Nashrieh Shimi va Mohandesi Shimi Iran
Year:2023 | Volume:42 | Issue:1|Papers Count:29

Ginger is one of the commonly used spices that has been exhibited to have pharmaceutical activities. These therapeutic properties are mainly attribute to gingerols and shogaols. In this study, the bioactive compounds of ginger rhizome were extracted. Silica gel column chromatography was employed to isolate gingerol. Gingerol obtained with acceptable purity. In order to enhance gingerol bioavailability, chitosan nanoparticles containing gingerol were prepared. Encapsulation efficiency was 80%. AFM and DLS analysis were performed to evaluate size and size distribution of nanoparticles. Results show that the nanoparticles have spherical morphology, narrow size distribution with average particle size of 21.11 nm. Cellular toxicity of nanoparticles in MCF-7 cell line was calculated using MTT method. The results indicate that chitosan nanoparticles containing gingerol, have good inhibitory effect on the growth of cancer cells. The nanoparticles eliminated 90% of cancer cells in 48 hours.

Nano Hydroxyapatite (nHA) composites have been widely used in bone regeneration due to their unique properties. In this paper, doped nHA composites with doping of MgO, ZnO, and CeO2 metal oxides into nHA structure were successfully attained using precipitation method. Also, chitosan (CS) was added to the nHA composites to improve the biocompatibility. As the results showed, doping the metal oxides into the nHA structure led to the change of the lattice parameters in nHA structure. Finally, bioactivity of the composites was investigated by MTT assay by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. MTT assay is shown that doped-nHA structure gives acceptable cytotoxicity against the MG-63 cell.

In this study, to improve the mechanical properties of polyaniline (PANI) its nanocomposite was prepared using polyaniline and carbon nanotube (CNT) as reinforcing agent. PVC- PANI - CNT nanocomposite was synthesized by mixing CNT with a solution of PVC containing dispersed PANI. Solution casting method was used to prepare PVC- PANI - CNT nanocomposite films. The effect of three factors including carbon nanotube weight percent, drying temperature of the nanocomposite film, sonication time of nanocomposite solution at different levels using the box-Behnken design (response surface method). According to this method, 15 tests were performed. The values for tensile strength of nanocomposite films were used as response to analysis of variance for data analysis. The linearity of the normal distribution curve for the remainder confirmed the correctness of the presented model. Two and three- dimensional Graphs of surface design method showed that tensile strength increases by increasing the weight percentage of carbon nanotubes to 0.66%. While more than it reduces the tensile strength. Also, by reducing the drying temperature of the film and increasing the sonication time, tensile strength increase. Some physicochemical properties of the nanocomposite films were investigated using FT-IR spectroscopy, SEM, TGA techniques.

Carbon nanotube/polystyrene nanocomposites were synthesized via microwave-assisted in-situ polymerization. Since carbon nanotubes can absorb microwave irradiation, they can form hot spots in the mixture, and the auto thermal polymerization of styrene monomers can be initiated from their surface without using any chemical initiator. In order to investigate the effectiveness of the microwave irradiation on the polymerization process, carbon nanotube/polystyrene nanocomposites were synthesized via heating. Samples were characterized by TEM, FESEM, FT-IR, TGA and Raman spectra, and the electrical conductivity of samples were also measured. The results showed that using microwave irradiation can result in forming a polymeric layer on carbon nanotubes, and the resultant nanocomposite had a few agglomerations. In addition, by increasing the power of microwave irradiation, the thickness of the polymeric layer increased and electrical conductivity decreased.

