In this research work effect of the different engine loads, engine speeds, EGR rates and biodiesel ratio in biodiesel diesel fuel blend on the emissions and performance parameters of a 4stroke single cylinder diesel engine have been investigated. The RSM method has been used to optimize the EGR rate, biodiesel percent and engine working mode. The highest decrease in NO_xemissions while using the biodiesel and EGR has been 63.76% with B10 fuel blend and 30% EGR rate. The simultaneous usage of EGR and biodiesel reduced CO emission of the engine by 4.04, 12 and 1.73% for low, medium and high engine speed. The biodiesel was decreased the HC emission of the engine and so it compensated the increase of HC due to EGR. The highest reduction in HC emission levels while using EGR and biodiesel simultaneously, has been 54.05%. It is noticeable that the total amount of the smoke emission levels while using EGR and biodiesel did not change considerably. The optimized condition proposed by the RSM method has been 45.3% engine load, 2080 rpm engine speed, 14.97 % EGR rate and 5.43% biodiesel blend with diesel fuel.

The purpose of this study was to model and optimize the offline refinement operations of sugarcane harvester hydraulic oil using RSM. For this purpose, the effects of independent variables of operating hours (250, 500 and 750 hours), Twin Dip Filter Mesh (7, 9 and 11 microns) and hydraulic oil refining times (0, 1 and 2) on variables of water contamination, uncleanness level (NAS), silicon (Si), viscosity (Vis) and oil acid number (TAN) were evaluated. The results indicated that all models were suitable for water contamination, uncleanness level (NAS), silicon (Si), viscosity (Vis) and oil acid number (TAN) for describing experimental data. In addition, the desirability function showed that the optimum conditions for the offline refinement operations of the hydraulic oil of the sugar cane harvester included 728.61 operating hours, the 7-micron filter mesh, and the two refining times of the oil. Under this condition, the amount of water contamination, the uncleanness level (particles 5 to 15 micrometers), Vis, Si, and TAN were equal to 187.63 ppm, 234000, 5.91 ppm, 66.34 centistokes and 0.65 (mg KOH g-1), respectively.

Present study describes the approach of applying Response Surface Methodology (RSM) with a Pareto-based multi-objective genetic algorithm to assist engineers in optimization of sheet metal forming. In many studies، Finite element analysis and optimization technique have been integrated to solve the optimal process parameters of sheet metal forming by transforming multi objective problem into a single-objective problem. This paper aims to minimize the objective functions of fracture and wrinkle simultaneously. Design variables are blank-holding force and draw-bead geometry (length and Diameter). Response surface model has been used for design of experiment and finding relationships between variables and objective functions. Forming Limit Curve (FLC) has been used to define the objective functions. Finite element analysis applied for simulating the forming process. Proposed approach has been investigated on a cross-shaped cup drawing case and it has been observed that it is more effective and accurate than traditional finite element analysis methods and the ‘trial and error’ procedure.

Response surface methodology (RSM) is a collection of statistical and mathematical techniques for designing experiments, modeling, improving, and optimizing processes. The aim of the present study was to optimize osmotic dehydration process of Rosa canina L. fruit by RSM. For this purpose, the effects of independent variables including temperature (20, 30 and 40 ºC), concentration of osmotic solution (40, 50 and 60% w/w) and dehydration time (2, 3 and 4 h) on the responses or dependent variables including water loss (WL), solid gain (SG), and weight reduction (WR) were evaluated. The results showed that all models obtained for WL, SG and WR were suitable to describe the experimental data. Moreover, the desirability function showed that optimum conditions of osmotic dehydration process of Rosa canina L. fruit were osmotic solution temperature of 31.78 ºC, solution concentration of 60 (% w/w) and dehydration time of 3.59 h. Under these conditions, the amount of parameters of WL, SG, and WR were obtained to be 27.38, 3.53 and 23.85 g per 100 g of sample, respectively.

In this study, sesame as a dietary supplement and hydroxypropyl methyl cellulose (HPMC) due to its ability to form a gel network during heating, were added to rice flour for making the flat bread. In order to determine the optimal amounts of sesame paste (in the range of 10-20%) and HPMC (in the range of 0.5-1.5%), in product formulation using response surface methodology (RSM) and central composite design (CCD), five levels of these two variables were selected and 12 baking tests were performed. Three qualitative parameters in the product, including compression stiffness, overall consumer acceptance and penetration hardness, were evaluated as responses. According to the results, sesame paste significantly (P˂0.05) reduced the quality parameters and HPMC only slightly improved them. The mathematical models obtained in this study can accurately predict the responses. Correct matching between predicted responses and the results in optimized bread, containing 10.3% sesame paste and 1.5% HPMC, indicates the high capability of RSM to optimize the formulation of gluten-free products.

