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In this research, a pseudo steady state model is developed based on the mass and energy balance equations to simulate conversion section of a styrene monomer production plant. The conversion section includes three radial flow reactors in series, equipped with inter stage coolers. Typically, dehydrogenation catalyst experiences deactivation due to loss and migration of promoters, and increasing temperature and steam flow rate are practical solutions to prevent production decay in the plant. In the first step, accuracy of the simulation results is proved against plant data. Since there are different paths to overcome catalyst decay and maintain production capacity at desired level, the main challenge is selection and sequence of manipulated variables to control production capacity considering minimum effort. In this research, a real time optimization strategy is proposed to calculate the optimal trajectory of manipulated variables to control production and selectivity at desired level based on the optimal control theory. The optimization results indicated applying obtained optimal trajectories on the system increases production capacity about 16.13%.

The main goal of this research is to investigate the CO2 solubility and regeneration of aqueous solution of methyl diethanolamine (MDEA) and monoethanolamine (MEA) mixed by 1,5-Diamino-2-methylpentane (DAMP) as absorption promoter. In the first step, the absorption capacity and rate of the solutions are experimented in an isothermal batch reactor at various MDEA to MEA ratios, and DAMP concentration. The CO2 cyclic capacity of solutions is investigated by performing CO2 absorption at 30 °C and solvent regeneration at 70 °C. Then, the effect of DAMP concentration on the boiling point, density, mass loading and pH of aqueous mixture of MEA and MDEA is analyzed. The experimental results show that increasing DAMP concentration in the samples increases the absorption rate and capacity of base solution. The results of cyclic absorption and desorption tests show that there is not a considerable difference between cyclic capacity of the base and promoted solutions at 70 °C.

This work evaluates the efficiency of the aqueous mixture of Methyl Diethanolamine (MDEA) and Diethanolamine (DEA) at various mass concentrations to remove CO2 and H2S from natural gas in an industrial sweetening unit in Fajr Jam Gas Refining Company located in the south of Iran and gives recommendations for modifying the process. The sweetening unit includes absorber and desorption towers, flash drum, lean and rich amine exchanger, kettle type reboiler and a reflux drum. The considered process is simulated by Promax simulator (version 3.2) taking into account operational constraints and sustainability of the environment. The validity of simulation has been evaluated by comparison between simulation results and the plant data. The main objective of this work is the modification of natural gas sweetening unit to achieve lower energy consumption. Thus, the effect of amine circulating rate and MDEA to DEA ratio on steam consumption in the regeneration tower, CO2 and H2S concentration in the treated gas, and the acid gas loadings have been investigated. Therefore, substitution of DEA solvent in the unit with the aqueous mixture of DEA and MDEA is proposed. In the examined cases, the mass concentration of MDEA and DEA lies between 15 and 45 wt% and 0–30 wt%, respectively, with the reference cases having MDEA 0 wt% and DEA 31.6 wt%. The results show that in the proposed cases of alternative mixtures including cases 1 (MDEA15 wt% and DEA 30 wt%), 2 (MDEA 20 wt% and DEA 25 wt%), and 3 (MDEA 25 wt% and DEA 20 wt%) the amount of reduction in amine circulation rate are between 11.1%v/v and 19.4%v/v compared to the original amine circulation rate. Likewise, steam consumption decreases between 24.4 %wt/wt and 27 %wt/wt. Influence of anti-foam injection for the different cases were also studied and it was found that anti-foam with the concentration of 5000 ppmv is more suitable for the optimum operation and is a more cost effective.

The main goal of this research is modeling and real time optimization of an industrial steam methane reformer considering catalyst deactivation. In the first step, the reformer is heterogeneously modeled based on the mass and energy balance equations considering a detailed kinetic model. To prove the accuracy of developed model, the simulation results are compared with the available plant data at steady state condition. In the second step, based on the mechanism of catalyst deactivation, a first order decay model is proposed and the parameters of the model are calculated to minimize the absolute difference between calculated methane conversion and plant data. In the third step, an optimal control problem is formulated to maintain hydrogen production capacity at the desired level. Based on the formulated optimization problem, optimal dynamic trajectories of feed temperature and steam to methane ratio are calculated considering two strategies. Then, the performance of developed optimization procedure is proved considering furnace temperature and feed concentration as disturbance. The simulation results show that operating at the proposed optimal condition increases hydrogen production about 11.6%. In addition, the process emission performance defined as hydrogen to carbon dioxide ratio in the product is 6.72 and 7.03 at the conventional and optimized conditions, respectively.

The prediction of the mechanical behavior of metallic foams with realistic microstructure and the effects of various boundary conditions on the mechanical behavior is an important and challenging issue in modeling representative volume elements (RVEs). A numerical investigation is conducted to determine the effects of various boundary conditions and cell wall cross sections on the compressive mechanical properties of aluminum foam, including the stiffness, plateau stress and onset strain of densification. The open-cell AA6101-T6 aluminum foam Duocel is used in the analyses in this study. Geometrical characteristics including the cell size, foam relative density, and cross-sectional shape and thickness of the cell walls are extracted from images of the foam. Then, the obtained foam microstructure is analyzed as a 2D model. The ligaments are modeled as shear deformable beams with elastic-plastic material behavior. To prevent interpenetration of the nodes and walls inside the cells with large deformations, self-contact-type frictionless interaction is stipulated between the internal surfaces. Sensitivity analyses are performed using several boundary conditions and cells wall cross-sectional shapes. The predicted results from the finite element analyses are compared with the experimental results. Finally, the most appropriate boundary conditions, leading to more consistent results with the experimental data, are introduced.

