Nashrieh Shimi va Mohandesi Shimi Iran
Year:2020 | Volume:39 | Issue:2 (96)|Papers Count:28

In the present study, polymeric nanoparticles were prepared via ionic gelation of tripolyphosphate (TPP) and chitosan. The morphologies and characteristics of chitosan nanoparticles were determined by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy, respectively, and their mean particle sizes and zeta potentials were obtained using DLS. FT-IR was confirmed tripolyphosphoric groups of TPP-linked with amine groups of chitosan in the nanoparticles. SEM was showed a spherical, smooth, and almost homogenous structure for the nanoparticles. The influence of many factors on the encapsulation of compsobuthus scorpion venom on the prepared chitosan nanoparticles (CS-NPs) was also evaluated. The optimum encapsulation efficiency (99. 98%) and loading capacity (80. 44%) were obtained by chitosan concentration of 2 mg/ml, chitosan to TPP mass ratio of 2, and compsobuthus scorpion venom initial concentration of 500 mg/mL. In vitro release of nanoparticles showed an initial burst release of approximately 20% in the first 8 hours, followed by a slow and steady rate release for about 72 hours. It could be concluded that the compsobuthus scorpion venom-loaded CS-NPs can be considered as an antigen delivery candidate.

Synthesis of stable drug carriers for drug delivery based on immunoglobulin G (IgG) in the release of oxaliplatin as an anticancer drug was carried out and characterized infrared spectroscopy (FT-IR) and Scanning Electron Microscopy (SEM). In this paper, the drug release tests were performed for pure IgG and two different ratios of drug / IgG nanoparticles (IgG-NPs) (1: 1 and 2: 1). Drug loading and encapsulation were determined for three systems. The results showed that the drug release was sustained in IgG NPs systems in comparison with pure IgG. Also, the release mechanism was studied and indicated that the mechanism was fickian diffusion. Therefore, the designed system is a suitable candidate for drug release of anticancer drugs.

In this study, we investigated a solid-phase extraction procedure for separation and preconcentration of trace levels of Cu (II) ion using a new L-Arginine functionalized Fe3O4 graphene nanocomposite. Experimental parameters such as pH, amount of nanocomposite, and ultrasonic time were studied in detail. The effect of potentially interfering ions on the recovery of Cu(II) was also examined and the results showed there is no considerable effect on the determination of Cu (II). Under optimized conditions, the method provided an enhancement factor of 36. 8, a linear range of 5-250 ng/mL of Cu (II), a detection limit of 1. 96 ng/mL, and a relative standard deviation 3. 81 % at 25 ng/mL of Cu (II). The method was validated by the extraction and determination of Cu (II) in water and rice samples.

Improved polyphenylsulfone nanocomposite membrane with iron oxide modified montmorillonite was prepared by mixing this additive with polymer solution by phase inversion method. In this study, the effect of the additive on membrane performance was investigated. For this purpose, the pure water flux, fouling, rejection of dyes and heavy metals were measured by a filtration cell. The hydrophilicity of membranes was studied by measuring the contact angle of water. The dispersion of additive in the polymer matrix, as well as the membrane morphology, was surveyed by FE-SEM analysis. The results obtained from the above experiments showed that the surface hydrophilicity increased after the incorporation of the modified clay. In addition, pure water permeability, salt rejection, and fouling resistance improved dramatically for the modified membranes.

