the mean of weights of right and left bones. Whencompared there was statistically significant difference between the mean weight of right male and rightfemale calcanei and left female calcanei.
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