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Research subject: In this study, EDTA-functionalized Fe₃O₄@SiO₂ magnetic nanocomposites with core-shell structure were synthesized to remove divalent cadmium ions from aqueous solutions.
Research approach: During the first step, Fe₃O₄@SiO₂ nanosphere core-shell is synthesized using nano Fe₃O₄ as the core, TEOS as the silica source and PVA as the surfactant. This strategy relies on the covalently bonding of ethylendiaminetetraacetic acid to bis(3-aminopropyl)amine and cyanuric chloride functionalized magnetic nanoparticles. In the next step, characteristics of surface functional groups, crystal structure, magnetic properties, size and surface morphology of these nanoparticles were investigated, identified and analyzed using physico-chemical characterization techniques including fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), vibration sample magnetometry (VSM) and Brunauer-Emmett-Teller (BET) surface area analyzer.  The adsorbent, due to its magnetic property, could be simply separated from the reaction mixture by a permanent magnet and reused in five consecutive cycles without considerable loss in its activity.
Main results: To probe the nature of the adsorbent, various experiments were investigated like adsorbent dose and contact time were optimized. Kinetic studies and the effect of different amounts of adsorbent to remove divalent cadmium ions from aqueous solutions show a maximum adsorption of 94% at ambient temperature. Moreover, the recyclability of Fe₃O₄@SiO₂-EDTA was investigated in order to remove the divalent cation for successive adsorption-desorption cycles. All the results of studies show that the synthetic nanocomposite Fe₃O₄@SiO₂-EDTA is an effective, recyclable adsorbent with excellent performance for the removal of divalent cadmium.

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 Research subject:
The kinetics of xylene isomerization reaction on Mo-Pt @ZSM5 catalyst has not been investigated so far. In this research, the single reversible reaction of meta-xylene to para-xylene has been studied to model this process. Considering that the feed of the industrial unit has only small amounts of non-xylene compounds, it seems reasonable regardless of other reactions and the results of this research also confirm it.
Research approach:
The desired reaction was carried out in the gas phase and constant temperatures of 375 ^oC and 378 ^oC on Mo-Pt @ZSM5 catalyst. The feed is taken from an industrial unit. In each test, the temperature is considered constant. In this research, in order to obtain a simple model, only the reversible reaction of meta-xylene to para-xylene is considered. The forward speed constant is considered as an adjustable parameter, and the backward reaction speed constant is calculated from the (meta-xylene)-(para-xylene) equilibrium constant reported in the literature. Since other reactions are neglected, the total mole fraction of meta-xylene and para-xylene is assumed to be constant and equal to their sum in the feed, and the mole fraction of ortho-xylene is calculated from the (meta-xylene)-(ortho-xylene) equilibrium constant reported in the literature. Using the mass balance and performance equation of the packed column as well as Ergun's equation to estimate the pressure changes along the column, a suitable differential equation system was proposed in this research and solved numerically using the ode45 function in MATLAB.
Main results: both the experimental data and the simulation results with the Aspen HYSYS software show that the temperature has little effect on the obtained results in the investigated temperature range. The optimal value of the reaction rate constant of metaxylene to paraxylene for the forward reaction is 1340 cm³ of product per gram of catalyst per hour. For the reverse reaction, it is obtained from the equilibrium constant data in terms of temperature. The results and the proposed simple kinetic model give a good prediction of the experimental data.

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Lipases, as an important enzyme group, are able to catalyze hydrolysis or synthesis of esters.The lipase from pseudomonas fluorescens (E.C.3.1.1.3) is a thermophilic kind of lipases (MW around 33 Kd). In this study, the effect of different concentrations of sorbitol on the activity and conformational stability of Psedomonas fluorescence lipase was evaluated using UV/Vis and Circular Dichroism (CD), respectively. According to the results of thermodynamic studies the 0.6 M concentration of sorbitol was selected for refolding and unfolding kinetic measurements with stopped flow fluorescence apparatus. Kinetics data indicate that unfolding of lipase is performed via two different pathways; one of them is probably involves a synchronous unfolding and dissociation of subunits and the other one comprises a two step unfolding in which the subunits are first dissociated followed by complete unfolding of subunits. We found that more population of protein molecules unfolded with slow phase unfolding pathway when sorbitol is present in the unfolding buffer. Furthermore; refolding kinetics data suggest that in the presence of sorbitol the energy barrier of refolding is reduced.