In this research work, TiO2, TiO2-Graphene, and TiO2-Graphene/Alginate catalysts were synthesized and characterized by different methods such as XRD, TEM, SEM, and EDX analysis methods. Photocatalytic activity of prepared samples was investigated by photocatalytic removal of malachite green and methyl orange as cationic and anionic dyes from aqouse solutions. The results showed that photocatalytic activity of samples depends on the chemical structure of pollutants. TiO2-Graphene/Alginate nanocomposite showed higher photocatalytic activity on the removal of cationic dye from aqouse solutions. While TiO2-Graphene sample showed higher photocatalytic activity on the removal of anionic dye from aqouse solutions comparison. The figures of merit based on electric energy consumption (electrical energy per order (EEO)) were evaluated in the photodegradation of malachite green in the presence of prepared samples. The results indicate that less energy is consumed during the degradation of malachite green in the presence of TiO2-Graphene/Alginate compared with other photocatalysts. To understand the nature of adsorption process, the equilibrium adsorption isotherms were studied. Based on results, for TiO2-Graphene/Alginate, Langmuir isotherm model with correlation coefficient of 0. 995 fitted the experimental data, respectively. According to the Langmuir isotherm model, the maximum adsorption capacity of TiO2-Graphene/Alginate for adsorption malachite green was about 86. 45 mg. g^(-1), which was about 4 times the adsorption capacity of Ag-TiO2. Also, recyclability of TiO2-Graphene/Alginate nanocomposite was investigated. The results showed that TiO2-Graphene/Alginate nanocomposite with recycling ability is highly stable.

Throughout the years, humans have entered the environment with potentially hazardous wastes such as heavy metals and radioactive substances, so that it has a direct impact on human health and existing ecosystems. Hence, the investigation on the necessary strategies to control and eliminate these hazards has been the goal of various researches. In this study, the elimination of cobalt 60 radionuclides was investigated due to their abundance in the wastewaters of nuclear industries such as spent fuel reprocessing plants and nuclear power plants. Thus, novel surface-modified hematite nanoparticles (α-Fe2O3 NPs) were prepared by hydrothermal method at 250 ° C and using iron(III) chloride hexahydrate (FeCl3. 6H2O) and oleic acid (C₁ ₈ H₃ ₄ O₂ ) as raw materials for the removal of cobalt-60 radiostations from aqueous solutions. The synthesized α-Fe2O3 NPs were characterized by XRD, FT-IR, SEM, TEM, and BET. According to the results, the synthesized nanocrystals were more (90%) of nanorods 60-30 nm, along with irregular hexagonal nanoscale particles at a thickness of 40-100 nm distributed among them. The specific surface area was determined 31. 29 m2/g and the effect of some variables such as pH, adsorbent weight, initial concentration of cobalt-60 radio cations, temperature, and contact time was significant on the absorption process. The optimized condition for cobalt-60 removal from aqueous solution was obtained in 25± 1 ° C, initial radio cation concentration of 1 mg/L, pH 6. 5, contact time of 2 h, and nano α-Fe2O3 sorbent concentration of 20 mg/L. On the other hand, the Redlich-Peterson isotherm model was suitable for describing homogenous cobalt-60 adsorption with the maximum uptake capacity 142. 86 mg/g at 25± 1 ° C. In contrast, analysis of experimental data showed that the cobalt-60 adsorption onto the synthesized nano α-Fe2O3 well fitted the Ho model as linear pseudo-second-order kinetics. Therefore, it can be concluded that the synthesized novel surface-modified α-Fe2O3 NPs is an effective, promising, and environment-friendly adsorbent with high capability in the removal of cobalt-60 radionuclides from aqueous solutions such as wastewaters.

The separation of nanocatalysts from the liquid phase often limits their use in industrial-scale processes due to their small size. To solve this problem, nanocatalyst is often embedded on the substrates. In this study, at the first stage, cerium doped TiO2 nanoparticles were prepared by the sol-gel method. Then, LECA granules are used as a support phase for immobilizing nanoparticles. Nanoparticles are characterized by Fourier-transform InfraRed (FT-IR) spectroscopy, X-Ray Diffraction (XRD), Field-Emission Scanning Electron Microscopy (FE-SEM), and nitrogen adsorption-desorption isotherms (BET). The FE-SEM studies showed a uniform coating of TiO2-Ce nanoparticles on the surface of LECA granules. A catalytic bed was constructed with a regular arrangement of the LECA granules and immersed in a photoreactor with the cyclic flow. The degradation of direct blue 71 (DB71) was investigated in the fixed bed photoreactor. The results showed that the fixed bed configuration (5. 3gr) could remove about 96% of the dye (DB71, 20ppm) during 1h irradiation under a UV light source. Furthermore, the ability of coated LECA granules in the degradation of dye was studied in the floating condition under sunlight. The results showed that with daily irradiation for 4 h, the catalyst can remove 94% of the color over three days.

