Numerical solution of Reynold’s equation governing noncircular gas bearing system using radial basis function
H.
Rasooli Shooroki
Faculty of Mathematics, Yazd University, Yazd, Iran
author
R.
Rashidi Meybodi
Department of Mechanical Engineering, Payame Noor University, Tehran, Iran
author
S. M.
Karbassi
Faculty of Advanced Education, Islamic Azad University, Yazd Branch, Yazd, Iran
author
G. B.
Loghmani
Faculty of Mathematics, Yazd University, Yazd, Iran
author
text
article
2014
eng
In this paper, the static characteristics of two-lobe, three-lobe and four-lobe noncircular gas journal bearing systems are
studied in detail. The Reynold’s equation governing the noncircular gas bearing systems are analyzed by using Radial Basis
Functions (RBF). The solutions are obtained numerically by solving systems of algebraic equations. The equilibrium position
of the rotor is obtained without using the trial and error method; which is the merit of our method.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
389
397
http://ijsts.shirazu.ac.ir/article_2555_85c60ec37dc6ac51bf5b56b645f983b6.pdf
dx.doi.org/10.22099/ijsts.2014.2555
A NSFD scheme for Lotka–Volterra food web model
S.
Zibaei
Department of Mathematics, School of Mathematical Sciences, Vali-e-Asr
University of Rafsanjan, Rafsanjan, Iran
author
M.
Namjoo
Department of Mathematics, School of Mathematical Sciences, Vali-e-Asr
University of Rafsanjan , Rafsanjan, Iran
author
text
article
2014
eng
A nonstandard finite difference (NSFD) scheme has been constructed and analyzed for a mathematical model that describes Lotka–Volterra food web model. This new discrete system has the same stability properties as the continuous model and,on the whole, it preservesthe same local asymptotic stability properties. Linearized stability theory and Schur–Cohn criteria are used for local asymptoticstability of this discrete time model. Numerical results are given to support the results.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
399
414
http://ijsts.shirazu.ac.ir/article_2556_15485c9c4d6bac19c0ab1d9049d4345b.pdf
dx.doi.org/10.22099/ijsts.2014.2556
E1, E2 and M1 transitions between n=3 levels in magnesium-like tungsten
G.
Günday Konan
Department of Physics, Sakarya University, 54187, Sakarya, Turkey
author
S.
Kabakçı
Department of Physics, Sakarya University, 54187, Sakarya, Turkey
author
L.
Özdemir
Department of Physics, Sakarya University, 54187, Sakarya, Turkey
author
text
article
2014
eng
Electric dipole (E1) transitions of 3s-3p and 3p-3d, and electric quadrupole (E2) and magnetic dipole (M1) transitions between fine structure levels of 3s3p and 3p2 in Mg-like tungsten (W62+) have been studied by multiconfiguration Hartree-Fock (MCHF) method. Multielectron ions of high-Z elements are of interest in atomic structure theory. In this work Breit-Pauli relativistic contributions and correlation effects have been considered. The magnesium-like tungsten lines obtained from this work are compared with other theoretical and experimental results.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
415
421
http://ijsts.shirazu.ac.ir/article_2557_96a6195489c4d481880b2c0965522a90.pdf
dx.doi.org/10.22099/ijsts.2014.2557
Analytical solutions for the fractional nonlinear telegraph equation using a modified homotopy perturbation and separation of variables methods
H.
Kheiri
Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran
author
S.
Irandoust-Pakchin
Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran
author
M.
Javidi
Department of Applied Mathematics, Faculty of Mathematical Sciences, University of Tabriz, Tabriz, Iran
author
text
article
2014
eng
In this paper, first a new homotopy perturbation method for solving a fractional order nonlinear telegraph equation is introduced. By applying the proposed method, the nonlinear equation is translated to linear equations for per iteration of homotopy perturbation method. Then, the obtained problems are solved with separation method. In the examples, it is illustrated that the exact solution is obtained in one iteration by conveniently separating source term of equation.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
423
433
http://ijsts.shirazu.ac.ir/article_2558_19fcab0c6999ed50cf09038e2fc4e390.pdf
dx.doi.org/10.22099/ijsts.2014.2558
A new model for vulnerability assessment of drought in Iran using Percent of Normal Precipitation Index (PNPI)
M.
Masoudi
Department of Natural Resources and Environment, College of Agriculture, Shiraz University, Iran
author
S.
