Nashrieh Shimi va Mohandesi Shimi Iran
Year:2021 | Volume:40 | Issue:1 (99)|Papers Count:28

In the current research work, the idea is to find an iron-chelating agent to nourish plants and eventually feed humans and reduce the lack of iron in people's nutrition. In this work EDDHA, the most applied chelating agent for agricultural purposes was modified to reduce its high solubility in water and improve its stability under sunlight. The high solubility of EDDHA in water causes the plant to lose the applied solution in the next watering and not have enough time to absorb the nutrition. With this modification, EDDHA is able to tolerate sunlight which has a strong UV portion. This UV irradiation causes the conventional EDDHA to isomerize and lose the valuable Fe ions but with the new and improved EDDHA there is no room for isomerization. The effect of prepared chelates on chlorophyll production, average leaf length and Width, and average plant length was investigated.

In this study, modified magnetic Iron-oxide (Fe3O4) nanocomposites were synthesized using nitrogen-doped graphene-oxide (Fe3O4/NGO). For the synthesis of the magnetic nanoparticles of iron-oxide, the sedimentary method was used. The magnetic nanocomposites were fabricated using the chemical method by a covalent bond between nitrogen-doped graphene oxide and the iron-oxide magnetic nanoparticles. To determine the physical and chemical properties of obtained nanoparticles, Fourier-Transform IinfraRed (FT-IR) spectroscopy, Energy-Dispersive X-ray (EDX) spectroscopy, thermal gravimetric Analysis (TGA), Field Emission Scanning Electron Microscopy (FESEM) analysis were applied. The results confirmed that nitrogen has doped in graphene and nanocomposites were synthesized successfully. The crystallite size of the nanocomposites were calculated 20-40 nm. Homogeneous distribution of spherical and ellipsoid Iron oxide nanoparticles was obvious in the FESEM images. The synthesized nanocomposites with small size present it as a great candidate for photocatalyst application.

Nano-structure of new Cu(II) coordination compound,[Cu(DPC)(H2O)3] was synthesized by sonochemical method. The new nano-structure was characterized by scanning electron microscopy(SEM), X-Ray powder Diffraction (XRD), IR spectroscopy, elemental analyses, and UV-Vis spectroscopy. The thermal stability of the compound has been studied by thermal gravimetric and differential thermal analyses. Copper oxide nanoparticles were obtained by direct calcination of the compound at 450, 500,550, and 600 under air atmospheres have different morphologies of nano-sized CuO. Also, the Nanoparticle of CuO was obtained by thermolysis of nano complexes in 180 with oleic acid as surfactant.

In the present study the main aim was to fabricate the nanofiber polymeric membrane with improved surface properties for application as an antifouling microfiltration membrane in wastewater treatment. The improved nanofiber microfiltration membranes were electrospun from the polyacrylonitrile solutions containing 0. 5 to 5 w/w% boehmite nanoparticles. Embedding the hydrophilic boehmite nanoparticles increased the surface hydrophilicity and antifouling properties of the membrane. Among the prepared nanofiber microfiltration membranes, the 3 w/w% boehmites embedded polyacrylonitrile nanofiber membrane (MD) was selected as the membrane with optimum antifouling properties and permeate flux. Concerning the results obtained, our prepared antifouling nanofiber membrane can be efficiently used for wastewater treatment applications.

In this study, polymer nanocomposites based on 2-aminophenol and Palm date have been introduced as an efficient and inexpensive catalyst and successfully used for the synthesis of benzylidene Bis(4-Hydroxycoumarin) derivatives. The polymer and nanocomposite were characterized by a Scanning Electron Microscope (SEM). Benzylidene Bis(4-Hydroxycoumarin) Derivatives have recently attracted much attention as an important class of heterocycles to their useful biological and pharmacological properties, herein we report a novel and efficient procedure for the synthesis of α , α ′-benzylidenebis (4-hydroxycoumarin) derivatives based on the reaction of 4-hydroxycoumarin and aromatic aldehydes using polymer nanocomposites based on 2-aminophenol and Palm date as a solid heterogeneous catalyst in excellent yields (84-99%) and very short reaction time (2-5 min) in aqueous media (50%) have been described.

