Prediction of biodiesel properties and its characterization using fatty acid profiles

Mehdi Ardjmand,Mahdieh Samavi,Barat Ghobadian,Aliakbar Seyfkordi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.7

Biodiesel, the mono-alkyl esters of vegetable oils or animal fats, is an eco-friendly alternative to petrodiesel. The molecular structures of biodiesels, fatty acid methyl esters were applied to predict the characteristics of biodiesel fuels. Based on the structural similarity of biodiesel and petroleum fractions, molecular weight of biodiesel was correlated with other characteristics including boiling point, viscosity and specific-gravity in the form of three equations. For 24 different kinds of biodiesel, the minimum average relative deviation (ARD) of these correlations was calculated to be 0.68%. Moreover, two correlations were developed to predict viscosity and flash point of biodiesel as a function of weighted-average number of carbon atoms (NC) and weighted-average number of double bonds (NDB) with ARD 3.72% and 4.24% respectively. Also, a high degree of correlation was shown by the logarithmic function with ARD 0.30% between specific gravity and viscosity of biodiesel. Proposed predictive models were verified by experimental data.

Efficacy Comparison of Nanoniosomal and Pegylated Nanoniosomal Cisplatin on A172 Cell Line

Mahrokh Babaei,Mehdi Ardjmand,Azim Akbarzadeh,Aliakbar Seyfkordi 한국조직공학과 재생의학회 2014 조직공학과 재생의학 Vol.11 No.5

In this study, Cisplatin was loaded into nanoniosom and pegylated nanoniosom employing reverse phase evaporation method. Span 60, cholesterol and Cisplatin were combined together at certain concentrations in this method. This study reports the efficacy of nanoniosome Cisplatin and pegylated nanoniosome Cisplatin on brain cancer (A172) cell line. All of the results are presented from three independent tests. The obtained results showed that the stability of prepared formulation was increased by pegylation. Encapsulation efficiency and loading efficiency of Cisplatin in pegylated and non-pegylated niosomal formulations were estimated 48.2±2.05%, 43.6±4.59%, 4.38±0.28%, 4.36±0.08%, respectively. The average diameters of pegylated and non-pegylated nanoparticles of niosomes were determined by Zeta sizer which was 205.5±4.60 nm and 242.1±5.10 nm, respectively. The release of drug was studied by dialysis method. The amounts of drug released from pegylated and non-pegylatednanoniosomes were calculated 82.73±1.36% and 97.53±0.55% during 48 hr, respectively. The toxicity of formulated Cisplatin was studied by MTT assay and the results revealed that the cytotoxicity effect of pegylated nanoniosomal Cisplatin was more than nanoniosomal Cisplatin. The IC50 for nanoniosomal Cisplatin was estimated 123.2±0.98 μg/mL while IC50 for pegylated nanoniosomal formulation was calculated 79.8±1.14 μg/mL.

Efficient storage and utilization of CO2 in open raceway ponds for cultivation of microalgae

Mohammad Javad Asadollahzadeh,Mehdi Ardjmand,Ali Akbar Seafkordi,Seyed Mohammad Heydarian 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.8

For efficient storage and utilization of CO2 in open raceway ponds, the effects of cultural and operationalparameters were studied. A 10 m2 indoors raceway pond was operated to determine CO2 storage capacity, average rateof absorbed CO2 losses and mass transfer coefficient for CO2 outgassing from various pH, salinity and alkalinity regimesof culture medium; mixing velocities and culture depths. Average rate of CO2 outgassing for saltwater (35 pptsalinity) at 40 meq/L alkalinity was 40-fold higher than seawater (35 ppt salinity and 2.3 meq/L alkalinity) at pH 8. Operating at lower pHs or salinities aggravated CO2 outgassing. An empirical equation for CO2 outgassing averagemass transfer coefficient, KL, was developed as a function of mixing velocity and depth. Nannochloropsis sp. PTCC6016was cultivated in the pond for 14 days. Due to higher amount of outgassing, CO2 utilization efficiency declined as theproductivity in the pond decreased.

