M. Morovat; O. Bakhtiari
Abstract
Ability and compatibility of the membrane processes for gas separation are evaluated by their membranes’ permeability and selectivity where both have been tried to enhance in promising membrane generation of mixed matrix membranes (MMMs). In the current study, two- and three-dimensional models ...
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Ability and compatibility of the membrane processes for gas separation are evaluated by their membranes’ permeability and selectivity where both have been tried to enhance in promising membrane generation of mixed matrix membranes (MMMs). In the current study, two- and three-dimensional models were constructed for MMMs, and the Fick's first law was solved numerically in them by using the Finite Element Method (FEM) and Computational Fluid Dynamic (CFD) tools. The effects of different MMMs structural parameters such as the volume fraction, size and mode of packing, i.e., regular or random, of the filler particles were investigated on the effective permeability of the pure gaseous penetrants through the MMMs. Furthermore, the interfacial equilibrium constant of the penetrants and their diffusivity ratios were also evaluated in view point of their impacts on the MMMs’ separation performance. Some well-known established models including Maxwell, Bruggeman, Lewis - Nielsen, Pal, and Chiew - Glandt were applied in the modeling. Deviation of the simulation results from the experimentally measured ones were low enough, however, at higher loadings of the filler particles the simulation deviation became greater. Simulated results through PSF - MCM-41 MMMs were compared with those of experimentally measured ones and AAREs of 31.0 (The lowest deviation), 42.7, and 41.0 % obtained for CO2, O2, and N2, respectively.
Modeling and Simulation
K.H. Hanon; E. Ebrahimi
Abstract
The purpose of this research is CFD modeling of the fluid flow inside an industrial valve in order to discover the areas with high shear stress and to determine the effect of hydrodynamic on the erosion rate. CFD results are compared with the existing experimental data in a valid reference and the model ...
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The purpose of this research is CFD modeling of the fluid flow inside an industrial valve in order to discover the areas with high shear stress and to determine the effect of hydrodynamic on the erosion rate. CFD results are compared with the existing experimental data in a valid reference and the model is verified with high accuracy. The impact of the pressure at inlet and the disc angle on the erosion is investigated. By increasing inlet pressure, maximum velocity, turbulence intensity, wall shear stress and particle erosion increased. However, the wall shear stress, turbulence intensity, and particle erosion are clearly reduced as the disc angle decreases. When the disc angle is less than 50o, the range of dependent parameters changes has a small value. Reducing the disc angle or increasing the inlet pressure led to an increase in cavitation. Therefore, to prevent the erosion of the butterfly valve, it is necessary to increase the disc angle or reduce the pressure at inlet. Erosion of the butterfly valve significantly occurred at the front and rear of the disc. Depending on the disc angle, the shear stress of wall for the modified configuration is 10 to 80 times lower than the original butterfly valve. Therefore, it can be stated that the modified geometry can reduce the wall shear stress and consequently the erosive for all the disc angles of the studied butterfly valve.
Materials synthesize and production
R. Omidi; M. Simiari; S. Ovaysi; M. Nazari; M. Rezaei
Abstract
In this work, nanoparticles of the metal fuel Zirconium (Zr) and nanoscale oxidizer BaCrO4 are synthesized considering their unique nanoparticle characteristics like mixing homogeneity and high surface/volume ratio. Using the synthesized fuel and oxidizer, the pyrotechnic mixture of Zr/BaCrO4 was developed ...
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In this work, nanoparticles of the metal fuel Zirconium (Zr) and nanoscale oxidizer BaCrO4 are synthesized considering their unique nanoparticle characteristics like mixing homogeneity and high surface/volume ratio. Using the synthesized fuel and oxidizer, the pyrotechnic mixture of Zr/BaCrO4 was developed under 4 different conditions and analyzed in terms of the thermal behavior and burning rate. In the synthesis stage, the oxidizer nanopowder BaCrO4 was developed through precipitating Barium Nitrate and Chromate Potassium in the vicinity of Dodecyl benzene sulfonate sodium (DBSS) stabilizer. Also, Zr nanopowder was prepared using direct reduction of Zr (NO3)2 by N2H2 and was coated by a 4% Collodion. Then, the pyrotechnic mixture Zr/BaCrO4 was charged and pressed in the constructed combustion chamber. The burning rate of the mixture was captured by the direct footage of the combustion process using digital cameras with 60 frame-per-second capabilities. The fastest burning occurs when both the fuel and the oxidizer are nano-scaled. The thermal behavior of the mixture was studied using the simultaneous thermal analysis (STA) machine within the temperature range of 25 to 1000 °C. Results of the thermal analysis show that the thermal decomposition temperature of the Zr/BaCrO4 mixture in the micron size is higher than in the nano size and the amount of destruction is lower. Increasing the concentration of zirconium in the nano-size from 10 to 50% leads to a decrease in the decomposition temperature from 565 to 437 °C, while the pyrotechnic mixture destruction rate increases from 39% to over 63%.