In this paper, the evolution of elastic–plastic damage in the composite laminates under fatigue conditions is modeled. Continuum damage mechanics (CDM) has been coupled with the bridge micromechanics model to estimate the fatigue damage and life for laminated composite structures. Based on the elastic–plastic bridging model, three damage variables are defined. These variables estimate the fiber, matrix, and fiber/matrix damage response at the ply scale. To model the beginning of plastic deformation, a yield function is utilized, and evolution equations of the damage variables are obtained. Then the developed deformation plastic model is calculated. The model parameters are calibrated by experimental data. The proposed model is implemented in Abaqus by a subroutine. The capability of the developed model under multiaxial loading is investigated. The constitutive behavior of composite laminates in different conditions is compared with experimental data. The estimated fatigue life of the CDM-plastic damage approach for different layups is in accordance with the experimental data. Numerical results confirm the plastic deformation model leads to more accurate fatigue life prediction, especially in low‐cycle fatigue. Finally, a stochastic model is applied to predict the fatigue life of composite laminates. In the stochastic approach, fiber volume fraction, critical damage parameters, and mechanical properties are modeled as random variables with normal distribution. The stochastic model emphasizes the importance of variations of mechanical properties.

The main goal of this research is modeling and optimal control of ethylbenzene dehydrogenation reactors to obtain optimal dynamic trajectories of feed temperature and steam flow rate to achieve maximum process performance. In this regard, a pseudo dynamic model is developed for ethylbenzene dehydrogenation reactors based on the mass and energy balance equations considering catalyst deactivation. The process consists of three radial flow reactors, equipped with inter-stage heat exchangers to manipulate feed temperature. To develop an accurate model, a catalyst decay model is selected and the parameters of considered model is calculated based on the plant data. After model validation, a dynamic optimization problem is formulated to achieve maximum styrene capacity and uniform production level as objectives, considering feed temperature and inlet steam flow rate as decision variables. To calculate the optimal trajectory of decisions, a quadratic time dependent correlation is considered for each decision variable and optimal values of coefficients are determined based on the formulated optimization problem. The simulation results show that feed temperature and inlet steam flow rate should be increased gradually during the process run time. It is appeared that, production capacity is improved about 26.42% compared to the conventional condition.

The main objective of this study is modeling and optimization of methanol oxidation over iron-molybdenum oxide catalyst in a fixed bed reactor. The considered process is modeled based on the mass and energy balance equations at steady state condition. To verify accuracy of the proposed model and considered assumptions, the simulation results are compared with the plant data. Then, the effect of feed temperature, coolant temperature and air-to-methanol molar ratio on the reactor performance is investigated. In addition, considering formaldehyde production capacity and selectivity as objectives, a multi-objective optimization problem is formulated considering feed and coolant temperature, and air to methanol ratio as decision variables. Based on the developed mathematical model of the process and multi-objective optimization model, Pareto optimal front is obtained by non-sorting multi-objective genetic algorithm. Then, the single optimal point is selected from developed optimal Pareto front by TOPSIS decision-making method. The performance of the optimized reactor is compared with the conventional reactor at steady state condition.

This work demonstrates the fabrication of a carbon paste electrode containing NiO/CNTs modified with 1-methyl-3-butylimidazolium bromide as the binder (CPE/1-M-3BIBr/NiO/CNTs), and its applications related to the highly sensitive detection of carmoisine. The CPE/1-M-3BIBr/NiO/CNTs system was successfully utilized for the nanomolar determination of carmoisine at pH = 7.0. The CPE/1-M-3BIBr/NiO/CNTs successfully resolved the oxidation signals of carmoisine and tartrazine with a peak separation of 450 mV. This is the first time that an application of an electrochemical sensor for the simultaneous determination of carmoisine and tartrazine, two important azo dyes, has been reported. In addition, wide dynamic linear concentration ranges (70–650 μM for carmoisine and 0.1–750 μM for tartrazine), low detection limits (20 nM for carmoisine and 0.06 μM tartrazine) and excellent reproducibility were reported. The CPE/1-M-3BIBr/NiO/CNTs were successfully used for the analysis of carmoisine and tartrazine in dried fruit and soft drink samples.

In this study, the performance of industrial axial flow adiabatic reactors to produce styrene through ethylbenzene dehydrogenation on the potassium-promoted iron catalyst studied at steady state condition. The dehydrogenation reactors have been modeled heterogeneously based on the one-dimensional mass and energy governing laws and considering a detailed kinetic model. The catalytic and thermal kinetic models have been applied in the mathematical model of process. To prove the accuracy of the considered model and assumptions, the simulation results are compared with the plant data at the same process condition. Also, Genetic algorithm as a powerful method in the global optimization has been considered to maximize styrene production as the objective function. The inlet feed temperature to each reactor is selected as attainable decision variables due to severe effect of temperature on the equilibrium and kinetic constant. This configuration has enhanced styrene production rate by 1.2% compared to industrial adiabatic reactor.

This study investigated the effect of milk packet waste (Tetra Pak™) and maleic anhydride–grafted polyethylene (MAPE) on the physical and mechanical properties of wood–plastic composites. Tetra Pak was used in four levels (0, 10, 20, and 30%) and MAPE was applied in two levels (0 and 3%). The morphology of the samples was characterized using the scanning electron microscope technique. The results showed that adding Tetra Pak and MAPE to samples increased the flexural strength and modulus of elasticity and reduced 24-h water absorption and thickness swelling. The results were also confirmed by electron microscopy images.

