Showing papers by "Islamic Azad University published in 1999"
TL;DR: In this article, the slags from blast furnace (iron making ) and converter (steel making) after magnetic separation are mixed with limestone of six different compositions, and ground materials are fired in a pilot plant scale rotary kiln to 1350 °C for 1 h. Initial and final setting times, consistency of standard paste, soundness, free CaO, and compressive and fractural strengths after 3, 7, and 28 days are measured.
154 citations
TL;DR: In this article, a thermodynamic model has been used to investigate vortex tube energy separation and an equation has been derived for the rate of entropy generation, which is used to model the irreversibility term.
88 citations
TL;DR: In this paper, the composition of the oils from leaves and flowers of three Salvia species (S. aethiopis L., S. multicaulis Vahl, and S. hypoleuca Benth) has been analyzed by a combination of GC and GC-MS.
Abstract: The composition of the oils from leaves and flowers of three Salvia species (S. aethiopis L., S. hypoleuca Benth. and S. multicaulis Vahl.) has been analysed by a combination of GC and GC–MS. During the flowering period, two oils (S. aethiopis and S. hypoleuca) consisted mainly of sesquiterpenes, while in S. multicaulis oil monoterpenes predominated over sesquiterpenes. The major components of the oil of S. aethiopis were β-caryophyllene (24.6%), α-copaene (15.5%) and germacrene D (13.5%). In the oil of S. hypoleuca, β-caryophyllene (22.0%), δ-elemene (15.5%) and bicyclogermacrene (15.1%) were found to be the major constituents. α-Pinene (26.0%), 1,8-cineole+limonene (20.0%) and camphor (19.0%) were the predominant compounds in the oil of S. multicaulis. Copyright © 1999 John Wiley & Sons, Ltd.
85 citations
TL;DR: In this article, the stability of penicillin G was analyzed as a function of temperature, pH, and the combined effects of pH and temperature by proposing a second-order polynomial model for the decomposition reaction rate constant.
55 citations
TL;DR: In this paper, the authors investigated the oils obtained by steam distillation of the flowers and leaves of Tanacetum polycephalum growing wild in Iran by a combination of GC and GC-MS.
Abstract: The oils obtained by steam distillation of the flowers and leaves of Tanacetum polycephalum growing wild in Iran were investigated by a combination of GC and GC–MS. About 10 compounds in the flowers and 10 compounds in the leaves have been identified. The main constituents of the oil of the flowers were camphor (59.1%), camphene (14.9%) and 1,8-cineole (10.1%), whereas the leaves oil comprised mainly camphor (53.5%), bornyl acetate (12.1%), camphene (10.9%), 1,8-cineol (7.8%) and borneol (6.1%). Copyright © 1999 John Wiley & Sons, Ltd.
39 citations
TL;DR: Fe and Ni were simultaneously determined in aqueous medium with xylenol orange at pH 4.0 using an artificial neural network consisting of three layers of nodes trained by applying a back-propagation learning rule.
38 citations
TL;DR: The essential oils of Achillea aucheri Boiss and A kellalensis Boiss et Hausskn, which are endemic to Iran, have been analyzed by GC and GC/MS as discussed by the authors.
Abstract: The essential oils of Achillea aucheri Boiss and A kellalensis Boiss et Hausskn, which are endemic to Iran, have been analyzed by GC and GC/MS The oil of A aucheri was found to contain 1,8-cineole (407%), α-terpineol (113%), β-pinene (108%) and α-pinene (103%) as major constituents The oil of A kellalensis was characterized by a higher amount of camphor (340%), borneol (126%), α-thujone (125%), 1,8-cineole (113%), bornyl acetate (73%) and camphene (70%)
32 citations
TL;DR: The chemical composition of the essential oil obtained from the aerial parts of Nepeta asterotrichus Rsch. was examined by using GC and GC/MS as discussed by the authors, and terpinen-4-ol (22.8%), 1,8-cineole (17.4%), 4aβ 7a, 7aβ-nepetalactone (14.8), linalool (12.5%), and γ-terpinene (10.6%) were found to be the major constituents.
