Full article
H. Abedin
Abstract
In this study, the effect of light wavelength on growth rate and lipid production of Synechocystis was investigated. Continuous cultivation system was used to have uniform cell density and avoid self-shading in order to obtain more precise results. Based on previous studies, red light is more efficient ...
Read More
In this study, the effect of light wavelength on growth rate and lipid production of Synechocystis was investigated. Continuous cultivation system was used to have uniform cell density and avoid self-shading in order to obtain more precise results. Based on previous studies, red light is more efficient than other colors in the visible spectrum for cultivation of Synechocystis; however, the optimum wavelength in red light spectrum remains still unknown. In order to determine the most efficient wavelength of red light, five different wavelengths including 600, 635, 660, 670, and 730 nm were used for growing Synechocystis in a chemostat setup. The results revealed that 635 nm was the most efficient wavelength for cultivation of Synechocystis in terms of both biomass production yield and growth rate. These findings can be attributed to the existence of phycocyanin, the principal light-harvesting supercomplex in Synechocystis, which absorbs maximally at around 620 nm. The results also indicated that cell size and fatty acid profile of Synechocystis were almost the same for different light wavelengths; however, the maximum light was absorbed at 635 nm.
Full article
S. Fadhil
Abstract
In this paper, the performance of nanofiltration membrane process in removing Pb(II) from aqueous solution was modeled by the pore flow-concentration polarization model. The model was fabricated based on the simultaneous resolving of Extended Nernst–Planck equation(ENP), film theory, and osmotic ...
Read More
In this paper, the performance of nanofiltration membrane process in removing Pb(II) from aqueous solution was modeled by the pore flow-concentration polarization model. The model was fabricated based on the simultaneous resolving of Extended Nernst–Planck equation(ENP), film theory, and osmotic pressure model. The effects of various operational parameters such as the applied pressure, feed concentration, and cross-velocity on lead Pb(II) ion rejection and solvent flux were investigated. The applied pressure, feed concentration, and cross-velocity varied between 10-50 bar, 5-15 ppm, and 0.2-1.2 m/s, respectively. It was found that lead rejection increased initially and reached the maximum value; then, it decreased with a further increase in pressure, while solvent flux increased linearly within the whole pressure range. This phenomenon is attributed mainly to the developed concentration polarization layer. This effect was significantly decreased with increasing cross-velocity to 1.2 m/s. Ultimately, the proposed model successfully predicted the filtration process in terms of real and observed rejections as well as solvent flux
Full length
H. Mohammadnezami; A. Irankhah
Abstract
Micro-reformers used for producing hydrogen with a high surface-to-volume ratio in small-scale fuel cells were investigated. To this end, scrutinizing and exploiting all areas of micro reformers is very important. Parallel micro-channels have shown good performance in eliminating dead volumes. Inlet/outlet ...
Read More
Micro-reformers used for producing hydrogen with a high surface-to-volume ratio in small-scale fuel cells were investigated. To this end, scrutinizing and exploiting all areas of micro reformers is very important. Parallel micro-channels have shown good performance in eliminating dead volumes. Inlet/outlet configuration has great effect on the velocity distribution through micro-channels. In this study, four configurations (1 inlet/1 outlet on the same and opposite sides; 1 inlet/2 outlets on the same and opposite sides) were studied through simulation and 1 inlet/2 outlets on opposite sides were found to have the lowest velocity difference, hence having the best configuration. Simulations were carried out at 600 °C, 1 atm, with S/C=3 and feed flow rate of 100 mL/min. Three channel patterns (i.e., parallel, splitting-jointing and pin-hole) were compared in terms of Figure of Merit (FoM) and specific conversion. Parallel channel design revealed a high value of specific conversion to be about 5.36 , while splitting-jointing and pin-hole were 5.33 and 4.91 , respectively. Based on FoM, pin-hole design had a high value of 1.34 , while the values of splitting-jointing and parallel designs were 0.037 and 1.28 , respectively.