The main goal of this research is to investigate absorption rate and capacity of carbon dioxide in aqueous mixtures of DAMP(1,5-Diamino-2-methylpentane)+MDEA(Methyl-diethanolamine), DAMP+MEA(Monoethanolamine), DAH(1,6-Diaminohexane)+MDEA and DAH+MEA in an isothermal stirred batch reactor. The experiments are designed in temperature ranging from 30 to 50 °C, at low pressure and various molar ratios. The results show that although there is an interaction between diamine and conventional amines at low diamine concentration, after a minimum absorption point, increasing DAMP and DAH concentration in conventional amines increases absorption capacity of solutions in all temperatures. Then, a rate equation is developed to predict absorption rate of aqueous solution of DAMP based on Zwitterion mechanism. The kinetic constant and order of reaction are determined considering the absolute difference between measured and predicted rate as the objective function. The results show that the reaction is first order with respect to amine concentration and third order in overall.

Thermolysis and air gasification are the best thermal alternatives to manage waste tires, which can cause a significant environmental impact. In this research, waste tire thermolysis and air gasification processes are modeled based on the thermodynamic framework. To determine the final product distribution, the Gibbs free energy function is minimized considering mass balance equations as equality constraints. To account the mass balance constraints in the objective function, the penalty method is used. To prove the accuracy of the developed model, predicted adiabatic temperature and product distribution through propane combustion and air gasification of a rubber-wood are compared with the reported data in the literature. Then, the effect of pressure, temperature and air to fuel ratio on the performance of thermolysis and gasification processes is investigated. Finally, the optimum condition of tire thermolysis and gasification are determined. The results show that maximum hydrogen efficiency in the pyrolysis and gasification process is 35.45% and 98.03%, respectively. The results prove performance of air gasification over thermolysis process to convert waste tire.

The main goal of this research is modeling and optimization of an industrial modified Claus process to achieve maximum sulfur recovery. The modified Claus process consists thermal conversion in furnace and catalytic conversion in two series fixed bed reactors. The furnace and catalytic reactors are modeled based on the mass and energy conservation laws at steady state condition. To prove the accuracy of the developed mathematical model, simulation results of conventional process are compared with the available plant data. Then, the optimal condition of Claus process is calculated considering sulfur recovery as the objective function using Genetic algorithm as a useful method in global optimization. The attainable decision variables are inlet temperature of furnace and fixed bed reactors, feed distribution along the furnace and flow rate of air in the furnace. The simulation results show that sulfur recovery is improved about 4.63% in the optimized process compared to the conventional process. In addition, performance of auto-thermal reactor as a substitute for conventional adiabatic reactors is investigated to enhance sulfur recovery and reducing sulfur contaminants emission in the Claus process.

A carbon paste electrode modified with 1-methyl-3-butylimidazolium bromide and CuO decorated single-wall carbon nanotubes (1-M-3-BIBr/CuO/SWCNTs/CPE) was utilized for nanomolar determination of amaranth in the presence of nitrite using square wave voltammetric (SWV) method. The structure of CuO/SWCNTs was investigated by SEM method. 1-M-3-BIBr/CuO/SWCNTs/CPE exhibited an enhancement in electro-oxidation current and active surface area. Also, 1-M-3-BIBr/CuO/SWCNTs/CPE exhibited indicated high catalytic activity toward the electro-oxidation of amaranth and simultaneous determination of it in the presence of nitrite. The 1-M-3-BIBr/CuO/SWCNTs/CPE achieved dynamic ranges 0.004–750 μM and 1.0–10,000 μM between the oxidation currents and the concentration of amaranth and nitrite, respectively. We obtained the detection limit of 1.0 nM and 0.5 μM for amaranth and nitrite, respectively. The 1-M-3-BIBr/CuO/SWCNTs/CPE was successfully applied to analysis of amaranth and nitrite in foodstuffs.

Crude oil is a mixture of hydrocarbons, dispersed water droplets, salt, and sediment in a continuous oil phase. Presence of natural surfactants, and applied drag forces on the dispersed water during the oil production, form a stable water-in oil emulsion. Although many demulsifier agents have been developed to break the crude oil emulsion, economic and environmental problems have limited their application. In this research, cellulose-based compounds are used as demulsifier due to their unique properties. They are biodegradable, non-toxic, and environmentally friendly. The efficiency of α-cellulose, microcrystalline cellulose, ethylcellulose at different viscosity grades, and the mixture of ethylcellulose and ethoxylated coco amine are investigated to break the crude oil emulsion through bottle test. According to the experimental data, although ethylcellulose is efficient to break emulsion, low dehydration rate is the main disadvantage of that agent. Moreover, to achieve the maximum dehydration capacity and rate, the optimal demulsifier formulation is obtained based on the experimental results. Finally, the effect of temperature, agent composition, and demulsifier concentration are evaluated on the dehydration capacity and rate of selected agents. The results show that the mixture containing ethylcellulose 46 mPa s and ethoxylated coco amine presents the higher dehydration rate and capacity.