Environmental Engineering,
B. Momenpoor; F. Danafar; F. Bakhtiari; A. Namjoo
Abstract
The properties of the Nanoclay-corn starch film were studied in the presence of Nanostarch. Nanostarch was synthesized through nanoprecipitation and characterized using the Particle Size Distribution Analysis, Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction Analysis (XRD), and ...
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The properties of the Nanoclay-corn starch film were studied in the presence of Nanostarch. Nanostarch was synthesized through nanoprecipitation and characterized using the Particle Size Distribution Analysis, Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction Analysis (XRD), and Fourier Transform Infrared Analysis (FTIR). The XRD analysis of nanostarch particles revealed a distinctive V-type diffraction peak, with particle diameters ranging from 25 to 100 nm. The impact of introducing nanostarch into the starch-nanoclay film was investigated in terms of the thickness, transparency, morphology, wettability, and mechanical properties of the nanocomposite film. The results indicated that adding nanostarch particles improved the optical transparency of the film along with its hydrophobicity and flexibility. The film having a weight ratio of 0.769 (nanoclay to nanostarch) showed the maximum hydrophobicity (107.85°), and elongation at break (58.6%). This suggests that the appropriate incorporation of nanostarch can enhance the film's flexibility. The maximum tensile strength (5.88 MPa) was obtained for the film with a weight ratio of 1 (nanoclay to nanostarch).
Biomedical and Biotechnology,
M. Takapoui; M. Saadatmand; F. Ghobadi
Abstract
Numerous bone disorders and injuries, such as osteoporosis, are among the most spreading types of human tissue injuries worldwide, and the available treatments for these injuries are often insufficient and inefficient. Nowadays a lot of attention has been paid to the regenerative medicine, specifically ...
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Numerous bone disorders and injuries, such as osteoporosis, are among the most spreading types of human tissue injuries worldwide, and the available treatments for these injuries are often insufficient and inefficient. Nowadays a lot of attention has been paid to the regenerative medicine, specifically tissue engineering because of its unique features. The extracellular matrix is a key component in tissue engineering because it must have specific properties to support cell survival and proliferation. Natural and synthetic polymeric hydrogels are among the materials commonly employed in tissue engineering. Because the extracellular matrix of bone is particularly mineralized and has a high elasticity, various nanoparticles are commonly utilized to improve the mechanical properties of polymeric hydrogels. In this study, first we extracted the collagen type I from rat tail and characterized it with FTIR spectrum and self-assembly, second we synthesised the bioactive glass nanoparticles and characterized them with XRD and EDAX. Then we developed a polymeric collagen hydrogel (3 mg/ml) scaffold, including bioactive glass nanoparticles (3 %w/v) which increase the mechanical properties of the scaffold (103 pa elastic modulus) in comparison to those of the collagen scaffold (0% w/v nanoparticles), that can be used for bone tissue engineering applications.
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 ...
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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
Energy
N. Gilani; S. Fallahdoost Moghadam; A. A. Yousefi
Abstract
A hydrothermal method was used to synthesize different photoanodes for their application in dye-sensitized solar cells (DSSC). These photoanodes included WO3, TiO2, Graphene-TiO2, WO3-TiO2, and a nanostructure of Graphene-WO3-TiO2. The morphology of the nanoparticles was analyzed using the scanning electron ...
