eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
319
325
10.22099/ijsts.2013.1630
1630
Combined effect of suspended particles and rotation on thermosolutal convection in a viscoelastic fluid saturating a Darcy-Brinkman porous medium
G. C. Rana
1
R. C. Thakur
2
Department of Mathematics, NSCBM Govt. P. G. College, Hamirpur-177 005, Himachal Pradesh
Department of Mathematics, Govt. P. G. College, Dhaliara, Kangra-177 103, Himachal Pradesh, India
In this paper, the combined effect of suspended (fine dust) particles and rotation on the onset of thermosolutal convection in an elastico-viscous fluid in a porous medium is studied. For the porous medium, the Brinkman model is employed and Rivlin-Ericksen model is used to characterize viscoelastic fluid. By applying normal mode analysis method, the dispersion relation has been derived and solved analytically. It is observed that the rotation, stable solute gradient, suspended particles, gravity field and viscoelasticity introduce oscillatory modes. For stationary convection, it is observed that the rotation, stable solute gradient have a stabilizing effect and suspended particles have a destabilizing effect on the system whereas Darcy number and medium permeability have stabilizing/destabilizing effects under certain conditions. The effects of rotation, stable solute gradient, suspended particles, Darcy number and medium permeability have also been shown graphically.
http://ijsts.shirazu.ac.ir/article_1630_6ad4ef4ca441fd758f0ca9b39f9312d5.pdf
Brinkman porous medium
Rivlin-Ericksen fluid
rotation
suspended particles
thermosolutal convection
viscosity
viscoelasticity
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
327
333
10.22099/ijsts.2013.1631
1631
Approximation of stochastic advection-diffusion equation
using compact finite difference technique
M. Bishehniasar
1
A. R. Soheili
2
Department of Mathematics, University of Sistan and Baluchestan Zahedan, Iran
The Center of Excellence on Modeling and Control Systems,
Department of applied Mathematics, School of Mathematical science,
Ferdowsi University of Mashhad, Mashhad
In this paper, we propose a new method for solving the stochastic advection-diffusion equation of Ito type. In this work, we use a compact finite difference approximation for discretizing spatial derivatives of the mentioned equation and semi-implicit Milstein scheme for the resulting linear stochastic system of differential equation. The main purpose of this paper is the stability investigation of the applied method. Finally, some numerical examples are provided to show the accuracy and efficiency of the proposed technique.
http://ijsts.shirazu.ac.ir/article_1631_22e92753f3dad7596b3b82cbc3100358.pdf
Stochastic partial differential equation
compact finite difference scheme
Stability
semi-implicit Milstein method
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
335
342
10.22099/ijsts.2013.1632
1632
Bayesian and non-bayesian estimation of stress–strength
model for Pareto type I distribution
A. I. Shawky
1
F. H. Al-Gashgari
2
Department of Statistics, Faculty of Sciences, King Abdulaziz University,
P.O. Box 80203, Jeddah 21589
Department of Statistics, Faculty of Sciences for Girls, King Abdulaziz University, P.O. Box 53873, Jeddah 21593, Saudi Arabia
This article examines statistical inference for where and are independent but not identically distributed Pareto of the first kind (Pareto (I)) random variables with same scale parameter but different shape parameters. The Maximum likelihood, uniformly minimum variance unbiased and Bayes estimators with Gamma prior are used for this purpose. Simulation studies which compare the estimators are presented. Moreover, sensitivity of Bayes estimator to the prior parameters is considered.
http://ijsts.shirazu.ac.ir/article_1632_bc2d251569304a0afdc39c565a46af4b.pdf
Bayesian estimator
Maximum likelihood estimator (MLE)
Pareto of first kind
uniformly minimum variance unbiased estimator (UMVUE)
stress-strength model
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
343
347
10.22099/ijsts.2013.1633
1633
On BC-generalized Landsberg Finsler metrics
M. Zamanzadeh
1
B. Najafi
2
Bijar Branch, Islamic Azad University Bijar
Department of Mathematics, Faculty of Science, Shahed University of Tehran, Tehran, Iran
Equality of -curvatures of the Berwald and Cartan connections leads to a new class of Finsler metrics, so-called BC-generalized Landsberg metrics. Here, we prove that every BC-generalized Landsberg metric of scalar flag curvature with dimension greater than two is of constant flag curvature.