Reliability analysis is very important in a practical engineering system. As these systems in space industry such as spacecraft and satellite are used to increase analysis accuracy, the system should be modeled carefully. Since the systems can impress the mission succession. In the real world, usually systems have multilevel performance and components have multimode failures. But often the binary-state model is used to determination of the reliability of the system. Although, the binary-state is simple and useful, so it cannot capture real states of a system. Therefore, calculation accuracy is decreased and mission risk is increased. Especially, if functions and operations in a mission or a system have a dependency, for example, the operations sequentially were occurred. The solar array mechanism is an important sub-system in a satellite, since if this system is failed, power generation may be stopped and satellite is failed. In this paper, a new method is proposed to model and assess reliability via the Universal generating function (UGF) for a solar array mechanism. The capability of this model for evaluation and determination of the reliability of the solar array mechanism as the multi-state system is shown, that subsystems/components work in a logical order or sequence. In comparison to Boolean algebra and crude Monte Carlo methods, the accuracy of this method is acceptable.

Compressive stress-strain behavior of open cell aluminum foam has been investigated using experimental and multiscale modeling methods. Mechanical behavior of cellular materials intensively depends on their microscopic structure and architecture which may degrade under loadings. To analyze the mechanical response of a full scale and complex aluminum foam component, one may develop multiscale modeling. In this way the degraded material properties are calculated through the analyses of a representative volume element (RVE) considering the micro-structural characteristic, architectural parameters and loading. In this study, open-celled AA6101-T6 aluminum foam is considered for the analyses. Geometrical characteristics of the foam using microscopic images are extracted, including thickness of cell walls, cell size, relative density and cross section of cell walls. The micro model is defined as RVE with nonlinear geometric and material behaviors considering the possible contacts between struts and it is conditioned on macroscopic quantity using appropriate boundary conditions. To validate the proposed model, different experiments have been performed for foam specimens with and without circular hole under compressive quasi-static loading. Finally, multiscale modeling has been proposed to analyze the foam components with complex and irregular shapes. It is shown that in order to model foams considering all the heterogeneities, even with larger size and having non-uniform stress field the use of currently existed finite-element and micro-structural models are not sufficient and the proposed multi-scale modeling which leads to acceptable results can be used for such analyses.

The effect of edible coating of gelatin (1, 2 and 3%) containing aqueous extract of rosemary (1% and 2%) on physiochemical (pH, total volatile nitrogen, peroxide values and water holding capacity) and microbiological (psychrotrophic) properties of duck fillet were evaluated. The pH of coated samples were significantly (plessthan0.05) lower than that of untreated sample. TVN (total volatile nitrogen) value increased with storage period in all the samples but coatings significantly decreased production of TVN compared to the control. Also the coatings decreased lipid oxidation of the meat as rosemary postponed primary oxidation of fillet, while this parameter in control group was sharply increased by time. WHC (water holding capacity) increased significantly (plessthan0.05) with storage period and level coatings. Coating had a significant reducing effect on growth of psychrotrophic bacteria during 9 days at 4°C. In conclusion, gelatin edible coating enriched with rosemary could retard chemical and microbial reactions related to spoilage of meat during refrigerated storage.

Mango (Mangifera indica) is one of the most important tropical fruits in the world. Twenty-two genotypes of native mangoes from different regions of southern Iran (Hormozgan and Kerman) were collected and analyzed for the ribosomal genes. GC content was found to be 55.5%. Fu and Li’s D* test statistic (0.437), Fu and Li’s F* test statistic (0.500) and Tajima’s D (1.801) were positive and nonsignificant. A total of 769 positions were identified (319 with insertion or deletion including 250 polymorphic and 69 monomorphic loci; 450 loci without any insertion or deletion including 35 Singletons and 22 haplotypes). Nucleotide diversity of 0.309 and a high genetic differentiation including Chi square of 79.8; P value of 0.3605 and df value of 76 was observed among mango genotypes studied. The numerical value of the ratio dN/dS (0.45) indicated a pure selection in the examined gene and the absence of any key changes. Cluster analysis differentiated the mango used in this research (M. indica L.) into two genotypes but could not differentiate their geographical locations. The results of this study indicated that a high genetic distance exists between HajiGholam (Manojan) and Arbabi (Rodan) genotypes and showed higher genetic diversity in mango of Rodan region. Results of present study suggested that for successful breeding, the genotypes of Rodan region mango especially Arbabi mango can be used as a gene donor and ITS can be a suitable tool for genetic evaluations of inter and intra species.

There is an urgent need to develop novel drugs for osteoporosis which occurs due to estrogen deficiency. Phytoestrogens derived from medicinal plants would be the best alternative to chemical drugs with harmful side effects. The main purpose of the present study was to investigate the effect of ferutinin compared to 17&beta, estradiol (E2) on bone mineralization of zebrafish larvae. Regarding the lack of publications, the histology analysis was performed after exposure to E2 to find effective treatment on bone mineralization of developing zebrafish larvae. Then, the larvae were exposed to four concentrations of ferutinin at three time points to assess the mortality, the expression of some related genes and histology of the ceratohyal and hyomandibular of treated larvae. The RT-PCR result of the treatment groups demonstrated the similar expression pattern in the larvae which were exposed to 1.25 &mu, g/mL of ferutinin and 2 &micro, M of E2 at 2 dpf, which confirmed the result of histology analysis. In addition, RT-qPCR of high concentration of ferutinin and E2 demonstrated that bmp2a/b and esr1 were downregulated and upregulated when the larvae were exposed to 5 &mu, g/mL of ferutinin and 10 &micro, M of E2, respectively.