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This paper peresents a mathematical model for the thin layer drying of the Viliamz cultivar of soybean. The thin layer drying behaviour of soybean was experimentally investigated and the mathematical modelling performed by using thin layer drying models provided in the literature. Experiments were conducted at inlet drying air temperatures of 30, 40, 50, 60 and 70ºC and at a fixed drying air velocity of 1 m s-1. Thirteen different thin layer mathematical drying models were compared according to their r values, RMSE, 2 and EF by non-linear regression analysis. The effect of drying air temperature on the model constants and coefficients was predicted using multiple regression analysis. According to the results, the Midilli et al. model was found to be the best mathematical equation for modelling thin layer drying of soybean.

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In this study the effect of microwave power on drying behavior, effective moisture diffusion, the best mathematical model of drying, activation energy values and energy consumption of the herb thyme was investigated. Results of regression analysis of mathematical models in MATLAB software points that the Midili model has the best described to the data. Effective diffusion coefficient of herb thyme was found to be between 15.416 and 213.802m²/s. Also the activation energy was determined to be 84.86 W/g for constant drying rate and 100 W/g for effective moisture diffusion. In addition, the minimum and maximum value of specific energy consumption drying of herb thyme was 6.994 to 19.607 kW/kg, respectively.    

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Potato (Solanum tuberosum) is one of the most important agriculture products which damage soon because of inappropriate storage and processing conditions. Drying process causes to increase the shelf life of potato. In current research, potato slices dried in a parallel flow dryer and its kinetics of drying and shrinkage was studied. The experiments were accomplished in three levels of slices thickness; 3, 6 and 9 mm and three levels of temperature; 50, 60 and 70 c. Air flow was considered as 0.012 m³/s in all tests. Drying rate, moisture reduction, variation of area and roundness of samples were investigated during drying period. Results showed the maximum drying rate has been occurred when temperature was 70 c and thickness was 3 mm. Area and roundness variation was increased while temperature increased and thickness decreased.  

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Drying characteristics of Quercus were determined experimentally as a function of temperature, air velocity, and variety (Quercus Persica and Quercus Libani). In order to estimate and select a suitable drying curve, five different thin layer drying models were fitted to the experimental data. Experiments were performed at the air temperatures of 50, 60 and 70°C. At each temperature level, two air velocities were adjusted: 0.5 and 1m/s. The effect of air temperature was found to be significant in comparison to air velocity for drying of fresh Quercus fruits. Increasing air velocity at constant air temperature resulted in the decrease of drying time. Among all the selected drying models, the Page model was found as the best mathematical model for describing the drying kinetics of Quercus fruits. Based on the results, drying temperature of 70 oC and air velocity of 1 m/s are the optimum values for drying Quercus fruit. Drying time and Page model constants were found to be dependent significantly on the variables studied.

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Methyl tertiary-butyl ether (MTBE) One of the gasoline additives used to increase octane and reduce greenhouse gas emissions, MTBE can enter the human blood flow through different ways including inhalation, oral and skin contact. Human carbonic anhydrase is one of the metalloenzymes that is found in almost all living organisms and has been extensively studied and many diseases are associated with carbonic anhydrase. In this study, the effect of MTBE proximity with human carbonic anhydrase II enzyme on enzyme activity was investigated by visible-ultraviolet spectroscopy and changes in enzyme Tm at different concentrations of MTBE were reported. In addition, the structural changes of the enzyme in the presence of MTBE were examined by intrinsic fluorescence spectroscopy. The results show that the enzyme activity in the presence of MTBE is inhibited by liner-complex mechanism. The results of intrinsic fluorescence spectroscopy of the enzyme show changes in the structure of the enzyme in the presence of MTBE. Also, following the binding of MTBE to the enzyme, the thermal stability of the enzyme is reduced and it becomes sensitive to temperature changes.

