Showing papers by "Islamic Azad University published in 2004"
TL;DR: In this paper, the photocatalytic degradation of acid red 27 (AR27) was investigated using UV radiation in the presence of TiO2-P25 as a function of initial concentration of AR27 ([AR27]0), oxygen concentration ([O2]), TiO 2-P 25 amount, light intensity (Ia), pH and temperature.
Abstract: The photocatalytic degradation of Acid Red 27 (AR27) was investigated using UV radiation in the presence of TiO2-P25 as a function of initial concentration of AR27 ([AR27]0), oxygen concentration ([O2]), TiO2-P25 amount, light intensity (Ia), pH and temperature. The activation energy of the photocatalytic degradation of AR27 was 8.24 kJ mol−1. The photocatalytic degradation rate follows pseudo-first order kinetic with respect to the AR27 concentration. The following rate of decolorization was achieved by kinetic modeling: r AR 27 =5.294 I a exp −8247 RT 0.79 O 2 1+0.79 O 2 4.23 AR 27 1+4.23 AR 27 0 The calculated results obtained from above equation were in good agreement with experimental data. This model predicts the concentration of AR27 during the photodegradation process at different temperatures, light intensities, AR27 and oxygen concentrations.
215 citations
TL;DR: Numerical algorithms for solving fuzzy system of linear equations (FSLE) based on the iterative Jacobi and Gauss Sidel methods in detail are considered and there are followed by convergence theorems.
213 citations
TL;DR: The photodestruction of Acid Orange 7 (AO7), an anionic acidic dye, was studied in the UV/H2O2 process and a simple kinetic model is proposed which is in agreement with experimental results.
160 citations
TL;DR: A combination of Taylor and Block-Pulse functions on the interval [0,1], that is called Hybrid functions, is used to estimate the solution of a linear Fredholm integral equation of the second kind.
124 citations
TL;DR: Omitting the percutaneous nephrostomy tube and removing ureteral catheter at the end of surgery in selected patients were safe and accompanied by significantly reduced postoperative discomfort, length of hospitalization, and analgesic requirements.
Abstract: Purpose : Significant early postoperative discomfort after percutaneous procedures is usually secondary to nephrostomy tubes and externalized ureteral catheters. We describe our modification of the traditional percutaneous nephrolithotomy (PCNL) approach that we name "totally tubeless PCNL." Patients and Methods : Between June 2000 and May 2001, 60 consecutive PCNLs were performed at our centers. At the end of the surgery, we omitted the nephrostomy tube and removed the externalized catheter in selected patients: no solitary kidney, stone size <3 cm, and without any obstructions or arterial bleeding. A total of 30 patients underwent totally tubeless PCNL (group 1). We compared their results with those of a control group of 30 patients who underwent standard PCNL (group 2). The incidence of complications, analgesic requirements, length of hospitalization, and time to return to normal activities were compared in the two groups. Results : In both groups, PCNL was performed successfully without any significan...
120 citations
TL;DR: The Adomian decomposition method is applied to solve systems of linear and nonlinear Fredholm integral equations of the second kind to prove convergence of the method.
109 citations
TL;DR: This paper introduces a fuzzy trapezoidal approximation using the metric (distance) between two fuzzy numbers to solve the inequality of the following type: For α ≥ 1, β ≥ 1 using LaSalle's inequality.
100 citations
TL;DR: The hybrid Legendre and Block-Pulse functions on interval [0,1) are used to solve the linear integro-differential equation system, and the quadrature formulae for the calculation of inner products of any functions are constructed.
95 citations
TL;DR: Fuzzy reachable set can be approximated by proposed method with complete error analysis, which is illustrated by solving some linear and nonlinear fuzzy initial value problems.
Abstract: In this paper, a numerical method for solving 'fuzzy differential inclusions' is considered.Fuzzy reachable set can be approximated by proposed method with complete error analysis, which is discussed in detail. The method is illustrated by solving some linear and nonlinear fuzzy initial value problems.
94 citations
TL;DR: The numerical solution for a fuzzy nonlinear equation by Newton's method is proposed and the fuzzy quantities are presented in parametric form.
90 citations
TL;DR: Among the menders, knees, back and shoulders problems were more prevalent compared to other body regions and a new workstation was developed and eight menders were asked to work in the new work station, which improved working posture noticeably.
TL;DR: This paper presents a method for ranking extreme efficient decision making units in data envelopment analysis models with constant and variable returns to scale using the leave-one-out idea and l"1-norm.
TL;DR: An approach is presented in which without solving linear programming problems only using simple formula, the equitable allocation of shared costs between all DMUs is achieved.
18 Dec 2004
TL;DR: The different methods of UM for image enhancement are compared and the results show that majority of these algorithms are very sensitive to the enhancement factor and are good for sharpening.