This study aimed to produce nanostructured iron (III) oxide with a high surface area and high porosity. Iron (III) oxide was synthesized using the sol-gel method. The resulting gels were dried using two different methods, i.e., ambient drying (at 80 oC) and supercritical carbon dioxide drying. The produced iron oxide aerogel and xerogel were then calcined at 350 oC for 4 hours. The physico-chemical properties of the iron (III) oxide nanostructures were investigated using X-ray diffraction (XRD), nitrogen adsorption-desorption, and field emission scanning electron microscopy (FE-SEM) analyses. The results showed that the iron (III) oxide aerogel consisted of spherical nanoparticles. The X-ray diffraction pattern demonstrated the aerogel had a crystalline phase of pure hematite (α-Fe2O3). In addition, the produced aerogel had a specific surface area of 140 m2/g, the volume of porosities was 0.32 cm3/g, and the average diameter of pores was 8.9 nm. The produced xerogel also had a specific surface area of 65 m2/g, a volume of porosities of 0.18 cm3/g, and an average pore diameter of 10.8 nm. Therefore, the results of BET analysis confirmed that drying of iron oxide nanostructures using the supercritical drying method can lead to better preservation of its porous structure.

A lot of researches have done on the performance of different powder from catalysts of the form in dry reforming of methane in fixed bed micro reactors. However, few reports have published on the catalyst thin layer method for using in microchannel reactor that has less mass and heat transfer limitation. Recently, sputtering and evaporation methods have investigated in microchannel reactors for making a thin-layer catalyst, but these methods have problems such as; high cost and uncontrolled catalyst loading. In this study, the catalyst coated on both sides of the stainless steel plate, and the roughness prepared among the sandblasting method. The catalyst tested in a microchannel reactor and identified the products by chromatography. In this paper, the LaNiO3 perovskite catalyst synthesized in two states with alumina support and without the support thus coated on the plate. For characterizing the catalyst EDX, XRD, SEM, FTIR have been used. The results showed that the catalyst with the support had better stability and conversion rate than the catalyst without support. The catalyst performance and its stability tested at 800°C for 28 hours. The catalyst at this temperature showed the best results in dry reforming of methane with an average ratio of H2/CO = 0.91 for catalyst without the support and an average ratio of H2 /CO = 0.97 for the catalyst with alumina support. Hence, using a microchannel reactor has various advantages compared with a fixed bed reactor, such as; increasing heat and mass transfer and using less amount of catalysts. The method of coating the catalyst in this research showed good performance and stability compared to costly coating methods, such as sputtering in microchannel reactors.

Oxidative desulfurization process using heterogeneous catalysts is considered as a complementary and promising method for hydrodesulfurization of liquid hydrocarbon fuels to remove their sulfur-resistant compounds. In this research, a titania-silica catalyst with a 10 wt.% loading of titania as the active phase was synthesized using two methods, i.e., sol-gel and wet impregnation, and the performance in the oxidative desulfurization of dibenzothiophene was investigated and compared. Oxidative desulfurization was carried out at a low temperature of 50°C, atmospheric pressure, an O/S molar ratio of 5, and a catalyst loading of 0.3 g per 3 g of fuel. To better identify the physico-chemical characteristics of the catalysts and find the structure-performance relationship, analytical techniques such as nitrogen adsorption-desorption, Fourier-transform infrared spectroscopy, X-ray fluorescence, and X-ray diffraction were employed. By comparing the performance of the catalyst samples, it was found that the conversion of dibenzothiophene in the presence of the catalyst prepared by the sol-gel method was higher, achieving 100% conversion within a short reaction time of 30 minutes. Furthermore, the effect of the presence of competitive nitrogen-containing compounds (indole and quinoline) and olefin (cyclohexene) on the oxidative desulfurization of dibenzothiophene with the optimized catalyst was evaluated. The highest and lowest negative effects were observed for cyclohexene and quinoline, respectively.