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The objective of this study was to investigate dehydration kinetics of barberry (Berberis vulgaris L.) at different drying temperatures (60 ºC, 70 ºC, 80 ºC), air velocities (0.3 m s-1, 0.5 m s-1, 1 m s-1) with two types of pretreatment. Drying time and colour quality during dehydration were experimentally determined. Barberries were dried from the initial moisture content of 73.44% (w.b.) to the required moisture content of 18% (w.b.). Dehydration kinetics was monitored by measuring barberries weights at regular intervals. Convective drying curves were obtained for the treated and untreated barberries. The effect of two dipping pretreatments on drying kinetics of barberries was also studied. The two pretreatments were thermal shocking by immersing barberries in hot water, followed by cold water cooling, and dipping in olive oil and food grade K2CO3. Colour of the dried product was altered significantly during drying. The results indicated that the use of low temperatures is adequate for preserving this property. The air temperature significantly affected drying time and hunter colour indices of barberries (P< 0.05). With heat shocking and treatment with olive oil and K2CO3, drying time was reduced to about 40% and 60%, respectively. The total colour change (ΔE) and hue angle (H) increased with temperature. Moisture transfer from the test samples was described by applying the Fick’s diffusion model for calculating the effective diffusivity. The effective moisture diffusivity (Deff) of barberry increased as the drying air temperature increased. The Deff values were higher for the treated samples than the untreated ones. These values were also higher for the samples treated with olive oil and K2 CO3 emulsion than those treated with hot water. The effective diffusivity of the untreated and the pre-treated varied between 2.57×10-13 and 9.67×10-12 m2 s-1, respectively. Higher colour change was observed in barberries treated with olive oil and K2CO3 emulsion. Statistical analysis showed that temperature and pretreatment had the most significant effect on drying time at p<0.01.

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The human amniotic membrane (HAM) is one of the rare allograft tissues that are in use in clinical trials. Biocompatibility, antibacterial effect, low immunogenicity, and scar prevention are properties that have made HAM attractive for tissue engineering (TE) applications, for example, as a cell carrier, injectable hydrogel, and cell culture substrate. In this research, the effect of digestion time on the structure, gelation kinetics, rheological and biological properties of amniotic membrane-derived hydrogels was studied. The results determined that digestion with pepsin should be performed at least for 24 h.  Prolonging the digestion time to 72 h increased the shear modulus, fiber diameter, and gelation rate. Cytocompatibility assays with L929 fibroblast cells showed that the digestion time had no effect on the cell toxicity of the hydrogels. However, cell proliferation was improved due to preserved constitutive bioactive molecules. The results of this research can be used to develop amniotic membrane-derived hydrogels for TE applications.

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The objective of this study was to investigate the drying kinetics of oyster mushroom, Pleurotus ostreatus Mushrooms were dried using a cabinet-type convective dryer. Air temperatures of 50, 60 and 70 oC were used for the drying experiments. The experimental drying data were fitted to different theoretical models to predict the drying kinetics. Nonlinear regression analysis was performed to relate the parameters of the model with the drying conditions. The performance of these models was evaluated by comparing the correlation coefficient (R2), root mean square error (RMSE) and the chi-square (χ2) between the observed and the predicted moisture ratios. Among all the models, the model of Midilli et al. was found to have the best fit in this study. Effective moisture diffusivities (Deff), diffusivity constant (D0) and activation energy (Ea) were calculated. The Deff varied from 9. 619x10-10 to 1.556x10-9 m2s-1 over the temperature range studied and Ea was 22.228 kJ mol -1.

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  Drying is one of the preservation techniques in which moisture removal through simultaneous heat and mass transfer occurs. Due to low energy efficiency and prolonged time of hot air drying, the new drying techniques such as infrared, must be employed. In this study, the effects of temperature and drying method on the kinetics of persimmon slices with 5 mm fixed thickness were investigated. The tests were performed at 3 temperature levels (50, 60 and 70^◦c) using both hot air and infrared dryers in 3 replicates. The experimental data obtained from drying treatments were fitted to 9 mathematical models in order to evaluate the drying kinetics of persimmon slices. The fitting quality of the proposed models was evaluated using the coefficient of determination (R²), root mean squares error (RMSE), chi- square (χ²) and sum square error (SSE). Based on the results, Wang and Singh model was found to be the best model fitted to the experimental hot air drying data at all temperature levels. In the case of experimental infrared drying data at 50 and 60^◦c, the logarithmic model showed the best fitting results while at 70^◦C, 2-term model showed the highest fitting quality. These models exhibited the highest value of R² and the least RMSE, χ² and SSE comparing to the other models

