Acceleration of methylene blue adsorption onto activated carbon prepared from dross licorice by ultrasonic: Equilibrium, kinetic and thermodynamic studies

M. Ghaedi,M. Danaei Ghazanfarkhani,S. Khodadoust,N. Sohrabi,M. Oftade 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Adsorption of methylene blue (MB) onto activated carbon (AC) prepared from dross licorice as adsorbent was studied following full AC characterization by FT-IR spectroscopy, scanning electron microscopy and BET (Brunauer, Emmett, and Teller). The effects of variables were studied and optimized by a central composite design (CCD) combined with response surface methodology (RSM) and desirability function (DF). The good agreement between experimental and predicted data at optimum values of all variables was explored. The optimum condition set as follow: 20 mg L-1 of MB concentration, pH 7 for sample solution, 0.20 g of AC and 16 min sonication as mass transfer process. The small amount of proposed adsorbent (0.2 g) was applicable for removal of MB (RE > 95%) at 16 min with high adsorption capacity (82.9 mg g-1).

Delay Analysis of Orderly Reattempts in Retrial Queueing System with Phase Type Retrial Time

Kumar, M. S.,Sohraby, K.,Kiseon Kim IEEE 2013 IEEE COMMUNICATIONS LETTERS Vol.17 No.5

<P>Retrial queueing systems play a major role in many communication systems. The delay analysis of such systems poses an interesting problem in communication engineering. This has motivated us to analyze the waiting time distribution of a multi-server retrial queueing system with phase type retrial time, impatience and Bernoulli abandonments. The impact of retrial time on waiting time and other system characteristics is analyzed by determining the waiting time distribution. Numerical examples are presented to reveal the impact of the parameters.</P>

Taguchi Method Prediction of Effect of Processing Parameters on Nanoparticle Size in Chemical Vapor Condensation Process

A. Tavakoli,M. Sohrabi,A. Kargari,최철진 대한금속·재료학회 2009 METALS AND MATERIALS International Vol.15 No.5

The Taguchi method has been applied to investigate the effect of various operating parameters such as decomposition temperature, bubbler temperature, carrier gas flow rate, precursor flow rate and pressure on particle size in the Chemical Vapor Condensation process. Also, the effect and contribution of each pertinent parameter on particle size and the interaction among them was determined by Taguchi analysis. It was observed that the decomposition temperature was the most significant process parameter affecting the particle size. Also, the predicted nanoparticle size was in good agreement with that found in the experiment. The Taguchi method has been applied to investigate the effect of various operating parameters such as decomposition temperature, bubbler temperature, carrier gas flow rate, precursor flow rate and pressure on particle size in the Chemical Vapor Condensation process. Also, the effect and contribution of each pertinent parameter on particle size and the interaction among them was determined by Taguchi analysis. It was observed that the decomposition temperature was the most significant process parameter affecting the particle size. Also, the predicted nanoparticle size was in good agreement with that found in the experiment.

Dynamic analysis of non-symmetric FG cylindrical shell under shock loading by using MLPG method

Ferezghi, Yaser Sadeghi,Sohrabi, Mohamad R.,MosaviNezhad, Seyed M. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

The Dynamic equations in the polar coordinates are drawn out using the MLPG method for the non-symmetric FG cylindrical shell. To simulate the mechanical properties of FGM, the nonlinear volume fractions for radial direction are used. The shape function applied in this paper is a form of the radial basis functions, by using this function all the requirements for an effective and suitable shape function are established. Hence in this study, the multiquadrics (MQ) radial basis functions are exploited as the shape function governing the problem. The MLPG method is combined with the the Newmark time approximation scheme to solve dynamic equations in the time domain. The obtained results by the MLPG method to be verified are compared with the analytical solution and the FEM. The obtained results through the MLPG method show a good agreement in comparison to other results and the MLPG method has high accuracy for dynamic analysis of the non-symmetric FG cylindrical shell. To demonstrate the capability of the present method to dynamic analysis of the non-symmetric FG cylindrical shell, it is analyzed dynamically with different volume fraction exponents under harmonic and rectangular shock loading. The present method shows high accuracy, efficiency and capability to dynamic analysis of the non-symmetric FG cylindrical shell with nonlinear grading patterns.