In the present study, the new compound from Dithiophosphorus with the formula [(S–) (S)P(OC6H4-p-CH3) (NHCH2CH2NH(Me)2) +] was prepared and determined by IR spectroscopy, 1H, 13C NMR, 31P NMR, elemental analysis and single crystal X-ray diffraction analysis. Structural analysis revealed that the compound was crystallized in monoclinic crystal system with P21/c space group. The crystal structure of the compound showed that asymmetric unit contains two molecules and the phosphorus atom displayed P(S)(S)(N)(C) a distorted tetrahedral environment. In the crystal structure N-H…S=P H-bonding produced a one dimensional molecular structure along the b axis. This pattern contains  and  motifs. Hirshfeld surfaces and two-dimensional fingerprint plots are generated using the Crystal Explorer software program in which the CIF input file is used. These analyses revealed that H…H interactions had 51.1 % and 50.9 % portions of total interactions for the two molecules. Antibacterial properties of the new compound were additionally tested against E. coli, P. aeruginosa, S. aureus and B. cereus.

A manganese (II) catalyst loaded onto the SBA-15 support containing a bidentate N-O Schiff-base ligand was prepared and it was applied in the synthesis of quinoxaline, pyrazine and pyrido pyrazine heterocycles. The nanocatalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), infrared spectroscopy and nitrogen adsorption/desorption isotherm. The results from X-ray diffraction and transmission electron microscopy show that the textile properties of SBA-15 are preserved after grafting of manganese (II) complex. A variety of aforementioned heterocycles were synthesized easily and with good yields under green conditions in aqueous medium via ring condensation of 1,2-diamines and 1,2-diketones in the presence of  catalytic amounts of catalyst.

In this research, an one- pot, three-component, efficient and environment friendly synthesis of some imidazolethiones using a new cobalt catalyst was  described. The catalyst used in this reaction is a complex of Co(II) based on 5-nitro-N1-((pyridin-2-yl)methylene)benzene-1,2-diamine ligand, which was first used in the synthesis of tertrasubstituted imidazolethiones. The reaction was performed under solvent-free conditions with benzoin, different arylisothiocyanates and primary aromatic amines in the presence of optimal amount of catalyst. The advantages of this method include simple procedure, short reaction time, high yields, recyclability of catalyst and the absence of any toxic and hazardous solvents.

In recent years, usage of sex pheromones as a replacement for pesticides against harmful insects has gained great interest due to their important ecological advantages like high specificity, biodegradability and low toxicity. The stem borer, Sesamia cretica Lederer (Lepidoptera, Noctuidae, Amphipyrinae), is one of the main insect pests of sorghum, maize, sugarcane, and cereal crops in the Mediterranean area. The components of sex pheromone of this insect was identified as consisting of (Z)-9-tetradecen-1-ol (80%), (Z)-9-tetradecen-1-yl acetate (10%), and (Z)-11-hexadecen-1-ol (10%). The previous reports for the synthesis of these compounds suffer from several problems such as difficult procedure, harmful solvents and low overall yields. in this research an efficient strategy for the synthesis of the main component of this pheromone is described from safe and readily available starting materials.

In this paper, a very effective method for the synthesis of 2-amino-4H-Chromene derivatives has been reported. These derivatives were obtained during a one-pot, three-component condensation reaction between aromatic aldehydes, malononitrile and β-naphthol in the presence of water as an environmentally friendly solvent and under microwave irradiation using heterogeneous nanocatalysts Sr2As2O7 and Sr2As2EuxO7+δ. This is the first report of using of the mentioned catalysts in the synthesis of Chromen derivatives. These catalysts were synthesized using the solvothermal method at 180 oC for 24 h and were characterized by various techniques such as UV-Vis, PXRD, FTIR, FESEM, and EDX.  To carry out the catalytic reaction, the reaction conditions were optimized and it was determined that when 15 mg of catalyst, water as solvent and microwave irradiation time (6 minutes) were used, a higher efficiency was obtained. Investigations showed that the aromatic aldehydes containing electron-donating and electron-withdrawing groups can produce the corresponding products, but the reaction efficiency with aldehydes with electron-withdrawing groups is higher (97-99%). The synthesized catalysts can be easily recycled and reused 4 times without significant decrease in catalytic activity. After the fourth step, the reaction efficiency was 71% for Sr2As2O7 and 73% for the doped sample. The advantages of this method are the use of environmentally friendly solvent, short reaction time, easy separation and production of products with high efficiency.