In this research, a nanocomposite of microspherical polypyrrole and dandelion-like Nickel-Cobalt oxide was successfully synthesized on the Nickel Foam (NF) substrate with a hydrothermal method and employed as the electrode material for supercapacitor. The prepared nanocomposite was characterized by, Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Energy-dispersive X-ray, and Fourier-Transform InfraRed spectroscopy (FT-IR). Also, electrochemical techniques were used for electrochemical characterization. NiCo2O4/PPy/NF electrode exhibits a high specific capacitance of 2342 F/g at a current density of 2. 33 A/g and good cycle stability (79% capacitance retention after 2500 cycles) on the three-electrode system. Also, an asymmetric supercapacitor device was successfully assembled using a hybrid of NiCo2O4/PPy/NF and rGO/NF as positive and negative electrodes. The fabricated device showed a specific capacitance of 186 F/g at a current density of 1. 8 A/g and good stability 80% after 1500 cycles. Results show that prepared electrode is suitable candidate for construction of high performance supercapacitors.

Undoubtedly, the formation of all the unique properties of the ZIF nanostructures depends on their proper and perfect synthesis. In this research, a simple and convenient method was used to synthesize ZIF-8 by a eutectic solvent of choline chloride with urea as an ionic liquid without the high energy at room temperature. Also, the effect of different operating parameters affecting the synthesis, such as salt/ligand molar ratio, temperature, ultrasound, and type of ionic liquid, were investigated. To evaluate the performance of this adsorbent, carbon dioxide capture, and equilibrium isotherms of this gas are accomplished at ambient temperature. The results demonstrated that the CO2 uptakes on synthesized ZIF-8 at room temperature in the low and high pressure of 1 and 14 bar are obtained 0. 27 and 4. 4 mmol/g respectively.

The present work reports the synthesis of MnSb2O6 nanomaterials by one step solid-state at 800 º C at 8 h using Sb2O3, MnCl2, and Mn(NO3)2 raw materials. The raw materials for the synthesis of the doped materials were Gd2O3, Tb2O3, and Ho2O3. Rietveld analysis was used for the investigation of the crystal phase-type, purity, and the other crystallographic parameters. It was found that MnSb2O6 was crystallized in the trigonal crystal system with the space group P321. SEM images were used for the investigation of the morphology of the obtained materials. The direct optical band gap energies of the obtained materials were obtained using the absorption spectra. The data showed that the values are 1. 85, 1. 90, 1. 89, 2. 1 eV for MnSb2O6, doped materials with Tb3+, Gd3+, and Ho3+, respectively. The XRD data indicated that the crystallographic unit cell parameter and unit cell volume values were not changed considerably when the lanthanide ions were intercalated into the crystal system. This means that the ions are positioned into the crystal cavity with a larger cavity value. FESEM images showed that the morphology of the obtained materials is multigoal structures. The photocatalytic performance of MnSb2O6 was studied for the degradation of malachite green in the aqueous solution under UVC irradiation. The power of the lamp was 18 W. The distance between the lamp and the surface of the solution was 30 cm. The degradation efficiency at the optimum conditions: 0. 7 mL of H2O2, 0. 03 g of catalyst, and 58 min reaction time was 81%. The volume and the concentration of malachite green were 100 mL and 60 ppm.

Different techniques such as physical and chemical absorption are used for the removal of carbon dioxide. Alkanolamines are widely used as a chemical absorbent for acid gas purifi cation. Among the alkanolamines, 2-(2-aminoethylamine)ethanol (AEEA) and 2-amino-2-methyl-1-propanol (AMP) have a high absorption capacity. In this work, the equilibrium solubility of CO2 in aqueous mixtures of AEEA and AMP is measured at different partial pressures (0. 25 to 0. 85)kPa and different temperatures (30 to 60) C• . The measurements are shown that carbon dioxide loading is increased by rising the amount of AEEA/AMP mole ratio in the solution. Also, the solubility of CO2 is increased at higher partial pressures. The Extended UNIQUAC method is used to model the behavior of the mixture. In order to model the quaternary system (AMP– AEEA– CO2– Water), binary interaction parameters for ternary subsystems (AMP– CO2– Water) and (AEEA– CO2– Water) are optimized. By the Extended UNIQUAC model the CO2 partial pressures are obtained in the ternary subsystems (AMP– CO2– Water) and (AEEA– CO2– Water) with average absolute percent deviations (AAD%) equal to 19. 23 and 12. 9, respectively. Finally, binary interaction parameters for the quaternary system (AMP– AEEA– CO2– Water) are optimized and the CO2 partial pressures in an aqueous mixture of AEEA + AMP are obtained with AAD% = 17. 54.