In this study, the effects of polyethylene glycol on the structural properties of gamma-alumina (γ-Al2O3) synthesized via a modified sol-gel process was investigated. To this end, polyethylene glycol (PEG) and aluminum isopropoxide (Al(OPri)) were used as the structure-directing agent and aluminum precursor, respectively. Nitrogen adsorption-desorption analysis was performed to obtain the specific surface area, pore-volume, and pore size distributions of the γ-Al2O3 samples synthesized with different mole ratios of PEG/Al(OPri). The maximum specific surface area (344 m2/g) and the pore volume (2. 2 cm3/g) was obtained for the γ-Al2O3 prepared with a PEG/Al(OPri) mole ratio of 0. 05. These surface area and pore volumes were about 40 and 340% higher than the sample synthesized in the absence of PEG. It was also observed that increasing the mole ratio of PEG/Al(OPri) to more than 0. 05 had no significant effect on the structure of γ-Al2O3. The best sample was further studied by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) analyses and the results were compared with the commercial γ-Al2O3 prepared from Merck Company with a specific surface area and pore volume of 174 m2/g and 0. 5 cm3/g, respectively. XRD analysis showed that the crystallite sizes of the best-synthesized sample and Merck product were 7 and 13 nm, respectively. Unlike previous γ-Al2O3 synthesis methods, in which synthetic samples with a high specific surface area typically had a small pore volume, the use of PEG in the sol-gel process could significantly increase both the specific surface area and the pore volume. Furthermore, PEG-assisted synthesis of γ-Al2O3 was less complex than the other methods.

In this research, zeolite and active alumina adsorbents were modified to increase the absorption of carbon dioxide using piperazine solution. The effect of different operating conditions including temperature, pressure, amount of adsorbent, particle size, and concentration of piperazine solution on the adsorption process were investigated. The results of the adsorption experiments showed that, with increasing pressure and decreasing temperature, the adsorption rate increased, and the highest amount of carbon dioxide absorption was at 25 ° C, 8 bar, 1 g of adsorbent, 200 micron particles, and 2% concentration weight is piperazine. Absorption capacity for active alumina increased from 166. 516 to 222 mg/g, absorbent for zeolite 13X from 194. 844 to 244. 084 mg/g. In general, the modified 13X zeolite adsorbent has a higher absorbance compared to modified activated alumina, but it also increases the level of absorption of active alumina. Thus, according to the results of this study, modified adsorbents with piperazine have a good effect on carbon dioxide absorption. At high temperatures, it also increases the absorption rate of the absorbent material.

The molecular dynamics simulation technique can be used to examine systems that are difficult to achieve the experimental The molecular dynamics simulation technique can be used to examine systems that are difficult to achieve the experimental values of some of their characteristics in unconventional conditions. In this work, molecular dynamics simulation methods of removal of heavy metals (zinc and copper) were evaluated by zeolites. The structural parameters, the adsorption of heavy metals of zinc and copper well as the adsorption energies were analyzed. Calculating the mean square displacements on zeolites, the amount of diffusion coefficient was calculated. The amount of diffusion coefficient in zeolite A is less than that of zeolite X, which indicates that the metal has less diffusion in zeolite and remains in the effluent and its removal by zeolite A is better. Heavy metal adsorption efficiency is 99. 9% based on simulation and experimental data. The results show that Zn removal from zeolite surface requires more energy than copper since absorbed ions exhibit high stability at adsorbent surfaces.

