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Lipase is used in the production of detergents, cosmetics, pharmaceuticals, flavour enhancers and foods. The lipase of yeast Yarrowia lipolytica can be used for production of important class of chemical intermediates in the pharmaceutical industry. Lipase production depends on media composition and environmental conditions. Y. lipolytica DSM 3286 strain was cultured on media containing different organic and inorganic nitrogen sources. Lipase production was investigated by measuring biomass and lipase activity was detected by ρ-nitrophenyl laurate (PNPL) spectrophotometric assay method at various times within a period of 7 days. In this study, the effect of different nitrogen sources was investigated on Y. lipolytica DSM 3286 lipase production. The maximal lipase production (34.7 U/ml after 48 h) was detected in medium containing yeast extract as nitrogen source. The optimum temperature and pH of the enzyme activity were 37 °C and 7, respectively. The final goal of this study is to develop and optimize lipase production by Y. lipolytica for use in pharmaceutical industry.

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In this paper, some applications of the Method of Least Squares (MLS) for the solution of various problems in electromagnetics engineering is briefly reviewed. Here, MLS is employed for the solution of various problems such as solution of equations, curve fitting to measured data, generalized Fourier coefficients, linear operator equations, inegro-differential equations, electrostatics and magnetostatics problems, boundary value problems (by the Least Square Boundary Residual Method LSBRM), design of impedance transformers and matching by step and tapered lines, optimum design of multihole directional couplers, coupled-line couplers, branch line couplers, ring couplers, analysis of wire antennas, antenna pattern synthesis, array synthesis and scattering. In this study, it becomes clear that MLS can be applied to devise effective numerical algorithms for the analysis and design of problems in the subject areas of radiation, scattering, antennas, microwaves, engineering mathematic, etc. Some papers and books published in the area of MLS applications for the analysis and design of problems in electromagnetics engineering are grouped and presented in references.

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The graphical technique for nonlinear circuits was described that enable us to optimize circuits to obtain maximum output power, maximum efficiency or minimum intermodulation. According to this method a high power amplifier in the Ka band was designed. Using a nonlinear model of the transistor, optimum slope for load-line was determined so that maximum power at the output was obtainable, then the output matching circuit was synthesized. Finally, the nonlinear network of the high power amplifier was analyzed by the harmonic balance method and the output load cycles were optimized by modification of the bias point or output matching network.

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  Parameter estimation of the nonlinear Muskingum model is a highly nonlinear optimization problem. Although various techniques have been applied to optimize the coefficients of the nonlinear Muskingum flood routing models, but an efficient method for this purpose in the calibration process is still lacking. The accuracy of artificial bee colony (ABC) algorithm is investigated in this paper to optimize the coefficients of nonlinear Muskingum model. The performance of this algorithm was compared with other optimization techniques. For evaluating the ability of the ABC algorithm, several statistical criteria such as sum of the square error, sum of the absolute error, mean absolute error and mean relative error were used in the present study. ABC is an intelligent algorithm, which can effectively overcome the prematurity and slowed convergence speed of the traditional evolution algorithms. It determines the best parameter values in terms of the sum of square residual between the observed and routed outflows. The simulation results show that the performance of ABC algorithm with the sum of the square of the deviations between the computed and observed outflows (SSQ) of 35.62 m3 s-1, the sum of the absolute value of the deviations between the computed and observed outflows coefficients (SAD) of 23.2 m3 s-1, the mean absolute errors between the routed and observed outflows (MAE) of 1.05 m3 s-1 and the mean relative errors between the routed and observed outflows (MRE) of 2.9% is comparable to those of other algorithms. Thus ABC provided an efficient way for parameter optimization of the nonlinear Muskingum model.