The chemical absorption technology is widely used in the industry to remove carbon dioxide post-combustion. It is necessary to develop and identify optimal chemical solutions to absorb more and reduce the absorption energy. The aqueous solutions of alkali metal hydroxides are considered by the researchers due to their low energy requirement and their compatibility with the environment in comparison with amine absorbers. In this research, hydroxide solutions, especially potassium hydroxide, have been used to absorb carbon dioxide. In absorption experiments, the effect of stirring and temperature on the absorption of carbon dioxide by aqueous hydroxide potassium in a laboratory-scale reactor has been studied. The results showed that with increasing stirring of the mixer from 50rpm to 150 rpm, the loading, absorption, and mass transfer flux of carbon dioxide increased 33%, 32%, and 36 respectively but the increase in the agitator over this amount would not have an effect on the absorption rate. The temperature increase was carried out in the range of 25-65° C with a 6 bar pressure, a concentration of 1. 5 mol/L, and a stirring speed of 150 rpm. It was observed that increasing the temperature to half the absorption process increased the loading, absorption rate, and absorption flux of carbon dioxide, but the equilibrium parameters decreased slightly with increasing temperature. In fact, with temperature increasing from 22° C to 65° C, the equilibrium loading, adsorption rate and absorption flux of carbon dioxide decreased 15%, 2. 4%, and 13%, respectively.

Aqueous alkanolamine solutions technology is one of the most important processes in natural gas sweetening. Water provides an implicit context for alkanolamine to absorb CO2 and H2S chemically. However, apart from their advantages, aqueous alkanolamine solution is not a good solvent for mercaptan removal and due to their innate exothermic reaction, it requires high reboiler duty performance in the desorption tower. Thereby it causes some undesirable side irreversible reactions such as decomposition of solvents, degradation so on. Nowadays mixture of aqueous alkanolamine solution and physical solvents such as sulfolane so-called hybrid solvents have been used to modify conventional aqueous alkanoleamine solvents. Hybrid solvents with optimum composition may possess both advantages of physical (SFL) and chemical (aqueous alkanolamine) solvents by which, not only CO2 and H2S would be absorbed chemically, but also mercaptan would be removed up to the allowed specification limit. In this work, the differential enthalpy related to H2S dissolution in both conventional (H2O – MDEA) and hybrid solvent (H2O-SFL – MDEA) were estimated from reported solubility data in the literature using Gibbs – Helmholtz equation. The process of differentiation was done after e-Pitzer modeling of experimental solubility data. As a result, the applied model provided sound results for solubility data in quaternary hybrid systems (ARD% equal to 5. 4%), and also the addition of Sulfolane in MDEA – H2O system has a marginal effect on dissolution enthalpy of H2S.

Removal of copper ions from aqueous solutions was carried out using a synthesized hydrogel polymeric made by sodium alginate/zeolite/chitosan. At first, a batch experiment was done to determine the diffusion coefficient. And then a column with radial feeding was designed and made. The continuous experiment was carried out with a feed by 500 ppm concentration, a flow rate of 16 cm3/min, and hydrogel beads with a radius of 1. 5 mm during the 97 min. Mass transfer and sphere diffusion equations were extracted in the bed and solved numerically. Concentration profile versus time derived from this model. To evaluate the model the results were compared by experimental data. The results show that the model has 9. 8% error. The effects of parameters including concentration (350, 500, and 700 ppm), a flow rate of 30, 16, 7. 5 mL /min, and particle radius of 1. 1. 5 and 2mm were investigated via model. The results showed that with increasing initial concentration, the lifetime of the bed was increased from 70 minutes to 76 minutes. As the flow rate increased, the filling time of the column decreased from 167 minutes to 37 minutes, and as the radius increased, the life span of the column has not sensible changes.

Heavy crude oil contaminated soil, in addition to affecting the lives of plants and animals, also endangers aquatic life. These metals are in the process of extraction of crude oil into the soil and thus have destructive effects on the environment itself. In this research, the removal of heavy metals lead, nickel, and chromium from crude oil contaminated soil using saponin biosurfactant was investigated. The results showed that by increasing the concentration of saponin, the percentage of removal of metals increased. So in the concentration of 3 g/l of saponin, the removal efficiency of nickel, chromium, and lead was 73%, 58%, and 43%, respectively. Also, increasing pH to 10 and temperature to 75 ° C had a negative effect on the removal efficiency of metals. The results also showed that optimum conditions for removal of nickel, chromium, and lead metals were at a temperature of 25° C, pH equal to 4, and saponin biosurfactant concentration of 3g/l. Compared to the SDS chemical surfactant, in optimal conditions and in the large mesh (850 µ m), the saponin yield was higher than SDS in Ni and Cr. Therefore, according to the results of this study, biological surfactants can be used instead of chemical surfactants from an environmental point of view.