Lipases are a group of hydrolases capable of catalyzing the hydrolysis of triacylglycerols to free fatty acids and glycerol. They are very important industrial enzymes because of the potential to be used in many industrial applications. In this research, potent lipase producer fungi were isolated and screened from olive mill wastewater and its disposal pond. In the qualitative test, 7 strains were identified as lipase producer fungi. One of the 7 isolated fungi, was identified based on macroscopic and microscopic examination as Aspergillus sp. that detected good lipase activity. The L25 Taguchi orthogonal array design of experiments with four factors in five levels was used to reach optimal fermentation conditions and medium composition for lipase production using Minitab 19 software. The optimum conditions derived were: WS/OF content ratio (0.5), fermentation time (7 days) and moisture content 1:2 (66%), glucose concentration as a co-substrate (0 g/L). Using optimal fermentation condition, maximum lipase activity (2754.73 U/g of the dry substrate) was obtained. The results demonstrated that the fungus isolated is a promising alternative for lipase production. This study aimed to better understand the microorganisms in OMW and take them to the potential candidates for the conversion of agricultural by-products into valuable secondary metabolites like lipase.

In this study, the electrowinning process was investigated in the production of metal cobalt from a low chloride solution concentration by both response surface methodology and artificial neural network. Initially, the solvent extraction process from two different feeds was performed to recover cobalt ions by dithiophosphinic acid to the organic phase and transferring it to the aqueous phase with HCl solution (1 M). Then, the metal production process was performed using the electrowinning method and examining the effective parameters such as time, pH of solution, ion concentration and current ampere. The optimization conditions for pH of aqueous solution, time, cobalt ion concentration, and ampere were obtained equal to 4, 40, 0.008 mol/L, 1 A, respectively. The results showed that the temperature of 15 ◦ C was more favorable for the process. Increasing the current ampere, time, and concentration of ions in the solution helps to increase the current efficiency. The acidity values ​​in the aqueous phase are essential for the electrowinning process and depend on the system’s conditions. The XRF and EDX analysis results showed that in optimum conditions, metal cobalt with purity above 99.8% was accumulated on the cathode surface. The modeling results of two methods showed that the artificial neural network is in better agreement with the experimental results than the response surface methodology.

Emerging pollutants from water are a significant concern in modern society, and surface adsorption has been identified as a promising method to eliminate them. Preparation of an effective adsorbent is crucial for the adsorption method. In this study, a new adsorbent of Metal organic frameworks, MIL-101(Cr)@ZnO, was synthesized by modifying MIL 101(Cr) with zinc oxide nanoparticles using the hydrothermal method. The adsorbent was characterized using XRD, FTIR, FESEM, EDX and BET analysis. The adsorbent's efficiency was evaluated by studies of adsorption equilibrium isotherms under optimal conditions pH = 9, amount of adsorbent 0.0035 g, volume 50 ml, time 60 minutes, at different temperatures (60, 40, 35 °C) and concentrations of methylene blue (6, 8, 9, 10, 11 mg/L). The equilibrium adsorption data were analyzed using Langmuir, Freundlich, Temkin, Alovich, and Dubinin-Radoshkevich(DR) two-parameter equilibrium isotherms models. The obtained results showed that the order of dye adsorption of the studied isotherms is as follows: Dubinin-Radoshkevich>Temkin>Freundlich>Alovich>Langmuir. Additionally, the order showed that the adsorption of methylene blue occurs in a multilayered form. The isotherm of Dubinin-Radoshkevich with the highest correlation coefficient (R2=0.9767) and low average free energy (E=0.975 J/mol) showed that physical adsorption is the dominant process of adsorption. The maximum adsorption capacity of Langmuir isotherm was determined at the temperature of 313 K with the value of qmax=258.7143 mg/g, the separation factor at the same temperature (RL=0.4364) indicating favorable adsorption. The Freundlich adsorption intensity and correlation coefficient values were n=1.3825 and R2=0.879, respectively. The heat of adsorption in the Temkin's model was calculated to be BT=57.192 J/mol, and the highest adsorption capacity was obtained from Elovich's isotherm qmax=333.3333 mg/g. Further, the amount of thermodynamic values showed that the adsorption process of the pollutant is a spontaneous and endothermic process. The present study's evidence indicates that the adsorption of methylene blue follows a physical process.