Hakimi
Department of Natural Resources and Environment, College of Agriculture, Shiraz University, Iran
author
text
article
2014
eng
The Percent of Normal Precipitation Index (PNPI) is a widely used drought index to provide good estimations about the intensity, magnitude and spatial extent of droughts. The objective of this study was analyzing spatial pattern of drought by PNPI index. In this paper, according to the data of 40 stations in Iran, during 1967-2009, the pattern of drought hazard is evaluated. Influenced zone of each station was specified by Thiessen method. An attempt was made to create a new model of drought hazard using GIS. Three criteria for drought were studied and considered to define areas under vulnerability. Drought hazard criteria used in the present model include: maximum severity of drought in the period, trend of drought, and the maximum number of sequential arid years. Both the vulnerability indicator map and also final hazard map are classified into 5 hazard classes of drought: None, slight, moderate, severe and very severe. The final drought vulnerability map was prepared by overlaying three criteria maps in the GIS and the final hazard classes were defined on the basis of hazard scores arrived at by the mean of the main indicators, deploying the new model. The final vulnerability map shows that severe hazard areas (58% of the country) which are observed more in the northwestern, southeastern and central parts of the country are much more widespread than areas under other hazard classes.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
435
440
http://ijsts.shirazu.ac.ir/article_2559_258f784e4a2bec508730c626b6028437.pdf
dx.doi.org/10.22099/ijsts.2014.2559
Numerical modeling of the temporal response of back-gated metalsemiconductor- metal photodetector in an equilibrium condition
A.
Habibpour
Depatment of physics, Islamic Azad University, Kazerun Branch, Kazerun, Iran
author
N.
Das
Department of Electrical and Computer Engineering, Curtin University, Australia
author
H. R.
Mashayekhi
Faculty of Science, University of Kerman, Kerman, Iran
author
text
article
2014
eng
We have simulated the carrier concentration and temporal response characteristics of a Back-Gated Metal- Semiconductor-Metal (BG-MSM) photodetector in one dimension as a function of optical pulse position on the active region in an equilibrium condition (without bias voltage to the photodetector). We have adopted a nonlinear ambipolar transport model to simulate the behavior of photo-generated carriers in the active region of the BG-MSM photodetector. From the simulation results, it is observed that for optical pulse positions in the cathode region, the magnitude of the response current is exactly the same but opposite that of the anode region. The response of the photodetector is zero when a pulse is positioned at the center of the active region. This important feature of the device could make it attractive for micro-scale positioning of highly sensitive instruments. Our simulation results agreed well with the experimental results.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
441
444
http://ijsts.shirazu.ac.ir/article_2560_78a43199e054cf68aafc6f8dc1f77ee6.pdf
dx.doi.org/10.22099/ijsts.2014.2560
Structure of quasi ordered ∗-vector spaces
G. H.
Esslamzadeh
Department of Mathematics, College of Sciences, Shiraz University, Shiraz 71454, Iran
author
M.
Moazami Goodarzi
Department of Mathematics, College of Sciences, Shiraz University, Shiraz 71454, Iran
author
F.
Taleghani
Department of Mathematics, College of Sciences, Shiraz University, Shiraz 71454, Iran
author
text
article
2014
eng
Let (𝑋,𝑋+) be a quasi ordered ∗-vector space with order unit, that is, a ∗-vector space 𝑋 with order unite together with a cone 𝑋+⊆𝑋. Our main goal is to find a condition weaker than properness of 𝑋, which suffices for fundamental results of ordered vector space theory to work. We show that having a non-empty state space or equivalently having a non-negative order unit is a suitable replacement for properness of 𝑋+. At first, we examine real vector spaces and then the complex case. Then we apply the results to self adjoint unital subspaces of unital ∗-algebras to find direct and shorter proofs of some of the existing results in the literature.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
445
453
http://ijsts.shirazu.ac.ir/article_2561_38b0fd0cff8b3aaffb439bd8ee4cc2e6.pdf
dx.doi.org/10.22099/ijsts.2014.2561
Existence solutions for nonlocal fractional differential equation with nonlinear boundary conditions
N.
Nyamoradi
Department of Mathematics, Faculty of Sciences, Razi University, 67149 Kermanshah, Iran
author
H.
Alaei Dizaji
Department of Mathematics, Payame Noor University, Iran
author
text
article
2014
eng
In this paper, by employing the Guo-Krasnoselskii fixed point theorem in a cone, we study the existence of positive solutions to the following nonlocal fractional boundary value problems
{ 𝐷0+ 𝛼 𝑢(𝑡) = 𝑓(𝑡, 𝑢(𝑡)), 𝑡 ∈ (0,1), 𝑢𝑡 + 𝑢′(0) = 12 [𝐻1(𝜑𝑢) + ∫ 𝐻2 𝐸(𝑠 𝑢𝑠)𝑑𝑠 , 𝑢1) + 𝑢′(1) = 0, c
where c𝐷0+ 𝛼is the standard Caputo derivative of order 𝛼 1 < 𝛼< 2, 𝐸⊆ (0,1) is some measurable set. We provide conditions on 𝑓 𝐻1, 𝐻2 and 𝜑such that the problem exhibits at least one positive solution.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
455
461
http://ijsts.shirazu.ac.ir/article_2562_89c639061537ef57883fe24a62f10c88.pdf
dx.doi.org/10.22099/ijsts.2014.2562
Friedel–Crafts acylation of aromatic compounds
A. R.
Hajipour
Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan
University of Technology, Isfahan 84156, Iran
author
S. H.
Nazemzadeh
Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan
University of Technology, Isfahan 84156, Iran
author
H.