Abstract: The chemical composition of the essential oil obtained from the aerial parts of Nepeta asterotrichus Rsch. F. et Aell. was examined by using GC and GC/MS. Among the 15 components identified in this oil, terpinen-4-ol (22.8%), 1,8-cineole (17.4%), 4aβ 7a, 7aβ-nepetalactone (14.8%), linalool (12.5%) and γ-terpinene (10.6%) were found to be the major constituents.
31 citations
TL;DR: The essential oil of the aerial parts of Tanacetum polycephalum was analyzed by capillary GC and GC/MS as mentioned in this paper, and the main constituents were camphor (18.2%), 1,8-cineole (17.0%), carveol (9.1%), and trans-isopulegone (8.0%).
Abstract: The essential oil of the aerial parts of Tanacetum polycephalum was analyzed by capillary GC and GC/MS. The main constituents were camphor (18.2%), 1,8-cineole (17.0%), carveol (9.1%) and trans-isopulegone (8.0%).
28 citations
TL;DR: The generalized Gaussian quadrature formula is applied for conditional Monte Carlo simulation to increase its speed and develop its domain of application, and a suitable criterion is presented for the efficiency of conditional Carlo simulation.
22 citations
TL;DR: In this paper, the reaction of 4amino-6-methyl-1,2,4-triazine-3(2,H)-thione-5-one with silver(I) nitrate in methanol gives the complex [Ag(AMTTO)2]NO3 (1). 1 was characterized by IR and 13C NMR spectroscopy and by an X-ray structure analysis.
Abstract: The reaction of 4-amino-6-methyl-1,2,4-triazine-3(2 H)-thione-5-one (AMTTO) with silver(I) nitrate in methanol gives the complex [Ag(AMTTO)2]NO3 (1). 1 was characterized by IR and 13C NMR spectroscopy and by an X-ray structure analysis [space group C2/c, Z = 4, lattice dimensions at –80 °C: a = 1306.7(2), b = 1139.0(2), c = 1089.2(1) pm, β = 94.54(1)°, R1 = 0.0294]. The cation possesses a highly distorted linear coordination sphere in the solid state.
TL;DR: In this paper, the lateral stiffness of building structures, including regular and irregular moment frames, braced frames, as well as frames with shear walls, is estimated for preliminary analysis and especially final check purposes.
Abstract: This paper presents a quick method for estimating the lateral stiffness of building structures, including regular and irregular moment frames, braced frames as well as frames with shear walls, which can be used for preliminary analysis and especially final check purposes. The method can be utilized for the calculation of the building displacement at different levels under lateral loads, the contribution of various lateral resisting systems to carrying the lateral loads, and finally the natural frequencies of the system. The basic idea of the method is based on some facts about the lateral deformation and stiffness of building structures, which make it possible to consider an equivalent single-bay single-story frame module for every story of the real multi-bay multi-story frame. This leads to a 3-diagonal or banded stiffness matrix in most cases. Even in the cases resulting in a full stiffness matrix the proposed method does not require solving a system of simultaneous equations for obtaining the lateral displacements. Several numerical examples show the higher efficiency and precision of the proposed method in comparison with the Kan method. The use of the main concepts of the proposed method for preliminary design purposes is also possible as a secondary application. Copyright © 1999 John Wiley & Sons, Ltd.
TL;DR: The essential oil of the aerial parts of Prangos latiloba Korov was analyzed by GC and GC/MS as discussed by the authors, with α-pinene (25.1%), limonene (16.1%) and myrcene (9-5%).
Abstract: The essential oil of the aerial parts of Prangos latiloba Korov was analyzed by GC and GC/MS. The main constituents were α-pinene (25.1%), limonene (16.1%) and myrcene (9-5%).
TL;DR: This paper investigates retrieval and indexing schemes in pixel domain, and points to the future work on image retrieval schemes, which will be a high demand for the image retrieval techniques in compressed domain.