Removal of selectable marker genes (SMGs) from genetically engineered (GE) plants is desirable because of the concerns about their probable negative effects on human health, other organisms and the environment. Different strategies are used to remove SMGs from GE plants including genome editing technologies. In this study, neomycin phosphotransferase II (nptII) selectable marker gene was successfully excised from the transgenic tobacco plants using CRISPR/Cas9 system. We relied on in planta transformation to surpass tissue culture procedure, which is costly and time-consuming. The plant leaves were agroinfiltrated by a Bean yellow dwarf virus (BeYDV)- based vector carrying Cas9 and sgRNAs designed based on the coding sequence of the nptII gene. After six days local and systemic leaves were collected and the presence of the viral vector and excision of nptII was checked using PCR. The presence of the virus in local and systemic leaves was detected. Also, excision of the nptII gene in local leaves was confirmed. Excision of the nptII sequence was significant in flower buds as a systemic tissue at flowering stage. Due to the systemic spread of the excising gene cassette, it is expected to have the nptII removed from the genome in the germlines, and thus, it is possible to have offspring free of the nptII gene. These findings present virus-base vectors as a promising method to edit plants genomes in planta.

Fault tree analysis is one of the most useful techniques in reliability analysis of multistate systems that analyze and handle complex systems via Monte Carlo simulations or mathematical approaches. Traditional fault tree cannot depict the exact evaluation of components and systems failures with respect to simplex analysis. On the other hand, the exact evaluation of system reliability with unknown data owning to components and elements is still difficult. Therefore, in this paper, in order to overcome this problem as for the quantitative analysis of fault trees, the reliability analysis of a multistate system (i.e. Launch Emergency Detection System) based on fault tree analysis and fuzzy failure rates is studied. Accordingly, using fuzzy arithmetic, events time-to-failure are generated and then the Top Event time to failure is calculated. Finally, the results of the analytical solution are compared with the results attained by presented approach and shows that, in spite of less effort and time consuming, this method has more accuracy and suitable for all real industrial and complex systems. This paper has further developed the method of FTA for the most generic case where both the system and the components have multiple failure states.

In this research, the performance of three ionic liquids namely Trioctylmethylammonium chloride, Trioctylmethylammonium bromide and 1-Hexadecyltrimethylammonium bromide are evaluated as the demulsifier agents to break crude oil emulsion through the bottle test method. Then, the response surface method (RSM) is applied to investigate the effect of demulsifier concentration, temperature, pH and fresh water ratio on the dehydration efficiency of the prepared agents. The experiments are designed based on the central composite design method (CCD). To find the optimum conditions of input variables, an accurate model is developed to predict the dehydration efficiency of agents based on the statistical testing of various models by the analysis of variance (ANOVA). The results shows that temperature and pH of aqueous phase are two main parameters in the demulsification process and the maximum dehydration is attained at neutral value of pH and nearly the maximum temperature in the all samples. Then, the optimum operating conditions of agents are determined by RSM.

The main aim of the present study is to develop a detail mathematical model to investigate the performance of an industrial electrostatic desalting process. The dehydration process consists of a mixing valve and an electrostatic coalescer drum. The equipments are modeled based on the population balance equation considering a detail circuit model in the coalescer drum. The electrode plates and crude oil emulsion are considered as a complex of parallel capacitors and dielectric material, respectively. To prove the accuracy of the model and assumptions, the outlet water cut from the coalescer drum is compared with the plant data. Then the effect of temperature, fresh water rate and current frequency on the strength of applied electric field on the emulsion, voltage decay, size distribution of water droplets and outlet water cut in the treated crude oil is investigated based on the developed model. The simulation results show that increasing current frequency from 50 to 300 Hz reduces water cut in the treated crude oil from 0.12% to 0.09%, respectively.

In this research, the efficiencies of two methods, including quantum dots (QDs) based photocatalysis and magnetic nanoparticles (MNPs) based adsorption for the decolorization of Victoria blue R (VBR) were investigated and compared, experimentally. Synthesis of functionalized zinc sulfide (ZnS) QDs and iron oxide (Fe3O4) MNPs was carried out by a simple chemical precipitation method. 2-mercaptoethanol (ME) and sodium dodecyl sulfate (SDS) were applied for capping and surface modification of ZnS QDs and Fe3O4 MNPs, respectively. The prepared nanoparticles have been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM). The mean particle size of ZnS QDs and Fe3O4 MNPs were approximated to be 1–3 nm and 50–80 nm, respectively. In the photocatalytic and adsorption investigations, influence of affecting parameters on the removal efficiencies was studied and optimized. According to the results, both methods can be considered as green, simple and efficient strategies for the removal of organic dyes. However, comparative investigation of the characteristics of the methods demonstrated that the efficiency of the QDs based photodegradation method for the removal of VBR is higher than MNPs based adsorption process. It was also found that the maximum decolorization of 95% and 65% can be achieved after 20 and 45 min at optimum pH 10, 7.5, in the presence of 8 and 10 mg of QDs and MNPs for 30 mg/L of VBR, respectively. Finally, isotherm adsorption model and photodegradation mechanism were discussed, too.

The aim of this study is to evaluate the impact of nano-SiO2 and bark flour (BF) on the natural fiber–plastic composites engineering properties made from high density polyethylene (HDPE) and beech wood flour (WF). For this purpose, WF and BF in 60 mesh size and weight ratio of (50, 0 %), (30, 20 %), (10, 40 %) and (0, 50 %) respectively were mixed with HDPE. In order to increase the interfacial adhesion between the filler and the matrix, the maleic anhydride grafted polyethylene was constantly used at 3 wt% for all formulations as a coupling agent. The nano-SiO2 particles with weight ratio of 0, 1, 2, and 4 % were also utilized to enhance the composites properties. The materials were mixed in an internal mixer (HAAKE) and then the bark and/or wood–plastic composite samples were made utilizing an injection molding machine. The physical tests including water absorption and thickness swelling, and mechanical tests including bending characteristics and un-notched impact strength were carried out on the samples based on ASTM standard. The results indicated that as the BF content increased in the composite, mechanical and physical properties were reduced, but the given properties were increased with the addition of nano-SiO2. The addition of nano-SiO2 had a negative impact on the physical properties, but when it was up to 2 %, it increased the impact strength.