This study aimed to remove heavy metal cobalt from Shahid Tondgoian petrochemical wastewater in Mahshahr special economic zone using a biological method. The biosorption experiments were performed by Saccharomyces cerevisiae in a laboratory-scale batch system. Synthetic waste was initially used to optimize the parameters of pH, temperature, contact time, and biomass concentration. The optimal parameters were determined: the time of equilibrium 60 min, the temperature 25 ° C, the biomass dose of 10%, and pH 5. 5. Then the experiments were carried out with the real wastewater from Shahid Tandoogian Petrochemical Company. The highest percentage of removal was 80% and the maximum adsorption capacity was 88. 2 mg/g. The equilibrium, kinetics, and thermodynamics of cobalt adsorption were also studied. The result indicated that Co adsorption had the highest consistency with Temkin isotherms while adsorption kinetics was best fitted with the pseudo-second order model. The thermodynamics of adsorption revealed that Co adsorption was spontaneous, feasible, and endothermic. Results confirmed that Saccharomyces cerevisiae possesses the potential to be used as a suitable candidate for Heavy metal removal from petrochemical industry wastewater.

In this research, the interaction effect of the photocatalyst and hydrogen peroxide under natural solar irradiation on the degradation of 2-Nitrophenol (2-NP) was investigated. For this purpose, TiO2 nano photocatalyst (P25) was utilized, and the effect of the photocatalyst loading, H2O2 concentration, and the simultaneous use of the photocatalyst and H2O2 was studied. The results show that optimum concentrations of the photocatalyst and H2O2 were 1000 mg/L and 200 mM, respectively, when each of them was used alone for the decontamination of 2-NP. Additionally, it was found that the sole effect of H2O2 (without catalyst) on the solar 2-NP degradation was more than P25 (without H2O2). The simultaneous use of these two materials was effective in the enhancement of the degradation efficiency, and it caused the reduction of their (required) optimum concentrations. However high concentrations of H2O2 resulted in lower efficiency, as detrimental effects of using excess hydrogen peroxide got prevailed. At the global optimum condition, the concentration of P25 and H2O2 were found to be 750 mg/L and 150 mM, respectively, and the degradation efficiency of 2-NP reach 95%, after only 1h of solar irradiation.

According to international standards, the sulfur of fuels used in the transport sector, as one of the most important sources of pollution, should be reduced to around 10 ppmw by 2010. The main reason for ultra-deep desulfurization is environmental problems such as air pollution, acid rain, and concerns for human health. Oxidative desulfurization (ODS) is a supplement to the hydrodesulfurization (HDS) process. In the Oxidative desulfurization process, desulfurization of refractory sulfur compounds was carried out under mild operation conditions (low temperature and low pressure). In this study, the performance of catalytic oxidative desulfurization was considered using tungsten and tungsten-cerium catalysts supported by alumina with different compositions of tungsten (W) and cerium (Ce), which were synthesized by incipient wetness impregnation. The effect of aromatic competitive compounds was investigated. The conversion of DBT for 20wt. % W, as the best catalyst, was reached 100% at the temperature of, the mass ratio of model fuel/catalyst=100, the molar ratio of O/S=5, and reaction time=60 min. The catalysts were characterized by FT-IR and FESEM. The data help explain the satisfactory catalytic performance.