In this research work, at first, bimetallic Pt-Pd particles/ ERGO nanohybrid was prepared on glassy carbon electrode (GCE) and then was used to determine bisphenol A (BPA). The morphology of modified electrode was studied by using field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and energy dispersive spectroscopy (EDS). Cyclic voltammetry (CV) of modified electrode in the presence of BPA in phosphate buffer indicated an oxidation peak at 0. 44 V which means the irreversible oxidation process of this compound. In addition, electrochemical impedance spectroscopy results showed that charge transfer of Pt-Pd/ERGO/GCE is lower than GCE and ERGO/GCE. Amperometric method was applied as a sensitive analytical method for the determination of BPA. A linear relationship between the oxidation peak current and BPA concentration was obtained in the range from 5 to 201. 5 µ M with a detection limit of 0. 75 µ M and sensitivity of 0. 13 µ A µ M-1. Moreover, the proposed electrode exhibits good selectivity for electrooxidation of BPA.

In this research, a simple, fast, inexpensive, and efficient microextraction method called Vortex Assisted-Solidified Floating Organic Drop MicroExtraction (VAE-SFODME) in pre-concentration and separation of ultra-trace amount of cadmium from aqueous environmental, biological, and food samples was studied. In this method, cadmium metal forms a complex with ammonium pyrrolidine dithiocarbamate (APDC) and is extracted into the organic phase, 1-dodecanol. After the phase separation, the enrichment analyte is determined by electrochemical atomic absorption spectroscopy. The use of vortex as a useful tool eliminated the organic solvent of the disperser, while also distributing fine extracting solvent in the solution and increasing the contact surface, increasing the extraction efficiency and the enrichment factor. Solvent 1-dodecanol was chosen as a suitable extraction solvent due to the proper melting point and low density than water. Experimental parameters related to extraction efficiencies such as extraction solvent volume, pH, the concentration of the chelating agent, extraction time, centrifuge condition, salt concentration, and the effect of interference ions were studied. Under the optimized conditions (Extraction solvent (1-dodecanol); 90 μ L, pH =2. 5, APDC; 12 μ L, extraction time; 3 min, centrifugation speed 4000 rpm for 2 min, no salt addition, and at room temperature) detection limit (S/N=3), determination limit, reproducibility (RSD, n=5) and enrichment factor were 0. 58 ng/mL, 1. 92 ng/mL, 0. 97% and 96 respectively. Meanwhile, in order to study the accuracy of the proposed method, environmental samples (refined water, urban water, and river water) and biological samples including human saliva and saliva, and salts with cadmium levels at concentrations of 20 and 40 ng/mL spiked, the recovery of spiked samples were very good and were in the range of 94. 5-101. 3%. Therefore, the proposed method can be used successfully in various aquatic, biological, and food samples.

In this research, a simple, fast, inexpensive, and efficient microextraction method called Vortex Assisted-Solidified Floating Organic Drop MicroExtraction (VAE-SFODME) in pre-concentration and separation of ultra-trace amount of cadmium from aqueous environmental, biological, and food samples was studied. In this method, cadmium metal forms a complex with ammonium pyrrolidine dithiocarbamate (APDC) and is extracted into the organic phase, 1-dodecanol. After the phase separation, the enrichment analyte is determined by electrochemical atomic absorption spectroscopy. The use of vortex as a useful tool eliminated the organic solvent of the disperser, while also distributing fine extracting solvent in the solution and increasing the contact surface, increasing the extraction efficiency and the enrichment factor. Solvent 1-dodecanol was chosen as a suitable extraction solvent due to the proper melting point and low density than water. Experimental parameters related to extraction efficiencies such as extraction solvent volume, pH, the concentration of the chelating agent, extraction time, centrifuge condition, salt concentration, and the effect of interference ions were studied. Under the optimized conditions (Extraction solvent (1-dodecanol); 90 μ L, pH =2. 5, APDC; 12 μ L, extraction time; 3 min, centrifugation speed 4000 rpm for 2 min, no salt added, and at room temperature) detection limit (S/N=3), determination limit, reproducibility (RSD, n=5) and enrichment factor were 0. 58 ng/mL, 1. 92 ng/mL, 0. 97% and 96 respectively. Meanwhile, in order to study the accuracy of the proposed method, environmental samples (refined water, urban water, and river water) and biological samples including human saliva and saliva, and salts with cadmium levels at concentrations of 20 and 40 ng/mL spiked, the recovery of spiked samples were very good and were in the range of 94. 5-101. 3%. Therefore, the proposed method can be used successfully in various aquatic, biological, and food samples.