Full length
N. Heidari; M. Rahimi; N. Azimi
Abstract
Wind energy is used to rotate a magnetic turbine in order to remove heat from the surface of a photovoltaic (PV) panel. A three-bladed turbine, which rotates with wind energy, has rotational motion underneath the studied PV panel in order to move Magnetic Nano-Particles (MNPs). In addition, effects of ...
Read More
Wind energy is used to rotate a magnetic turbine in order to remove heat from the surface of a photovoltaic (PV) panel. A three-bladed turbine, which rotates with wind energy, has rotational motion underneath the studied PV panel in order to move Magnetic Nano-Particles (MNPs). In addition, effects of the magnetic field strength (B=450-830 mT), rotational velocity of the magnetic turbine (ω), and the concentration of MNPs (ϕ) on the heat removal from the PV panel area were investigated. Results showed that heat removal from PV panel was intensified by motion of pinned MNPs in the ferrofluid via the exerted external force of magnetic field. Concurrent application of available magnetic field along with ferrofluid led to 7.6-24 % temperature reduction for a PV panel. Furthermore, the produced electrical energy of the PV panel was augmented between 2.55-3.13 W depending on ϕ, ω, and B. Moreover, the impact of ω on cooling performance was also investigated, and a significant enhancement to generated power was observed. Eventually, the maximum amount of the produced power (3.13 W), maximum power enhancement percentage (32.63 %), and thermal efficiency (24 %) were achieved for B=830 mT, ω=50 cycles/min, and ϕ=0.05 (w/v).
Full article
E. Tohfegar; J.S. Moghaddas; E. Sharifzadeh; S. Esmaeilzadeh-Dilmaghani
Abstract
In this work, hydrophobic silica aerogels were synthesized using sol-gel method and drying at ambient pressure. The surface morphology, pore size, and the presence of functional groups on the surface of the nanoparticles were analyzed using FE-SEM, TGA, FT-IR, and EDX, respectively. After calcination ...
Read More
In this work, hydrophobic silica aerogels were synthesized using sol-gel method and drying at ambient pressure. The surface morphology, pore size, and the presence of functional groups on the surface of the nanoparticles were analyzed using FE-SEM, TGA, FT-IR, and EDX, respectively. After calcination at 500 °C, the hydrophilic property of the adsorbents was evaluated by water contact angle measurements. The calcinated silica aerogels were used for adsorption of nitrate from aqueous solution in both batch and continuous processes. In the batch process, the effect of initial nitrate concentration, contact time, pH level, and adsorbent dosage were investigated. Results showed that the nitrate removal percentage increased with the decrement of the pH level and the initial nitrate concentration. On the other hand, increasing the contact time and the adsorbent dosage resulted in higher removal percentage. Accordingly, process optimization resulted in a nitrate removal of 92.2 %. Furthermore, it was found that the equilibrium results were in agreement with the Langmuir isotherm model better than with the Freundlich model and also the adsorption kinetics followed the pseudo-second-order model. In the continuous process, the effects of the input flow rate, the bed height, and the initial nitrate concentration were investigated.
Full article
P. Khadiv-Parsi; H. Moradi; M. Shafieeardestani; P. Taheri
Abstract
In this research, the metal-organic framework of HKUST-1 (Hong Koung University of Science and Technology) was synthesized for use in modern drug delivery systems by the thermal solvent method. It was activated in two conditions: under vacuum pressure and by a freeze-drying method. The synthesized HKUST-1 ...
Read More
In this research, the metal-organic framework of HKUST-1 (Hong Koung University of Science and Technology) was synthesized for use in modern drug delivery systems by the thermal solvent method. It was activated in two conditions: under vacuum pressure and by a freeze-drying method. The synthesized HKUST-1 Metal-Organic Framework was analyzed by IR, XRD, BET, and SEM. In order to examine and compare the results, the IR sample was synthesized using the sample before and after the activation of the sample. Regarding the XRD pattern, the peak area of 2θ = 11.760 showed the highest intensity. The SEM images showed an octagonal morphology in which the particle size was in the range of 5-65 μm. Furthermore, by using the BET method, the surface area of 1306 m2/g was calculated.