The present study seeks to investigate the effect of beverage storage carton (Tetra Pak™) waste and maleic anhydride-grafted polyethylene (MAPE), coordinated to light polyethylene on the mechanical properties of wood–plastic composites. Four levels of Tetra Pak™ (0%, 10%, 20%, and 30%) and two levels MAPE (0% and 3%) were used. At first, the materials were mixed in a Haake internal mixer and then the samples were made through the injection molding method. The results showed that the composites containing 30% of Tetra Pak™ and 3% MAPE have the highest strength and tensile modulus. Moreover, the sample Tetra Pak™ and containing 3% of MAPE has the highest impact resistance. These results have been confirmed by scanning electron microscopy.

In this research, a conventional shell and tube reactor is supported by the hydrogen and vapor membrane tubes for water vapor removal and hydrogen permeation in the single step DME synthesis process. The proposed dual membrane structure is heterogeneously modeled based on the mass and energy conservation laws at steady state condition. To prove the accuracy of the developed model and assumptions, the simulation results of the conventional DME reactor are compared with the available data. Then, the performance and operability of the proposed structure is compared with the hydrogen membrane, water membrane and conventional reactors. The simulation results show that the DME production capacity in the dual membrane reactor is improved about 17.2% compared to the conventional process. Higher DME production rate due to shift the thermodynamic equilibrium limitations, and lower CO2 production are the main advantages of the proposed reactor.

This research focuses on carbon dioxide absorption using aqueous solution of 1,5-diamino-2-methylpentane (DAMP) in an isothermal batch reactor. Equilibrium CO2 loading by the proposed aqueous solution is measured at the temperature range 30–50 °C, CO2 partial pressure range 5–150 kPa, and different solvent concentrations. To prove the performance of the proposed diamine to capture CO2, absorption and desorption capacity, absorption rate and cyclic capacity of 1,5-diamino-2-methylpentan is measured and compared with MEA and MDEA. The experimental results show that the equilibrium CO2 loading of 1,5-diamino-2-methylpentane, MDEA and MEA are 0.86, 0.43 and 0.54 at 30 °C, respectively. Lower volatility of 1,5-diamino-2-methylpentane compared to MEA results in a lower solvent loss through CO2 removal process. Applying the proposed amine in the absorption towers can decrease solvent circulating rate and required equilibrium stages.

In this work, a simple, efficient and powerful photocatalytic methodology based on application of pure zinc sulfide (ZnS) quantum dots (QDs) is presented for the removal of naphthalene, as a model molecule of industrial pollutants. A facile room-temperature precipitation method was applied for the synthesis of ZnS QDs, in the presence of 2-mercaptoethanol as capping agents. The characterization of the prepared QDs was carried out by X-ray diffraction (XRD), transmission electron microscopy, high-resolution scanning electron microscopy, scanning tunneling microscopy, fluorescence, and UV–Vis absorption spectroscopies. The XRD investigations indicated that the prepared ZnS QDs are crystalline, with cubic zinc blend structure, with the average particle diameters of 1.2 nm. The fluorescence and UV–Vis absorption investigations showed a narrow and sharp emission band at 424 nm with a broad adsorption band around 235 nm. In addition, the prepared ZnS QDs were used as nanophotocatalysts, for the removal of naphthalene, as a model molecule. The influence of the experimental parameters on the removal efficiency of the ZnS QDs was studied. According to the results, the highest photocatalytic degradation of naphthalene in the presence of ZnS QDs (>95 %) was obtained at alkaline pH, in the presence of 10 mg of QDs, after a reasonable reaction time.

Membrane reactors are an advanced technology with vast application capacities for equilibrium limited endothermic reactions. The main propose of this study is to offer an optimized packed-bed membrane steam methane reforming (SMR) tubular reactor for sustainable CH4 conversion by implementing triple-objective optimization model based on optimum H2/CO ratio for low temperature Fischer-Tropsch (F-T) process. In this study a one dimensional pseudo-homogeneous model based on mass, energy, and momentum conservation laws is used to simulate the behavior of a packed-bed membrane reactor for production of syngas by SMR. In the optimization section, the proposed work explores optimal values of various decision variables that simultaneously maximize CH4 conversion, H2 selectivity, and CO selectivity by applying elitist non-dominated sorting genetic algorithm (NSGA-II). Pareto optimal frontier between triple objectives is obtained in three spaces and best optimal value is selected by using LINMAP, TOPSIS, Shannon's entropy and Fuzzy Bellman-Zadeh decision making methods. The final optimal solutions illustrate that the membrane reactor presents higher CH4 conversion which can be operated under milder conditions than the conventional reactor.

The main aim of present study is to develop a mathematical model to analyze the performance of an industrial gravitational coalescer to separate water from crude oil. The considered process consists of a mixing valve and coalescer tank that connected in series. Gravitational coalescer is a huge two-phase separator that separates free water from crude oil based settling time. In this research, the water removal from crude oil is simulated based on a two-dimensional model at steady state condition. The population balance method is used to predict drop size distribution in mixing and coalescence stages considering breakage and coalescence terms. To prove accuracy of the considered model and considered assumptions, the outlet water cut, water removal efficiency and salt content from gravitational coalescer are compared to plant data. Then, effect of temperature, fresh water rate, and mixing pressure drop is studied on water and salt removal efficiencies. The simulation results show that there is an optimum condition to maximize water and salt removal efficiency in desalting process.