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A hydrothermal method was used to synthesize different photoanodes for their application in dye-sensitized solar cells (DSSC). These photoanodes included WO3, TiO2, Graphene-TiO2, WO3-TiO2, and a nanostructure of Graphene-WO3-TiO2. The morphology of the nanoparticles was analyzed using the scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), ultraviolet-visible spectroscopy (UV-vis), and Fourier-transform infrared spectroscopy (FTIR). The results demonstrated that the graphene-WO3-TiO2 nanostructure had a large surface area, having provided more active sites for the efficient conversion of solar energy. Notably, the DSSC incorporating the graphene-WO3-TiO2 nanoparticle electrode outperformed cells based solely on TiO2 and WO3, achieving a higher short-circuit current density of 7.5 mA.cm-2, an open-circuit voltage of 0.68 V, a fill factor of 0.46, and a power conversion efficiency of 2.4%. In contrast, the pure TiO2 and WO3 cells only achieved efficiencies of 0.88% and 0.69% Respectively. The excellent electron mobility of the ternary nanostructure facilitated the charge trapping and injection into the conductive substrate, reducing recombination. Additionally, the scattering effect of the WO3 nanorods and graphene enhanced the light harvesting in the photoanode, leading to an increase in the overall efficiency of the solar cell. These findings highlight the potential of the synthesized graphene-WO3-TiO2 nanostructure as a promising photoanode material to be applied in DSSC.
Modeling and Simulation
T. Fattahi; E. Salehi; Z. Hosseini
Abstract
The Ethanol-water separation involves a well-known azeotrope that confines the achievement of the ethanol purity to the values higher than 95 wt% using straightforward distillation. Many attempts have been made to identify how it can be possible to produce ultra-pure ethanol (99.95 wt%) for various valuable ...
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The Ethanol-water separation involves a well-known azeotrope that confines the achievement of the ethanol purity to the values higher than 95 wt% using straightforward distillation. Many attempts have been made to identify how it can be possible to produce ultra-pure ethanol (99.95 wt%) for various valuable applications. In practice, minimizing the total cost of the process is of high importance beside having the finished product with utmost purity. As a consequence, finding the best process conditions imposed to apply the simulation and statistical optimization methods in combination. Numerical optimization provides the best trade-offs to achieve the goals. In this research, the separation of the ethanol/water mixture (87 wt%) was simulated using azeotropic distillation in Aspen plus© environment. Indeed, cyclohexane was chosen as an effective azeotrope-former. The UNIQUAC equation was used to describe the phase behavior. The two-column arrangement, in which the first column was used to dehydrate ethanol and the second to recover the entrainer, was applied in this simulation. The effect of important process variables, including the number of the trays in columns and the feed-tray position in each tower on the total capital cost were investigated. Finally, the process variables were optimized via the Response Surface Methodology to minimize the total cost of the process. The results uncovered that the total capital cost would be minimized if the number of the trays in the azeotropic (C1) and recovery (C2) columns were set to 34 and 40, whereas, the feed-tray numbers were adjusted to 19 and 9 respectively.
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.
Energy
Abbas Mohammadi; Barat Ghobadian
Abstract
A continuous process was designed and optimized at a conceptual stage for the biodiesel production from waste vegetable oils. Unlike previous studies, the process was optimized taking into account the technical and economic considerations, simultaneously, to find the optimum operating conditions fort ...
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A continuous process was designed and optimized at a conceptual stage for the biodiesel production from waste vegetable oils. Unlike previous studies, the process was optimized taking into account the technical and economic considerations, simultaneously, to find the optimum operating conditions fort he commercial scale productions. The effect of major variables on the yield of the process was studied by modeling esterification and transesterification reactors. The mole fraction of free fatty acids (FFAs) in the feedstock, production rate, conversion and molar ratio of the reactants in both reactors were chosen as major variables. By considering the economic potential as the objective function of the process optimization, the optimum mole fraction of FFA was obtained as about 0.50 (24 wt %). Also, the optimum values of the conversion and molar ratio of the reactants in the esterification and transesterification reactors were found as 82-89 % (depending on the different production rates), 11:1 and 96 %, 8:1 respectively. It was found that the economic potential increases linearly as the production rate increases. Therefore, the production rate should be set at its maximum possible practical value. The break-even point at the optimum values of these variables, as mentioned above, occurs at the production rate of 157 ton/yr.
Modeling and Simulation
P. Sharafi; E. Salehi; H.R Sanaeepur; A. Ebadi Amooghin
Abstract
In this work, the separation of carbon monoxide (CO) from a synthesis gas (syngas) mixture was modeled. It was considered a copper-based adsorbent consisting of cuprous chloride (CuCl) on an activated carbon (AC) support (CuCl/AC) in a pressure swing adsorption (PSA) process. First, the adsorption of ...