Abstract: This paper investigates image retrieval and indexing schemes in pixel domain, and points to the future work on image retrievalschemes. Image retrieval schemes generate indices for images in pixel or compressed domain based on their features in thecorresponding domain. These indices are used to retrieve images from a database. The features in pixel domain are extractedfrom the color, shape or texture characteristics ofimages. The application ofthese three methods depends on the characteristic ofthe image database, and the query image. In the near future the image databases contains the compressed version of images,therefore there will be a high demand for the image retrieval techniques in compressed domain.Keywords : Image Retrieval, Image Indexing, Image Processing 1. INTRODUCTION Current developments in visual information systems and fast expansion of web sites require flexible, efficient and effectiveimage retrieval schemes. Search for images in databases based on the pattern recognition methods is very difficult. The reason isthe disability of current computer vision schemes in extracting the high level information as human perception can do 3,12 Lowlevel image information such as color, shape and texture can be converted into quantitative factors. These factors can express theimage in different resolutions and are suitable for image retrieval. Several image features can be combined to improve theretrieval effectivity in content based image retrieval schemes (CBIR).Indexing is a suitable method for image retrieval, because it reduces the search space and improves the search time. In imageindexing an N-dimensional vector based on the image features, for each image in the database is generated, and saved with theimage. As this N-dimensional vector represents the image characteristics, it can be used in retrieval process instead of the imageitself. A distance function or a similarity measure is used to find the similarity between two image feature vectors.Two criteria for comparing image retrieval schemes are efficiency and effectivity. These two factors are respectively the speed ofretrieval and the rate of successful search in fmding similar images with the query one. All the image retrieval schemes try toreduce the search space and increase the speed to improve the efficiency and employ rotation, translation and scaling invariantfeatures to improve the effectivity.This paper investigates image retrieval and indexing techniques in pixel domain, which are referred to schemes that the imagefeatures are directly extracted from the image pixels rather than doing any transformation on pixels. There are methods thatextract features from the compressed version of the image, compressed domain indexing
TL;DR: In this article, the stability of VO 2 + with leucine in mixed solvent systems of methanol + water and dioxane + water has been determined spectrophotometrically at (25 ± 0.1) °C and I = 0.15 mol.
Abstract: The stability constant on complexation of VO 2 + with leucine in mixed solvent systems of methanol + water and dioxane + water have been determined spectrophotometrically at (25 ± 0.1) °C and I = 0.15 mol.dm -3 of sodium perchlorate as ionic medium in the pH range (1.20-10.20) with high ligand-to-metal ratios. Linear relationships are observed when log K is plotted versus 1/D, where K and D represent stability and dielectric constants, respectively. The results are discussed in terms of the effect of solvent on protonation and complexation.
TL;DR: It may be concluded that alpha1- and alpha2-adrenoceptor stimulation decreases the physostigmine-induced yawning behavior in rats.
Abstract: In the present study, effects of adrenoceptor agonists and antagonists on physostigmine-induced yawning was investigated. Intraperitoneal (i.p.) injection of different doses of physostigmine (0.03, 0.05, 0.1, and 0.2 mg/kg) induced yawning in rats. The maximum response was obtained by 0.2 mg/kg of the drug. The alpha1-adrenoceptor agonist, phenylephrine, and the alpha2-adrenoceptor agonist, clonidine, decreased yawning induced by physostigmine. Prazosin and higher doses of phenoxybenzamine reduced the inhibitory effect of phenylephrine. Higher doses of yohimbine also reduced the clonidine response. The adrenoceptor antagonists, prazosin, phenoxybenzamine, and propranolol, did not significantly alter the physostigmine response. However, yohimbine, or lower doses of prazosin, decreased the physostigmine response. It may be concluded that alpha1- and alpha2-adrenoceptor stimulation decreases the physostigmine-induced yawning behavior in rats.