Solanum nigrum L. (SN) is a herbal plant indigenous to the north-east of Asia. The plant is believed to have various biological activities. In this study, the optimum conditions for the extraction of phenolic compounds from Solanum nigrum were determined using response surface methodology (RSM).
Extraction was carried out using different solvents in order to determine the best solvent for the highest extraction yield. Central composite design was employed to optimise the three independent variables such as incubation temperature (25–70 ºC), time (30–240 min) and liquid-to-solid ratio (10–20 ml/g). Total phenols (TP) was measured using Folin – Ciocalteu method and IC50 scavenging activity was analyzed using DPPH method.
The preliminary experiments with p The result of this study indicated the suitability of the response surface methodology employed in optimizing the extraction conditions. The optimized conditions showed a fast and high extraction yield of phenolic and antioxidant compounds from Solanum nigrum.

Apple is a valuable agricultural product that can be dried in the form of slices to create much added value in the economic landscape. In the present research, a laboratory hot-air channel dryer was employed for economic optimization of the drying process of red apple slices by means of response surface methodology (RSM). In the RSM technique, by designing experiments in which all independent parameters are changed simultaneously, the simultaneous effect of all parameters on the test output(s) was determined which provided a complete picture of how the parameters affect the test output for the researcher. For designing the experiment by means of RSM in this research, two parameters of temperature and velocity of air passing through the dryer channel were selected as independent variables and two parameters of drying time and energy consumption were chosen as target (response) variables for optimization. In order to design the experiments by RSM approach, the central composite design (CCD) method was used. Finally, by performing pre-designed experiments and using analysis of variance (ANOVA), the optimal drying conditions of red apple slices were determined as the passing air temperature equal to 70 °C and the passing air speed equal to 3 m/s, where the amount of energy consumption and the drying duration of validation test were 1.51 kWh (in comparison to predicted value of 1.36 kWh) and 46 minutes (in comparison to predicted value of 41 minutes), respectively.

Dairy sludge is one of the main and inexpensive wastes of the dairy industry, which contains the nutrients necessary for the growth of lactic acid bacteria (LAB) to produce microbial metabolites, and for its efficient use, optimization of fermentation conditions is critical. In order to optimize the production of dry biomass, three independent variables of dairy sludge concentration (5, 12.5 and 20%), pH (6, 7 and 8) and the inoculation rate of Lactobacillus fermentum strain 4-17 (1, 3 and 5%) were used. Before fermentation, the cell growth and morphology of this bacterium were examined in order to determine the function of the growth rate and confirm the presence of bacteria in this medium. The independent variables were optimized using response surface method (RSM) with central composite design (CCD) in order to maximize dry biomass production by this bacterium. The optimization results showed that the maximum amount of dry biomass production related to the optimal treatment included 20% dairy sludge concentration, 1% inoculation rate and pH 8. Also, according to the results, the dairy sludge substrate is suitable for the fermentation of this bacterium. As a result, the effect of dairy sludge bed concentration and pH on dry biomass production by this bacteria was very significant.

In this study dispersed deinked pulp (DIP) of Latif Company which includes a mixture of straw printers, mixed office waste (MOW) and mechanical recycle paper was used to investigate the effect of bleaching variables on pulp and paper properties. Six variables of bleaching process including the amount of hydrogen peroxide, sodium hydroxide, and sodium silicate, bleaching time, bleaching temperature and final pH were optimized in order to improve wet and dry tensile index of handsheet. Design Expert software was used for analyzing and modeling. Results in from of the central composite design (CCD) were investigated and response surface methodology (RSM) was modeled and analyzed. Optimized wet and dry tensile were obtained by appling 1.55% hydrogen peroxide, 1.55% sodium hydroxide and 1.55% silicate, 90 minutes bleaching time, 83 0C bleaching temperature, and final pH equal to 8.5. The result showed that bleaching variables affect significantly the optical properties sample as well as mechanical strength of paper, and also dry and wet tensile strengths can be improved by optimization of bleaching condition.