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In this work, the separation of carbon monoxide (CO) from a synthesis gas (syngas) mixture was modeled. It was considered a copper-based adsorbent consisting of cuprous chloride (CuCl) on an activated carbon (AC) support (CuCl/AC) in a pressure swing adsorption (PSA) process. First, the adsorption of syngas components on the CuCl/AC adsorbent at 303.15 K was simulated to determine the required data. Next, the PSA process to separate CO from syngas using CuCl/AC absorbent at ambient temperature and pressure of 1000 kPa was evaluated by computational fluid dynamics simulation. The simulation results showed that with an adsorption bed of 2 m in height and 1 m in diameter, CO with appropriate purity (~ 99.5%) is separated from syngas by CuCl/AC. In addition, reducing the inlet feed pressure, or in other words, its velocity or flow can increase the efficiency of the operation (e.g, with a shorter bed height of 0.5 m, a CO purity of more than 99.8% can be achieved at 700 kPa, but with a significant increase in operating cost).
Polymer Engineering and Technology,
A. Mehralizadeh; F. derakhshanfard; Z. Ghazitabatabaei
Abstract
General Purpose Polystyrene (GPPS) has weak properties and this weakness made the applications of this polymer be limited. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of preparing polymer ...
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General Purpose Polystyrene (GPPS) has weak properties and this weakness made the applications of this polymer be limited. Therefore, the use of the mixtures of polymers can improve these properties. Different parameters like the mixing speed can affect the quality of the properties of preparing polymer from the mixture of several polymers. In this research, the polymer blend of GPPS and Acrylonitrile-Butadiene Styrene (ABS) has been investigated. In order to prepare this polymer mixture, GPPS has been considered as the main phase (base polymer) and ABS has been considered as the scattered phase (additive). Firstly, the blended polymers with different weight percentages (0, 0.04, 0.08 and 0.12) of ABS/GPPS in different mixing speeds (30, 40, 50 and 60 rpm) have been prepared and for each mixture, the Melt Flow Index (C), Vicat Softening Temperature, Tensile at Break and impact test have been measured. The laboratory data collected from different tests, has been simulated by the Multi-Layer Perceptron (MLP) method of Artificial Neural Networks (ANN) and the results of the simulated data covered the laboratory data perfectly. The results declare that the presence of ABS in the mixed polymer improved the Tensile strength and thermal properties. In order to reach the highest quality in carried out tests, it is considered to use ABS in a high percentage (0.12) and the maximum possible mixing speed (60 rpm).
Modeling and Simulation
H. Kadkhodayan; T. Alizadeh
Abstract
In the present study, a new method has been suggested to solve the problems of the very low solubilityof sulfide ores in acidic solution and also the production of toxic impurities for the first time. In this work, the polyoxometalate (POM) oxidizer was applied for the dissolution of sulfide ores, extraction ...
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In the present study, a new method has been suggested to solve the problems of the very low solubilityof sulfide ores in acidic solution and also the production of toxic impurities for the first time. In this work, the polyoxometalate (POM) oxidizer was applied for the dissolution of sulfide ores, extraction of metals, and removal of toxic and harmful wastes. In this procedure, POMs were used as strong oxidizers of sulfur compounds to dissolve sulfide ores. Also, acid was applied as a solvent and catalyst to increase the reaction rate. The Taguchi experimental design along with the ProMax simulation software was applied for studying the leaching of sulfide ores by POM oxidizers as a novel plan in experimental to industrial scales. The optimum data achieved by the Taguchi method was used as the input data to the simulation and sensitivity analysis of the process was executed by the ProMax software. The effects of curicital operating parameters such as the concentration of acid (CA) in the 60-90 g/l range, the reaction temperature (TR) with the values of 60-90 ºC, the rotation rate (R) with the amounts of 50- 300 rpm, the retention time (τ) in the 0.5-2.0 h range, the concentration of polyoxometalate oxidizer with the values of 0.1- 0.5 g/l, the acid types of H2SO4, HNO3, HCl, H3PO4, the grain sizes of sulfide ores (Sparticle) in the 0.5-3.0 mm range and polyoxometalate with the types of [Mo6O19]2-, [Mo8O26]4-, [V10O28]6- and [H2W12O40]10- on the extraction efficiency of metals and removal of toxic heavy metals from sulfide ores by polyoxometalates were investigated. The optimum conditions to extract maximize metals from the sulfide ores were obtained as the CA; 80 g/l, TR; 90 ºC, R; 300 rpm, τ; 1.0 h, m POMs; 0.5g/l, acid type of H2SO4, Sgrain;1.0 mm and POMs type of [H2W12O40]10-. Under optimized conditions, the extraction efficiency of zinc, copper, and lead and the removal of toxic heavy metals from sulfide ores were determined as above 85%, 81%, 83%, and 99.9% receptivity.