Self-assembly electrode based on silver nanoparticle toward electrogenerated chemiluminescence analysis of glucose

Ali Shokuhi Rad,Mehdi Ardjmand,Mohsen Jahanshahi,Ali-Akbar Safekordi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.8

Electrogenerated Chemiluminescence (ECL) involves applying a certain electric potential to a chemical reaction, resulting in the oxidation or reduction of the substance which reacts to produce light. We determined the amount of glucose by its reaction to glucose oxidase (GOX) on the surface of the proposed modified electrode, which results hydrogen peroxide (H2O2) as side product. After that the reactions between luminol and H2O2 under oxidizing conditions generate dependent light which can be used to analyze. In the current article at first we proposed a convenient method to obtaining a self-assembly modified electrode. A nano based modified glassy carbon (GC) electrode (Glucose oxidase/Ag nanoparticles/cysteamine (CA)/p-aminobenzene sulfonic acid/GC electrode) was prepared, and the ECL behavior of luminol in the presence of glucose was examined. Compared to the bare GC electrode, the modified electrode incorporating glucose oxidase significantly enhanced the response of the ECL biosensor to glucose due to the enhanced specificity of the modified surface to enzymatic reaction, and the sensitivity of the luminol ECL reaction. Under optimal conditions, the electrode was established to respond linearly to glucose in the concentration range 5.0×10−7 to 8.0×10−3 mol/L, and the detection limit was established to be a glucose concentration of 4.0×10−8 mol/L.

A novel mathematical method for prediction of rapid expansion of supercritical solution (RESS) processed ibuprofen powder size distribution

Fatemeh Zabihi,Ali Vaziri,Mohammad Mehdi Akbarnejad,Mehdi Ardjmand,Maryam Otadi,Ahmad Reza Bozorgmanesh 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

A fundamental understanding of the interplay among the variables involved in a rapid expansion of supercritical solution (RESS) process is necessary in order to achieve control of product within the desired specifications. A model is proposed where the experimental data are fitted to a 2-D Sp-line equation that results in a mathematical pattern matching function that can easily be processed analytically to yield a continuous motion estimate. This model presents a novel promising method to interpolate between any two experimental results. Comparison of the mean particles size values which are calculated as a function of nozzle temperature (TN) and pre-expansion pressure (Ppre-expansion)with the experimental data, results in a ±8% accuracy. The optimum operational point that leads to the minimum mean particles diameter (40 nm) is determined through mathematical optimization of this equation and confirmed experimentally. Furthermore, 600 more values of mean particle size are predicted by varying the nozzle temperature and dissolution pressure and the results are presented in the form of a 3-dimesional curve.

A new electrochemical biosensor for hydrogen peroxide using HRP/AgNPs/cysteamine/p-ABSA/GCE self-assembly modified electrode

Ali Shokuhi Rad,Mohsen Jahanshahi,Mehdi Ardjmand,Ali-Akbar Safekordi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.12

An electrochemical hydrogen peroxide biosensor was designed by immobilizing horseradish peroxidase (HRP) on Ag nanoparticles/cysteamine/p-aminobenzene sulfonic acid/glassy carbon (GC) electrode. Ag nanoparticles can act as tiny conduction centers on electrodes that adsorb redox enzymes, facilitating the transfer of electrons with no requiring any loss of biological activity. The forerunner film was first electropolymerized on the glassy carbon electrode with p-aminobenzene sulfonic acid (p-ABSA) by cyclic voltammetry. The cysteamine (CA) was bound on the surface of the film by electrostatic force, then Ag nanoparticles were immobilized on the cysteamine monolayer, and lastly HRP was adsorbed onto the surfaces of the Ag nanoparticles. A dramatic decrease in the overvoltage of H2O2was observed with improved sensitivity, which makes the modified electrodes of great promise for oxidase-based amperometric biosensors. The biosensor responded to H2O2 in the linear range from 1.2×106 mol/L to 9.8×103 mol/L with a detection limit of 1.1×108 mol/L. Moreover, the obtained biosensor exhibited good accuracy and high sensitivity.

Beryllium oxide (BeO) nanotube provides excellent surface towards adenine adsorption: A dispersion-corrected DFT study in gas and water phases

Mitra Sherafati,Ali Shokuhi Rad,Mehdi Ardjmand,Amir Heydarinasab,Majid Peyravi,Mahmoud Mirzaei 한국물리학회 2018 Current Applied Physics Vol.18 No.9

Zigzag (5, 0) BeO nanotube (BeONT) has been examined in detail towards adsorption properties of adenine nucleobase on its surface via D2-DFT calculation method in the gas and water phases. A detailed surface study reveals that there are four orientations for nucleobase adsorption that none of the vibrational spectrums demonstrated imaginary frequency, recognizing that all of the relaxed structures are at the minimum of energy. The minimum and maximum adsorption energies are both in chemisorption regime with calculated values of −140 (−118 BSSE corrected) and −191 (−168 BSSE corrected) in the gas phase, and −181 and −310 kJ/mol in the water phase, using meta-hybrid functional (□B97XD) and 6-31G** basis set. For all positions, BeONT showed p-type semiconducting property because of receiving electronic charge from adenine molecule. Our findings suggest that BeONT could be used as a possible strong carrier for adenine molecule in practical applications.