A highly sensitive sensor based on a carbon paste electrode modified with a CdO nanoparticle and 1-methyl-3-butylimidazolium bromide was used for the voltammetric analysis of vitamin C in the presence of nicotin amide adenine dinucleotide. The highly sensitive sensor shows excellent enhancement and electrocatalytic activity towards vitamin C. The variation of pH shows the number of protons is equal to number of electrons for vitamin C electrooxidation. The electrooxidation peak current of vitamin C and nicotin amide adenine dinucleotide increased linearly with their concentration in the ranges of 0.07–480 μmol L− 1 vitamin C and 0.5–700 μmol L− 1 nicotin amide adenine dinucleotide. The limits of detection for vitamin C and nicotin amide adenine dinucleotide were 0.03 μmol L− 1 and 0.1 μmol L− 1, respectively. Simultaneous determination of vitamin C and nicotin amide adenine dinucleotide was investigated by using the square wave voltammetry technique. The proposed sensor showed good stability, sensitivity, selectivity, and reproducibility and can be used for some important food sample analyses.

This paper focuses on modeling and optimization of multi-stage spherical reactors to produce styrene through ethylbenzene dehydrogenation. A steady state heterogeneous mathematical model is developed based on the mass and energy conservation laws to predict the performance of the proposed configuration. For proving the accuracy of the considered model, simulation results are compared with available plant data. In optimization stage, the optimal feed temperature is calculated to maximize styrene production and minimize toluene and benzene production based on the multi-objective model and Pareto frontier curve. To achieve a single optimal point, the multi-objective model is converted to a single objective problem by weighted sum method. The simulation results show that styrene production is improved about 60000 kmole per year compared to conventional configuration. It is proved that lower pressure drop is one of main advantages of the proposed configuration.

The aim of present study is to develop a mathematical model to predict water and salt separation efficiencies in an industrial two stages crude oil desalting process. The considered process consists of mixing valve and electrostatic drums connected in series. The desalting plant is modeled based on the population balance method considering water droplet breakage and coalescence terms to predict droplet size distribution. The class method as a common mathematical technique is selected to solve population balance equation. The accuracy of the developed mathematical model and considered assumption is evaluated using taken data from an industrial desalting plant. Then, the effect of mixing valve pressure drop, flow rate of fresh water and strength of electric field is studied on the desalting and dehydration efficiencies. The simulation result shows that increasing flow rate of fresh water from 3% to 6% decreases salt content in the treated crude oil from 2.06 to 0.71 PTB.

The main objective of this research is improving the CO2 solubility in aqueous solution of MDEA by different polyamines including ethylenediamine (EDA), diethylenethriamine (DETA), thriethylenetetramine (TETA), tetraethylenepentamine (TEPA) at low pressure conditions. Since the polyamines have more than one basic nitrogen groups, they could absorb CO2 with higher rate and capacity compared to tertiary amines such as MDEA. In this regard, the performance of prepared solutions are experimented in an isothermal batch reactor in the temperature range of 293.15–313.15 K, promoter fraction ranged from 0 to 15%, and pressure range 0–200 kPa. The prepared solvents are evaluated in terms of CO2 absorption capacity, initial absorption rate and regeneration efficiency based on the number of ratio of secondary to primary functional groups in the promoter. The results show that increasing the promoter fraction in the prepared solution improves the absorption capacity and rate. Based on the experimental data, the higher CO2 solubility, absorption rate, the boiling point and lower vapor pressure are the main advantages of the TEPA promoted MDEA solution in addition to higher absorption capacity and effective loading.

Due to environmental limitations and issues, the main goal of this research is modification of conventional Claus sulfur recovery process to decreases sulfur contaminant emission. In this regard, two environmentally friendly alternatives are proposed based on the isothermal concept in reactors. Since Claus reaction is exothermic and reversible, the adiabatic fixed bed reactors in the catalytic section of Claus process are substituted by the isothermal reactors. The furnace and catalytic reactors are modeled based on the mass and energy conservation laws at steady state condition. To prove accuracy of the developed model, the simulation results of conventional process are compared with the available plant data. Then, the optimal condition of modified processes are calculated considering sulfur recovery as the objective function using the Genetic algorithm as a useful method in global optimization. The attainable decision variables are inlet temperature of furnace and reactors, coolant temperature, feed split fraction and air flow rate in the furnace. The simulation results show that H2S conversion in the proposed cases increases about 1.87 % and 1.78 % compared to the conventional process. Generally, the main advantages of proposed structures are higher sulfur recovery and lower sulfur contaminant emission such as COS and CS2 emission.