Today, the use of solvents containing nanoparticle to improve the rate of absorption of acid gases have been noticed by many researchers. In this study, the physical absorption of carbon dioxide in water nanofluid containing alumina nanoparticles in a wetted wall column was investigated. The central composite design of response surface methodology was used to analyze and optimize nanofluid performance system. In this regard, the performance of the absorption process was evaluated by measuring the liquid phase mass transfer coefficient based on independent variables including: nanoparticle concentration (0-1 g/l), nanofluid flow rate (100-300 ml/min) and fluid temperature (25-45 ℃). Using analysis of variance, a quadratic model was proposed to predict the mass transfer coefficient in the water-alumina nanofluid with R2 = 0.977. Results show that by adding 1 and 0.5 g/l of alumina nanoparticle in the water-based nanofluid, the gas absorption rate increases by 47 and 19%, respectively. The results indicated that increasing concentration of nanoparticle and fluid flow rate have the greatest effect on the mass transfer coefficient.

Today, the CO2 emission from the combustion of fossil fuels is recognized as one of the main causes of global warming and its consequent problems. Oxy-fuel combustion (OFC) is an effective way to separate CO2 from combustion flue gas. CO2 Compression and Purification Unit (CO2CPU) is a relatively new industrial unit for the separation of CO2 from the combustion gas produced by OFC process. However, the high energy required for the compression and refrigeration process is one of the main challenges of this unit. Therefore, identification and sensitivity analysis of the parameters affecting the process are needed for appropriate optimization and control of these parameters. The present study, while introducing this unit, aimed at sensitivity analysis, optimization and improvement of the process. The process was simulated in the Aspen Plus environment. In addition, Peng-Robinson thermodynamic equation of state was applied to estimate the thermodynamic properties and it was improved using the data ​​in the literatures to increase the accuracy of the thermodynamic coefficients. Given that the interaction of operational parameters is effective on the optimization results, the response surface methodology (RSM) was employed for optimization. The results of this study show that the process can be performed at 25 bar pressure by improving the operating conditions, while the operating pressure of this process was previously reported to be 30 bar. Obviously, reducing operating pressure decreases not only the operating costs but also the investment costs and thus, the total costs.

Storage and dispose of CO2 in aquifers is a promising techniques to mitigate global warming and reduce greenhouse gases (GHG). Measurement of CO2 dissolution rate in saline aquifers is dependent on the finding an appropriate model for gas diffusion. Indirect methods, especially pressure decay, are currently being used to measure molecular diffusivity. The most important point in this method is the useage of appropriate model and analyze the experimental results. In this paper, non-Fick modeling method is used to analyze the experimental data of pressure decay method for CO2 emission in saline aquifers and the results are compared with Fick model with two different types of boundary conditions. For this purpose, by the inverse solution and minimizing the error function between the pressure-time values of the modeling and the experimental using optimization are estimated diffusion coefficient, mass transfer coefficient and delay time. The results show that with respect to the non-equilibrium boundary condition the diffusion coefficient was more than doubled compared to the equilibrium boundary condition and the non-equilibrium boundary condition is more consistent with the experimental results. On the other hand, the nonfickian model delays the equilibrium arrival with a delay time regulator term and is more consistent with the experimental results, especially in the early moments.