Several studies have been carried out to remove and reduce p-nitrophenol from contaminated water and industrial effluents, and various methods have been used such as catalytic oxidation electro-Fenton, electrochemical, microbial degradation, and so on. But these methods have problems such as low sensitivity, high cost the need for specific temperature conditions, and a long time. One of how scientists have considered the catalytic hydrogenation of these materials in recent years is to convert para nitrophenol into aminophenol derivative by making heterogeneous nanocatalyst, toxic substances, and carcinogens of p-nitrophenol. For this purpose [NiLx(DMF)], [NiLx(PPh3)] (L1= salicylidene-2-aminothiophenol and L2= salicylidene-2-aminophenol) complexes were placed on a titanium dioxide and the catalyst was identified with techniques such as IR، FE-SEM, EDX/mapping، XRD and ICP. Then, after selecting the best nanocatalysts, evaluate for the reduction of p-nitrophenol to p-aminophenol in the presence of NaBH4 as a reducing agent and at ambient temperature and pressure. The reaction was followed by UV-Vis spectroscopy. In presence of [NiL1(PPh3)]/TiO2 catalyst, the reaction was completed at about 8 min with k = 5/3× 10-3 s-1. The reported results so far in various sources have often been used a lot of the amount of reducing agent or catalyst, or the reaction has been completed over a longer period of time. In this work, in addition to using the minimum amount of catalyst and NaBH4, the completion time of the reaction is also appropriate.

In this study, the effect of anionic sodium dodecyl sulfate surfactant on the InterFacial Tension (IFT) of water and oil that is important in the Enhanced Oil Recovery (EOR) was studied using an experimental method and molecular dynamics simulation. For this purpose, the interfacial tension between the water solution and droplet decane was investigated in two conditions. In the first case, the solution consists of pure water molecules and chimneys, and in the second case, sodium dodecyl sulfate surfactant was added to the solution. In the SDS1 system, interfacial tension decreased from 54. 83 mN /m to 7. 32 mN /m and in the SDS2 system, the interfacial tension of 59. 06 mN /m decreased by 8. 28 mN /m. The results showed that the addition of anionic sodium dodecyl sulfate surfactant reduces interfacial tension in the second case. On the other hand, the number of molecules was evaluated and the molecular ratio was affected in the process of decreasing surface tension. The larger the number of water molecules and decane, the greater the ability to reduce the interfacial tension. According to the results, the higher the number of surfactant molecules with respect to water and alkanes, the more interfacial tension reduction is observed. Also, molecular simulations were performed to investigate the effect of surfactant concentration on interfacial tension at constant water and alkane (16 surfactant molecules, 120 molecules of dihydrates, and 800 molecules of water) (SDS3). The results showed that the interfacial tension decreased to 12. 66 mN / m which has a lower performance than the SDS1 mode.

This study aimed to achieve a formulation for an additive to produce oxo-biodegradable polypropylene films that accelerates oxidative degradation of the films after preservation of properties over a span of desired service life, so that, it can be used by microorganisms as a food source. Thermal oxidation behavior of thin polypropylene films (250 ± 50 μ m thick) containing various weight ratios of manganese stearate as pro-oxidant to a commercially used phenolic antioxidant (Songnox 1010) has been studied in both melt and solid states. Thermo-oxidative stability in melt state was studied using differential scanning calorimetry (DSC). The rate of thermal oxidation in solid-state was investigated via oven aging experiments at 90 ° C followed by measuring changes in carbonyl index, tensile properties, melt flow index, and density. It was shown that the efficiency of the phenolic antioxidant in thermo-oxidative stabilization of the polymer in both melt and solid states can be changed by altering the weight ratio of manganese stearate to the antioxidant. On the basis of the obtained results, it was concluded that a sample containing 0. 1 wt% of the pro-oxidant and 0. 35 wt% of the antioxidant is suitable for attaining desired stability in both melt and solid states and also can undergo rapid thermal oxidation after a certain period of being stable in the solid-state. Thus, it was concluded that the mentioned formulation can be applied for designing an oxo-biodegradable product, which, in addition to having the desired stability in melt processing as well as during its final usage as a film, experiences fast thermal oxidation and becomes prepared for the eventual biodegradation.

In this paper we report the synthesis and characterization of three new mixed-ligand cobalt and manganese complexes containing H2pydco = pyridine-N-oxide-2, 6-dicarboxylic acid, bipy = 2, 2ꞌ ˗ bipyridine and phen = 1, 10˗ phenanthroline. The proposed formula and structures of these compounds have been determined by elemental analysis, infrared spectroscopy, Thermal gravimetric analysis (TGA-DTA), and melting point. A search of the Cambridge Structural Database (CSD version 5. 38 updates May 2017) returned 2017 complexes with pyridine-2, 6-dicarboxylic acid and 49 complexes with pyridine-N-oxide-2, 6-dicarboxylic acid ligands. It can be emphasized that the lack of similar and suitable complexes containing N˗ oxidized H2pydco ligand in the articles of any comparison in this family has been confronted. In addition, the cytotoxicity of these three complexes was used to evaluate their antiproliferative activity on HeLa cells (human ovarian carcinoma), MCF-7 (human breast cancer), HT-29 (human colon cancer), K-562 (human myeloid cell cancer), Neuro-2a (mouse murine neuroblastoma), and L929 (rat cell fibroblast cell line, normal cell) were evaluated by MTT assay and compared with cisplatin as a reference. The results showed more cytotoxicity for complexes 2 and 3 against MCF-7 and HT-29 cell lines compared to cisplatin.

