ali taherkhani - Academia.edu (original) (raw)

Papers by ali taherkhani

Due to the existence of plentiful dynamic faults e.g. Ipak, in north of Qazvin, Eshtehard and Mus... more Due to the existence of plentiful dynamic faults e.g. Ipak, in north of Qazvin, Eshtehard and Musha and also devastating earthquakes happened during last century like; Buinzahra’s 1962 earthquake with a magnitude of 7.2 Richter and historic earthquakes in the region like; Qazvin’s 5.4 Richter earthquake in 1901, Qazvin is considered as an active area from tectonic and seismic power point of view. Considering seismic power and according to statistical studies about the earthquakes happened in the region and also with an investigation on kind, length and activity of faults in the area, three independent seismic fields are distinguishable: Buinzahra with a high velocity and seismic power, Qazvin with moderate to high velocity and seismic power and Takestan with weak to moderate velocity and seismic power.

Nano particles of CaSnO3 and MgSnO3 ,because of their thermal stability and chemical and physical... more Nano particles of CaSnO3 and MgSnO3 ,because of their thermal stability and chemical and physical reactions in the air have attract many researchers and find various applications in various application In many areas such as making sensors, ceramic dielectrics and battery electrodes.in this article the nano SnO2 powders are prepared by Solid state one stage synthesis method firstly and then the physical and cristla properties of Nano powders are examined in various temperatures. The powder which was a mixture of MCl2,M(OH)2 with SNCl4.5 H20 (M=Mg & Ca) with Sn/M weight ratio of 1:1, in particle sizes of 6 to 44 nano meter were prepared and were heated in temperatures of 200,400 and 800 siliceous degrees. In the first stage ,the above mentioned powder materials are combined in room temperature and after grinding, the prepared powder is centrifuged in 30 minutes and finally is decanted for investigation of heat effect, the prepared nano powders are annealed for 4 hours. As far as the g...

Synthesis, characterization, and thermal behavior of nanoparticles Cobalt(II) chloride has been i... more Synthesis, characterization, and thermal behavior of nanoparticles Cobalt(II) chloride has been investigated in this work. Cobalt (II) chloride was synthesized by using of mill device. The general formula of this compound is MCl2 (M = Co). The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and the size and structure of synthesized nanoparticles has been analyzed by x-ray diffraction (XRD). Morphology of surface and structure of synthesized nanoparticles has been done by scanning electron microscopy (SEM). This compound has many applications in mineral synthesis as a catalyst. The nano particles of CoCl2 with approximate size of 41 nm synthesized and we can see them with porous and spongy morphology in SEM pictures. Thermal behavior of this nanoparticles considered by using of DTA /TGA thermal analysis device.

In this research, beside structural and geological considerations, an exact and partial investiga... more In this research, beside structural and geological considerations, an exact and partial investigation is performed on side movements in some part of Taleghan. Regarding increasing damages happening due to side movements, the issue of predicting and proposing solutions and controlling methods and preventing loses and damages resulted during recent decades have been seriously discussed. The aim of this article is an exact investigation of predicting the risk of slides in future, using models which have most concordance with natural conditions of the area being studied. Seismic power dominant on each area, particularly, imposes highest influence on occurrence or intensification of slopes’ breakage. Among common methods of zoning the risk of landslide, three, Kanagava, Mura & Warson and Nilsson adjusted methods, were chosen by which the area being studied was divided into areas with potential risk of slide. In all the methods mentioned, tectonic and seismic power elements are emphasized...