Abstract: Contrast enhancement by the unsharp masking (UM) approaches are computationally and conceptually the simplest methods. In this paper, the different methods of UM for image enhancement are compared. These algorithms have been tested and compared for the same conditions. The results show that majority of these algorithms are very sensitive to the enhancement factor and are good for sharpening. This factor must be estimated recursively by considering the statistics of neighboring pixel values.
TL;DR: In this article, the authors investigated down core variations of heavy metals such as; Zn, Ni, Co, Mn, Fe and Al in a sediment core from Bay of Gorgan adjacent to the Caspian Sea was studied.
Abstract: In the present investigation down core variations of heavy metals such as; Zn, Ni, Co, Mn, Fe and Al in a sediment core from Bay of Gorgan adjacent to the Caspian Sea was studied. Inter-relationship amongst various parameters was brought out through correlation coefficients and cluster analysis. The results of present study reveals that Zn, Ni, Co and Mn possess both lithogenous and non-lithogenous sources. The increasing trend of Al towards top of sediment core is indicative higher erosion in the recent years. Interestingly, concentration of all studied metals increases toward core top (except for Fe) that might be indicative of influence of man’s activities residing in catchment area of Gorgan Bay and also oil exploration in the Caspian Sea. Further, 210 Pb and 137 Cs techniques were used to find out rate of sedimentation. The result of dating is indicative of sedimentation rate between 1.4 to 2.45 mm/yr. based on 210 Pb and 137 Cs activities respectively.
TL;DR: In this paper, a novel lanthanum(III) sensor based on bis(thiophenal)phenylen-1,3-diamine (TPD) is described.
Abstract: A novel lanthanum(III) sensor based on bis(thiophenal)phenylen-1,3-diamine (TPD) is described. The sensor was prepared by incorporating the TPD into plasticized PVC membrane. The sensor displays high selectivity for lanthanum with respect to many common alkali, alkaline earth, transition and heavy metal ions. The effect of membrane composition and pH and influence of additive anionic on the response properties of were investigated. The sensor with 35% PVC, 54% solvent mediator, 8% ionophore and 3% anionic additive, shows the best potentiometric response characteristics. It displays a Nernstian behavior (19.6 mV per decade) over the concentration range 1.0×10 −7 to 1.0×10 −1 M. The detection limit of the electrode is 2.0×10 −8 M (∼3.0 ng/ml). The response time of the electrode is very fast (10 s) in whole concentration range. The sensor can be used in the pH range 3.5–9.5 for at least 2 months. The membrane sensor was used as an indicator electrode in potentiometric titration of lanthanum ions with EDTA. It was successfully applied in determination of fluoride ions in mouth wash preparations.
TL;DR: In this article, the Hill equation was used to analyze the binding isotherm and enthalpy curve for Me2SnCl2-DNA interaction, and the first set of binding sites is occupied by one mole of ligand bound per near 1 base pair of DNA.
TL;DR: In this article, a coal sample from Iran was desulfurized with combination of microwave irradiation and peroxyacetic acid washing in a batch reactor, and the effect of irradiation time and power, peroxide acid reaction time and temperature and particle size on reduction of sulfur was investigated.
TL;DR: In this paper, a 1:2 proton transfer self-associated compound LH2 was synthesized from the reaction of dipicolinic acid, pydcH2, (2, 6-pyridinedicarboxylic acid), and guanidine hydrochloride, (GH+)(Cl) using X-ray diffraction.
Abstract: A novel 1:2 proton transfer self-associated compound LH2, (GH+)2(pydc2—), was synthesized from the reaction of dipicolinic acid, pydcH2, (2, 6-pyridinedicarboxylic acid), and guanidine hydrochloride, (GH+)(Cl—). The characterization was performed using IR, 1H and 13C NMR spectroscopy and single-crystal X-ray diffraction. LH2 · H2O crystallizes in the space group C2/c of the monoclinic system and contains eight molecules per unit cell. The unit cell dimensions are: a = 26.480(5)A, b = 8.055(2)A, c = 14.068(3)A. The first coordination complex (GH)2[Cd(pydc)2] · 2H2O, was prepared using LH2 and cadmium(II) iodide, and characterized by 1H and 13C NMR spectroscopy and X-ray crystallography. The crystal system is triclinic with space group P1¯ with one molecule per unit cell. The unit cell dimensions are: a = 8.5125(7)A, b = 11.0731(8)A, c = 13.2404(10)A. The cadmium(II) atom is six-coordinated with a distorted octahedral geometry. The two pydc2— units are almost perpendicular to each other. The protonation constants of the building blocks of the pydc-guanidine adduct, the equilibrium constants for the reaction of pydc2— with guanidine and the stoichiometry and stability of the Cd2+ complex with LH2 in aqueous solution were accomplished by potentiometric pH titration. The solution studies strongly support a self-association between pydc2— and GH+ with a stoichiometry for the CdII complex similar to that observed for the isolated crystalline complex. In fact, the [Cd(pydc)2]2— complex was found as the most abundant species in solution (> 90 %) at a pH >5.