Accuracy of Endoscopic Ultrasonography for Determination of Tumor Invasion Depth in Gastric Cancer

Razavi, Seyed Mohsen,Khodadost, Mahmoud,Sohrabi, Masoudreza,Keshavarzi, Azam,Zamani, Farhad,Rakhshani, Naser,Ameli, Mitra,Sadeghi, Reza,Hatami, Khadijeh,Ajdarkosh, Hossein,Golmahi, Zeynab,Ranjbaran, M Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Background: Gastric cancer (GC) is one the common lethal cancers in Iran. Detection of GC in the early stages would assesses to improve the survival of patients. In this study, we attempt to evaluate the accuracy of EUS in detection depth of invasion of GC among Iranian Patients. Materials and Methods: This study is a retrospective study of patients with pathologically confirmed GC. They underwent EUS before initiating the treatment. The accuracy of EUS and agreement between the two methods was evaluated by comparing pre treatment EUS finding with post operative histopathological results. Results: The overall accuracy of EUS for T and N staging was 67.9% and 75.47, respectively. Underestimation and overestimation was seen in 22 (14.2%) and 40 (25.6%) respectively. The EUS was more accurate in large tumors and the tumors located in the middle and lower parts of the stomach. The EUS was more sensitive in T3 staging. The values of weighted Kappa from the T and N staging were 0.53 and 0.66, respectively. Conclusions: EUS is a useful modality for evaluating the depth of invasion of GC. The accuracy of EUS was higher if the tumor was located in the lower parts of the stomach and the size of the tumor was more than 3 cm. Therefore, judgments made upon other criteria evaluated in this study need to be reconsidered.

Dynamic analysis of non-symmetric FG cylindrical shell under shock loading by using MLPG method

Yaser Sadeghi Ferezghi,Mohamad R. Sohrabi,Seyed M. MosaviNezhad 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.67 No.6

The Dynamic equations in the polar coordinates are drawn out using the MLPG method for the non-symmetric FG cylindrical shell. To simulate the mechanical properties of FGM, the nonlinear volume fractions for radial direction are used. The shape function applied in this paper is a form of the radial basis functions, by using this function all the requirements for an effective and suitable shape function are established. Hence in this study, the multiquadrics (MQ) radial basis functions are exploited as the shape function governing the problem. The MLPG method is combined with the the Newmark time approximation scheme to solve dynamic equations in the time domain. The obtained results by the MLPG method to be verified are compared with the analytical solution and the FEM. The obtained results through the MLPG method show a good agreement in comparison to other results and the MLPG method has high accuracy for dynamic analysis of the non-symmetric FG cylindrical shell. To demonstrate the capability of the present method to dynamic analysis of the non-symmetric FG cylindrical shell, it is analyzed dynamically with different volume fraction exponents under harmonic and rectangular shock loading. The present method shows high accuracy, efficiency and capability to dynamic analysis of the non-symmetric FG cylindrical shell with nonlinear grading patterns.

Synthesis and activity measurement of the some bifunctional platinum loaded Beta zeolite catalysts for n-heptane hydroisomerization

Goodarz Talebi,Sayed Javid Royaee,R.L. Keiski,M. Huuhtanen,Hamid Imamverdizadeh,Morteza Sohrabi 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.5

In this study, two types of Beta zeolites having different Si/Al ratios (11.7 and 24.5) were synthesized hydrothermally using tetraethyl ammonium hydroxide (TEAOH) as a template. Different amounts of platinum (0.2%, 0.5% and 1.2%) were loaded on the protonated form of zeolite by incipient wet impregnation method applying hexachloroplatinic acid in 0.2N Cl progressive ion solutions. Catalytic hydroisomerization reactions were carried out at atmospheric pressure in a fixed bed reactor with vertical placing and downward flow at three different temperatures, various WHSV (weight hourly space velocity) and n-H2/n-HC (molar hydrogen/hydrocarbon) ratio. Increase in Si/Al ratio in zeolites structures from 11.7 to 24.5 promoted selectivity and yield. It was found that optimum platinum content depends on the Si/Al ratio (zeolite acidity) in catalysts. Monobranched to dibranched isomers ratio were correlated with a linear function of n-heptane conversion. Such a correlation was found to be valid for various Si/Al ratios, metal content, processing temperature and pressure, WHSV and hydrogen to hydrocarbon ratio. This observation may indicate that in isomerization reactions, the monobranched isomers are first produced but subsequently transformed into multibranched isomers.