Modeling and Simulation
p. Amjadian; N. Almasi; N. Azimi
Abstract
In this paper, CFD modeling of ferrofluid convection heat transfer in a micromixer with static magnetic field (SMF) and rotating magnetic field (RMF) is investigated. Applying a magnetic field and the existence of magnetic nanoparticles lead to the creation of transverse vortices in the micromixers by ...
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In this paper, CFD modeling of ferrofluid convection heat transfer in a micromixer with static magnetic field (SMF) and rotating magnetic field (RMF) is investigated. Applying a magnetic field and the existence of magnetic nanoparticles lead to the creation of transverse vortices in the micromixers by movement of nanoparticles, that improves heat transfer. There is a cylindrical pit in the microcmixer with heat source that is applied to its bottom wall. Top wall of the pit is adjacent to a fixed permanent magnet, which creates the SMF. CFD modeling first is done for heat transfer process in the micromixer in the absence of the magnetic field. Secondly, simultaneous effect of the SMF and magnetic nanoparticles on the flow pattern and heat transfer rate of ferrofluid is evaluated. Results showed that ferrofluid leads to the improvement of the heat transfer rate compared to pure water. The secondary flows induced by nanoparticles’ motion toward SMF decreases the velocity in the area of application of the magnetic field, so the heat transfer coefficient decreases. But, in the case of RMF, applying the magnetic field causes the nanoparticles to rotate inside the pit, which leads to an increase in the heat transfer coefficient. CFD results of heat transfer coefficient are compared with experimental results in a reliable reference and acceptable agreement between them is observed.
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 ...
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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.
M. Mozafari; A. Ganjizade; .S. N. Ashrafizadeh
Abstract
In this work, the demulsification of water-in-crude oil emulsions by dielectrophoresis via applying a non-uniform electric field in a lab-scale cylindrical cell was studied. The stability of emulsions was assessed through monitoring the size distribution of water droplets at 0, 3, 6, and 24 hours after ...
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In this work, the demulsification of water-in-crude oil emulsions by dielectrophoresis via applying a non-uniform electric field in a lab-scale cylindrical cell was studied. The stability of emulsions was assessed through monitoring the size distribution of water droplets at 0, 3, 6, and 24 hours after the preparation of emulsion. The effect of operating parameters including the temperature, demulsifier concentration, water salinity, and time on the demulsification of water was investigated. Sodium dodecyl sulfate and sodium chloride were used as demulsifier and salt respectively. The experiments were designed by the response surface methodology (RSM) based on the central composite design (CCD). The operating parameters including the voltage, temperature, demulsifier concentration, salinity of water, and separation time were optimized. The contours and 3-D response surfaces of the water separation were acquired. A quadratic polynomial model, which was statistically highly significant (R2=0.9950, n=32), was provided by the RSM to predict the amount of the separated water. Comparison among the experimental and RSM-optimized values indicates a good agreement. The optimum amount of the water separation was obtained at the voltage of 15 kV, temperature of 60 °C, demulsifier concentration of 123 ppm, salinity of water of 12260 ppm, and separation time of 12.4 minutes. Under such conditions, the separation of water reached 98 %. The results obviously show that the electric field can be used as an appropriate means for the breakage of W/O emulsions.
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.
Separation Technology,
P. Valeh-e-Sheyda; Sh. Sarlak
Abstract
The increased demand of the world for energy and its reliance on fossil fuels ultimately contribute to the surge in the levels of carbon dioxide in the atmosphere. To achieve a green, efficient carbon capture, a novel multi-component amine-amino acid solvent including methyldiethanolamine (MDEA), diisopropanolamine ...