The cloud point extraction method, based on separation in the micellar environment, was used for preconcentration of aluminum, zinc, copper, and manganese before measuring by UV/Vis spectrophotometer. In this method, extraction of metals after complex information with the ligand of N-benzoyl-N-phenyl hydroxylamine was performed by two surfactants Triton X-100 and Sodium Dodecyl Sulphate (SDS). Each metal separately in the micellar medium was extracted. The effects of surfactant concentration Triton X-100 and sodium dodecyl Sulphate and ionic strength on the extraction yield were investigated using Box-Behnken experimental design and then the optimum condition was determined after searching point-to-point. Under optimum conditions, the detection limit for aluminum, manganese, zinc, and copper, respectively, 3. 46, 3. 08, 2. 76, and 2. 22 μ g/L, and the relative standard deviation for six times for concentration of 300 micrograms per liter of zinc and copper was 3. 02 and 3. 12 percent respectively and for 500 micrograms per liter of aluminum and manganese samples were 3. 93and 4. 00 μ g/L respectively. Preconcentration factors for aluminum, manganese, zinc, and copper were 3. 6, 4. 3, 4. 5, and 5. 0 respectively. Finally, measuring of these metals was successfully performed under optimal conditions for two real samples of water.

In view of the biological and pharmaceutical significance of coumarin and 3, 4-dihydroquinolone structures, such as anticancer, anticoagulation of blood vessels and anti-HIV activities, and advantageous of synthesis of hybrid molecules by the combination of known pharmacophores for the development of a diverse range of novel pharmaceutical agents as potent drugs with many improved properties, in this article, various novel tetra-and pentacyclic heterocycles of 3, 4-dihydroquinolones annulated tetrahydropyranocoumarin and α-pyrone were synthesized via domino Knoevenagel hetero Diels-Alder reaction of N-acrylated anthranilaldehyde with 4-hydroxy-coumarin and α-pyrone (4-hydroxy-6-methyl-2H-pyran-2-one) in the presence of 50 mol% ZnBr2 as a mild and low cost catalyst in refluxing acetic acid in one step. All products achieved with high yields with excellent regioselectivity and stereoselectivity.

Regarding the important role of azacycloheptatetraenes and their relative carbenes in organic chemistry, the structure and stability of ten triazacycloheptatetraenes and their corresponding carbenes as well as their racemization are studied at ab initio and DFT levels. The species of 7a is introduced as the most stable triazacycloheptatetraenes with the largest di-imine angle and the lowest twist angle. The species of 1a and 9a are found as the most unstable allenes through lone pairs’ repulsion of their adjacent nitrogens. Their non-planar symmetry results to their optical activity. Racemization of triazacycloheptatetraenes performs through their singlet triazacycloheptatrienylidenes and depends on the topology of nitrogen atoms. Species with one of their nitrogen atoms in the 1 position of the ring, including 1, 2, 4-; 1, 2, 5-; 1, 3, 4-; 1, 3, 5; and 1, 4, 5-isomers, show racemization through their corresponding anti-aromatic singlet triazacycloheptatrienylidenes as TS. In contrast, aromatic singlet carbenes appear as TS for 2, 3, 4-; 2, 3, 5-triazacycloheptatetraenes. In addition species with a nitrogen atom in the 1 position of the ring especially 2a have smaller Δ E#, Δ E#, Δ H#, and Δ G#.