Process simulation, in both laboratory and industrial scales, is a method that, if it be capable enough to close the gap between the computational results and the operational results, it can help to understand and optimize these processes. The basis of valid simulation is the knowledge of the models and equations related to the physio-chemical properties and the ability to review and reduce the limiting assumptions of the process under investigation. For the mathematical modeling of mass transfer phenomena through the membrane, different models with various efficiency and accuracy are presented. According to the basic concepts of solution-diffusion theory, this theory has the potential to simulate osmotic membrane processes, including forward osmosis, as a desalination process. In this paper, an overview on the development of mathematical models for forward osmosis and how to determine its parameters by the empirical method is presented. The results showed that the Bui et al. model is the complete model for calculating water flux by considering all different external and internal concentration polarization types. On the other hand, the main parameters of the membrane (water and solute permeability and structural parameter) can be calculated by numerical calculations and experimental results using the proposed Tiraferri et al. method.

In this research, the adsorption of nickel ions in the batch system by orange peel carbon has been investigated and the effect of factors such as pH, contact time, initial concentration of nickel in solution, adsorbent amount, and the temperature has been considered. The surface details and functional groups were investigated by SEM and FTIR analyzes, respectively. In the study of the effect of pH, the highest percentage of nickel uptake for orange peel carbon occurred at pH = 6, which is equivalent to 58 mg/g. With increasing the contact time between the adsorbent and the solution and after 210 minutes, the adsorption percentage increased to 98.57%. In the study of the effect of the initial concentration of nickel in the range of 20 to  150 mg/L, the results showed that with increasing concentration, the percentage of adsorption decreased from 98% to 96%, and with increasing the amount of adsorbent from 0.01 to 0.1 g per 25 ml. Nickel solution, the adsorption percentage increased from 90% to 98%. The effect of temperature showed that with increasing the temperature from 25 to 45°C, the percentage of adsorption decreased from 99% to 97.8%. Thermodynamic properties were studied at three temperatures of 25, 35, and 45°C. The negative free energy value of the standard Gibbs (∆ Go) which is equivalent to -121.3 kJ / mol, indicates that the adsorption process is spontaneous and physical. In the kinetic study of the contact time effect, it was observed that the results fit well with the second-order kinetic model with a correlation coefficient of 99%. In investigating the effect of the initial concentration of nickel in solution and fitting experimental data with Langmuir, Freundlich, Temkin, Dubin Radushkovich isotherms, and according to the values ​​obtained at R2, Freundlich's isotherm had the highest compatibility with 100% correlation coefficient.

Nitrate is one of the most important water pollutions that affect human life. Electrocoagulation is a common method for removing nitrate from water. In this research, using Design expert software and the CCD method, 48 experiments were performed in different parameters, including initial nitrate concentration in the range of 10-30 mg/L, 5-11 for pH, 2-10 cm for electrode distance, 5-30 V for voltage, and 20-120 min for process time. The electrodes were made of aluminum (anode) and iron (cathode), and the reactor volume was 2 liters. The highest nitrate removal was obtained in Ci = 16 mg/L, PH = 9.3, ED = 4 Cm, V = 23 v, ET = 90 min, reached . Then, the effect of sodium chloride salt, mechanical stirrer, and the number of electrodes was investigated in optimal points.

In this study, salt separation from crude oil was investigated using nickel oxide nanoparticle absorber. The effect of parameters such as pH (4, 5, 6, 7. 8, and 9), time (15, 30, 45, and 60 min), amount of adsorbent (0.25, 0.3, 0.5, 0.75, and 1 g), and temperature (40, 50, 60, and 80 ℃) on the degree of salt separation from crude oil was studied. When the pH was decreased, the salt absorption was decreased.  Increasing the temperature increased the desalting percentage. Also in the alkali range due to the presence of OH- ions in the solution, there is a possibility of better complexation between the adsorbent and the cations. Therefore, the best adsorption was observed at near-neutral pH. The best conditions for salt absorption, pH 7, temperature 80 ℃, absorbance 0.75 g, and absorption time 45 min were obtained.

