Abatement of Cr (VI) from wastewater using a new adsorbent, cantaloupe peel: Taguchi L16 orthogonal array optimization

Bahman Ramavandi,Ghorban Asgari,Javad Faradmal,Soleyman Sahebi,Babak Roshani 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.12

Taguchi orthogonal design was applied for multivariate optimization of Cr (VI) abatement by canta-loupe peel powder (CPP), as a novel adsorbent, from industrial wastewater in a batch mode. Effective factors in theadsorption process, such as temperature, CPP dose, Cr (VI) concentration, wastewater pH, and contact time, were con-sidered using an L16 orthogonal array design. The best conditions for adsorbing of Cr (VI) were determined by the Taguchimethod and desirability approach as pH of 2, chromium concentration of 100 mg/L, contact time of 5 min, CPP dosageof 0.5 g/L, and wastewater temperature of 25 oC. Analysis of variance results indicated that the pH was the most im-portant variable influencing the chromium removal percentage, and its contribution value was obtained 45.01%. TheLangmuir model proved best fit for the experimental data and maximum adsorption capacity of Cr (VI) onto CPP wasobtained 166.25 mg/g. The final part of the study includes an examination of the CPP through an analysis of the removalof chromium from real industrial wastewater. It can be concluded that the CPP presents a promising and efficient al-ternative for eliminating of Cr (VI) from industrial wastewaters.

Evaluation and Optimization of Factors Affecting the Performance of a Flow-through System Based on Immobilized Acetylcholineesterase as a Biosensor

Bahman Ebrahimi,Seyed Abbas Shojaosadati,Seyyed Mohammad Mousavi 한국생물공학회 2010 Biotechnology and Bioprocess Engineering Vol.15 No.3

A flow-through system based on acetylcholineesterase (AChE) was studied. The system was prepared by mixing AChE and a multiwall carbon nanotube (MWCNT). Two important parameters, the ratios of AChE:MWCNT (X1) and AChE-MWCNT:sol-gel (X2)were optimized using response surface methodology. The results revealed that an enzyme immobilized within the MWCNT-sol-gel was more effective compared to one conducted with sol-gel. The optimum feed flow rate was 0.4 mL/min and ATChI concentration was found to be 1 mM. The optimum ratios of X1 and X2 for immobilization on ceramic packing were 1.07 and 0.43, respectively. The sensitivity of this flow-through system was 1.82 × 10−5/μM and long-term stability analyzed after 120 days was 74% of initial absorbance. With respect to an incubation time of 14 min, the detection limit for paraoxon was 7.3 × 10−12 mol.

On the hereditarily hypercyclic operators

Bahman Yousefi,Ali Farrokhinia 대한수학회 2006 대한수학회지 Vol.43 No.6

LetX be a separable Banach space. We give sucientconditions under which T : X ! X is hereditarily hypercyclic.Also, we prove that hereditarily hypercyclicity with respect to aspecial sequence implies the hereditarily hypercyclicity with respectto the entire sequence.

Predicting the vapor-liquid equilibrium of carbon dioxide+alkanol systems by using an artificial neural network

Bahman Zarenezhad,Ali Aminian 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

A multi-layer feed-forward artificial neural network has been presented for accurate prediction of the vapor liquid equilibrium (VLE) of CO_2+alkanol mixtures. Different types of alkanols namely, 1-propaol, 2-propanol, 1-butanol,1-pentanol, 2-pentanol, 1-hexanol and 1-heptanol, are used in this study. The proposed network is trained using the Levenberg-Marquardt back propagation algorithm, and the tan-sigmoid activation function is applied to calculate the output values of the neurons of the hidden layers. According to the network's training, validation and testing results,a six layer neural network is selected as the best architecture. The presented model is very accurate over wide ranges of experimental pressure and temperatures. Comparison of the suggested neural network model with the most important thermodynamic correlations shows that the proposed neuromorphic model outperforms the other available alternatives. The predicted equilibrium pressure and vapor phase CO_2 mole fraction are in good agreement with experimental data suggesting the accuracy of the proposed neural network model for process design.

Integrated Simulation Modeling of Business, Maintenance and Production Systems for Concurrent Improvement of Lead Time, Cost and Production Rate

Bahman Paknafs,Ali Azadeh 대한산업공학회 2016 Industrial Engineeering & Management Systems Vol.15 No.4

The objective of this study is to integrate the business, maintenance and production processes of a manufacturing system by incorporating errors. First, the required functions are estimated according to the historical data. The system activities are simulated by Visual SLAM software and the required outputs are obtained. Several outputs including lead times in different dimensions, total cost and production rates are computed through simulation. Finally, data envelopment analysis (DEA) is utilized in order to select the best option between the defined scenarios due to the multicriteria feature of the problem. This is the first study in which the lead times, cost and production rates are simultaneously considered in the integrated system imposed of business, maintenance and production processes by incorporating errors. In the current study, the major bottlenecks of the system being studied are identified and suggested different strategies to improve the system and make the best decision.