In continuation of our efforts on the synthesis of diaryl disulfide compounds using coupling reactions and try to finding efficient, simple, and general methods for the direct synthesis of C-X (S, Se, Te) bonds, In this work, for the first time a transition-metal-free synthesis of diaryl dichalcogenides has been reported. Potassium t-Butoxide can efficiently promote the coupling reaction of aryl halides (and-OTS) with elemental S, Se, and Te powder in DMSO without the aid of transition metal catalysts. Under the optimal conditions, a series of symmetrical diaryldisulfide, diaryldiselenide, and diarylditelluride were obtained in good to excellent yield.

The catalytic activity of CuPF6 has been studied for the selective oxidation of benzylic alcohols to the corresponding aldehydes using tert-butyl p-nitrobenzoperoxoate an oxidizing agent. This system showed excellent catalytic activity for the oxidation of benzylic alcohols to the corresponding aldehydes with high selectivity. The complete conversion of the benzylic alcohols to the corresponding aldehydes is achieved within a short reaction period at 40 ° C. The catalytic performance is obtained to be dependent on the electronic and steric effects of the substituents present on the phenyl ring. Electron donating groups on the para and meta position of phenyl ring increase the efficiency and reduce the reaction time (electronic effects). Also, different types of groups, such as donor and withdraw, on the ortho position of phenyl ring reduce the reaction efficiency and increase reaction time (steric effects). The oxidation of 1-phenylethanol and 1-indanol to the corresponding ketones was performed using a tert-butyl p-nitrobenzoperoxoate in the presence of CuPF6 for 5 hours, with a yield of 15% and 23% respectively. Oxidation of non-benzylic alcohols could not be oxidized to the corresponding aldehydes or ketones even after 24 h. Thus, tert-butyl p-nitrobenzoperoxoate was found to act as a highly chemoselective oxidant for the oxidation of primary and secondary benzylic alcohols in the presence of CuPF6 as a catalyst.

In this work, a new oxazolidine-based ligand, 2-(2-(pyridin-2-yl)oxazolidin-3-yl)ethanol (AEPC), and its zinc complex, [Zn(AEPC)Br], were prepared and identified by elemental analysis, molar conductivity, FT-IR and 1H NMR spectroscopies. Based on the DFT calculations, in the structure of the complex, the zinc atom has coordination number four with tetrahedral geometry. Under ultrasonic irradiation and gelatin media, the nano complex of [Zn(AEPC)Br] is prepared. For evaluation of the biological properties of ligand and complex, Docking studies using the GOLD software on the ten human proteins were done and the results revealed that there are hydrogen bonds and short contact interactions between new compounds and studied macromolecules.

In this work, some thermodynamic properties of nanoparticles, nanofluids containing a base fluid, and nanofluids with two different bases were assessed at the pressure range from 0. 1 to 45 MPa and a temperature range from 273 to 363 K. this study focuses on nanofluids such as Al2O3, CuO, Co3O4, SnO2, TiO2-Rutile, TiO2-Anatase, ZnO and the base fluid containing H2O, Ethylene glycol and polyethylene glycol (with a molecular weight of 400). The used Equation of State (EOS) is the Tao– Mason (TM) equation of state which is based on statistical mechanics and its parameters can be calculated by a potential function. According to the quantum properties of nanoparticles, a quantum correction was used to calculate the second virial coefficient. To consider the polar effects of the material, the Morse three-parameter potential function was used which is more flexible than the usual two-parameter potentials functions such as Lenard Jones 6-12. Initially, the pure-component parameters of nanoparticles were fitted to the saturated liquid density data, and then the parameters were used for mixtures. Also, a binary parameter was fitted to consider the interactions between two different molecules in the mixtures. In total, from 1181 data points examined, the average absolute deviation between the calculated densities and the experimental ones is of the order of 0. 5%. According to the results, this equation of state has good accuracy for calculating and predicting the density of nanofluids.