In this study, the solubility results and tie-lines in ternary systems (water + butyric acid + organic solvent) were obtained at 298.2 K and 101.3 kPa. Methyl ethyl ketone and diethyl ether were selected as organic solvents. The binodal curves were determined experimentally using the cloud point method. The tie-line results were obtained using acid-base titration, Karl-Fisher method, and refractive index measurement. Both ternary systems show type one of liquid-liquid equilibrium. For investigation of the quality of both ternary systems, Othmer-Tobias and Hand equations were correlated with the empirical results. The distribution coefficients and selectivity factors were calculated in both ternary systems to evaluate the solvent's ability in extracting butyric acid from an aqueous solution. The average separation factor was calculated at 41.12 for methyl ethyl ketone and 296.71 for diethyl ether, respectively. Finally, for each system, the experimental tie-lines were correlated by a thermodynamic model including NRTL and UNIQUAC; also, the binary interaction parameters were estimated.

Museum carpets are valuable artifacts of Iran, and moisture is one of the important environmental factors that play a significant role in the destruction of museum carpets. Moisture causes chemical deterioration and biological reactions in carpets, moisture accelerates the process of wear and fading of color. This research is of an experimental-analytical type, which has been carried out with environmental surveys, as well as library and laboratory studies, with the aim of identifying and introducing the appropriate relative moisture level for the protection of museum carpets with natural fibers of wool, cotton and silk. Therefore, to answer the question of how much moisture as an important damaging environmental factor from the perspective of preventive protection affects the tensile strength of museum carpets with natural fibers of wool, cotton and silk; The tensile strength test of the carpet along the length and width of the modeled samples has been carried out. Finally, according to the data obtained from the tensile strength test of the carpet along the length and width of the samples, it indicates that the destructive effect of moisture on the tensile strength of the carpet in it reduces by 7.830% along the length and 5.876% along the width. Analysis of variance, Tukey and LSD tests can be concluded that moisture has a destructive effect on museum carpets and reduces the tensile strength of the carpet and has a significant effect on the tensile strength of the carpets.

Microfluidic is a science and technology that studies fluid in volumes of 10-9 to 10-18 liters using channels with dimensions on a micro-scale. One of the most critical applications of this technology is fluid flow analysis. Separation processes in microfluidic devices have received much attention in the last two decades. Among the various separation processes, liquid-liquid extraction has advantages such as low molecular diffusion distance and high interface-specific surface area, leading to efficient mass transfer in microfluidic devices. Stable isotopes are valuable tools for research into mineral availability and metabolism. Stable isotope applications as radiation-free detectors, Diagnosis of the disease, and nuclear imaging can also be used as the primary material or raw material for the production of radiopharmaceuticals, Nuclear imaging, Biochemical analysis, and radiotherapy. Due to the very low abundance of some isotopes, it is essential to separate and concentrate them. This research combines liquid-liquid extraction and microfluidic technology to extract and separate calcium ions as a new method.  In this study, to evaluate the possibility of performing calcium ion extraction simulations, in the studied microfluidic system, the ratio of two-phase velocities was selected so that the current inside the microchannel was flowing in parallel. First, the exact location of the interface was determined by the level set method, then the amount of mass transfer from the aqueous to organic phase was measured using the transport of diluted species method. The microchannel geometry was changed to a spiral geometry, and the extraction rate was investigated to study the effect of geometry on the extraction rate. In the Y-Y microchannel, the extraction efficiency was 60.062%, while in the spiral microchannel, the yield was 71.97%. in other words, by changing the microchannel geometry from Y-Y to the spiral, the mass transfer rate is improved by 11.9%.

