Regular Article
Thermodynamics,
M. Rahmanzadeh Derisi; N. Esfandiari
Abstract
One of the methods to reduce the particle size is the GAS method. In this method, the solute and antisolvent should be dissolved well in a solvent. But the solute is not dissolved in a solvent. The aim of studying this model is to determine the phase equilibrium and thermodynamic conditions of (CO2, ...
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One of the methods to reduce the particle size is the GAS method. In this method, the solute and antisolvent should be dissolved well in a solvent. But the solute is not dissolved in a solvent. The aim of studying this model is to determine the phase equilibrium and thermodynamic conditions of (CO2, solvent, 5-Fluorouracil) in the GAS process. The solvents include methanol, ethanol, acetone, 1-propanol, and 1-butanol. The Peng-Robinson equation of state with a linear combination of Vidal and Michelsen mixing rules (PR-LCVM) was used for the thermodynamic modeling. The volume expansion of the binary system (CO2, solvent) and ternary system (CO2, solvent,5-Fluorouracil) at the temperature range of 313.15-319.15 K was investigated. The Pmin values for the binary system were 66.7, 69.6, 60, 73.7, and 76.8 bar respectively for methanol, ethanol, acetone, 1-propanol, and 1-butanol at 313.15 K,. The Pmin for the ternary system was also calculated. The comparison between the Pmin values of binary and ternary systems showed that for a constant temperature and a certain solvent, the calculated minimum pressure in the ternary system was greater than the same in the binary system
Regular Article
Energy
A. Mohammadi; B. Ghobadian
Abstract
A batch process was developed for the production of biodiesel from high free fatty acid feedstocks. The mixed-integer nonlinear programming (MINLP) problem, caused due to applying the hierarchical procedure together with Malone’s algorithm for the conceptual design, was solved. Meanwhile, the optimum ...
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A batch process was developed for the production of biodiesel from high free fatty acid feedstocks. The mixed-integer nonlinear programming (MINLP) problem, caused due to applying the hierarchical procedure together with Malone’s algorithm for the conceptual design, was solved. Meanwhile, the optimum states of major process parameters such as the utilization of the process equipment, paralleling, splitting, and the merging of unit operations, the process cycle time (CT), and the combination of batch and continuous units were determined. Based on the present optimization study, the optimum value of the process cycle time and the optimum number of the esterification reactors in series were obtained as 3.257 h/batch and 3 stages respectively. The batch process was found to be suitable for a capacity of less than 260 tons/yr, while the continuous process was suitable for a capacity of greater production rates. The results showed that the production rate had a direct effect on the economic potential of the process and that it should be set at its maximum possible practical value. Also, the break-even point for the optimum state occurred at the production rate of 130 tons/yr.
Regular Article
Thermodynamics,
F. S. Fattahi
Abstract
In the present investigation, the physicochemical parameters of dyeing woolen yarn with the CI Acid Red 1 dye in terms of the kinetics and thermodynamic of adsorption were studied. Different models (Zero order, First order, Second order, Parabolic, Cegarra–Puente and modified Cegarra–Puente ...
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In the present investigation, the physicochemical parameters of dyeing woolen yarn with the CI Acid Red 1 dye in terms of the kinetics and thermodynamic of adsorption were studied. Different models (Zero order, First order, Second order, Parabolic, Cegarra–Puente and modified Cegarra–Puente models) were employed to discover a suitable dyeing apparatus. It was found that the modified Cegarra-Puente model best fitted to the investigational data with the maximum correlation (R2 ≥ 0.99). The dyeing-rate constant, half dyeing times, rise time and fixation time were then calculated. Thermodynamic parameters, for instance the Gibbs free energy (∆G#), enthalpy (∆H#), entropy (∆S#), and the activation energy (Ea), were considered. The thermodynamic parameters imply that the dying procedure could be improved by increasing the system temperature. Also, dyeing woolen yarns with CI Acid Red 1 decreases randomness and enhances the order of reaction systems by immobilizing dye molecules onto the solid fiber surface
Regular Article
Modeling and Simulation
E. Salehi; S. Tahmasbi; V. Tahmasbi; M. Rahimi
Abstract
An adaptive neuro-fuzzy inference system (ANFIS) was applied to simulate the batch adsorption of triglyceride (TG) from the human blood serum using the cinnamon powder, which has appeared as a potential biosorbent for serum purification, in our previous work. The obtained experimental results were used ...