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30 Nov 1999TL;DR: In this article, the surface ion-imprinted polymer (IIP) particles were prepared and applied as a electrode modifier in stripping voltammetric detection of lead(II) ion.
Abstract: In this study, the novel surface ion-imprinted polymer (IIP) particles were prepared and applied as a electrode modifier in stripping voltammetric detection of lead(II) ion. A carbon paste electrode (CPE) modified with IIP nanoparticles and multi-walled carbon nanotubes (MWCNTs) was used for accumulation of toxic lead ions. Various factors that govern on electrochemical signals including carbon paste composition, pH of the preconcentration solution, supporting electrolyte, stirring time, reduction potential and time were studied in detail. The best electrochemical response for Pb(II) ions was obtained with a paste composition of 7% (w/w) of lead IIP, 10% MWCNTs, 53% (w/w) of graphite powder and 30% (w/w) of paraffin oil using a solution of 0.1 mol L-1 acetat buffer solution (pH=4.5) with a extraction time of 15 min. A sensitive response for Pb(II) ions in the concentration range of 3 to 55 µg L-1 was achived. The proposed electrochemical sensor showed low detection limit (0.5 µg L-1), remarkable selectivity and good reproducibility (RSD = 3.1%). Determination of lead(II) content in different environmental water samples was also realized adopting graphite furnace atomic absorptions spectrometry (GF-AAS) and the obtained results were satisfactory.
TL;DR: The essential oil of the aerial parts of Semenovia suffruticosa (Freyn et al. as discussed by the authors ), which is a native plant of Iran, has been analyzed by GC and GC/MS, and the major constituents were linalool (13−9%), lavandulyl acetate (11.5%), (E)-β-ocimene (8.6%), terpinen-4-ol (7.7%), and lavandulol (6.6%).
Abstract: The essential oil of the aerial parts of Semenovia suffruticosa (Freyn et. Bornm.) Manden, which is a native plant of Iran, has been analyzed by GC and GC/MS. The major constituents were linalool (13–9%), lavandulyl acetate (11.5%), (E)-β-ocimene (8.6%), terpinen-4-ol (7.7%) and lavandulol (6.6%).
Journal Article•
TL;DR: The results are a proof for the changes in latency of P100 peak and the shape of VEP pattern which is reflecting more in flash than pattern reversal stimulation and it is suggested to related medical specialist to take into consideration the effect of monthly cycle in recording VEP in female subject.
Abstract: Visual Evoked potential (VEP) is one of the electrophysiological technique which is used by Neurologist and Ophthalmologist for better diagnosis of optic nerve fiber and visual cortex diseases such as Multiple Sclerosis, Optical neuritis and etc. Among the female patients used to contact the Qods electrophysiological laboratory, the authors observed the extraordinary changes in VEP pattern, which was not expected by authors, hence the research was carried out to see the possible causes of such changes. One of the trails was the physiological monthly cycle and it's possible effect on VEP pattern. For this purpose 20 normal female subjects in age group between 18-28 years were selected and they undergone VEP recording in one of ordinary and monthly cycle days, both with checkerboard pattern reversal as well as flash stimulation. The results is a proof for the changes in latency of P100 peak and the shape of VEP pattern which is reflecting more in flash than pattern reversal stimulation. Finally it is suggested to related medical specialist to take into consideration the effect of monthly cycle in recording VEP in female subject.
TL;DR: The water-distilled essential oil from dried aerial parts of achillea tenuifolia Lam was analyzed by GC and CG/MS as discussed by the authors and 48 components were characterized representing 88% of the total oil.
Abstract: The water-distilled essential oil from dried aerial parts of achillea tenuifolia Lam. Was analysed by GC and CG/MS. 48 Components were characterized representing 88% of the total oil. Camphor (18%), 1,8-cineole + limonene (9%) and spathulenol (7%) were the major constituents of the oil obtained in a yield of 0.23%.
TL;DR: In this article, high-strength carbon fibers were submitted to various thermochemical treatments in order to obtain a uniform and tough coating of copper particles on their surfaces, which is crucial for a reliable composite material.
