[Show abstract][Hide abstract] ABSTRACT: Drawbeads are often applied in the deep drawing process to improve control of the material flow during the forming operation. Drawbeads restrain the sheet from flowing freely into die cavity. This paper deals with analysis of effect of draw bead geometry in sheet metal drawing process. Finite element analysis of drawing of circular blanks into axi-symmetric hemispherical cup was done. Circular and rectangular drawbeads were introduced into the Finite Element models and their influence in distribution of strain and thickness were investigated. DYNAFORM and LS-DYNA, a commercially available explicit FEA code were used to model and analyze the forming process respectively. These outcomes are compared with experimental results. The numerical results were found in good agreement with the experimental results. Plastic strain and Von-Mises stresses produced by rectangular drawbeads are higher when compared with the use of circular drawbead. Due to its geometry rectangular drawbead bends and unbends the sheet four times and restrains the material more than circular drawbead.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 04/2012; DOI:10.1007/s13369-012-0276-4 · 0.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Biosorption using microbial cells as adsorbents is being seen as a cost-effective method for the removal of heavy metals from wastewaters. Biosorption studies with Phanerochaete chrysosporium were performed for copper (II), lead (II), and cadmium (II) to evaluate the effectiveness and to optimize the operational parameters using response surface methodology. The operational parameters chosen were initial metal ion concentration, pH, and biosorbent dosage. Using this method, the metal removal could be correlated to the operational parameters, and their values were optimized. The results showed fairly high adsorptive capacities for all the metals within the settings of the operational parameters. The removal efficiencies followed the order Pb > Cu > Cd. As a general trend, metal removal efficiency decreased as the initial metal ion concentration increased, and the results fitted the Langmuir and Freundlich isotherms well.
[Show abstract][Hide abstract] ABSTRACT: In this study, salt bath nitrocarburizing and oxidizing of 304, 316, 304L and 316L were experimented. The salt bath nitrocarburizing experiment was carried out at a temperature of 560 0 C and for a time period of 120, 150 and 180 minutes. The oxidation process was carried out at a temperature of 373 0 C and for duration of 60 minutes. Vickers' micro hardness and salt spray test were carried out for the above-mentioned stainless steels before and after diffusion hardening. It was found that salt bath nitrocarburizing effectively increases the hardness of stainless steels 304, 316 304L and 316L. From the microstructure of the nitrocarburized and oxidized specimens, the case depth was measured. The depth of diffusion layer could be attributed to the attraction between the alloying elements Molybdenum and Nitrogen. Also the corrosion resistance of nitrocarburized and oxidized steels is observed to be superior to the untreated specimens.