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The increased demand of the world for energy and its reliance on fossil fuels ultimately contribute to the surge in the levels of carbon dioxide in the atmosphere. To achieve a green, efficient carbon capture, a novel multi-component amine-amino acid solvent including methyldiethanolamine (MDEA), diisopropanolamine (DIPA), and Arginine (ARG) was designated for the CO2 absorption in a T-microreactor. The potential absorption of the aqueous solutions of the desired mixed amines has been assessed through the CO2 absorption percentage (AP) and the total volumetric gas-phase mass transfer coefficient (TGMTC) over a wide range of the gas flow rates (60-240 mL/min), solvent flow rates (2-6 mL/min), under the three mixing concentrations of MDEA: DIPA: ARG (28:8:4), (28:6:6), and (28:4:8)) wt%. The research findings demonstrate an increment of 31% in the absorption percentage of CO2 by reducing DIPA to 4 wt% and raising the concentration of arginine to 8 wt% in the ternary amine solutions. Additionally, the highest mass transfer coefficient of 38.06 (kmol/m3.h.kPa) was achieved utilizing the aqueous solution of MDEA+DIPA+ARG (28+4+8) wt%.
Transport Phenomena,
A.R. bahramian
Abstract
The impact of bed loading on minimum spouting velocity (ums) of polydispersed TiO2 particles was studied in a conical fluidized bed. The experiments were performed at different bed loadings according to Gaussian and narrow-cut particle size distribution (PSD). The bed consisted of simple-agglomerates ...
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The impact of bed loading on minimum spouting velocity (ums) of polydispersed TiO2 particles was studied in a conical fluidized bed. The experiments were performed at different bed loadings according to Gaussian and narrow-cut particle size distribution (PSD). The bed consisted of simple-agglomerates in size range of 30-90 µm belonging to Geldarts’ group A classification. The effect of PSD and interparticle force (IPF) on the predicted ums and hysteresis in the pressure profiles were studied through a combination of computational fluid dynamics and discrete element method (CFD-DEM). The experimental data showed that the choice of bed with Gaussian PSD-type led to more accurately predicting ums than the narrow-cut particle PSD. The impact of IPF on the expected ums became more critical than the PSD type because of an increase in bed loadings. The lowest deviations the results were obtained in the low bed loadings, which is confirmed the accuracy of simulation results. The simultaneous effects of PSD-type and IPF led to a change in the fluidization behavior of the bed. The bed with narrow-cut PSD has a hydrodynamic behavior similar to spouting and slugging regimes, while the fluidization quality of the bed improves by fine particles.
Process Control and Engineering, Process Safety, HSE
A. Bahramian
Abstract
In this study, the inactivation performance of units against pathogenic and biotoxin threats in a water treatment plant is studied. The assessment of the units and hazards of the water treatment plant against each of threats is studied by the RAMCAP risk analysis. The experiments showed that the Aflatoxin ...
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In this study, the inactivation performance of units against pathogenic and biotoxin threats in a water treatment plant is studied. The assessment of the units and hazards of the water treatment plant against each of threats is studied by the RAMCAP risk analysis. The experiments showed that the Aflatoxin was eliminated only by disinfection units. The reverse osmosis unit had high efficiency in removing Ricin, while the sand filtration had the lowest efficiency in removing biotoxins. The microbial analysis showed the total coliform bacteria, thermotolerant coliform and HPC index were increased slightly by increasing the incoming water's pH and turbidity, while their count were significantly reduced by increasing the free residual chlorine. Changes in the water temperature also had minor effects on microbial indexes. The RAMCAP analysis is used to reduce the vulnerability of units to conventional threats by determining
Modeling and Simulation
K. Jalalvandi; A. Parvareh
Abstract
In this study, the fluid flow together with solid particles has been studied using Computational Fluid Dynamics (CFD). The gas-solid flow (air and sand particles with the size of 150 µm) inside a 76.2 mm diameter pipe with various bend angles including 45, 60, 90, 120, 135, and 180° was modelled ...