TL;DR: A new scheme which overcomes the problems of previous retrieval systems such as sensitivity to illumination, false edges, translation, rotation, noise is introduced and the computational cost of this method is comparable to the previous methods.
Abstract: One of the requirements for the fast growing technology of multimedia and Internet is image retrieval. A retrieval scheme needs to be efficient, and effective in finding similar images. This requires a robust retrieval scheme against rotation, reflection, translation, scaling, illumination and noise with low computational cost. In this paper a new scheme which overcomes the problems of previous retrieval systems such as sensitivity to illumination, false edges, translation, rotation, noise is introduced. The computational cost of this method is comparable to the previous methods. In this new scheme the image edges will be extracted first, then the edge angles are quantized. Based on correlation between amplitude and phase of neighboring edges the edge orientation correlogram, which is a 2D matrix, is generated. This matrix is normalized and ordered in such a wy that it becomes invariant to rotation, reflection, scaling and translation. This matrix can be used as a feature vector for describing the image and also as an index in image databases. The experimental result shows this new method is superior to other color-based, color-spatial and shape-based indexing schemes.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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23 Dec 1999
TL;DR: In this article, the authors analyzed the relationship between default risk and momentum effect using data from companies listed on Tehran Stock Exchange and found that there is no relationship between the two factors.
Abstract: The purpose of this paper is to analyze the relationship between default risk and momentum effect using data from companies listed on Tehran Stock Exchange.To calculate default risk,we used Black-Scholes-Merton (BSM) option pricing model. To describe momentum effect, by determining the formation period to be 6 months, and the holding period to be 3,6, or 12 months, we firstlyexamined the profitability of short term (3/6), midterm (6/6), and long term (12/6) momentum strategies and found that during 2010-2015 time period, only midterm momentum strategy is profitable.Then,we showedthere is no relationship between default risk andmomentum effect.
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22 Dec 1999TL;DR: In this paper, the authors investigate auditors' different biases and decision-making factors on errors based on a cognitive approach in the capital market and conclude that auditors’ choices are influenced by perception, judgment and decision options processes, which may affect auditing errors.
Abstract: Based on the capital market’s nature, accountants and auditors’ information is provided by an effective influence of personal decisions and market results, derived systematically by information structure and market participants’ features. Auditors’ choices are influenced by perception, judgment and decision options processes, which may affect auditing errors. The study purpose is to investigate auditors’ different biases and decision-making factors on errors based on a cognitive approach in the capital market. The model’s objective is practical based on a descriptive-analytical methodology. The statistical population of the study includes all certified auditors of Iran's Securities and Exchange Organization (SEO), whom were provided with the researcher-made questionnaires with valid narration and reliability. The collected data were analyzed by AMOS software. The findings indicate that components of the cognitive bias are predictable by auditors’ errors based on the priority level and maximum influences, including mental accounting bias (63%), availability bias (45%), heuristic bias (60%), and ambiguity aversion bias (58%). Also, components of decision-making are predictable by auditors’ errors based on the priority level and maximum influences, including decision case (54%), job experience (57%), decision-making situation (58%) and individual features (45%).
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01 Dec 1999TL;DR: In this article, the authors investigated the relationship between managerial entrenchment and the internal control weakness by operant conditioning behavior theory test and found that there is positive and significant relationship between the managerial entengagement and internal control weaknesses.