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An adaptive neuro-fuzzy inference system (ANFIS) was applied to simulate the batch adsorption of triglyceride (TG) from the human blood serum using the cinnamon powder, which has appeared as a potential biosorbent for serum purification, in our previous work. The obtained experimental results were used to train and evaluate the ANFIS model. Temperature (°C), the adsorption time (h), the stirring rate (rpm), the dose of adsorbent (g) and the adsorbent milling time (min) (or the particle sizes of the powder) were considered as the model inputs and TG removal (%) was chosen as the model response. The ANFIS model was trained with 75 % of the available data while 25 % of the remaining data was used to verify the validity of the obtained model. Sobol sensitivity analysis results indicated that the cinnamon dose with 71 % and the adsorbent milling time (or the particle size of the powder) with 15 % impact share were the most influential variables on the TG removal. Furthermore, the specific surface area and the number of reactive adsorption sites were found to be the most important characteristics of the adsorbent. Generally, the results of this study confirmed the advantages of applying the ANFIS and Sobol approaches for the data-based modeling of the bioprocesses.
Regular Article
Biomedical and Biotechnology,
Y. Beygi-Khosrowshahi; S. Zakhireh
Abstract
Bone tissue engineering requires approaches to provide a suppression/promotion environment for the bone growth. Scaffold biomaterials have profound regulatory effects on the functionality of mesenchymal stem cells (MSCs). In the present study, the three-component bioceramic of selenium/reduced graphene ...
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Bone tissue engineering requires approaches to provide a suppression/promotion environment for the bone growth. Scaffold biomaterials have profound regulatory effects on the functionality of mesenchymal stem cells (MSCs). In the present study, the three-component bioceramic of selenium/reduced graphene oxide/hydroxyapatite (Se/RGO/HA) was developed and its performance to repair bone defects was compared to that of HA. The Se/RGO/HA nanocomposite scaffold was synthesized using the chemical bath technique, characterized by the X-ray diffraction spectra, field emission scanning electron microscopy, energy dispersion X-ray spectrometery, and Fourier transform infrared spectroscopy analyses. Human adipose-derived MSCs (hAD-MSCs) were used to investigate the in-vitro osteogenic properties of the Se/RGO/HA scaffold. The effect of the combined scaffold on the cell proliferation was analyzed by the MTT assay. Cell adhesion behaviors were evaluated using the optical microscopy and SEM. The osteogenic properties of the Se/RGO/HA scaffold were examined by the measurement of the alkaline phosphatase (ALP) activity and western blotting technique. The hAD-MSCs proliferation for HA and the Se/RGO/HA nanocomposite were 2 ± 0.1 and 1.1 ± 0.05 respectively. The Se/RGO/HA nanocomposite had cytotoxic effects on the KHOS-240S cancer cells. Additionally, good cell attachment and osteoblast-like morphology were characterized on the designed scaffold. The ALP activity and mineralization potential of cells seeded on Se/RGO/HA were higher than those seeded on HA. The Osteocalsin protein for Se/RGO/HA and HA were 64 ± 1 and 12 ± 0.1 respectively. Furthermore, the expression of Osteocalcin, a bone-specific protein, was synergistically increased by the incorporation of Se and RGO into HA. In conclusion, the presence of RGO inside Se could significantly increase the positive effects of HA on the osteogenic potential of hAD-MSCs.
Regular Article
Modeling and Simulation
N. Hajilary; S. Hashemi; M. Hajiabadi
Abstract
MXene membranes perform well in biofuel separation due to their excellent hydrophilicity, flexibility, and mechanical strength. For the first time, computational fluid dynamics was used to model the dehydration of ethanol through the pervaporation system by the MXene membrane. We discretized the momentum ...
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MXene membranes perform well in biofuel separation due to their excellent hydrophilicity, flexibility, and mechanical strength. For the first time, computational fluid dynamics was used to model the dehydration of ethanol through the pervaporation system by the MXene membrane. We discretized the momentum and continuity equations using finite element methods and predicted the mass transport. Experimental results and model data were in good agreement (less than 10 %). The feed velocity, feed concentration, and membrane thickness all had positive effects on the separation factors while the temperature had a decreasing effect. This model's efficiency has decreased by 35 % after increasing the feed flow rate by 10 times. In addition, the separation factor increases tenfold when temperature is raised from 25 to 70 °C.