Objectives In this study, the mycosynthesis of silver nanoparticles was investigated using the endophytic fungi isolated from Taxus baccata L. (Iranian Yew). Methods Endophytic fungi were isolated from Taxus baccata L. (Iranian Yew) and were subjected to mycosynthesis of silver nanoparticles (AgNPs), extracellularly. The characterization of produced AgNPs was done using UV-V spectroscopy, TEM, and FTIR. Further antimicrobial activity of synthesized AgNPs was tested against Bacillus subtillis, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus sp., and Salmonella typhi, using the agar well diffusion assay method. To identify the fungal isolate, the ITS region was amplified by polymerase chain reaction (PCR), using universal primers ITS1 and ITS4. For obtaining closely related phylogenetic sequences, sequence analysis of ITS- rDNA was run using the BLAST algorithm of the NCBI database. Results The endophytic fungus, Nemania sp., was found to be a good producer of AgNPs. The surface plasmon resonance band in UV-Vis spectroscopy was at 460 nm, which confirmed the formation of AgNPs. The size range of the synthesized AgNPs was 5 to 70 nm, according to the TEM analysis. The FTIR study of AgNPs showed major peaks around 1035, 1392, 1514, 1644, 2922, and 3443 cm-1, which were responsible for different functional groups possibly involved in the synthesis and stabilization of AgNPs. Antibacterial activity showed maximum zone of inhibition of 17 mm against B. subtilis. Conclusions Nemania sp. can be a fungal system for extracellular mycosynthesis of AgNPs, which is a simple and ecofriendly method for nanoparticle synthesis.

The main goals of this research are dynamic operability and controllability analysis of the commercial isobutane dehydrogenation Oleflex process to produce isobutene. The process consists of three series moving-bed radial flow reactors that inter-stage furnaces have placed between reactors. The dehydrogenation reactors are modelled based on the mass and energy conservation laws considering a two-dimensional heterogeneous model. Isobutane dehydrogenation, hydrogenolysis, propane dehydrogenation and coke formation reactions have been considered in the kinetic model. To prove the accuracy of the considered model and assumptions, the simulation results are compared with plant data. The open loop sensitivity analysis is carried out to evaluate dynamic characteristics and operability of the process. Also, the process controllability is investigated considering the conventional feedback PI and PID controllers. The simulation results show that the conventional PID controller is capable to reject load and track set point.

In this research, a conventional steam methane reforming (SMR) reactor is modified to enhance CH 4 conversion and decreasing pressure drop considering membrane and distributed feeding policy. In the proposed structure, some feeding points are considered along the membrane reactor and steam is injected to the reactor through feeding nodes. It is demonstrated that a suitable distributed feeding policy improves performance of SMR process. The modified membrane reactor is modeled based on the mass and energy conservation laws. In the optimization section, the optimal rate of steam injection at considered nodes are calculated to maximize CH 4 conversion and minimize pressure drop based on the multi-objective optimization considering coke formation limitations. The elitist non-dominated sorting genetic algorithm is employed to obtain the Pareto frontier in two objective spaces. The single optimal solution is selected from Pareto frontier by the decision-making methods including Shannon Entropy, LINMAP and TOPSIS. The results show that as well as lower pressure drop and higher methane conversion, hydrogen production is improved about 18.09% in the optimized configuration based TOPSIS methods.

The aim of present study is development of a mathematical model to predict water and salt removal efficiencies in an industrial crude oil desalting plant at steady state condition. The considered desalting process consists of the mixing valve and AC electrostatic desalting drum that were connected in series. The mixing valve and desalting drum are modeled based on population balance method considering water droplet breakage and coalescence to predict the droplet size distribution. The class method as a common mathematical technique is selected to solve population balance equation. The accuracy of the developed mathematical model and considered assumptions are evaluated via industrial data from a desalting plant. Then, the effect of pressure drop in the mixing valve, flow rate of fresh water and strength of electric field on the desalting and dehydration efficiencies are assessed. The results show that electric field has a significant effect on the process efficiency, so increasing electric field strength from 1.0 kV/cm to 2.0 kV/cm improves water separation efficiency from 93.92% to 97.85%.

This article presents a study of 3D water entry problems by weakly compressible smoothed particles hydrodynamics (WCSPH) method. Water entry of prismatic wedges, circular cylinders and spherical bodies are presented. All cases are performed at a constant speed considering the effect of gravity. First-order density filter, turbulence modeling and a pressure filter are applied. Pressure distribution and free surface profiles are produced in all cases. For prismatic wedge water entry, computed results are compared against 2D BEM solution, but for circular cylinder water entries, the obtained results are compared against the VOF, analytical and experimental solutions. Furthermore, the obtained results for sphere water entry are compared against available experimental data. Favorable agreements are achieved in all the considered cases. It is demonstrated that the third dimension can affect the pressure distribution up to 50 % for the wedges and 40 % for the circular cylinders in the mid-length. Also, the spray height can be decreased nearly 30 % for a wedge and 50 % for a circular cylinder. Furthermore, the effect of deadrise angle of the wedge on the three-dimensionality effect is analyzed.

In this research, green and aqueous based synthesis routes were performed for chemical preparation of pure and transition metal ions doped ZnS quantum dots at room temperature. Doping of ZnS QDs by three transition metal ions (Mn2+, Co2+, Ni2+ ions) as dopants have been investigated by various techniques. In the optical absorption studies, a broad absorption band in the wavelength range of 280–300 nm clearly reveals quantum size effect in ZnS QDs. The crystal structure and the approximate size of QDs were measured by XRD pattern. The average particle size of QDs was found to be around 1–3 nm. In addition, the photocatalytic activities of the prepared ZnS QDs as their abilities to remove methyl violet (MV) cationic dye, as a model molecule, were studied. Effect of the experimental parameters, such as the type of dopant and the amount of QDs, pH of the initial dye solution, irradiation time, ionic strength of reaction media, and initial dye concentration on the decolorization efficiency (DE) of QDs as green nano-semiconductors were studied. The results demonstrated that doped QDS (for 5% of dopants) effectively bleached out MV, showing positive photocatalytic enhancement over pure ZnS nanoparticles.