Abstract: Purpose: In the shadow of separation of the ownership from the control and the problem of representation arising from it in the modern business world, there is a need to pay attention to the CEOs' approaches toward takeover as decision makers in this area. Managerial entrenchment is considered as one of the consequences of separation of ownership from control that explains the difference between the incentives in the corporate management and causes a disturbance in internal control as a communication mechanism between the corporate's performance and the capital market. Paying attention to operant conditioning behavior like tournament incentives as a functional behavioral stimulus in CEOs reduces the profit-seeking attitudes among them and increases the effectiveness of the corporates' performance mechanisms in disclosing financial reporting. The purpose of this research is to study the relationship between the managerial entrenchment and the internal control weakness by operant conditioning behavior theory test. Design/methodology/approach: In this research, 95 companies listed in Tehran Stock Exchange were evaluated between 2013 and 2018. Considering the duality of internal control assessment, logistic regression in SPSS software was used in this research. Findings: Results of the research showed that there is positive and significant relationship between the managerial entrenchment and the internal control weakness. But there is a negative and significant relationship between the tournament incentive and the internal control weakness. Moreover, it was found that the negative relationship between the managerial entrenchment and the corporates' internal control is mediated by the tournament incentive. Originality/value: Considering that little attention has been paid to motivational issues of the CEOs under the representation theory over the past few years, the present research attempts to investigate managerial entrenchment approach with the effectiveness of internal controls through analysis of the operant conditioning behavior theory to provide more reliable experimental results for the investors and the shareholders.
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30 Nov 1999TL;DR: An amplified sensor based on paste electrode modified with MgO nanoparticle (MgO/NPs) and 1-hexyl-3methylimidazolium hexafluorophosphate (HMH) was designed and used for determination of methyldopa (MD).
Abstract: In this research, an amplified sensor based on paste electrode (PE) modified with MgO nanoparticle (MgO/NPs) and 1-hexyl-3-methylimidazolium hexafluorophosphate (HMH) was designed and used for determination of methyldopa (MD). The CP/MgO/NPs/HMH showed good catalytic activity toward oxidation of MD and improved drug current about 3.58 times. In addition, CP/MgO/NPs/HMH showed a diffusion process and pH dependence behavior for electro-oxidation of MD in aqueous solution. However, differential pulse voltammogram of CP/MgO/NPs/HMH showed a linear dynamic range to sensing of MD in concentration range 1.0 nM – 400 µM with detection limit 0.5 nM. The recovery range 98.25% - 102.5% was obtained for sensing of MD in real samples using CP/MgO/NPs/HMH.
TL;DR: In this article, a new high-performance thin-layer chromatography (HPTLC) method for the determination of theophylline in plasma has been developed, which achieved separation of the drug from the complex matrix within a short 50 mm migration distance and 25 min migration time on silica gel 60 F 254 layers using toluene-isopropanol-acetic acid (80:20:5) as the mobile phase.
Abstract: A new high-performance thin-layer chromatography (HPTLC) method for the determination of theophylline in plasma has been developed. Plasma samples were prepared by the internal reference method. Denaturation was carried out through cold centrifugation. Separation of the drug from the complex matrix was accomplished within a short 50 mm migration distance and 25 min migration time on silica gel 60 F 254 layers using toluene-isopropanol-acetic acid (80:20:5) as the mobile phase. The analyte was quantified by absorbance/reflectance densitometry using peak-area ratio analysis. Validation parameters were investigated considering the special features of the method.
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01 Dec 1999
TL;DR: In this paper, the linear models are adapted by the ordinary Lasso method (Tibshirani, 1996), Adaptive Group LASSO (Zu, 2006) and the least squares method (OLS) to predict the expected return on stock portfolios in the shortest time and using the least effective features.
Abstract: In this study, for the selection of the characteristics of the company that provides the incremental information to investors and financial analysts, the linear models are adapted by the ordinary Lasso method (Tibshirani, 1996), Adaptive Group LASSO (Zu, 2006) and the least squares method (OLS). The main objective of this research is to determine which method can predict the expected return on stock portfolios in the shortest time and using the least effective features. The research sample is1340observations, including 134companies listed in Tehran Stock Exchange, and the research variables from the financial statements of the companies and the stock market reports between 2008and 2018. The results of this study show that by employing the least squares regression method, 7 characteristics, the typical 5- characteristics LASSO method and in the Adaptive Group LASSO method, only 4characteristics, contain incremental information to predict the expected returns of stock portfolios. In the second place, by applying the Adaptive Group LASSO regression method, one can achieve the same results with using the least characteristics.