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In this study, the fluid flow together with solid particles has been studied using Computational Fluid Dynamics (CFD). The gas-solid flow (air and sand particles with the size of 150 µm) inside a 76.2 mm diameter pipe with various bend angles including 45, 60, 90, 120, 135, and 180° was modelled at the fluid flow velocity of 11 m/s. The k-ω turbulence model was employed to model the flow turbulence and the E/CRC erosion model have been used to predict erosion rates. The hydrodynamics of the flow, the particles motion as well as the probable erosion regions were predicted. The CFD simulation results showed that increasing the curvature angle increases the erosion rate. While, increasing the pipe diameter, decreases the erosion rate. The maximum erosion rate was predicted at the end part of the curvature for 45 and 60 ° angles, while it was observed in the middle region for 120 and 135 ° curvatures. Finally, the maximum erosion rate for the 180 ° curvature was observed in two regions at the end of the first and second half. Using these results, precautionary considerations for the erosion, and the suitable plans for the repair and maintenance of the equipment can be offered.
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 ...
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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).
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.
Biomedical and Biotechnology,
Sahar Jahangiri; Leila Amirkhani; Abolfazl Akbarzadeh; Reza Hajimohammadi
Abstract
In recent years, the development of nanoparticles has received much attention in the controlled drug release and biomedicine fields. This research aims to develop new methods for the physical modification of Fe3O4 superparamagnetic nanoparticles with polymers through the physical retention. In this study, ...
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In recent years, the development of nanoparticles has received much attention in the controlled drug release and biomedicine fields. This research aims to develop new methods for the physical modification of Fe3O4 superparamagnetic nanoparticles with polymers through the physical retention. In this study, first, the degradable polycaprolactone-ethylene glycol copolymer and magnetic nanoparticles were synthesized. The anticancer drug doxorubicin was prepared using a dual-emulsion (w/o/w) copolymer containing magnetic iron nanoparticles. FT-IR, NMR, XRD, VSM, and, SEM analyzes were used to characterize copolymers and magnetic nanoparticles with drug-containing copolymer coatings. The results showed that nanoparticles had superparamagnetic properties and their particle size was between 70-150 nm. The drug encapsulation efficiency was about 96 %. The influence of pH and temperature on the drug release curve was investigated. The drug release was 31 % and 26 % after 144 hours in pH = 5.8 and 7.4 respectively. Since the extracellular fluid of the tumor is acidic, the rate of the drug release in these media will be better than the same in other cells. The kinetics of the drug release was also studied based on zero-order, first-order, Higuchi and Korsmeyer-Peppas models. Among the kinetic models, Higuchi was found to be the best model based on the correlation coefficient. The performance of the drug-loaded magnetic-copolymer nanoparticles with that of other similar studies was compared. The results revealed that the magnetic PCL-PEG copolymer with pH-sensitive properties can be used as an effective carrier for anticancer drugs delivery.
Biomedical and Biotechnology,
F. Soltani-Tehrani; M. Fattahi; M. Motevassel
Abstract
Drug delivery systems (DDSs) have become a crucial aspect of cancer therapy, and researchers are continuously striving to identify the optimal methods for targeted delivery and release of therapeutic agents. Metal-Organic Frameworks (MOFs) have emerged as a promising class of materials for DDSs due to ...
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Drug delivery systems (DDSs) have become a crucial aspect of cancer therapy, and researchers are continuously striving to identify the optimal methods for targeted delivery and release of therapeutic agents. Metal-Organic Frameworks (MOFs) have emerged as a promising class of materials for DDSs due to their exceptional storage capacity, unique characteristics, and high durability. This comprehensive review explores the wide-ranging applications of MOFs in various fields, including catalysis, gas separation and storage, fuel purification, water treatment, medication administration, and imaging. The review paper evaluates different approaches to synthesize MOFs, such as self-assembly of metal ions and clusters and the solvothermal method, to optimize their performance characteristics.The present study aims to shed light on the numerous challenges associated with utilizing MOFs in clinical settings. However, MOF nanocomposites that incorporate reinforcement phases represents a promising strategy for addressing these issues. With the incidence of cancer on the rise, targeted MOFs offer a potential solution to the lack of selectivity of certain drugs by virtue of their distinctive physical and chemical properties. This investigation delves into how MOFs can be employed to regulate drug release in DDSs and presents research on key applications of MOFs in the realm of cancer therapy. The application of UiO-66 for drug delivery systems and explore the different physical characteristics and chemical structures of dicarboxylate ligands incorporated into UiO-66 topology MOFs were investigated. Overall, the review paper provides a comprehensive overview of the diverse applications of MOFs and their potential for drug delivery systems in cancer therapy.