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Abstract

Research Subject: Sulfide removal from sour water is essential, before reuse or release of sour water into the environment. Regarding the high costs of traditional methods, biological removal can be used as a reliable alternative.
Research Approach: Biological sulfide removal from sour water was investigated in a batch reactor using Thiobacillus sp. as a dominant species of a mixed culture. A conceptual model was developed to describe the process of H₂S removal from sour water in the batch reactor. The model considers H₂S and O₂ transfer between liquid and gas phases, biological oxidation of H₂S to sulfate and elemental sulfur, and chemical oxidation of H₂S to thiosulfate in the liquid phase. The governing equations were derived using the principles of mass conservation and biochemical reactions. Several batch runs were performed to obtain experimental data on the variation of sulfide, sulfate, thiosulfate, and oxygen concentrations in the system as a function of time, and an algorithm was devised to use the method of Particle Swarm Optimization together with the numerical solution of the model equations to estimate biokinetic parameters. Additional batch runs under different conditions were performed to verify the accuracy of the model. These results indicated reasonable accuracy of the model to predict the performance of a batch reactor for the removal of H₂S from sour water. The novelty of this model is considering different pathways for sulfide oxidation which includes product selectivity.
Main Results: The maxim specific oxygen uptake rate (SOUR=OUR/X) is one of the most important parameters in the evaluation of the biological activity of the microorganisms. The calculated value for this parameter was almost constant (16 mg DO g^-1 VSS min^-1) during all sulfide oxidation tests indicating that the maximum specific oxidation capacity of the biomass is independent of substrate and biomass concentration. Results exhibited bacteria prefer to partially oxidized sulfide to elemental sulfur, however this preference is a function of dissolved oxygen and substrate availability.

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Land-use planning is a science that determines the type optimum of land-use through studying the ecological characteristics of the land as well as its socio-economic structure. The primary objective of this study is to evaluate the land-use and natural resources for future sustainable land planning using GIS. In this study, the Makhdoom’s systematic method was used to analyze the ecological and resources maps of the study area. At first, ecological capability maps of different land-uses including forest, agriculture, rangeland, environmental conservation, ecotourism and development of village, urban and industry were developed by overlaying geographical maps in GIS for the township. The final step of this study was the prioritization of land-uses considering the ecological and socio-economic characteristics of the study area using a quantitative model. The results indicated that the maximum area of proposed use was 39.30 % that was related to range and dry farmingand minimum area of proposed use was 3.3 % which was related to irrigation agriculture with range.

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Propane and butane that are the contents of LPG are separated from natural gas in the unit 107 of 5^th refinery of South Pars Gas Company (SPGC). The concentration of methyl mercaptan and ethyl mercaptan in the propane stream are 551 and 46ppm, respectively, and the concentration of these components in butane stream are 1218 ppm and 0.8%, respectively. In order to remove mercaptans from butane and propane, aqueous solution of sodium hydroxide with 15 to 20% wt. is used for the scrubbing. In this research, using the Petro-SIM software, which is a particular simulator for oil and gas industries, the units 113, 114, and 115 of 5^th refinery of SPGC are simulated. The results of the simulation are compared with the data of both experimental data and design documents, and they are goodly match. Then, using the software optimizer the operating parameters is optimized. The optimization results show that by increasing the extraction temperature in the unit of 115 up to 46 ° C, the concentration of mercaptan in the products can be reduced. The other independent parameters do not affect the final result of the process.

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In this study, the optimum combination of major factors affecting the acceptability of whey-based Ricotta cheese i.e. fat at three levels (0, 5, 10%), salt at three levels (0, 1, 2%), and starter culture at two levels (0, 3%) was determined in a complete randomized design method with a factorial experiment. Ricotta cheese trials made by mixing whey and milk in a ratio of 5:1 were then organoleptically judged on the basis of the main attributes such as color, flavor, texture, and overall acceptability. The collected data were then statistically analyzed using a seven point hedonic method. The results show that the addition of fat had a significant effect on all sensory attributes (p< 0.05). The incorporation of salt in the formulation also had a significant effect on flavor, color, and overall acceptability (p< 0.05) as well as on texture (p< 0.01), whereas the addition of starter culture had a significant effect only on texture (p< 0.01) and overall acceptability (p< 0.05). It was concluded that a combination of 5% fat, 2% salt, and 3% starter culture gains a higher score and could be recommended as the preferred formulation for Iranian consumers.

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Research subject: Superabsorbents are hydrophilic hydrogels that can accommodate large amounts of water in their three-dimensional structures and have wide applications in various sciences such as pharmaceuticals, medicine, and agriculture. These materials are hydrophilic polymers that are physically or chemically cross-linked. Conversion and swelling ratio of synthesized hydrogels are two counter effects. Therefore, determining the appropriate conditions for polymerization to achieve optimal properties and swelling rate of hydrogels is a challenge for researchers.
Research approach: In this study, optimizing the synthesis conditions of semi-interpenetrating poly (acrylic acid)/xanthan hydrogels, the response surface methodology (RSM) was used by Box-Behnken design (BBD). The variables of this method were the molar ratio of the cross-linking agent (X₁), the weight percentage of xanthan gum (X₂) as the reaction medium, and the amount of initiator (X₃), each of which was considered at three levels. The evaluated responses in RSM were the rate of polymerization conversion (Y₁) and the rate of swelling (Y₂) of the hydrogels in the water.
 