Karimi
Pharmaceutical Research Laboratory, Department of Chemistry, Isfahan
University of Technology, Isfahan 84156, Iran
author
text
article
2014
eng
An efficient method for the Friedel–Crafts acylation of a wide range of aromatic compounds in good to excellent yields under solvent-free conditions, using iron zirconium phosphate (ZPFe) was investigated. The catalyst is easy to prepare and shows interesting catalytic properties. The catalyst was characterized by some instrumental techniques such as XRD, ICP-OES, SEM and TEM. A wide variety of benzene derivatives reacted easily with benzoyl chloride and some of its derivatives to afford the corresponding aromatic ketones in clean and good yields with the para isomer predominating typically using 3mol% of catalyst. The use of inexpensive materials, simple and clean work-up, short reaction times in most cases and good yields are the main advantages of this method. This work introduces a new application of this catalyst, not described in the literature until now. Also, the catalyst can be recovered and reused for three times without a significant loss in its activity and selectivity.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
463
471
http://ijsts.shirazu.ac.ir/article_2563_12abf4a75c21b1b2ed8a550b3c2bbe21.pdf
dx.doi.org/10.22099/ijsts.2014.2563
Numerical technique for integro-differential equations arising in oscillating magnetic fields
M.
Ghasemi
Department of Applied Mathematics, Faculty of Mathematical Sciences,
Shahrekord University, P.O. Box 115, Shahrekord, Iran
author
text
article
2014
eng
In this paper, we propose the Chebyshev wavelet approximation for the numerical solution of a class of integro-differential equation which describes the charged particle motion for certain configurations of oscillating magnetic fields. We show that the Chebyshev approximation transform an integral equation to an explicit system of linear algebraic equations. Illustrative examples are included to demonstrate the validity and applicability of the new technique.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
473
479
http://ijsts.shirazu.ac.ir/article_2564_460fcd2e3895b13df5b4ce1025525b93.pdf
dx.doi.org/10.22099/ijsts.2014.2564
Effective workflow for optimization of intelligent well completions
T.
Behrouz
Institute of Petroleum Engineering (IPE), School of Chemical Engineering,
Faculties of Engineering, University of Tehran, Tehran, Iran
author
M. R.
Rasaei
Institute of Petroleum Engineering (IPE), School of Chemical Engineering,
Faculties of Engineering, University of Tehran, Tehran, Iran
author
R.
Masoudi
Institute of Petroleum Engineering (IPE), School of Chemical Engineering,
Faculties of Engineering, University of Tehran, Tehran, Iran
author
text
article
2014
eng
Intelligent wells provide the ability for monitoring and control of downhole environment of the wells. Downhole monitoring is achieved through sensors while control is realized with downhole valves. Recovery from intelligent wells can be improved by proper selection of candidate wells/fields and optimizing the number, location and performance of the installed Interval Control Valves. Design criteria, however, suffer from incomplete understanding of the precise determination of these parameters, their interaction and combined effects. Having known the candidate well, we presented a new workflow to optimize the number, location and performance of Interval Control Valves as the main element of intelligent wells. This is a very computationally demanding and time consuming task; therefore a proxy model is developed and applied to speed up the process. Primary evaluations show that optimization of each parameter independently is not the best practice because of their interrelation and combined effects on objective function. An integrated optimization approach is therefore developed in which all the Interval Control Valves’ parameters are optimized together during the process. Considerable improvement in cumulative oil production and control of produced water is achieved by applying this method on real field data.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
481
487
http://ijsts.shirazu.ac.ir/article_2565_bf062ef8fb77d7f45954165c1a95757a.pdf
dx.doi.org/10.22099/ijsts.2014.2565
Synthesis and characterization of new acyclic octadentate ligand and its complexes
F. H. A.
Al-Jeboori
Ministry of Science and Technology, Baghdad, Iraq
author
K. k.
Hammud
Ministry of Science and Technology, Baghdad, Iraq
author
M. J.
Al-Jeboori
College of Education-Ibn-Al-Haitham, Baghdad University, Baghdad, Iraq
author
text
article
2014
eng
The reaction of an equivalent of 2- mercaptoethyl ammonium chloride with an equivalent of 2,6-diformyl -4- methyl phenol produced monoamine which was reacted with half equivalent of 1,2-diamine ethane to produce ethylene-bis-6-(2-mercapto-ethyl-imine)-methyl -4- methyl phenol [H4L]. The ligand was reacted with metal ions[Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II)] at reflux ethanol, under nitrogen at atmosphere. The ligand and derivative 2,6-diformyl-4-methylphenol and metal ion complexes were characterized by elemental microanalysis, IR, UV, (1H, 13C, 1H-1H, 1H-13C)NMR and mass spectroscopies and suggested structures and octahedral for the complexes [Cr, Mn, Co, and Ni] while complexes of [Fe, Zn, Cd, and Hg] suggested tetrahedral geometry and a distorted square planar geometry around copper complex.
Iranian Journal of Science and Technology (Sciences)
Springer
1028-6276
38
v.
4
no.
2014
489
497
http://ijsts.shirazu.ac.ir/article_2566_7e6b8b7d40182dd87f66611188880820.pdf
dx.doi.org/10.22099/ijsts.2014.2566