Ein neuer assoziierter Proton-Transferkomplex aus Dipicolinsaure und Guanidin und sein Cadmium(II)-Komplex — Synthese, Kristallstruktur und Untersuchungen in Losung
Eine neue assoziierte 1:2 Protontransfer-Verbindung LH2, (GH+)2(pydc2—), wurde bei der Reaktion von Dipicolinsaure, pydcH2, (2, 6-Pyridindicarbonsaure), und Guanidinhydrochlorid, (GH+)(Cl—) erhalten. Die Charakterisierung erfolgte durch IR, 1H- und 13C-NMR-Spektroskopie sowie Einkristall-Rontgenstrukturanalyse. LH2 · H2O kristallisiert monoklin in der Raumgruppe C2/c, Z = 8. Die Gitterkonstanten sind: a = 26.480(5)A, b = 8.055(2)A, c = 14.068(3)A.
Als erster Koordinationskomplex wurde aus LH2 and Cadmium(II)-iodid (GH)2[Cd(pydc)2] · 2H2O prapariert und durch 1H- and 13C-NMR-Spektroskopie sowie Rontgenstrukturanalyse charakterisiert: Triklin, Raumgruppe P1¯, Z = 1, a = 8.5125(7)A, b = 11.0731(8)A, c = 13.2404(10)A. Das Cadmium(II)-Ion ist verzerrt-oktaedrisch koordiniert. Die zwei pydc2—-Einheiten stehen immer senkrecht zu einander. Die Protonisierungskonstanten der pydc-Guanidin-Addukte, die Gleichgewichtskonstanten der Reaktion von pydc2— mit Guanidin und die Stochiometrie und Stabilitat des Cd2+-Komplexes mit LH2 in wasriger Losung wurde durch potentiometrische pH-Titration bestimmt. Die Untersuchungen in Losung zeigen deutlich die Selbstassoziaton zwischen pydc2— und GH+ mit einer Stochiometrie des CdII-Komplexes entsprechend der des isolierten kristallinen Komplexes. Der [Cd(pydc)2]2—-Komplex war in Losung bei pH >5 die zu > 90 % vertretene Spezies.
TL;DR: In this article, the inefficiency of the traditional TOC algorithm in handling the multiple bottleneck problem is discussed through an example and an improved algorithm, which is much more efficient and can reach the optimum solution with considerable speed, is presented.
Abstract: One of the most important decisions made in production systems is determining the product mix in such a way that maximum throughput would be obtained. Several algorithms to determine the product mix under the theory of constraints (TOC) have been developed. In this paper, the inefficiency of the traditional TOC algorithm in handling the multiple bottleneck problem is discussed through an example. Then, the latest algorithm and its disadvantages will be discussed and an improved algorithm, which is much more efficient and can reach the optimum solution with considerable speed, will be presented. Finally, the improved algorithm and the integer linear programming (ILP) method will be compared with each other through the example.
TL;DR: In this article, a dysprosium [Dy(III)]-selective solvent polymeric membrane sensor based on N,N-bis(pyrrolidene) benzne-1,2-diamine, poly(vinyl chloride)(PVC), the plasticizer benzylacetate (BA), and anionic site is described.
Abstract: In this work a dysprosium [Dy(III)]-selective solvent polymeric membrane sensor based on N,N-bis(pyrrolidene) benzne-1,2-diamine, poly(vinyl chloride)(PVC), the plasticizer benzylacetate (BA), and anionic site is described. This sensor responds to Dy(III) activity in a linear range from 1.0×10−5 to 1.0×10−1 M, with a slope of 20.6±0.2 mV per decade and a detection limit of 6.0×10−6 M at the pH range of 3.5–8.0. It has a fast response time of<20 s in the entire concentration range, and can be used for at least 2 months without any considerable divergence in the electrode potentials. The proposed sensor revealed comparatively good selectivity with respect to common alkali, alkaline earth, transition and heavy metal ions. It was used as an indicator electrode in the potentiometric titration of fluoride ions and in determination of concentration of F – ions in some mouth washing solutions.
TL;DR: The Adomian decomposition method is applied to solve a system of nonlinear equations and convergence of the method is proved.
TL;DR: This paper reviews the policy incentives for promotion of RETs in the Islamic Republic of Iran and concludes that with appropriate policy formulations and strategies, RETs can bring about the required socio-economic development in Iran.