In thisarticle, a statistical modeling methodology was presented for the optimization of Lavan oil refinery atmospheric distillation unit operation. The simultaneous effects of crude oil and gas condensate flow rates on liquefied petroleum gas, light and heavy naphtha, middle distillate (gasoil), and fuel oil production were investigated using Response Surface Methodology (RSM) by Design Expert Software. For this purpose, 623 experimental data under various operating conditions were used. To identify the significance of their effects and interactions, analysis of variance (ANOVA) was performed for each parameter on the production of liquefied petroleum gas, light and heavy naphtha, middle distillate (gasoil), and fuel oil. The results indicate that the R2 values are more than 0. 92 and adjusted R2 are in a reasonable agreement with R2. After that, optimization was also carried out to increase the production of valuable products such as light and heavy naphtha and to reduce the fuel oil production as undesirable products. According to the optimal conditions and consideration of operational constraints, the maximum amount of naphtha production and minimum fuel oil production as the main goal of this study were gained in the total feed flow rate 56500 BPD and with a 57% gas condensate and 43% of crude oil blending. Also, the process modifications were applied and the optimum operating conditions were implemented successfully.

The application of atmospheric spraying micronized powder device is a new method to dry and powder thermosensitive solutions. The inlet material could be pure ort with dispersed particles or a solution of different materials. In this research, stearic acid was used as the molten organic compound for producing powder, and calculations were performed to design a device with a production capacity of up to 500 kg/h and powder diameters of up to 300 µ m. In order to better understanding the heat and momentum transfer phenomenon and powders freezing process inside the chamber, powder’ s temperature, velocity, and phase profiles were calculated. Based on mathematical model results, the inlet cooling air temperature has a significant impact on powders diameter and increasing that temperature from 5 oC to 30 oC could duplicate the diameterof the produced powders. Chamber wall temperature is another important parameter and usinga cooling system has a significant effect on powders freezing time and device required height.

Ljungstrom is used in steam power plants for heating of boiler’ s air and increase its temperature to around combustion temperature by energy recovery of outlet smoke. Due to moving parts and therefore high depreciation, the main drawback of Ljungstroms is the possibility of air leakage into the smoke channel (more than 20%) which leads to an increase in the passing air through the fans and reduction of generating energy of power plants. On the other hand, a wickless heat pipe or thermosyphon is a thermal spreader with no moving parts and no external control. Thereforethe application of thermosyphon heat exchangers instead of conventional Ljungstroms can be considered as a reasonable suggestion. In this study, the Ljungstrom of Mashhad steam power plant with specified geometry (surface area: 12040 m2) and operation conditions (thermal performance coefficient: 71%) is considered and the final goal is the design of thermosyphon heat exchanger systems with different geometries in case of pipe size and materials, working fluid, the number of pipes, and transverse and longitudinal pitch. The comparison of designed thermosyphon heat exchangers with Ljungstroms in case of required thermal surfaces and occupied volume is investigated too. In this research, two approaches with different working fluids have been considered. The second design with 522 heat pipes which were charged by mercury showed better performance than the first design which was made with 900 heat pipes and charged by thermex as the working media. Reduction of the required heat transfer surface, prevention of air leakage to the air stream, and elimination of electrical energy used by moving parts of Ljungstrom are some benefits of this study.

Sanitary disposal is one of the waste disposal methods, which contains a lot of harmful effects especially air pollution. As a result of the biodegradation process, pollutant gas contains Biogas, Methane, Carbon Dioxide, produced from landfills within which, Methane gas has a huge effect on air pollution in comparison to other gases. In this paper, seven cities of Iran, including Tabriz, Tehran, Shiraz, Bandar Abbas, Khoy, Astara, and Mashhad have been studied for the simulation of pollutant gas emissions according to various climatic conditions in them. After collecting population growth rate, type of landfill area, and the average lifetime of the displacement site pollutant Emissions from Landfills were simulated by using LandGEM software. The findings of this study demonstrate that the highest methane production rate among the studied cities, due to the humid and normal weather for Astara and the dry weather for other cities will occur in 1415 (2036) in Tehran. Using the results obtained from this study, it is possible to design methane gas collection systems for each site. therefore, in addition to the use of pollutant gases, its accumulation in the landfill site and the explosion probabilities are also prevented.