http://ijsts.shirazu.ac.ir/article_1633_c8dcd51ee11af2c9a5cef5d64ae37a05.pdf
Finsler structure
Landsberg metric
generalized Landsberg metric
scalar flag curvature
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
349
358
10.22099/ijsts.2013.1634
1634
A preemptive restarting approach to beating the
inherent instability of Lanczos-type algorithms
M. Farooq
1
A. Salhi
2
Department of Mathematics, University of Peshawar, 25120, Khyber Pakhtunkhwa
Department of Mathematical Sciences, University of Essex, Wivenhoe Park, Colchester, CO4 3SQ, UK
Lanczos-type algorithms are well known for their inherent instability. They typically breakdown occurs when relevant orthogonal polynomials do not exist. Current approaches to curing breakdown rely on jumping over the non-existent polynomials to resume computation. This may have to be used many times during the solution process. We suggest an alternative to jumping, which consists of restarting the algorithms that fail. Three different strategies can be taken: (ST1) Restarting following breakdown of the algorithm in use; (ST2) pre-emptive restarting after a fixed number of iterations; (ST3) restarting when near breakdown is detected through monitoring. We describe a restarting framework with a generic algorithm that invokes one or the other of the three strategies suggested. Four of the most prominent recently developed Lanczos-type algorithms namely, and will be presented and then deployed in the restarting framework. However, we will only report on results obtained with strategy ST2 as it is the only viable one at the moment.
http://ijsts.shirazu.ac.ir/article_1634_6f943b0d0733d9fee2c5c1cae69b892c.pdf
Lanczos algorithm
Systems of Linear Equations
Formal Orthogonal Polynomials, Restarting, Switching, Breakdown
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
359
363
10.22099/ijsts.2013.1635
1635
Symplectic Hodge theory, harmonicity, and Thom duality
M. Bahramgiri
1
Graduate School of Management and Economics Sharif University of Technology
We study the notion of harmonicity in the sense of symplectic geometry, and investigate the geometric properties of harmonic Thom forms and distributional Thom currents, dual to different types of submanifolds. We show that the harmonic Thom form associated to a symplectic submanifold is nowhere vanishing. We also construct symplectic smoothing operators which preserve the harmonicity of distributional currents and using these operators, construct harmonic Thom forms for co-isotropic submanifolds, which unlike the harmonic forms associated with symplectic submanifolds, are supported in an arbitrary tubular neighborhood of the manifold.
http://ijsts.shirazu.ac.ir/article_1635_1a20b2d7b1e35b156f03b7bb2f5ad63e.pdf
Harmonicity
duality
Thom class
Hodge theory
symplectic
distributional currents
smoothing operators
oriented submanifold
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
365
378
10.22099/ijsts.2013.1636
1636
Some kinds of -fuzzy ideals of ternary semigroups
N. Rehman
1
M. Shabir
2
Department of Basic Sciences, Riphah International University, Islamabad, Pakistan
2Department of Mathematics, Quaid-i-Azam University, Islamabad, Pakistan
Generalizing the concepts of -fuzzy (left, right, lateral) ideals, -fuzzy quasi-ideals and -fuzzy bi (generalized bi-) ideals in ternary semigroups, the notions of -fuzzy (left, right, lateral) ideals, -fuzzy quasi-ideals and -fuzzy bi (generalized bi-) in ternary semigroups are introduced and several related properties are investigated. Some new results are obtained.
http://ijsts.shirazu.ac.ir/article_1636_9f7826714c3ad66e4cae9235cc70f2ce.pdf
Ternary semigroups
-fuzzy ideals
-fuzzy quasi-ideals
-fuzzy ideals bi-ideals
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
379
388
10.22099/ijsts.2013.1637
1637
An optimal control approach for arbitrary order
singularly perturbed boundary value problems
M. Zarepour
1
G. B. Loghmani
2
Department of Mathematics, Yazd University, P.O. Box: 89195-741 Yazd, Iran
Department of Mathematics, Yazd University
The aim of this paper is to introduce a new approach for obtaining the numerical solution of singulary perturbed boundary value problems based on an optimal control technique. In the proposed method, first the mentioned equations are converted to an optimal control problem. Then, control and state variables are approximated by Chebychev series. Therefore, the optimal control problem is reduced to a parametric optimal control problem (POC) subject to algebric constraints. Finally, the obtained POC is solved numerically using an iterative optimization technique. In this method, a new idea is proposed which enables us to apply the new technique for almost all kinds of singularly perturbed boundary value problems. Some numerical examples are solved to highlight the advantages of the proposed technique.
http://ijsts.shirazu.ac.ir/article_1637_a9995d56a60e51847fb33cd32294b719.pdf
Singularly perturbed boundary value problem
parametric optimal control
Optimal control problem
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
389
396
10.22099/ijsts.2013.1638
1638
Boundary layer problem for system of first order of ordinary differential equations with linear non-local boundary conditions
M. Jahanshahi
1
A. R. Sarakhsi
2
S. Asharafi
3
N. Aliev
4
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran
Department of Mathematics, Azarbaijan Shahid Madani University, 5375171379, Tabriz, Iran
Department of Mathematics, Baku State University, Baku, Azerbaijan
In this paper we study the boundary layer problems in which boundary conditions are non-local. Here we try to find the necessary conditions by the help of fundamental solution to the given adjoint equation. By getting help from these conditions, at first the boundary condition is changed from non-local to local. The main aim of this paper is to identify the location of the boundary layer. In other words, at which point the boundary layer is formed.