Main results: Based on the 17 experiments proposed by RSM (BBD), the cross-linker, xanthan gum, and initiator were combined and radical polymerization was performed into silicone molds at 65 ° C. The results of ANOVA analysis showed that the data error of this study was small and the coefficient of determination (R2) of both proposed models for the responses Y₁ and Y₂ was higher than 0.9. The 46 experiments proposed for the optimal point by RSM (BBD) with the desirability of more than 50% indicate the synthesis of hydrogels that have both a good conversion rate and an optimal amount of swelling. For example, by 13% of cross-linking agent, 0.043 g of initiator and 1% wt. the solution of xanthan, hydrogels with a 95% conversion rate, and 102% water uptake were prepared. These hydrogels can be used in a variety of fields, including the treatment of colored wastes in factories, agriculture, pharmaceutical systems, medical attractions, and more.

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Research subject: Saponin compounds have been considered as anti-cancer, antimicrobial, antifungal, anti-inflammatory, and antiviral activity agents. In addition, they are also used as foaming agents in some food industries. There are few studies for assessing the extraction of this substance, so far. The main purpose of this study is to assess and compare the extraction yield of Saponin by conventional extracting using solvent and super-critical fluid method.
Research approach: In the extraction with solvent, the effect of three independent parameters including mass of solid material, percentage of ethanol solvent, and time of extraction on process performance was investigated. Yield of extraction and Saponin concentration were considered as indexes for evaluating the process performance. In the super critical fluid extraction, the effects of extraction time, pressure, and temperature were investigated. In this method, carbon dioxide was used as super critical fluid and 80% ethanol was used as co-solvent. In order to design of experiment and process optimization, response surface methodology and central composite design was used.
Main results: In optimum condition of extraction with solvent, the mass of solid material, ethanol solvent percentage, and extraction time were 5.4 g, 77.5%, and 7 h, respectively. In this condition, the maximum efficiency of extraction yield of 1.12 mg of saponins per a gram of dry primary substance was obtained. The results indicated that time and solvent percentage were significant parameters.  Further, interaction between two factors of time and solvent percentage was significant. For supercritical fluid extraction, in optimum condition, extraction time, pressure, and temperature were 10 h, 400 bar, and 50 °C, respectively. Extraction yield in this condition was 20% more than the yield of conventional method. It is concluded that the supercritical fluid extraction method has higher performance than conventional method.

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Pinch technology used as a tool for energy calculation and target design in context of energy optimization. In 2004, After enthalpy-exergy analysis for Chahar mahal beet sugar factory and applying some changes in heat transfer system, the steam consumption per beet decreased by 34% compared previous year. To enhance the efficiency of energy utilization, pinch analysis was employed to get a better insight into the energy situation in 2004. Based on the results obtained, three tubular heat exchangers were added to the heat exchanging system at a position which by exergy analysis was founded tobe the best, The results showed that the steam consumption per unit weight of beet sugar decreased from 54% in 2004 to 46% in 2005.

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Lovastatin is a potent agent for lowering cholesterol of blood. Since one of the main reasons of mortality in developing countries is cardiovascular disease, which is caused by precipitation of fatty acid (especially cholesterol) in blood vessels; therefore diets containing lovastatin may prevent this type of disease. In this study, Lovastatin, monacolin K or competitive inhibitor of the HMG-CoA reductase (operative enzyme for cholesterol synthesis) was produced by submerged fermentation using Monascus purpureus PTCC5303. Seven chemical and nutritional parameters including maltose, peptone, MgSO4.7H2O, MnSO4.H2O, KH2PO4, thiamin and pH screened using Plackett Burman experimental design for monacolin production. Among different parameters, maltose and MgSO4.7H2O showed significant effect on biomass and monacolin production. The concentration of these agents were optimized using response surface methodology for lovastatin production in the shaker flask. The optimized medium contained 26 g/L maltose, 5 g/L peptone, 0.1 g/L MgSO4.7H2O, MnSO4.H2O 0.5 g/L, 4 g/L KH2PO4, Vitamin B1 0.1 g/L and pH 7. After 10 days of fermentation in the shaker flask with 130 rpm agitation and 30 ºC, we achieved maximum lovastatin production which was 63 mg/l.

