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Showing papers by "Islamic Azad University published in 2002"


Journal ArticleDOI
TL;DR: In this article, the equilibrium and stability equations of a rectangular plate made of functionally graded material under thermal loads are derived, based on the classical plate theory, when it is assumed that the material properties vary as a power form of thicknesscoordinate variable z and when the variational method is used, the system of fundamental differential equations is established.
Abstract: Equilibrium and stability equations of a rectangular plate made of functionally graded material under thermal loads are derived, based on the classical plate theory. When it is assumed that the material properties vary as a power form of thicknesscoordinate variable z and when the variational method is used, the system of fundamental differential equations isestablished. Thederived equilibrium and stability equationsforfunctionally graded plates areidenticalwith theequationsforhomogeneousplates. Bucklinganalysisoffunctionally graded platesunderfour typesofthermalloadsiscarriedoutresultinginclosed-formsolutions.Thebucklingloadsarereducedtothecritical buckling temperature relationsfor functionally graded plates with linearcomposition of constituent materials and homogeneous plates. The results are validated with the reduction of the buckling relations for functionally graded plates to those of isotropic homogeneous plates given in the literature.

381 citations


Journal ArticleDOI
TL;DR: In this paper, a general analysis of one-dimensional steady-state thermal stresses in a hollow thick cylinder made of functionally graded material is developed, where the temperature distribution is assumed to be a function of radius, with general thermal and mechanical boundary conditions along the inside and outside surfaces.

361 citations


Journal ArticleDOI
TL;DR: In this article, the equilibrium and stability equations of rectangular functionally graded plates (FGPs) are determined using the variational approach, where the material properties vary with the power product form of thickness coordinate variable z.
Abstract: In the present article, equilibrium and stability equations of rectangular functionally graded plates (FGPs) are determined using the variational approach. Derivation of equations are based on the classical plate theory. It is assumed that the material properties vary with the power product form of thickness coordinate variable z. Equilibrium and stability equations for FGPs are the same as the equations for homogeneous plates. The equilibrium and stability equations are employed to study the buckling behaviour of functionally graded plates with all edges simply supported and subjected to in-plane loading conditions. By equating power law index to zero, predicted relation is reduced to the buckling equation of homogeneous plates which is available in the literature.

248 citations


Journal ArticleDOI
TL;DR: The basic idea is to transform the fuzzy CCR model into a crisp linear programming problem by applying an alternative α-cut approach and a ranking method for fuzzy DMUs using presented fuzzy DEA approach is proposed.
Abstract: In this paper, a fuzzy version of CCR model (Charnes, Cooper and Rhodes (1978)) with asymmetrical triangular fuzzy number is presented and a procedure is suggested for its solution. The basic idea is to transform the fuzzy CCR model into a crisp linear programming problem by applying an alternative α-cut approach. Thereby, the problem is converted to an interval programming. In this method, instead of comparing the equality (or inequality) of two intervals, a variable is defined in the interval, not only satisfies the set of constraints, but also maximizes the efficiency value. We also propose a ranking method for fuzzy DMUs using presented fuzzy DEA approach. To demonstrate the concept, numerical examples are solved and solutions are compared with Guo and Tanaka (2001).

225 citations


Journal ArticleDOI
TL;DR: In this article, the buckling analysis of radially loaded solid circular plate made of functionally graded material is presented, where the edge is either simply supported or clamped and the plate is assumed to be geometrically perfect and the equilibrium and stability equations, derived through variational formulation, are used to determine the prebuckling forces and critical buckling loads.

179 citations


Journal ArticleDOI
TL;DR: In this paper, the nonlinear equilibrium and linear stability equations are derived using variational formulations for thermal buckling of solid circular plates under uniform temperature rise, gradient through the thickness, and linear temperature variation along the radius.
Abstract: Thermal buckling of circular plates made of functionally graded material is discussed. The nonlinear equilibrium and linear stability equations are derived using variational formulations. The thermal buckling of solid circular plates under uniform temperature rise, gradient through the thickness, and linear temperature variation along the radius are considered, and the buckling temperatures are derived. The buckling temperatures are derived for simply supported and clamped edges. The results are verified with known results in the literature.