Today, the use of renewable energies has become increasingly important due to the fossil fuels being consumed which cause environmental pollution. The use of solar energy due to the abundance and availability of this energy and the ability to save and convert it into other forms of energy has been considered. In this work, a stepped solar still is simulated in two dimensions using Comsol software. Also, increasing the number of stairs and adding a number of Fins to increase the amount of fresh water produced has been studied. The simulation results were compared with the experimental data. The average error rate for fresh water produced and the temperature of saline water obtained from the software with experimental values are 11.78 and 1.75 percent, respectively. The results show that as the number of steps increases, the amount of fresh water produced increases. In addition, adding three thermal fins with a size of 0.3 cm on the stairs compared to the existing state of the device, the amount of fresh water produced increases by 9.65%.

In this research, a simple supercritical carbon dioxide dryer was designed and constructed for the production of various aerogels. The most significant advantage of the constructed device was its automatic heating and cooling system, which allowed better control of the operational conditions during the drying process and the production of nanostructured materials with increased porosity. The constructed device had the capability to operate in a temperature range of 5°C to 90°C and pressures up to 140 bar. To evaluate the performance of the constructed device, nickel oxide (II) gel was synthesized using the sol-gel method and dried using the supercritical carbon dioxide drying method. The prepared aerogel was calcined at a temperature of 300°C for 2 hours. The physical and chemical characteristics of the nickel oxide aerogel were examined using X-ray diffraction (XRD) analysis, Brunauer-Emmett-Teller (BET) nitrogen adsorption and desorption, and field emission scanning electron microscopy (FESEM). The results indicated that the nickel oxide aerogel had an open porous structure and was composed of spherical nanoparticles. The synthesized aerogel had a specific surface area of 167 m²/g, pore volume of 0.61 cm³/g, average pore diameter of 6.14 nm, and average crystallite size of 6.4 nm. The obtained results demonstrated that drying nickel oxide nanostructures using the constructed supercritical carbon dioxide dryer led to better preservation of its porous structure.

The presence of high combustion temperatures requires effective cooling methods in the combustion chamber. Most chambers in liquid propellant engines have regenerative cooling. A new way to improve heat transfer performance in the regenerative cooling process is to add nanoparticles to the cooling fluid. In this study, the regenerative cooling in a liquid propellant engine was simulated numerically by fluent software. The engine is designed to work on a mixture of kerosene as fuel and liquid oxygen as an oxidizer with a thrust of 300 kN. In the following, carbon nanotubes and alumina nanoparticles were used in 2% and 5% volume fraction to be added to kerosene for nanofluid production. In this study, the fluid flow in the three-dimensional cooling channel is assumed to be steady-state, turbulent and the k-ε turbulence model is used for turbulent flow, and the nanofluids are modeled as single-phase. Addition of nanoparticles alumina and carbon nanotube to kerosene as cooling fluid increased the heat transfer coefficient by 8% and 15%, respectively. According to the results, carbon nanotubes have a higher ability to increase heat transfer coefficient and improve regenerative cooling than alumina nanoparticle.

In this present study, in order to achieve the high feedstock conversion and maximum yield of bio-crude, the operational parameters of Nannochloropsis sp. microalgae hydrothermal liquefaction process such as temperature(270-310-350ºC), residence time (20-40-60 min) and feedstock ratio percentage (5-10-15 wt%) have been appropriately evaluated .Thereafter, three different activated carbon based catalysts (Co/AC, Zn/AC, Co-Zn/AC) have been manufactured. Catalytic experiments have been carried out on the obtained optimum condition of the HTL process. It has been proved by CHNS and GC-MS results that existence of all three different catalysts has a positive effect on quality and quantity of derived bio-crude, however, because of synergetic effect of Cobalt and Zinc in the bimetallic catalyst, hydrocarbon percentage which is the most favorable portion of achieved bio-crude was increased dramatically. Not only that, but higher mass content of microalgae devoted to bio-crude production (40.12 wt.%) alongside with lower gas and hydrochar percentage.