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Abstract:
Research Subject: Superplasticizers can be synthesized in different ways. The aim of this study is to present a two-step method for the synthesis of polycarboxylate ether and to investigate the temperature change in synthesis. In the first stage synthesis, the main chain and in the second stage synthesis, the side chains are created.
Research Approach: The synthesis of the primary copolymer was done by mass method and free radical mechanism. FTIR analysis was performed to identify the functional groups formed according to the predictions and to reach the desired copolymer. Then the copolymer viscosity was determined as a parameter determining the progression of the main chain length and in the second step, polycarboxylate ether was synthesized by solution using an optimized AA copolymer. First, FTIR analysis was performed to confirm the structure and HNMR test was performed to confirm the final synthesis. Then, GPC test was performed to determine the characteristics of the synthesized ether polycarboxylate, including the average molecular weight of the polymer and the molecular weight distribution curve, and MW and PDI values ​​were reported. Finally, the slump test was performed to confirm the performance.
Main Results: With increasing the temperature of copolymer synthesis, the length of the main chain also increases and the intensity of this increase is higher at high temperatures, but on the other hand, temperatures higher than 70 ° C also caused the destruction of the copolymer, which was detectable in the form of viscosity reduction and discoloration of the solution. Therefore, the initial synthesis should be performed at 70 ° C for 8 hours. The synthesis of polycarboxylate ether with equal molar ratios and maintaining the same conditions and only at different temperatures showed that the best synthesis temperature is 70 ° C for 6 hours. By increasing the molecular weight of polycarboxylate ether, by increasing the side chain, a better slump and flow in concrete was created.

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Background: Prediction of future climate change is based on output of global climate models (GCMs). However, because of coarse spatial resolution of GCMs (tens to hundreds of kilometers), there is a need to convert GCM outputs into local meteorological and hydrological variables using a downscaling approach. Downscaling technique is a method of converting the coarse spatial resolution of GCM outputs at the regional or local scale. This study proposed a novel hybrid downscaling method based on artificial neural network (ANN) and particle swarm optimization (PSO) algorithm. Materials and Methods: Downscaling technique is implemented to assess the effect of climate change on a basin. The current study aims to explore a hybrid model to downscale monthly precipitation in the Minab basin, Iran. The model was proposed to downscale large scale climatic variables, based on a feed-forward ANN optimized by PSO. This optimization algorithm was employed to decide the initial weights of the neural network. The National Center for Environmental Prediction and National Centre for Atmospheric Research reanalysis datasets were utilized to select the potential predictors. The performance of the artificial neural network-particle swarm optimization model was compared with artificial neural network model which is trained by Levenberg–Marquardt (LM) algorithm. The reliability of the models were evaluated by using root mean square error and coefficient of determination (R²). Results: The results showed the robustness and reliability of the ANN-PSO model for predicting the precipitation which it performed better than the ANN-LM. It was concluded that ANN-PSO is a better technique for statistically downscaling GCM outputs to monthly precipitation than ANN-LM. Discussion and Conclusions: This method can be employed effectively to downscale large-scale climatic variables to monthly precipitation at station scale.

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Research subject: In recent decades, hybrid optimizations methods based on natural phenomenon have placed special position according to their capabilities in finding optimal solutions without expensive computational loads and disassociation on choosing initial points. Artificial Neural Network is used as one of the powerful tools of Artificial Intelligence for process simulation. The employment of the neural network in the modeling of m-Cresol alkylation process of with isopropanol as well as meta-heuristic methods in obtaining the optimal conditions for the catalyst and the reaction can prepare an effective step towards a high efficiency process.
Research approach: In the present study, the artificial neural network is applied to model alkylation of m‐Cresol with isopropanol process. In addition, the bee colony is employed in order to optimize the process yield. To verify its performance, the proposed method is used in prediction of the m‐Cresol conversion and Thymol selectivity of the alkylation process with isopropanol 120 data. In this process, the input variables are Weight Hourly Space Velocity (WHSV), pressure and temperature; m-cresol conversion and thymol selectivity are considered as the output variables of the neural network. Five hidden neurons are considered for the proposed neural network. 120 data is used to train the neural network. The meta-heuristic approach based on bee colony (BC) is applied to maximize the yield of the process.
Main results: The results confirm that the proposed method develops the accurate model with an R² value of greater than 97.5%. The maximum yield is obtained 28.9% by bee colony algorithm with adjustable variables that are WHSV of 0.062 hr^-1, the pressure of 1.5 bar and the temperature of 300^oC. In addition, in order to achieve the better performance of the optimization algorithm, the appropriate values of acceleration coefficient and population size are chosen 100 and 10 during the trial-and-error phase.