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Pistachio plays an important role as exportation of Iran. The method of drying process has a remarkable influence on the quality of dried products. There are various methods for drying pistachio; however, choosing a suitable method of drying depends on  reliability, healthiness and rapids. In current research, the effect of temperature in three levels of 40, 50 and 60°C and rotational speed of the dryer agitator in three levels of 5, 10 and 15rpm on reduction rate of drying period and drying kinetics of a common Iranian pistachio (Kalleh Ghoochi v.), in a new intelligent- vacuum rotary dryer, was investigated. This dryer  was consisted of a cylindrical chamber and a twin electrical heater which dried products in a vacuum medium. The experimental data was analyzed in a statistical software "SPSS 10 "  In accordance with the results, temperature and rotational speed of the agitator had a significant effect on drying period. When temperature and speed were 60°C and 15rpm respectively, drying period was short and equaled  185 min, but in temperature of  40°C and speed of 5rpm, drying period was long and equaled 325 min.  Increasing the temperature also increased the rate of drying  significantly. Results indicated that increasing  temperature from 40°C to 50°C caused 25% decrease in the drying period and increasing temperature from 40°C to 60°C caused 39% decrease in drying period. 

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Vacuum drying of Salicornia herbacea L. was performed at different drying temperatures (50, 60, 70, and 80C) to evaluate the drying characteristics and the effect of drying temperatures on the quality of Salicornia. As the drying temperature increased, the drying time decreased significantly (P< 0.05). The drying rate decreased with decrease in moisture content and increase in drying time. On the other hand, the drying rate increased with increase in drying temperature. The logarithmic model exhibited the best fit to the experimental drying data among the tested models. The drying constants estimated using the logarithmic model were found to be affected by the drying temperature. The activation energy for drying was 15.02 kJ mol-1. The surface color of the Salicornia herbacea samples was significantly affected by the drying temperature (P< 0.05). CIE L*-, b*-, and Chroma (C*)-values increased significantly, while a*- and hue angle (h*)-values decreased significantly after drying at all of the drying temperatures (P< 0.05).

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Electrokinetics is a common and practical method for contaminant removal from fine grain soils. In spite of several researches performed on the factors affecting the application of electrokinetics method for contaminant removal from soils, there are still extensive attentions of researches on the influence of soil components on the efficiency of this method upon contaminant removal. The main objective of this research is to investigate on the impact of carbonate elimination and contaminant concentration on the Pb removal from carbonated kaolinite in electrokinetics process. To achieve this objective a natural kaolinite sample which had 4% natural carbonate and a carbonate eliminated kaolinite were laboratory contaminated with 5 and 20 cmol/kg-soil of lead nitrate. After achieving equilibrium, the laboratory contaminated samples were dried in oven at 40 centigrade temperature for 96 hours. Then, 27% water was added to samples as initial water content. To achieve homogeneous distribution of water content, the sample was kept in a plastic bag for 24 hours. Then sample was passed through #10 sieve to have a more homogeneous sample. Finally, the soil sample was compacted in five layers at dry density of 1.7 g/cm3 in the electrokinetics cell. Then, the electrokinetics method was performed on these samples for contaminant removal. Electrokinetics experiments performed for a 240 hours period. After the end of experiment, the soil sample was taken from cell and sectioned in 5 slides. Each slice was analyzed for water content, soluble and adsorbed contaminant. In addition to electrokinetics experiment, buffering capacity test was performed by titration of soil sample with nitric acid. For this purpose, the diluted nitric acid in 1:10 soil:acid solution was added to sample. The soil solution sample kept on the shaker for 96 hours. After equilibrium the pH of soil solution was measured. This experiment was performed for different concentration of nitric acid. The final type of experiment include batch equilibrium experiment in which different concentrations of 5, 10, 20, and 30 cmol/kg-soil of lead nitrate was prepared. Then 20 milligram of each solution was added to 2 grams of kaolinite sample. After the shaking period and centrifuging the sample, the pore fluid was analyzed to measure the soluble and retained heavy metal. The results of experimental study indicate that the reduction of carbonate in carbonate rich kaolinite and an increase in contaminant concentration causes a reduction in soil buffering capacity. This means that as the concentration of carbonate in soil sample decreases, one faces with a reduction in contaminant retention capacity of soil. In addition, in such a case a reduction in pH happens which consequently enhances the contaminant removal from soil. Furthermore, carbonate elimination causes an increase in contribution of electro-osmosis on soil improvement which is followed by water content variation and consolidation of soil.