Abstract: Around the globe, developing countries have reported different cases of successfully implemented Renewable Energy (RE) program supported by bilateral or multilateral funding. In developing countries subsidy has played a big role in RE program marketing and whether this will lead to sustainable development is yet to be determined. The adoption of implementation strategies that will support sustainable development and overcoming barriers that hinder expansion of Renewable Energy Technolog ies (RETs) still remains as a big challenge to stakeholders involved in promotion of RE resources in developing countries. In this respect, developing countries need to re -examine their environmental policy for promotion of RETs in order to define its role in revitalization of their economies. This paper reviews the policy incentives for promotion of RETs in the Islamic Republic of Iran. Setting -up international collaborative business ventures between local industry in Iran and RE companies in developed cou ntries is proposed as an implementation strategy that will appropriate diffusion of RETs in the country. An organizational framework that may help to attain this objective is discussed and a structural model for RE business partnership is presented. It is concluded that with appropriate policy formulations and strategies, RETs can bring about the required socio -economic development in Iran.
TL;DR: This paper investigates inputs/outputs estimate in the presence of undesirable factors and proposes a multiple objective linear programming (MOLP) model that could estimate input/output levels, regardless of the efficiency or inefficiency of the DMU.
TL;DR: In this work, a mathematical relation between the apparent reaction rate constant of the AR27 removal and used H2O2 was established and the results indicate that the apparent Reaction rate constant in the UV/H2O 2 process is a function of H 2O2 concentration.
TL;DR: In this paper, the unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite moving plate with transpiration W 0 is investigated when the axial velocity and wall tempera- ture vary arbitrarily with time.
Abstract: The unsteady viscous flow and heat transfer in the vicinity of an axisymmetric stagnation point of an infinite moving plate with transpiration W0 are investigated when the axial velocity and wall tem- perature vary arbitrarily with time. The free stream is steady and with a strain rate of a. An exact solu- tion of the Navier-Stokes equations and energy equation is derived in this problem. A reduction of these equations is obtained by the use of appropriate transformations for the most general case when the tran- spiration rate is also time-dependent, but results are presented only for uniform values of this quantity. The general self-similar solution is obtained when the axial velocity of the plate and its wall tempera- ture vary as specified time-dependent functions. For completeness, sample semi-similar solutions of the unsteady Navier-Stokes equations have been obtained numerically using a finite difference scheme. All the solutions above are presented for different values of dimensionless transpiration rate, S = W0/ � a�, whereis the kinematic viscosity of the fluid. The effects of the sundry parameters, including transpira- tion rate, Prandtl number, oscillation frequency and accelerating/decelerating parameter, on the velocity and temperature profiles, as well as surface shear stresses and heat transfer coefficient, are investigated and results are shown through graphs.
TL;DR: In this approach, organization classification remains unchanged under perturbations of the interval data, and radius of stability for all decision making units, with interval data is found.
Journal Article•
TL;DR: The survey was performed using the cross-sectional method on 506 students selected using multi-stage random sampling and the fluorosis level according to Deans classification and DMFT with its standard method were surveyed.
Abstract: The survey was performed using the cross-sectional method on 506 students selected using multi-stage random sampling. The fluorosis level according to Deans classification and DMFT with its standard method were surveyed. The water fluoride level was estimated in 6 town sources twice, using Alizarin chemical method. The fluorosis and DMFT prevalence in the samples was determined. A total number of 506 students (55.6% boys and 44.4% girls) aged 13 +/- 3 years were examined. The water fluoride level was 2.43 +/- 0.23 ppm and in all the samples, which was more than normal. 19.9% of the subjects being surveyed were healthy 43.6% had mild, 25% moderate and 11.5% had severe fluorosis. Severe fluorosis was found in 65.8% of girls and 34.2% of boys (p < 0.05). The mean DMFT value was 1.8 +/- 1.73 and was higher in girls in comparison with boys (p < 0.05).
TL;DR: An evaluation of literature and recent collections made by Iranian researchers resulted in a list of 396 species of lichenized fungi and eight species ofLichenicolous or allied fungi for Iran, of which 97 species are new for Iran while some species not confirmed by recent collections are doubtful.
Abstract: Seaward, M. R. D., Sipman, H. J. M., Schultz, M., Maassoumi, A. A., Haji Moniri Anbaran, M. & Sohrabi, M.: A preliminary lichen checklist for Iran. – Willdenowia 34: 543-576. – ISSN 0511-9618; © 2004 BGBM Berlin-Dahlem. An evaluation of literature and recent collections made by Iranian researchers resulted in a list of 396 species of lichenized fungi and eight species of lichenicolous or allied fungi for Iran. Of these, 97 species are new for Iran while some species not confirmed by recent collections are doubtful. Pertinent literature references and, for the newly reported species, locality and collection data are presented.