In this work,SnO2 nano powder is prepared by One-Step solid state synthesis method and beside phy... more In this work,SnO2 nano powder is prepared by One-Step solid state synthesis method and beside physical and crystalline characterization of the nano powder in various temperatures ,it was used for making a sensor sensitive to Carbone monoxide gas. The stages of preparation and making the needed powder, manufacturing of the sensor including inner layer , heater, placing the layer, Electrodes are investigated in this paper. Then the sensitivity and stability of the sensor is studied using various diagrams. Nano particles of SnO2 are prepared using the primary powders of CaCl2,Ca(OH)2,SnCl4 .5H2O with the weight ratio of 2:1 for Sn/Ca in sizes of 3 to 68 nanometers and are heated from 200 to 1000 Celsius degrees. using FTIR,SEM, XRD and TGA ,the morphology and nano structure of SNO2 particles were checked and used for making the nano sensor finally.the manufactured sensor was examined by different concentrations of Carbone monoxide and diagrams of sensitivity and stability was studied i...

The synthesis of nanoparticles has become a highly developed field owing to the scientific and te... more The synthesis of nanoparticles has become a highly developed field owing to the scientific and technological interest due to the structural peculiarities and unusual physical and chemical properties. The one step solid-state reaction technique was employed to prepare nanopowders of SnO2, Sr2SnO4 and SrSnO3 through differentweight ratio of Sn : Sr. This technique was found to give spherical products of uniform size and shape in over 90% yields. The materials have a variety of applications in ceramic dielectrics, gas-sensing materials and battery electrode bodies. Characterization of species was carried out using X-ray diffraction, SEM and TGA analysis. Investigation of samples revealed that, agglomerations ofwell connected, small grains lumped together with large number of pores have been formed. The XRD pattern analysis has shown that the change in crystalline sizes after calcining at various temperatures.

In this work, a multi-objective optimization is used to design Pareto optimal decoupled sliding m... more In this work, a multi-objective optimization is used to design Pareto optimal decoupled sliding mode controllers for a cart-pendulum system with external disturbances. Three conflicting objective functions which have been used in Pareto design of the sliding mode controller are, namely, the integral of the absolute magnitude of cart position, and pendulum angle with the total energy consumption. The simulation results clearly show that an effective trade-off can be compromisingly achieved among the different sliding mode controllers obtained using the methodology of this work.

Synthesis, characterization, and thermal behavior studies of nanoparticles Iron(II) chloride has ... more Synthesis, characterization, and thermal behavior studies of nanoparticles Iron(II) chloride has been studied in this research. Iron(II) chloride was synthesized by planetary high-energy ball mill. The general formula of this compound is FeCl2. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy (FT-IR) and also Size and structure of synthesized nanoparticles were studied by analyzing X-ray diffraction (XRD) and morphology of surface and structure of synthesized nanoparticles were studied by scanning electron microscopy (SEM). This compound has many applications in mineral synthesis as a catalyst. The nanoparticles of CoBr2 synthesized with smaller size of 35 nm, and its SEM images show that the morphology of particles surface isas like as layer and hunk. Also thermal behavior of this nanoparticles considered by using of DTA /TGA thermal analysis.

Ars Mathematica Contemporanea

Investigating the equality of the chromatic number and the circular chromatic number of graphs ha... more Investigating the equality of the chromatic number and the circular chromatic number of graphs has been an active stream of research for last decades. In this regard, Hajiabolhassan and Zhu [Circular chromatic number of Kneser graphs, Journal of Combinatorial Theory Series B, 2003] proved that if n is sufficiently large with respect to k, then the Schrijver graph SG(n, k) has the same chromatic and circular chromatic number. Later, Meunier [A topological lower bound for the circular chromatic number of Schrijver graphs, Journal of Graph Theory, 2005] and independently, Simonyi and Tardos [Local chromatic number, Ky Fan's theorem and circular colorings, Combinatorica, 2006] proved that χ(SG(n, k)) = χc(SG(n, k)) if n is even. In this paper, we study the circular chromatic number of induced subgraphs of Kneser graphs. In this regard, we shall first generalize the preceding result to s-stable Kneser graphs. Furthermore, as a generalization of Hajiabolhassan and Zhu's result, we prove that if n is large enough with respect to k, then any sufficiently large induced subgraph of the Kneser graph KG(n, k) has the same chromatic number and circular chromatic number.