In this research, the structural, electronic and optical properties of mix diimine-dithiolate complexes with general formula [M(diimine)(dithiolate)] (M = Ni, Pd, Pt; diimine = phenanthroline)phen(; dithioalt = 1, 2-benzenedithiolate) bdt), maleonitriledithiolate (mnt)) are reported through density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. Natural Bond Orbital (NBO) analyses are also performed for scrutinizing the structural properties of the considered complexes. The results show that the M– S bond has a stronger covalent character than the M– N bond and is always polarized towards the sulfur atom. The absorption spectra of these complexes were obtained by using the time-dependent density functional theory associated with the polarized continuum model (PCM). Obtained results indicate that the substitution of bdt ligand and Pt metal enhances the intensity of the absorption significantly and the overall absorption spectrum can be red-shifted. Moreover, the latter complex [Pt(phen)(bdt)] has the highest light-harvesting efficiency (LHE). Overall, this study can widen for diimine-dithiolate complexes with a suitable combination of metal ions and ligands to be explored as dye-sensitized solar cells.

The main object of this research, is modeling and multi-objective optimization of radial flow moving bed reactors to produce propylene through propane dehydrogenation considering catalyst deactivation. The propane dehydrogenation process consists of four series catalytic reactors equipped with inter-stage heaters that the feed flows radially and the catalyst moves downward along the axial direction due to gravitational force. In the first step, the dehydrogenation reactors are heterogeneously modeled based on the mass and energy conservation laws considering catalyst decay. To prove the accuracy of the developed model, the simulation results are compared with the plant data. In the next step, the optimal operating condition of the process is obtained considering propane conversion and propylene selectivity as objective functions. In this regard, a multi-objective optimization problem is formulated and the optimal Pareto front is developed by non-sporting genetic algorithm II. Then, a single optimal solution is selected from the list of alternatives in the Pareto front curve by one of the decision-making methods. The results showed that applying the obtained optimal condition to the system improves propylene production capacity by about 3. 12 %.

The main goal of this research is dynamic modeling and optimization of the steam methane reforming process in an industrial hydrogen plant in a crude oil refinery. In the first step, the process is heterogeneously modeled based on the mass and energy balance equations considering catalyst deactivation. Since the reforming reactions are under mass transfer control in the catalyst, the effectiveness factor is calculated and applied in the model. Then, to verify the accuracy of the model, the simulation results are compared with the plant data. The simulation results show that hydrogen production capacity decreases and approaches from 27. 4 to 24. 4 mole/s due to catalyst deactivation. In the next step, considering the uniform hydrogen production as an objective function and operational limitations in the process, a single objective optimization problem is formulated to overcome the production decay. Based on the formulated optimization problem, the optimal dynamic trajectories of feed temperature, furnace temperature, and steam to methane ratio are calculated during the process run time. Based on the simulation results, the hydrogen production is improved by about 6% applying optimal conditions to the system.

The phosphate coating is one of the most widely used surface treatments of ferrous and non-ferrous metals, due to its low-cost, easy mass production, and ability to afford excellent corrosion resistance, wear resistance, adhesion, and lubricative properties. In this research, formulation of drawing phosphate bath for better cold drawing performance of low carbon steel St37 pieces was investigated. The morphologies of these coatings were observed using scanning electron microscopy (SEM), and their chemical composition and structures were characterized using Energy Dispersive X-ray Spectroscopy (EDS) and X-Ray Diffraction (XRD) analysis. The Wear and friction resistances were investigated by the pin on disk method. The protective properties of phosphate coatings in a 5 wt% NaCl solution have been studied. The results showed that zinc phosphate coating essentially consists of hopeite (Zn3 (PO4 )2 4H2O) and phosphophyllite (Zn2Fe (PO4)2 4H2O) crystal structures. The corrosion resistance for the drawing phosphate coating was obtained 52 hours. The morphologies of the crystals were needle-shaped in the drawing phosphate coating. The use of simultaneous phosphate coating and lubricant layer reduces significantly the friction coefficient (from 0. 6 to 0. 15).

