Optimization of laser welding of tri – metal joint via response surface methodology

 Laser welding input parameters play a major role in determining the quality of a weld joint. In the nuclear power plants, hybrid structures of nickel and steel alloys offer an advantage in comparison to conventional materials, e.g. in heat exchanger tube areas. Due to demand in the nuclear industry for new material combinations based on commercially available and qualified materials, research into thermal joining of dissimilar materials has been initiated. The use of laser for joining mild steel / nickel with 316L austenitic stainless steel filler material and structures offers some advantages compared with usual thermal joining processes. The main aim is the control of phase formation, which occurs during thermal joining of mild steel to nickel. In this research work microstructure study and optimization of laser welding of mild steel / nickel sheets with wire feeding was done using Central Composite Design(CCD) and Response Surface Methodology (RSM) are used to build the mathematical model. By means of the laser power, welding speed and pulse width on the tensile strength model was developed and tested by analysis of variance method (ANOVA), the relationship between process parameters and output response and interaction among the process parameters are analyzed and discussed in detail. The scanning electron microscopes (SEM) with energy dispersive X-ray spectroscopy (EDS) technique were used for microstructure study of the bi-metal and tri-metal joints of the weld

Tris(2,4-di-tert-butyl­phen­yl) phosphate

The title compound, C42H63O4P, was isolated from the leaves of Vitex negundo. Two of the tert-butyl groups are disordered over two orientations with occupancy ratios of 0.57 (1):0.43 (1) and 0.67 (1):0.33 (1). Several intra­molecular C—H⋯O inter­actions are observed in the mol­ecular structure

Modelling of reaction between antioxidants and free radicals

Ph.DDOCTOR OF PHILOSOPH

Seamless Vertical Handoff using Invasive Weed Optimization (IWO) algorithm for heterogeneous wireless networks

AbstractHeterogeneous wireless networks are an integration of two different networks. For better performance, connections are to be exchanged among the different networks using seamless Vertical Handoff. The evolutionary algorithm of invasive weed optimization algorithm popularly known as the IWO has been used in this paper, to solve the Vertical Handoff (VHO) and Horizontal Handoff (HHO) problems. This integer coded algorithm is based on the colonizing behavior of weed plants and has been developed to optimize the system load and reduce the battery power consumption of the Mobile Node (MN). Constraints such as Receiver Signal Strength (RSS), battery lifetime, mobility, load and so on are taken into account. Individual as well as a combination of a number of factors are considered during decision process to make it more effective. This paper brings out the novel method of IWO algorithm for decision making during Vertical Handoff. Therefore the proposed VHO decision making algorithm is compared with the existing SSF and OPTG methods

1-(2-Bromo­acet­yl)-3-methyl-2,6-diphenyl­piperidin-4-one

In the title compound, C20H20BrNO2, the piperidone ring adopts a boat conformation. The phenyl rings are oriented at dihedral angles of 97.8 (2) and 96.0 (1)° with respect to the best plane through the piperidine ring. The dihedral angle between the two phenyl rings is 49.7 (1)°. In the crystal, bifurcated C—H⋯O hydrogen bonds form a R 2 1(7) ring motif, linking the mol­ecules into centrosymmetric dimers

Ethyl 4-hy­droxy-2,6-diphenyl-1-(2-thio­morpholino­acet­yl)-1,2,5,6-tetra­hydro­pyridine-3-carboxyl­ate

In the title compound, C26H30N2O4S, the thio­morpholine ring adopts a chair conformation whereas the tetra­hydro­pyridine ring is in a half-chair conformation. The dihedral angle between the two phenyl rings is 33.3 (2)°. A strong intra­molecular O—H⋯O hydrogen bond generates an S(6) motif. In the crystal, mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds, generating a ribbon-like structure propagating along the a axis

3′-(4-Chloro­benzo­yl)-4′-(4-chloro­phen­yl)-1′-methyl­spiro­[indoline-3,2′-pyrrolidin]-2-one

In the title compound, C25H20Cl2N2O2, the pyrrolidine ring adopts an envelope conformation and the best plane through the five ring atoms makes a dihedral angle of 87.03 (8)° with the indoline ring. Mol­ecules are connected by pairs of N—H⋯O hydrogen bonds into centrosymmetric dimers with an R 2 2(8) graph-set ring motif. C—H⋯O hydrogen bonds stabilize the crystal structure