International Journal on Smart Sensing and Intelligent Systems

The problem of multi-objective robust feedback linearization controller design of nonlinear syste... more The problem of multi-objective robust feedback linearization controller design of nonlinear system with parametric uncertainties is solved in this paper. The main objective of this paper is to propose an optimal technique to design a robust feedback linearization controller with multi-objective genetic algorithm. A nonlinear system is considered as a benchmark and feedback linearization controller is designed for deterministic and probabilistic model of the benchmark. Three and four conflicting objective functions are used in Pareto design of feedback linearization controller for deterministic and probabilistic design, respectively. The simulation results reveal the effectiveness of the proposed method.

Aerospace Science and Technology, 2015

Abstract The mechanical behavior of elastic–plastic polyurethane foams was studied experimentally... more Abstract The mechanical behavior of elastic–plastic polyurethane foams was studied experimentally under high-velocity local impact loading in normal and oblique directions, in particular, the energy absorption and the situation of damage zone were investigated. In order to obtain the mechanical properties, at first quasi-static compressive global loading was performed on the foams. Then, several samples of rigid polyurethane with different thicknesses (between 10 and 80 mm) and densities (between 40 and 320 kg/m3) were prepared and subjected to high-velocity normal impact loading (with projectile velocity range between 30 and 140 m/s). The results showed that the foam with density of 320 ( kg / m 3 ) at thickness of 40 (mm) has the highest energy absorption between them and also increasing the density and thickness of the foam increases the energy absorption and the area of the damage zone on rear side of the foam. Furthermore, it was found that the damage area consists of two different cylindrical and frustum-like zones. It was shown that the absorbed energy was dependent on both density and thickness; therefore, it was attempted to statistically formulize the relationship between absorbed energy on the one hand and thickness and density on the other hand based on experimental data. The effect of projectile nose including the five shapes such as flat-ended, hemi-spherical, semi-elliptical, right-conical and sharp-conical was investigated on penetration depth of projectile into the target. The results have revealed that the penetration depth increases with decreasing in the curvature radius of projectile nose cross-section; hence, the foams were too weak against sharp noses. On the other hand, performing the oblique impacts showed that increasing the oblique angle increases the damage area and changes the shape of rear side from ellipsoid-like to triangle-shape.

Journal of Analytical Methods in Chemistry, 2012

We propose chlorpromazine (CHP) as a new mediator for the rapid, sensitive, and highly selective ... more We propose chlorpromazine (CHP) as a new mediator for the rapid, sensitive, and highly selective voltammetric determination of homocysteine (Hcy) using multiwall carbon nanotube paste electrode (MWCNTPE). The experimental results showed that the carbon nanotube paste electrode has a highly electrocatalytic activity for the oxidation of Hcy in the presence of CHP as a mediator. Cyclic voltammetry, double potential step chronoamperometry, and square wave voltammetry (SWV) are used to investigate the suitability of CHP at the surface of MWCNTPE as a mediator for the electrocatalytic oxidation of Hcy in aqueous solutions. The kinetic parameters of the system, including electron transfer coefficient, and catalytic rate constant were also determined using the electrochemical approaches. In addition, SWV was used for quantitative analysis. SWV showed wide linear dynamic range (0.1–210.0 μM Hcy) with a detection limit of 0.08 μM Hcy. Finally, this method was also examined as a selective, si...

Ionics, 2014

In this work, a ZnO/nanoparticles (NPs) modified carbon ionic liquid paste electrode (ZnO/NP/CILP... more In this work, a ZnO/nanoparticles (NPs) modified carbon ionic liquid paste electrode (ZnO/NP/CILPE) was fabricated and used to investigate the electrochemical behavior of folic acid. ZnO/NP/CILPE was prepared by mixing hydrophilic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim]-[PF 6 ])), ZnO/NPs, graphite powder, and liquid paraffin together. The fabricated ZnO/ NP/CILPE showed great electrocatalytic ability to the oxidation of folic acid, and an irreversible oxidation peak appeared at 0.75 V (vs. Ag/AgCl) with improved peak current. Under the optimized conditions of pH 9.0, the plot of peak current vs. folic acid concentration consisted of two linear segments with slopes of 1.776and 0.033 μA/μM in the concentration ranges of 0.05-1.5 μM and 1.5-550.0 μM, respectively. The detection limit was 0.01 μM (3σ). The proposed sensor was successfully applied for the determination of folic acid in fortified food and pharmaceutical samples.