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Research subject: Nowadays, due to the prevalence of coronavirus and the increasing use of disinfectant solutions and gels, the use of glycerin has also increased dramatically. But the suggested processes in this field need to be optimized in terms of production and energy consumption.

Research approach: In this paper, the transesterification method has studied and simulated, during which vegetable oil is converted into biofuel, and glycerin is also produced as a by-product of this process. For this purpose, process simulation of a conventional unit with 5.5 m³/min feed has been done in Hysys. Also, due to the importance of equipping the transesterification reactor, by importing the necessary process information, this equipment has been simulated in COMSOL MultiPhysics and the effective parameters have been studied in order to optimize the of product conversion. After validation of model, to better understand the factors affecting the performance of the transesterification reactor, the effect of selected parameters first examined by one-variable at the time design of experiment approach.
Main result: Finally, it has been shown that the feed temperature and the flowrate both have significance impact on quantity and quality of product and while providing a model for calculating the amount of glycerol produced per unit of energy consumed, the effective parameters are optimized by the response surface method. In optimal conditions of the ratio of product production to energy consumption, the temperature value was 470.7 K and the feed flow rate was 0.586 m³/s. According to the gained results, it can be obtained by adjusting the flow rate in the optimal amount, using a preheater in the production processes of biofuels and glycerin can have a significant effect on the amount of products produced so that the optimal temperature for the output of this preheater is at least 470.7 K should be considered. In the current research an optimization scheme has been suggested which can be used for different Biodiesel-Glycerol production units with varies range of flowrate.
 

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Production of recombinant proteins such as β-NGF using prokaryotic hosts is the topic of many recent researches. However, bacterial cell culture media are cheaper than eukaryotic cell culture media, but in industrial production scale they are not cost effective at all for biotech companies. Therefore, survey to find inexpensive cell culture medium that bacterial cells not only can grow in it but also produce recombinant proteins is very important. In this study, for the first time date syrup and yeast extract mixture was used as an inexpensive medium. In RSM (response surface methodology) studies different concentrations of date syrup and yeast extract were used as carbon and nitrogen sources respectively. The results indicate that the 20 g/lit of carbon and 5 g/lit of nitrogen are optimum for bacterial growth. Also the data show that recombinant bacteria not only can grow but also can produce recombinant proteins such as β-NGF using this synthetic medium.

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Optimization of protein hydrolysate from head and arms of cuttlefish (Sepia pharaonis) was examined. For this purpose, response  surface  methodology  (RSM)  was  employed  to  investigate  the effects  of different  operating  conditions  on  hydrolysis  process  of  cuttlefish protein by the application of alcalase enzyme. A Box-Behnken design with three factors at three levels was used for hydrolysis optimization and to check any individual or interaction effects between the experimental factors. In this method, the effects of three independent variables, including temperature, pH and enzyme to substrate ratio, were investigated on hydrolysis rate as a surface response. The mathematical model showed a good fitness with experimental data. Optimum conditions for temperature, pH and enzyme quantity were determined as 54.33 ˚C, 8.49 and 1.97 %,  respectively, which caused nearly 14.5 % hydrolysis degree. Based on the lack of fitness factor which was not significant, it was deduced that the resulted model was capable of prediction at different studied levels of variables. In this study, in order to confirm the conditions that proposed by mathematical equation, the hydrolyzed protein was produced accordingly at which resulted in a 16.8% hydrolysis degree. This finding was according to the aim of present trial by producing a protein hydrolysate with maximum hydrolysis degree. Then the functional properties of protein hydrolysate powder from optimized conditions were measured. Functional properties of this protein powders indicated a good solubility, but weak levels of emulsifying and foaming capacities.