In this research, artificial neural networks(ANNs) have been used to predict the viscosity of lubricant/refrigerant mixtures. Temperature, pressure, molecular weight, the mole fraction of refrigerant, and viscosity of refrigerant are used as input variables and viscosity of refrigerant + lubricant mixtures is used as a target. The total number of experimental data point of viscosity that used in this study is 1053 that is trained, validated, and tested with random70%(837 data points), 15% (158 data points), and 15% (158 data points), respectively. The results of the AAD% for the train, validation and test sets of data are 0. 39, 0. 48, and 0. 49, respectively. Therefore, studied ANN models with 15 neurons in a hidden layer are in good agreement with experimental data.

Industries are severely needed to the promising capabilities of magnetorheological fluids. In most systems that need to regulate the motion by the viscosity change, there is always a solution based on Magnetorheology, resulting in improved performance and cost. The unique properties such as fast response, simple relationship between electrical power and output mechanical power, controllability, and easy and smart performance, have made these fluids a desirable technology for use in vehicle suspension systems. A suitable magnetorheological fluid for use in a vehicle suspension system should have features such as low viscosity in the absence of a magnetic field, promising rheological properties, and fast response in the range of a few milliseconds, good stability against temperature changes and settling and non-abrasive. Also, one of the most important characteristics of a suitable magnetorheological fluid for use in the smart damper is it’ s durability against in-use thickening (IUT). It means that in some of the industrial magnetorheological fluids in successive cycles of operation, some parts of the magnetizable particles and also the formed oxide layer on the surface of particles settle and form a hard cake that greatly reduces the effectiveness of the fluid. With a proper selection of materials and synthesis methods, the durability of the fluid in successive cycles can greatly improve. Materials and production methods of magnetorheological fluid should be selected in such a way that the above-mentioned properties are present in the sample for industrial applications.

In the present study, the hydrodynamics of tapered fluidized beds (TFBs) for two types of particles, namely, Geldart D and Geldart B with mean diameters of 2 mm and 0. 287 mm, respectively, were studied by CFD-DEM in 3D frameworks. The particles phase was simulated by dense discrete phase model (DDPM) in which the particle-particle collision was modeled by the discrete phase method (DEM). While the continuous phase (gas phase) was simulated by the Eulerian approach by considering k-ε turbulent model for this phase. The well-known drag model of Gidaspow was applied for computing the momentum exchange between the phases. It was found that the bed pressure drop and the bed expansion ratio predicted by the proposed model were in close agreement with the corresponding measured data. By evaluating power spectral density in TFBs, it was found that the dominant frequency is about 2. 3 Hz for a TFB which is quite different than that calculated in bubbling fluidized beds (BFBs). Due to the fact that this study is one of the few Eulerian-Lagrangian works on TFBs, it can be a suitable basis for future studies in numerical simulation of TFBs.

Windows have the most contribution to energy loss through the buildings envelope. One of the offered solutions to improve the energy efficiency of the windows and glazing units is the filling of the vacant space of the multilayer glazing systems with aerogel. Aerogels are the lightest commercialized solids and have the lowest thermal conductivity among solid materials. Furthermore, their good acoustic insulation as well as daylight and solar energy transmittance properties, make them interesting insulation materials that can be used in the vacant space of multilayer glazing units. Multilaye r polycarbonate planes recently have found extensive applications in buildings. In this work, the vacant space, air gaps, of the polycarbonate planes were filled with silica aerogel and their thermal performance as an innovative glazing system was investigated. Polycarbonate planes with different thicknesses (5-15 mm) were filled with granular aerogels and the amount of reduction in the heat loss through the planes at different temperatures (40-70oC) was measured. Also, the effect of aerogel granule size on the thermal efficiency of the planes was investigated. Granule size in the range of 2-3 mm showed the best performance. Depending on the plane thickness, applied temperature, and aerogel granule size, the energy loss through aerogel-filled planed is reduced 21 to 66 % in comparison with conventional air-filled planes. Typically, the U-value of the 10 mm polycarbonate plane was reduced from 2. 74 W/m2K in the air-filled plane to 1. 1 W/m2K in the aerogel-filled plane.