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In recent years, aluminum, magnesium and titanium alloys are highly regarded in the aerospace and automotive industries due to their high strength to weight ratio and resistance to corrosion. The main problem of the use of these alloys is their low formability at room temperature. To solve this problem, the metal forming process is done at high temperatures. Since oil’s heat resistant temperature is not more than 300°c, other fluids such as air and nitrogen gas should be used in high temperatures. In this study, blow forming equipment at high temperatures has developed, and changing of AL6063 tubes cross-section from circular to square has investigated experimentally and compared with the results of the experiments at room temperature. After producing square products, thickness distribution, corner’s radius, forming pressure, and effect of pressure time in corner’s radius at different temperatures were compared and the location of bursting was also examined. The results indicated that by increasing temperature, formed radius and pressure time reduces significantly, so that the amount of radius decreases from 19.5 mm in the temperature of 25°c and 154 bar forming pressure, to 5.8 mm in the temperature of 500°c at 11 bar forming pressure. The results showed that by increasing time pressure, which causes to decrease velocity of process, the formed corners has been sharper. By investigating burst of specimens, bursting occurs in the area of converting circular cross section to square one, which has a high deformation and tensile strain.

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Hot metal gas forming is a process to form metals with low formability or high strength at room temperature such as aluminum, magnesium and titanium. With increasing temperature, the formability of these metals increases and the strength decreases. In this process, for producing parts with desirable properties, determination of optimal parameters is essential. In this study, hot metal gas forming process was simulated by using Abaqus software, and the influences of input parameters on the outputs were evaluated with simulation results. In order to validation of simulation results, the experimental test was carried out by using hot metal gas forming setup. For modeling hot metal gas forming process, an artificial neural network in Matlab software were trained by using data obtained from the numerical simulation. In this neural network, pressure, axial feeding and time were assumed as input parameters and the radius, minimum and maximum thickness were considered as output. In the next stage, this model was implemented as input function in multi-objective genetic optimization algorithm to obtain Pareto front and the optimum process parameters. Obtained optimum parameters include: pressure 13.07bar, axial feeding 0.78mm and time 65.73s and the values of corner radius, minimum and maximum thickness obtained from the optimum parameters are 5.49mm, 0.92mm and 1.57mm respectively.

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Fungal spoilage plays an essential role in the deterioration of food and in the creation of foodborne disease. In addition, the production of various mycotoxins by fungi can cause serious dangers such as carcinogenic, teratogenic, immunotoxic, neuromastoxic, toxic dead, mycotoxicosis and Kashin Beck disease. On the other hand, despite the increasing resistance of molds to synthetic preservatives, that may produce carcinogenic nitrosamine, no effective strategy has been proposed to safely reduce of microbial growth for public health. Therefore, due to the safe and probiotic properties of the lactic acid bacteria that have been approved (GRAS and QPS), can be used as natural preservatives to prevent fungal spoilage of food. The ability to prevent and inhibitory fungal spoilage by lactic acid bacteria is mainly due to the production of antimicrobial compounds such as organic acids, fatty acids, hydrogen peroxide, phenyllactic acid, cyclic delpeptide, proteinaceous compounds, diacetyl, bacteriocin and reuterin. Also, the most important inhibitory mechanisms of lactic acid bacteria against fungal corruption include membrane  destabilization, proton  gradient interference,  enzyme  inhibition,  and  creation  of  reactive  oxygen  species. Therefore, in this paper, it has been tried to overview of antifungal metabolites and their chemical structure, inhibitory mechanisms and probiotic properties of the lactic acid bacteria.

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Masske butter or butter derived from yogurt is a traditional butter used in southern Khorasan with a wide range of lactic bacteria. The aim of this study was to investigate the antibacterial effect of lactate isolates against of Staphylococcus aureus and Salmonella enterica. In this research, lactic isolates were first detected by PCR method, and then microdilution method was used to evaluate the antimicrobial activity of the isolates. BLAST of sequences of S16 rDNA gene with sequences stored in the NCBI database led to the identification of the genus Lactobacillus bulgaricus, Enterococcus faecium, Lactobacillus plantarum, Lactobacillus fermentum, Lactobacillus delbrueckii and Enterococcus hirae. The results of antimicrobial activity evaluation against Staphylococcus aureus and Salmonella enterica bacteria showed that all isolates were able to inhibit the growth of these two pathogens, and their inhibitory percent from 55/46 to 84/49 and from 55/46 to 56/55 respectively was variables. Also, the results showed that Lactobacillus plantarum B38, Enterococcus hierae B224, Lactobacillus delbrueckii B37 had the highest inhibitory effect against Staphylococcus aureus (P>0.05) and Lactobacillus plantarum B38 showed the highest percentage of inhibition against Salmonella enterica (P<0.05). In addition, it was found that the inhibitory effect of all isolates against Staphylococcus aureus was significantly higher than Salmonella enterica (P< 0.05). Therefore, lactic acid bacteria isolated from the Masske butter can be used to control the food borne pathogens and food spoilage microorganisms.
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Norbixin is the water-soluble part of anatto natural pigment which has healing, anti-cancer and antioxidant properties. The aim of this study was to evaluate the antimicrobial effect of commercial Norbixin 1% (widely used in the food industry) on Clostridium sporogenes, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Bacillus licheniformis. In this study, two methods of Well diffusion and Disk diffusion were used to evaluate the antimicrobial effect of Norbixin (1%) at concentrations of 2, 4, 6 and 8%. The results of the Well method showed that Staphylococcus aureus with 22.74 mm and Clostridium sporogenes with 14.44 mm have revealed the highest and lowest sensitivity, respectively. The results of Disk method showed that the highest mean diameter of Norbixin inhibitory in all tested concentrations is attributed to Listeria monocytogenes with mean diameter of 19.09 mm and then is related Staphylococcus aureus at a concentration of 4% with a diameter of 18.21 mm. It was also observed that in the Disk diffusion method, Norbixin was able to prevent the growth of Escherichia coli (9.09 mm) at concentrations of 4 and 8%. Accordingly, it was found that Norbixin has an inhibitory effect on both gram-positive and gram-negative bacteria, and this effect on gram-positive bacteria was more than gram-negative. Therefore, due to the disadvantages of synthetic preservatives and the unique properties of commercial Norbixin pigments such as natural and safe, having antimicrobial and therapeutic properties as well as good thermal resistance (because of apocarotenoid structure during processing), this pigment can be used as a natural antibacterial preservative and health-giving properties in various foods.