Prediction of CO2 freezing points for the mixtures of CO2-CH4 at cryogenic conditions of NGL extraction plants

Bahman ZareNezhad 한국화학공학회 2006 Korean Journal of Chemical Engineering Vol.23 No.5

carbon dioxide freezing phenomenon is investigated at the cryogenic operating conditions of the turbo-expansion-based NGL plants. The Peng-Robinson equation of state is used for predicting the CO2liquid and vapor mixtures of CO2-CH4. A new quadratic temperature dependent kij corelation is also presented for properdescription of binary interactions at low temperatures. The overall average absolute relative deviation between experi-mental and predicted CO2 freezing temperatures is 0.26% .

Electrofacies analysis of the Asmari reservoir, Marun oil field, SW Iran

Bahman Soleimani,Iman Zahmatkesh,Hossein Sheikhzadeh 한국지질과학협의회 2020 Geosciences Journal Vol.24 No.2

This article integrates core and well log data to determine reservoir electrofacies of the Oligo-Miocene Asmari Formation in the western Dezfol Embayment, SW Iran. At the start, an unsupervised neural network was employed based on the selforganizing map (SOM) technique to identify and extract electrofacies groups of Asmari Formation in the Marun oilfield, which is a mixed siliciclastic and carbonate reservoir. Using inexpensive and accessible petrophysical wireline logs, such as gamma ray, sonic, density and neutron, along with calculated reservoir data (water saturation and effective porosity) from 12 reference wells and their correlation with reservoir core data, led to recognition of seven electrofacies including first four class as limestone rocks (EF1–EF4) and others three classes as sandstone rocks (EF5–EF7). Based on the porosity and permeability maps and water saturation at different depth levels, EF4 and EF7 with low porosity and permeability, high water saturation are considered as non-reservoir relating mostly to sedimentary textures of mudstone and argillaceous sandstones, respectively. By contrast, EF1 and EF5 with high values of porosity, permeability and low percent of water saturations characterize the best reservoir quality rocks, and EF2, EF3 and EF6 have medium reservoir quality. EF1 consists of dolomitic skeletal grainstone, in which biomoldic, vuggy and intercrystalline porosity is the dominant pore type, while the intergranular porosity is the major pore type in EF4 as an unconsolidated sand electrofacies. In general, the results obtained in this study indicate a satisfactory agreement between core data and log facies. This correlation allows rockfacies to be classified in the cored wells and predict those facies in the uncored wells. Using the methodology outlined here, it is possible to track reservoir electrofacies from conventional well log data.

Simulation of reactive precipitation processes using the network-of-zones model

Bahman ZareNezhad 한국화학공학회 2007 Korean Journal of Chemical Engineering Vol.24 No.6

2-D network-of-zones model is extended and applied to a reactive precipitation process in batch mode.The simulations are performed for a network of size 2(1010) for an elementary reaction through the solution of1400 ODEs. The complicated interactions between mixing efficacy and the system kinetics are systematically investi-gated. When the stirrer speed is very slow, the crystal size distribution (CSD) of the product in the precipitator is de-termined by the intensity of mixing. Conversely, at higher stirrer speed, the CSD is controlled by the system kinetics.More effective mixing leads to an increase in the number of crystals, a reduction of the average size and a narrowercrystal size distribution. The extended network-of-zones model presented in this work can be used conveniently forintegrating computational fluid dynamics and reactive precipitation processes.

Identification of Grape Cultivars Grown in Khoramabad - Lorestan- Iran

Bahman Zahedi,Mohamad Sanei 한국원예학회 2006 한국원예학회 기타간행물 Vol.- No.-

An efficient simulation method for reliability analysis of systems with expensive-to-evaluate performance functions

Bahman Farahmand Azar,Ali Hadidi,Amin Rafiee 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.55 No.5

This paper proposes a novel reliability analysis method which computes reliability index, most probable point and probability of failure of uncertain systems more efficiently and accurately with compared to Monte Carlo, first-order reliability and response surface methods. It consists of Initial and Simulation steps. In Initial step, a number of space-filling designs are selected throughout the variables space, and then in Simulation step, performances of most of samples are estimated via interpolation using the space-filling designs, and only for a small number of the samples actual performance function is used for evaluation. In better words, doing so, we use a simple interpolation function called “reduced” function instead of the actual expensive-to-evaluate performance function of the system to evaluate most of samples. By using such a reduced function, total number of evaluations of actual performance is significantly reduced; hence, the method can be called Reduced Function Evaluations method. Reliabilities of six examples including series and parallel systems with multiple failure modes with truncated and/or non-truncated random variables are analyzed to demonstrate efficiency, accuracy and robustness of proposed method. In addition, a reliabilitybased design optimization algorithm is proposed and an example is solved to show its good performance.