Regular Article
Biomedical and Biotechnology,
Sh. mashayekhiyan; M. Jahanshahi; M. Jafarkhani; K. Entezari; M. Niazi; H. Kabir
Abstract
Electrospun nanofiber is one of the promising alternatives for use in tissue engineering and drug delivery due to its controllable characteristics. However, choosing an appropriate biomaterial for a specific tissue regeneration plays a significant role in fabricating functional tissue-engineered ...
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Electrospun nanofiber is one of the promising alternatives for use in tissue engineering and drug delivery due to its controllable characteristics. However, choosing an appropriate biomaterial for a specific tissue regeneration plays a significant role in fabricating functional tissue-engineered constructs. Heart extracellular matrix (ECM)-derived electrospun nanofiber which mimic the physicochemical and structural characteristics of cardiac tissue is advantageous for cardiac tissue engineering. In this study, acellular calf heart ECM has been investigated as a potential biomaterial to be electrospun in a novel combination with poly vinyl pyrrolidone (PVP), gelatin (Gel) and polycaprolactone (PCL) for cardiac tissue engineering. The obtained fibers were aligned, uniform, and bead free. After fabrication, the scaffolds were cross-linked in glutaraldehyde vapor to become mechanically stronger and dissoluble in the aqueous environments. Considering surface topography, biocompatibility, hydrophilicity, and mechanical properties, the fabricated hybrid electrospun ECM/PVP/Gel/PCL fibers can be proposed as a biomimetic scaffold for heart tissue engineering applications.
Regular Article
Reaction Engineering, Kinetics and Catalysts,
F. Tahriri zangeneh; S. sahebdelfar; A. Taeb
Abstract
The dehydrogenation of propane to propylene over Pt-Sn-K/γ-Al2O3 catalysts prepared by sequential impregnation was studied. Three drying rates, that is, 5, 10 and 15 °C/min were applied after incipient wetness impregnation of the support (1.6–1.8 mm in diameter) with KNO3. The obtained ...
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The dehydrogenation of propane to propylene over Pt-Sn-K/γ-Al2O3 catalysts prepared by sequential impregnation was studied. Three drying rates, that is, 5, 10 and 15 °C/min were applied after incipient wetness impregnation of the support (1.6–1.8 mm in diameter) with KNO3. The obtained catalysts were characterized by N2 physisorption, SEM-EDAX analysis and XRF for textural and chemical properties. Catalytic performance tests were performed in a fixed-bed quartz reactor under kinetically controlled conditions for proper catalyst screening. The EDAX measurement results illustrated that the potassium concentration profile changed with drying rate with the catalyst prepared by lower drying rate exhibited highest K concentration at the center as well as highest propylene yield. These were attributed to the retraction of impregnation solution during drying at slow rates which results in lower concentration of acidic sites in catalyst center, thereby reducing the contact time of the propylene product with strong acid sites during reaction.
Regular Article
Materials synthesize and production
A. Ebrahim Pourshayan; A. Rabbani; S. farahani; Y. Rabbani; H. Ahmadi Danesh Ashtian; M. shariat; Gh. Nejad; A. A. Emami Satellou
Abstract
Magnetorheological fluids contain suspended magnetic particles that arrange in chains in the presence of a magnetic field, causing the conversion of the fluid from a liquid state to a quasi-solid state. These fluids can be used in valves as a tool for pressure drop and flow interruption. This research ...
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Magnetorheological fluids contain suspended magnetic particles that arrange in chains in the presence of a magnetic field, causing the conversion of the fluid from a liquid state to a quasi-solid state. These fluids can be used in valves as a tool for pressure drop and flow interruption. This research aims to investigate the feasibility of using magnetorheological fluid (MRF) in industrial valves. The rheological properties of the MRF sample were measured with the MCR300 rheometer in the presence of a magnetic field. In this connection, the Bingham plastic continuous model was used to predict fluid behavior, and model coefficients were obtained using MATLAB software. Then, the model's coefficients were used to simulate the behavior of the magnetorheological fluid in the presence of the magnetic field in the valve. The geometry and dimensions of the valve were designed according to the dimensions of industrial samples. Then the CFD simulation with Fluent software was done by using the Bingham model and fluid characteristics obtained from experimental results. The results showed that the pressure increased by increasing the magnetic field at the center of the sleeve. The magnetic field up to 0.5 Tesla, increases pressure and decreases amplitude. Therefore, as the magnetic field increase, the amplitude of the maximum pressure on the sleeve was significantly reduced.
Regular Article
Environmental Engineering,
A. Kazemi-Beydokhti; H. Hassanpour souderjani
Abstract
Due to the dangerous effects of sulfur in hydrocarbon compounds and its impact on environmental health, a new formulation based on surface-modified carbon nanotubes and a cobalt oxide has been prepared. Oxidative desulfurization is the main section of this process that is utilized to reduce this impurity. ...