Chinese Chemical Letters, 2012

A carbon paste electrode (CPE) chemically modified with multiwall carbon nanotubes and ferrocene ... more A carbon paste electrode (CPE) chemically modified with multiwall carbon nanotubes and ferrocene (FC) was used as a selective electrochemical sensor for the simultaneous determination of trace amounts of cysteamine (CA) and folic acid (FA). This modified electrode showed very efficient electrocatalytic activity for the anodic oxidation of CA. The peak current of differential pulse voltammograms of CA and FA increased linearly with their concentration in the ranges of 0.7-200 mmol/L CA and 5.0-700 mmol/L FA. The detection limits for CA and FA were 0.3 mmol/L and 2.0 mmol/L, respectively. The diffusion coefficient (D) and transfer coefficient (a) of CA were also determined. These conditions are sufficient to allow determination of CA and FA both individually and simultaneously.

Due to the importance of rolling bearings as one of the most commonly used industrial machinery e... more Due to the importance of rolling bearings as one of the most commonly used industrial machinery elements, it is necessary to develop proper monitoring and fault diagnosis procedure to suppress malfunctioning and failure of these elements during operation. For rolling bearing fault detection, it is expected that a desired time domain analysis method has good computational efficiency. In this paper, first, the features in time and frequency domain such as Mean Square, Moments, Cumulant, kurtosis, Skeweness, Zero Crossing Rate, Peak Rate, standard deviation, maximum value, Crest factor, Clearance factor, Shape factor and Impulse factor which are widely used in fault diagnostics, have been extracted from the vibration signal. Indeed, the numbers of 12 features have been extracted from the time domain signal. Then they are going to PCA algorithm, After PCA processing, the redundant features can be removed effectively. In this work, 12 features decrease to six efficient features. Although most of the features are reduced, the average diagnosis accuracy does not decrease. For some states, the diagnosis accuracy arises a little for the information fusion performance of PCA. Then, the features that extracted have been classified successfully using MSVM classifier.

Analytica Chimica Acta, 2003

Applied Organometallic Chemistry

Eurasian Chemical Communications

In this research, nanoparticle of lanthanum oxide (a) has been synthesized in a coprecipitation m... more In this research, nanoparticle of lanthanum oxide (a) has been synthesized in a coprecipitation method and its ability to be antibacterial has been studied. The La2O3 crystalline nanoparticle (a) was prepared at a nominal temperature of 673 K for 4 hours. The samples were identified using FT-IR, XRD, VSM, SEM, and EDX methods. Using the infrared spectroscope (FT-IR), the covalent bonding of La2O3 in the sample is confirmed. X-ray diffraction (XRD) shows that the single-phase sample has a hexagonal structure with average particle size 69 nm. Moreover, the size of the particles seen in the SEM images corresponds to each other. Using the Vibration Sample Magnetometer (VSM), the magnetic properties of the nanoparticle (a) were studied and the result shows that the nanoparticle has paramagnetic behavior. The antibacterial effects were also examined in vitro against standard bacterial strains, the Gram-positive Staphylococcus aureus; S. aureus ATCC 25923 and Enterococcus faecalis; Enter faeca ATCC 29212, and also the Gram-negative Escherichia coli; E. coli ATCC 25922 and Pseudomonas aeruginosa; P. aeruginosa ATCC 27853. Using these strains, the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zones (IZ) were obtained. Antibacterial activities of lanthanum oxide nanoparticle are more than agents lanthanum salts.