http://ijsts.shirazu.ac.ir/article_1638_138c842f9ce699a3b1ca11ff19b5855a.pdf
Singular perturbation problems
boundary layer
fundamental solution
necessary conditions
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
397
402
10.22099/ijsts.2013.1639
1639
On generalized I-statistical convergenceof order
E. Savas
1
Department of Mathematics, Istanbul Commerce University, Uskudar-Istanbul
The goal of this paper is to generalize the recently introduced summability method and introduce double statistical convergence of order by using ideal. We also investigate certain properties of this convergence.
http://ijsts.shirazu.ac.ir/article_1639_5c4780979b216e7f063511e6a922a483.pdf
ideal
filter
I- double statistical convergence of order α
I_λ- double statistical convergence of order α, closed subspace
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
403
410
10.22099/ijsts.2013.1640
1640
On characterization of spacelike dual biharmonic curves
in dual Lorentzian Heisenberg group
T. Korpinar
1
E. Turhan
2
V. Asil
3
Department of Mathematics, Mus Alparslan University, 49250, Mus, Turkey
Department of Mathematics, Firat University, 23119, Elazig, Turkey
3Department of Mathematics, Firat University, 23119, Elazig
In this paper, we study spacelike dual biharmonic curves. We characterize spacelike dual biharmonic curves in terms of their curvature and torsion in the Lorentzian dual Heisenberg group . We give necessary and sufficient conditions for spacelike dual biharmonic curves in the Lorentzian dual Heisenberg group . Therefore, we prove that all spacelike dual biharmonic curves are spacelike dual helix. Moreover, we give their explicit parametrizations of spacelike dual biharmonic curves. Finally, we illustrate our main results in Figs. 1 and 2.
http://ijsts.shirazu.ac.ir/article_1640_c99b982ac35eddb02110b1791a7b0378.pdf
Bienergy
biharmonic curve
Helix
Heisenberg group
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
411
420
10.22099/ijsts.2013.1641
1641
Graded prime spectrum of a graded module
N. A. Ozkiırisci
1
K. H. Oral
2
U. Tekir
3
Department of Mathematics, Faculty of Arts and Science, Yildiz
Technical University, 34210, Esenler, Istanbul
Department of Mathematics, Faculty of Arts and Science, Yildiz Technical University, 34210, Esenler, Istanbul, Turkey
Department of Mathematics, Faculty of Arts and Science, Marmara University, 34722, Goztepe, Istanbul, Turkey
Let be a graded ring and be a graded -module. We define a topology on graded prime spectrum of the graded -module which is analogous to that for , and investigate several properties of the topology.
http://ijsts.shirazu.ac.ir/article_1641_2c038b0eafc3b894e8058709f74ed513.pdf
Graded module
graded prime spectrum
graded prime submodule
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
421
429
10.22099/ijsts.2013.1642
1642
The multi-step homotopy analysis method: A powerful
scheme for handling non-linear oscillators
M. Zurigat
1
S. Al-Shara
2
S. Momani
3
A. Alawneh
4
Department of Mathematics, Al al-Bayt University, Mafraq, Jordan
Department of Mathematics, Al al-Bayt University, Mafraq, Jordan
Department of Mathematics, University of Jordan, Amman
Department of Mathematics, University of Jordan, Amman, Jordan
This paper presents approximate analytical solutions for nonlinear oscillators using the multi-step homotopy analysis method (MSHAM). The proposed scheme is only a simple modification of the homotopy analysis method, in which it is treated as an algorithm in a sequence of small intervals (i.e. time step) for finding accurate approximate solutions to the corresponding problems. Several illustrative examples are given to demonstrate the effectiveness of the present method. Figurative comparisons between the MSHAM and the classical fourth-order Runge-Kutta method (RK4) reveal that this modified method is very effective and convenient.
http://ijsts.shirazu.ac.ir/article_1642_70909ef1ebb1fef861842127d76a1c61.pdf
Non-linear oscillators
homotopy analysis method
numerical solutions
eng
Springer
Iranian Journal of Science and Technology (Sciences)
1028-6276
1028-6276
2013-09-16
37
3.1
431
438
10.22099/ijsts.2013.1643
1643
A system of generalized resolvent equations involving
generalized pseudocontractive mapping
R. Ahmad
1
M. Akram
2
Department of Mathematics, Aligarh Muslim University, Aligarh-202002, India
Department of Mathematics, Aligarh Muslim University, Aligarh-202002
Generalized resolvent equations; variational inclusions; algorithm; convergence; generalized pseudocontractive mapping
http://ijsts.shirazu.ac.ir/article_1643_65e5be04ad85dbab8e469418090b76a7.pdf
Generalized resolvent equations
variational inclusions
algorithm
convergence
generalized pseudocontractive mapping