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Search Results: 1 - 10 of 297708 matches for " J. Faiz "
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The Effect of Power System Stabilizer on Small Signal Stability in Single-Machine Infinite-Bus
G. Shahgholian,J. Faiz
International Journal of Electrical and Power Engineering , 2012, DOI: 10.3923/ijepe.2010.45.53
Abstract: Power system oscillations are a characteristic of the system and they are inevitable. Power System Stabilizer (PSS) can help the damping of power system oscillations. This controller has become an accepted solution for oscillatory instability problems and thus improves system stability. Small signal stability is the system ability to maintain synchronism when a small disturbance occurs. This study provides an analysis of the small signal stability of the power system under different system conditions and operating loads. Several simulations have been done to show the effect of the line parameters on the power system oscillations stability.
Linear delay differential equation with a positive and a negative term
Faiz Ahmad
Electronic Journal of Differential Equations , 2003,
Abstract: We study a linear delay differential equation with a single positive and a single negative term. We find a necessary condition for the oscillation of all solutions. We also find sufficient conditions for oscillation, which improve the known conditions.
Degeneracy in the Blasius problem
Faiz Ahmad
Electronic Journal of Differential Equations , 2007,
Abstract: The Navier-Stokes equations for the boundary layer are transformed, by a similarity transformation, into the ordinary Blasius differential equation which, together with appropriate boundary conditions constitutes the Blasius problem, $$ f'''(eta )+frac{1}{2}f(eta )f''(eta)=0,quad f(0)=0,; f'(0)=0,; f'(infty )=1. $$ The well-posedness of the Navier-Stokes equations is an open problem. We solve this problem, in the case of constant flow in a boundary layer, by showing that the Blasius problem is ill-posed. If the second condition is replaced by $f'(0)=-lambda $, then degeneracy occurs for $0 Keywords Navier-Stokes equations --- Blasius problem --- degeneracy --- Wang equation --- well-posed problem --- ill-posed problem
On Solving Centrosymmetric Linear Systems  [PDF]
Moawwad El-Mikkawy, Faiz Atlan
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.412A003

The current paper is mainly devoted for solving centrosymmetric linear systems of equations. Formulae for the determinants of tridiagonal centrosymmetric matrices are obtained explicitly. Two efficient computational algorithms are established for solving general centrosymmetric linear systems. Based on these algorithms, a MAPLE procedure is written. Some illustrative examples are given.

Suppressed response to hormonal contraceptives in women of Khairpur, Sindh, Pakistan  [PDF]
Yasmeen Faiz Kazi, Sobia Saleem, Nasreen Kazi
Health (Health) , 2013, DOI: 10.4236/health.2013.511248

Objective: Contraception has gained gradual popularity in many parts of the developing world including Pakistan. Despite this increase in acceptance, the birth rate remains high. Failure of contraception has been reported in the literature, which made us aim to conduct this study. The efficiency of hormonal contraceptives in the study area was assessed and this is the first report from Pakistan. Methods: A total of 200 women (aged 20-30 and 31-40 years; n = 100 each) with minimum consistent use of hormonal contraceptives in the form of pills (Combined oral contraceptives) for 12 months were enrolled in this study. Blood samples were collected from women of each age group and corresponding control groups (n = 100) from local hospitals and reproductive health service center. Serum levels of the fertility hormones viz leutinizing and follicle stimulating hormones were measured through ELISA technique. Results: Our data revealed that over all in the both age groups, 72% women had normal, 16% increased and 12% showed decreased levels of leutinizing hormone (p > 0.05) and 67% women showed normal, 33% showed decreased and no increased levels were found for follicle stimulating hormone (p > 0.05). No age-wise significant difference in response was observed among both the age groups tested. Conclusion: Statistically insignificant difference in serum leutinizing hormone and follicle stimulating hormone seen among both the age groups of hormonal contraceptive users and control group indicates less effective hormonal contraception response in the study area.

Solitary Fungus Ball of the Sphenoid Sinus  [PDF]
Faiz Alouni, Y. Yousof, Shahram Talebian Khorasani
International Journal of Otolaryngology and Head & Neck Surgery (IJOHNS) , 2013, DOI: 10.4236/ijohns.2013.26047

A 50-year-old woman with long standing nonspecific disturbing headaches of the mid-face and rear of the head plus retro-orbital pain for about one year duration was proved to suffer from the fungus ball involvement of the left sphenoid sinus after operation. The diagnosis was established by histopathologic examination of the specimen removed at the time of operation.

Algorithms for Solving Linear Systems of Equations of Tridiagonal Type via Transformations  [PDF]
Moawwad El-Mikkawy, Faiz Atlan
Applied Mathematics (AM) , 2014, DOI: 10.4236/am.2014.53042

Numeric algorithms for solving the linear systems of tridiagonal type have already existed. The well-known Thomas algorithm is an example of such algorithms. The current paper is mainly devoted to constructing symbolic algorithms for solving tridiagonal linear systems of equations via transformations. The new symbolic algorithms remove the cases where the numeric algorithms fail. The computational cost of these algorithms is given. MAPLE procedures based on these algorithms are presented. Some illustrative examples are given.

Poly(Acrylamide-Co-Acrylic Acid)-Zinc Acetate Polymer Electrolytes: Studies Based on Structural and Morphology and Electrical Spectroscopy  [PDF]
Mohd Faiz Hassan, Siti Zulaikha Mohd Yusof
Microscopy Research (MR) , 2014, DOI: 10.4236/mr.2014.22005

Solid polymer electrolytes (SPEs) of polyacrylamide-co-acrylic acid (PAA) as the polymer host and zinc acetate (ZnA) as an ionic dopant were prepared using a single solvent by the solution casting technique. The amorphous and crystalline structures of film were investigated by X-ray diffraction (XRD). The surface morphology of samples was examined by scanning electron microscopy (SEM). The composition and complex formation of films were characterized by Fourier transform infrared (FTIR) spectroscopy. The conductivity of the PAA-ZnA films was determined by electrochemical impedance spectroscopy. According to the XRD and FTIR analyses, all electrolyte films were in amorphous state and the existence of interaction between Zn2+ cations and the PAA structure confirms that the film was successfully prepared. The SEM observations reveal that the electrolyte films appeared to be rough and flat with irregularly shaped surfaces. The highest ionic conductivity (σ) of 1.82 × 10-5 Scm-1 was achieved at room temperature (303 K) for the sample containing 10 wt % ZnA.

New Algorithms for Solving Bordered k-Tridiagonal Linear Systems  [PDF]
Moawwad El-Mikkawy, Faiz Atlan
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.37107
Abstract: The present article is mainly devoted for solving bordered k-tridiagonal linear systems of equations. Two efficient and reliable symbolic algorithms for solving such systems are constructed. The computational cost of the algorithms is obtained. Some illustrative examples are given.
A New Symbolic Algorithm for Solving General Opposite-Bordered Tridiagonal Linear Systems  [PDF]
Faiz Atlan, Moawwad El-Mikkawy
American Journal of Computational Mathematics (AJCM) , 2015, DOI: 10.4236/ajcm.2015.53023
Abstract: In the current article we propose a new efficient, reliable and breakdown-free algorithm for solving general opposite-bordered tridiagonal linear systems. An explicit formula for computing the determinant of an opposite-bordered tridiagonal matrix is investigated. Some illustrative examples are given.
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