In this article measure pH is intended in the culture solution and designed embedded system automatically and without human intervention be able to instantly measure the pH and help to control the pH at a higher speed. For this reason, using the camera and color processing solution and artificial neural network algorithms and algorithms can be implemented on a processor. The network was instructed by experimental solution data. The network layers of RBF are three and inputs in three categories of RGB is sent to the network and accordance with a standard solution, RBF error in training error reached 0. 35 and test error reached 0. 1 and in ANFIS network training error is less than 0. 06 and test error reached to 0. 01 then ANFIS is more accurate than RBF network. This percentage of errors obtained with 37 different solutions and this error can be reduced by increasing its number

The energy consumption in different industries is increasing so fast in recent years. Although fossil fuels have been the main source of energy, some deficiencies such as their limitations and instability and also their drastic impacts on the environment and greenhouse emissions have obliged people to provide their required energy from alternative sources, especially regenerative ones. One of such energy sources is the application of Microbial Fuel Cells (MFC) which is used for electricity generation. In MFSs proton and electron are produced in anode anaerobic chamber through the oxidation of microorganism substrates. Protons diffuse through the proton exchange membrane and electrons go to the cathode chamber through the external circuit. Electrons and protons produce water in presence of oxygen as an electron acceptor. Consequently, the process of MFCs is significant in terms of economic aspects. Modeling and simulation are methods of characterization of MFCs. For this purpose, after the modeling and simulation of a two-chamber MFC, important parameters namely temperature and substrate flowrate were investigated. Investigations on the effect of substrate flowrate in three steps (0. 8 Qa= 18 cm3/h, 1. 2 Qa = 27 cm3/h, Qa = 22. 5 cm3/h) showed that the highs power was achieved in 22. 5 cm3/h. Additionally, the effect of temperature was assessed in 298-333K, where the highest power was achieved in 298K.

In this study, the optimization of a semi-continuous culture of hybridoma cells have been investigated to maximize the production of monoclonal antibodies by using a genetic algorithm. The culture time was ten days. The objective function was the monoclonal antibody production and the independent variables were daily feeding profiles of the substrate (glucose and glutamine). To achieve the optimal feeding strategy, a seventh-order kinetic model was used to model the hybridoma semi-continuous cultivation process. The governing differential equations have been solved using MATLAB software. The modeling results show that the optimal amount for monoclonal antibody production based on the uniform feeding profile of the substrate is 233 mg and based on the variable feeding profile of the substrate is 314 mg, which shows 34% improvement in monoclonal antibody production. In addition, the results of the model have a consistent agreement with the previous research by Trembli et al. and Miguel et al.

Along with the development and industrialization of societies, the demand for heavy metals is on the rise, while the rich mineral ores of these metals have declined. Today, other sources of metals with higher grades, such as spent catalysts, fly ashes, electroplating sludge, and most importantly, electrical and electronic wastes have been taken into consideration. Recovery of heavy metals from these secondary sources by conventional methods such as pyrometallurgy and hydrometallurgy has some disadvantages including high energy consumption and high utilization costs, the risk of environmental pollution, and public health threats. Due to the strict environmental regulations, especially in the field of toxic waste disposal and also with the cost of applying these rules, there is a need for new, environmentally friendly, and more effective technology for recycling wastes. In this discussion, the methods of electrical and electronic waste recycling, which include pyrometallurgy, hydrometallurgy, and biohydrometallurgy have been studied. Among them, bioleaching has been introduced as an effective, inexpensive, and eco-friendly method.