143 citations


Journal ArticleDOI
TL;DR: The authors investigated the use of interpersonal metadiscourse in two major academic fields: the social sciences (SS) and the natural sciences (NS) by using genre analysis, and found that the authors of the SS writers employed interpersonal metaddiscourse more frequently than the NS writers.
Abstract: By using genre analysis, this study investigates the way writers use interpersonal metadiscourse to partly reveal their identity and examines their selected mode of interaction in two major academic fields: the social sciences (SS) and natural sciences (NS). A total of 55 academic research articles from the SS and NS were selected as the corpus of this study. A comparison of the two disciplines was made, based on the use of interpersonal metadiscourse through `hedges', `emphatics' and `attitude markers'. The analysis showed that the SS writers employed interpersonal metadiscourse more frequently than the NS writers. One-to-one comparison further showed that they varied significantly in their use of hedges and attitude markers but there was little difference in their use of emphatics. However, the use of hedges and emphatics was significantly different within each discipline. A qualitative in-depth analysis revealed that the choice of validity markers was closely related to the type of article being studied.

131 citations


Proceedings ArticleDOI
07 Aug 2002
TL;DR: A prototype and analytical studies of a spherical rolling robot, a new design of an omnidirectional robot system that can arbitrarily begin to move in any direction to the target, and autonomously roll and reach any desired position is described.
Abstract: This paper describes a prototype and analytical studies of a spherical rolling robot, a new design of an omnidirectional robot system. The robot can arbitrarily begin to move in any direction to the target, and autonomously roll and reach any desired position. Our design considers a spherical robot with an internal mechanism for propulsion. The propulsion mechanism distributes weights radially along spokes fixed inside the sphere and enables the robot to accelerate, decelerate, and move with constant velocity. A mathematical model of the robot's dynamic and motion is instructed. An algorithmic motion planning is developed and, partly, pseudo-code of that is presented. For a number of missions, it is shown experimentally that the model agrees well with the results.

131 citations


Journal Article
TL;DR: In this article, the authors present dynamic properties of fine grained soils in south of Tehran through field and laboratory studies, based on field geoseismic investigations, new Vs -N(SPT) correlations for fine graining soils are presented.
Abstract: Shear modulus, damping ratio and shear wave velocity profiles are important input parameters in site response analysis. For seismic microzonation in south of Tehran, many field and laboratory studies were performed. Field investigations include seismic refraction, down-hole, SASW and SPT while laboratory tests encompass stress controlled cyclic triaxial and resonant column tests on undisturbed samples of low to medium plastic silty materials. This paper presents dynamic properties of fine grained soils in south of Tehran through field and laboratory studies. Based on field geoseismic investigations, new Vs -N(SPT) correlations for fine grained soils are presented. Also laboratory test results reveal that effective confining pressure at stage of consolidation has a remarkable effect on both strain dependent shear modulus and damping ratio of very low plastic soils but by increasing soil plasticity this effect disappears. Evaluation of plasticity effects on deformation properties shows that for PI<12, plasticity index does not have any outstanding effect on these properties, while by increasing PI, shear modulus ratio will increase and damping ratio will decrease.

102 citations


Journal ArticleDOI
TL;DR: It is concluded that the histaminergic system has an interaction with opioidergic system that is involved in the memory retention process.

101 citations


Journal Article
TL;DR: In this article, the evolution of shallow-water chondrichthyan assemblages on the shelves of Central Iran and the Tafilalt Platform, Morocco, related to time and environmental changes is discussed.
Abstract: Ichthyoliths, mainly shark teeth, from the Famennian of Iran and Northwest Africa are described Evolution of shallow-water chondrichthyan assemblages on the shelves of Central Iran and the Tafilalt Platform, Morocco, related to time and environmental changes, is discussed Four new taxa, viz Deihim mansureae gen et sp nov, Protacrodus serra sp nov, Phoebodus depressus sp nov, and Ph gothicus transitans subsp nov are erected and provisional reconstructions of heterodonty in dentitions of several Famennian sharks are proposed