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Due to the dangerous effects of sulfur in hydrocarbon compounds and its impact on environmental health, a new formulation based on surface-modified carbon nanotubes and a cobalt oxide has been prepared. Oxidative desulfurization is the main section of this process that is utilized to reduce this impurity. After decorating cobalt oxide on the surface of nanotubes, the TEM images and Thermogravimetric analysis were studied to evaluate the structure of this complex. The results show that the combination of metal oxide and functionalized nanoparticles presents better efficiency in sulfur removal. In addition, the reaction rate raised by increasing the number of functional groups on the surface of nanotubes. Then, the influence of temperature, reaction time and the concentration of the oxidizing agent in the sample was investigated. The results show that the higher temperature and higher number of oxidizing agents could provide better efficiency in the desulfurization process. Due to the presence of CNTs in the synthesized catalyst, it is possible that sulfur compounds adsorbed with CNT. By matching the data with the Pseudo first and second order adsorption kinetic, it was found that the adsorption is done as a Pseudo first order adsorption kinetic. Since the ODS process is performed by a chemical reaction, the reaction kinetics were adapted to the first order equation and calculate the activation energy required for the reaction. This result can be utilized for better desulfurization of hydrocarbon fuels for different applications.
Regular Article
Reaction Engineering, Kinetics and Catalysts,
A. Irankhah; Y. Davoodbeygi
Abstract
One of the effective catalysts for hydrogen purification and production via medium temperature shift reaction, is Cu-Ce solid solution. Cu0.1Ce0,9O1.9 was produced using co-precipitation method and then was utilized as support for 5Cu/Ce0.9Cu0.1O1.9 catalyst which was synthesized employing wet impregnation ...
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One of the effective catalysts for hydrogen purification and production via medium temperature shift reaction, is Cu-Ce solid solution. Cu0.1Ce0,9O1.9 was produced using co-precipitation method and then was utilized as support for 5Cu/Ce0.9Cu0.1O1.9 catalyst which was synthesized employing wet impregnation method. X-ray diffraction (XRD) analysis showed that crystalline sizes of Ce0.9Cu0.1O1.9 and 5Cu/Cu0.1Ce0,9O1.9 were 9.22 and 18.33 nm, respectively. The Catalysts were evaluated in medium temperature shift reaction at 300-390 °C and at gas hourly space velocities (GHSV) of 12000 and 30000 h-1, in a fixed bed reactor. Due to higher concentration of Cu and synergic positive effects of both active metal and support, 5Cu/Cu0.1Ce0,9O1.9 catalyst showed better performance. It was also concluded that, because of low residence time at high levels of GHSV, increasing GHSV leads to decrease CO conversion. Then 5Cu/Cu0.1Ce0,9O1.9 was evaluated in microchennel reactor in 2 GHSVs of 12000 and 30000 h-1 and results were compared with the fixed-bed reactor. It can be concluded that microchannel reactor is better in higher GHSVs (lower residence time of gas flow). A microchannel reactor provides a high surface-to-volume ratio and gases pass over the thin layer of catalyst on the coated plates. Hence, due to the better access to the catalytic bed, the reactants react even in a short time, which improves the microchannel performance compared to the fixed bed reactor
Regular Article
Thermodynamics,
ُS.Saba Ashrafmansouri
Abstract
Considering the high number of ionic liquids (ILs) and impracticability of laboratory measurements for all ILs’ properties, applying theoretical methods to predict the properties of this large family can be very helpful. In the present research, ILs’ thermophysical properties are predicted ...
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Considering the high number of ionic liquids (ILs) and impracticability of laboratory measurements for all ILs’ properties, applying theoretical methods to predict the properties of this large family can be very helpful. In the present research, ILs’ thermophysical properties are predicted by a combination of statistical associating fluid theory and group contribution concept (SAFT-γ GC EoS). The studied ionic liquids are 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][CF3SO3]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim][CF3SO3]), 1,3-dimethylimidazolium methylsulfate ([mmim][MeSO4]), 1-ethyl-3-methylimidazolium methylsulfate ([emim][MeSO4]), 1-butyl-3-methylimidazolium methylsulfate ([bmim][MeSO4]), 1-ethyl-3-methylimidazolium methanesulfonate ([emim][MeSO3]) and 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]). The thermophysical properties including coefficient of thermal expansion, coefficient of thermal pressure, coefficient of isentropic compressibility, coefficient of isothermal compressibility, speed of sound, isochoric and isobaric heat capacities are estimated within broad ranges of pressure and temperature (0.1-60 MPa and 273-413 K). The comparison among the SAFT-γ predictions and some available experimental data show good ability of SAFT-γ EoS to estimate the ILs’ second-order derivative thermophysical properties.