Experimental Investigations on Electron Beam Welding of Austenetic/Ferritic Stainless Steel for Space Applications

Abstract Electron Beam Welding is one of the widely used processes in industries for joining dissimilar materials. The primary advantage of Electron Beam Welding is its high depth to width ratio which results in a very strong weld. The quality of weld depends upon the parameters, viz. Accelerating voltage, beam current, welding speed, focus current, vacuum level, etc. The primary objective of the study is to optimize the parameters so as to obtain the best quality of the weld for a chosen product. The experiments were designed based on Taguchi methods to minimize the number of iterations. Specimens were welded with different combinations of the parameters based on Taguchi's L9 Orthogonal Array and they were characterized using optical microscope. Based on the values of the depth of penetration the optimum parameters are reported. Multiple regression analysis and results of ANOVA depict that the beam current have maximum influence in determining the depth of penetratio

Micro-grid Concept for Coordinated Control of Renewable Energy Power Plants and a Way to Integrate with Main Grid

Even though research papers discussed increasing fossil fuel costs, it is proven in today's scenario. Therefore, it is confirmed that Renewable Energy (RE) technologies will take a primary role in generating electricity in this era. This has created real operational challenges for the grid operators. With technology transfer and new technology development, capacity building is potentially focused on through grants. The power system was preferred to have large inertia for its smooth operations. With the latest technologies and speedy responses, the modernized systems could create inertia by properly and instantly coordinating and controlling many small plants. Further, accurate prediction algorithms release stress by giving advanced information about the system. It is a new direction of modernized control, and it always starts with a small design. It then integrates with an extensive system through a supervisory control loop. These incorporated technologies are opening several new opportunities for RE-based technologies. The research on micro-grid was initiated about two decades ago. It has been developed parallel with the possible development of RE technologies and prediction algorithms. The recent hike in fossil fuel costs pushes the micro-grid-based RE power generation to the front. Accordingly, this paper presents the coordinated control of a few RE power plants, using a micro-grid concept while integrating the micro-grid with the primary grid through the supervisory control concept. The proposed idea is simulated using the EMTDC/PSCAD, and it shows an excellent result. Furthermore, it will become more attractive over expensive fossil fuel systems in this era.</p

The effect of dividend policies on wealth maximization – a study of some selected plcs

This research article examines how share value thus shareholders wealth is affected by dividend policies. This study seeks to analyze the effect of firm’s dividend policies on shareholders’ value of public companies in Nigeria, to empirically examine the linkage of dividend payout with information asymmetry, and to analyze the effect of various dividend policies on shareholders wealth. This study is based on survey design covers a one-year period with a sample of 10 quoted companies in the Nigeria stock exchange. In so doing, the methodology adopted is the Anova. This study shows the relevance of dividend and further proves that dividend policies of public limited companies influence the wealth of shareholders in Nigeria