Proceedings ArticleDOI
28 Oct 2002
TL;DR: In this article, a new definition of single-phase instantaneous active power p(t) and reactive power q(t), is used in control circuits, and the principle of operation is explained using analytical and simulation results.
Abstract: The single-phase pq theory is used for instantaneous reactive power and current harmonics compensation of single-phase loads. A new definition of single-phase instantaneous active power p(t), and reactive power q(t), is used in control circuits. Generation of reference compensating current of single-phase active filter is based on canceling the alternating component of p(t) for harmonic compensation and q(t) for reactive power compensation. The principle of operation is explained using analytical and simulation results.

Journal ArticleDOI
TL;DR: In this article, a group method of data handling (GMDH)-type neural networks are used for the modelling of the explosive compaction process of metallic powders, and the singular value decomposition (SVD) can be effectively used to find the vector of coefficients of quadratic subexpressions embodied in such GMDH-type networks.
Abstract: Group method of data handling (GMDH)-type neural networks are used for the modelling of the explosive compaction process of metallic powders. The aim of such modelling is to show how two characteristics of the explosive compaction, namely, the compaction energy and the compact density percentage change with the variation of important parameters, involved in the explosive compaction of metallic powders. It is also demonstrated that singular value decomposition (SVD) can be effectively used to find the vector of coefficients of quadratic sub-expressions embodied in such GMDH-type networks. Such application of SVD will highly improve the performance of GMDH-type networks to model the very complex process of explosive compaction of metallic powders. Moreover, it is shown that the use of dimensionless input variables, rather than direct physical input variables, in such GMDH-type network modelling leads to simpler polynomial representation of the explosive compaction process which can be used for modelling and prediction purposes.

Journal ArticleDOI
TL;DR: In this paper, the interactions of calcium and magnesium ions with caffeine and theophylline have been investigated in aqueous solution at physiological pH. Fourier Transform infrared (FTIR) spectroscopy and absorption spectra were used to determine the cation binding mode and the association constants.

Journal ArticleDOI
TL;DR: An essential oil composition of Mentha longifolia (L.) Huds was analyzed by GC and GC/MS as discussed by the authors, and three components were identified representing 99.3% of the oil.
Abstract: An essential oil composition of Mentha longifolia (L.) Huds. was analyzed by GC and GC/MS. Twenty-three components were identified representing 99.3% of the oil. Carvone (61.8%) and limonene (19.4%) were the most abundant constituents.

Journal ArticleDOI
TL;DR: Water-distilled essential oil from the aerial parts of Ferulago angulata (Schlecht.) Boiss was analyzed by GC and GC/MS and twenty-five components were characterized, representing 88.7% of the total components detected with β-phellandrene and α-p Hellandrene as the major constituents.
Abstract: Water-distilled essential oil from the aerial parts of Ferulago angulata (Schlecht.) Boiss. was analyzed by GC and GC/MS. Twentγ-five components were characterized, representing 88.7% of the total components detected with β-phellandrene (32.0%) and α-phellandrene (13.8%) as the major constituents.

Journal ArticleDOI
TL;DR: The composition of the essential oil of Parsa, an endemic plant of Iran was analyzed for the first time by GC and GC/MS and thirteen components, mainly monoterpenes, were characterized, representing 89.1% of the total components detected.
Abstract: The composition of the essential oil ofTanacetum khorassanicum (Krasch.) Parsa, an endemic plant of Iran was analyzed for the first time by GC and GC/MS. Thirteen components, mainly monoterpenes, were characterized in the oil, representing 89.1% of the total components detected. (E)-Myroxide (19.8%), camphor (16.4%), isopulegone (13.4%) and 1,8-cineole (11.4%) were identified as major constituents.

Journal ArticleDOI
16 May 2002
TL;DR: It is shown by example that Definition 3 in Ming Ma (Fuzzy Sets and Systems 111 (2000) 351) is not a metric.
Abstract: We show by example that Definition 3 in Ming Ma (Fuzzy Sets and Systems 111 (2000) 351) is not a metric.

Journal ArticleDOI
TL;DR: It is concluded that activation of both dopamine D1 and D2 receptors may suppress naloxone-induced jumping in morphine-dependent mice, and that stimulation of dopamine D 1 receptors during development of morphine dependence may increase diarrhoea through peripheral mechanism.

Journal ArticleDOI
TL;DR: In this article, a coprecipitated mixture of nickel and aluminum hydroxides was used to extract the nickel ions in the tetrahedral coordinated sites of a nickel aluminate spinel.

Journal ArticleDOI
TL;DR: The essential oil obtained by hydrodistillation of the aerial parts of Artemisia aucheri Boiss was analyzed and 17 components were identified, constituting 88.2% of the oil.
Abstract: The essential oil obtained by hydrodistillation of the aerial parts of Artemisia aucheri Boiss. was analyzed by GC and GC/MS. Seventeen components were identified, constituting 88.2% of the oil. The major components were camphor (45.5%) and 1,8-cineole (14.3%).

Journal ArticleDOI
TL;DR: The volatile constituents of the aerial parts of Tanacetum balsamita have been examined by GC and GC/MS, mainly monoterpenes, of which carvone was the major one.
Abstract: The volatile constituents of the aerial parts of Tanacetum balsamita have been examined by GC and GC/MS. Twenty-one components were detected, mainly monoterpenes, of which carvone (68%) was the major one.

Journal ArticleDOI
TL;DR: Novel spiroindoles 5 are prepared easily via a one-pot, 1,3-dipolar cycloaddition reaction of azomethine imines with isatin imines under thermal conditions.

Journal ArticleDOI
TL;DR: Water-distilled essential oil from aerial parts of Ruta chalepensis L. was analyzed and 11 compounds representing 92.9% of the oil were identified.
Abstract: Water-distilled essential oil from aerial parts of Ruta chalepensis L. was analyzed by GC and GC/MS. Eleven compounds representing 92.9% of the oil were identified. 2-Undeeanone (52.5%) and 2-nonanone (24.1%) were the major constituents.

Journal ArticleDOI
TL;DR: This is the first report of the occurrence of INSV on ornamentals in Iran, and within the genus Tospovirus the TSWV peanut isolate has been reported from Iran.
Abstract: Impatiens necrotic spot virus (INSV) (genus Tospovirus, family Bunyaviridae) has been detected in commercial nurseries and field-grown ornamentals in Mahallat (Markazi) and Tehran provinces of Iran. INSV on ornamentals was first reported in 1990 (2). Ornamental plants with small necrotic spots, leaf yellowing, ring spots, necrotic vein clearing, wilting, and dwarf symptoms were collected. For mechanical inoculation on selected host species, leaf samples were triturated in chilled 0.01 phosphate buffer, pH 7.2, containing 0.02% sodium sulfite. Cowpea (cv. Mashad local), Chenopodium amaranticolor, Datura mete, Nicotiana rustica, N. tabacum (cv. White Burly), and Lycopersicon sp. produced local necrotic symptoms 5 days postinoculation. N. rustica, N. tabacum cv. White Burley, and D. metel also developed systemic mosaic symptoms that were followed by total wilting and death of the plant. The severity of the disease was higher in warm weather (July and August in greenhouses). Thrips tabaci and Frankliniella intonsa were often present at the site of INSV infection. Triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) was applied using a commerical polyclonal antibody kit (As-0115) in combination with monoclonal antibody 5E4 (As-0117) prepared against nucleoprotein of INSV isolate Pv-0280 (antibody kits and positive control were a gift from DSMZ, Braunschweig, Germany). Samples were tested for the presence of TSWV and INSV. The ornamental species found infected with INSV were Rosa sp., Gazania sp., Chrysanthemum sp., Leucanthemum sp., Matricaria camomila, Pelargonium roseum, Salvia sp., and Dianthus caryophyllus, which were collected from the Mahallat area; and Gazania sp. and Bougainvillea spectabilis collected from the Tehran Province. ELISA values of field-infected samples (OD405, read after 1h) diluted at 1:10 (wt/vol) were 0.317 (minimum) and 0.914 (maximum), and 0.312 for the positive control. None of the samples reacted in TAS-ELISA with Tomato spotted wilt virus (TSWV) (antibody kits, As-0105, As-0106, and As-01106, gift from DSMZ). A few samples of Chrysanthemum sp. and Leucanthemum sp. (collected from the Mahallat area) reacted in TAS-ELISA with TSWV, indicating they were doubly infected with TSWV and INSV. Within the genus Tospovirus the TSWV peanut isolate has been reported from Iran (1). To our knowledge, this is the first report of the occurrence of INSV on ornamentals in Iran. References: (1) A. R. Golnaraghi et al. Plant Dis. 85:1286, 2001 (2) M. D. Law and J. W. Moyer. J. Gen.Virol.71:933, 1990.

Journal ArticleDOI
TL;DR: In this article, the properties of AMTTO complexes [Cu(AMTTO)Cl2] (2), [CA(AMtTO)2]Cl (3), and [CA (PPh3)2Cl] (4) have been described and characterized by IR spectroscopy and elemental analyses.
Abstract: The complexes [Cu(AMTTO)Cl2] (2), [Cu(AMTTO)2]Cl (3), and [Cu(AMTTO)(PPh3)2Cl] (4) have been prepared and characterized by IR spectroscopy and elemental analyses. Also single-crystal X-ray diffraction studies on compound 2, 3 and 4 revealed that AMTTO acts in 2 as a bidentate ligand via nitrogen and sulfur atoms, in 3 and 4 as a monodentate via sulfur atoms. Complex 3 was already mentioned in literature, but the structure was not described in detail. The molecules in 2 form infinite chains through additional weak Cu—S interactions along [010] indicating the Jahn-Teller distortion of the d9 ion Cu2+. The infinite chains are connected by hydrogen bonding along [100]. Crystal data for 2 at —80°C: monoclinic, space group P21/m, a = 666.7(1), b = 609.4(1), c = 1132.6(2) pm, b = 95.46(2)°, Z = 2, R1 = 0.0365; for 3 at —80°C: orthorhombic, space group Pbcn, a = 1291.2(2), b = 1146.5(1), c = 1000.5(1) pm, Z = 4, R1 = 0.0315; for 4 at —80°C: monoclinic, space group, P21/n, a = 879.4(1), b = 1849.3(2), c = 2293.8(3) pm, β = 92.38(1)°, Z = 4, R1 = 0.0688.

Journal ArticleDOI
TL;DR: A new kinetic-spectrophotometric method is described for the determination of ultra trace amounts of Pd(II) and the influence of more than 40 potential interfering ions was studied for the selectivity.

Journal ArticleDOI
TL;DR: In this paper, the NH-acids such as pyrrole, indole, imidazole, or benzimidazoles were added to methyl or ethyl propiolate under neutral conditions in the presence of a catalytic amount of triphenylphosphine.
Abstract: The f -addition of NH-acids such as pyrrole, indole, imidazole, or benzimidazole to methyl or ethyl propiolate proceeds under neutral conditions in the presence of a catalytic amount of triphenylphosphine to give the corresponding f -substituted alkyl acrylates.

Journal ArticleDOI
TL;DR: The essential oil isolated by hydrodistillation from aerial parts of Chaerophyllum macrospermum (Spreng.) Fisch was analyzed by GC and GC/MS and sixteen components were identified, constituting 99.6% of the oil.
Abstract: The essential oil isolated by hydrodistillation from aerial parts of Chaerophyllum macrospermum (Spreng.) Fisch. et C.A. Mey., and was analyzed by GC and GC/MS. Sixteen components were identified, constituting 99.6% of the oil. The major components were (E)-β-ocimene (40.0%), tricyclene (19.4%), δ-3-carene (18.3%) and mycrene (10.1%).

Journal ArticleDOI
TL;DR: A histamine-induced impairment of memory retention through histamine H(1) receptors and an alpha(2)-adrenoceptor mechanism may be involved in the histamine response.