Kahn Process Network (KPN) is a popular model of computation for describing streaming applications arising in media and signal processing. KPN is a collection of sequential processes that communicate through unidirectional unbounded fifos. The illusion of unbounded fifos has to be met with finite memory in real implementations. This could potentially lead to a violation of Kahn semantics, thereby resulting in "artificial deadlocks". In this paper we address this issue and present a runtime mechanism for early detection and resolution of such artificial deadlocks.

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Centrifugal pumps are being used widely for many applications throughout the world. Lot of work is been carried out on performance improvements, hydraulic vane and volute profiles due to which considerable increase in the efficiency is been observed. It is very difficult to carry out the experimental tests to study the boundary layer behavior and its effect on the performance of the pump. Boundary layer separation plays a very important role in causing the secondary flows in the vane passage which affect the fluid flow path resulting in loss of effective energy transfer to the fluid by vane. Due to the centripetal force acting on the flow due to the curved path of the vane passage, separation of the boundary layer on pressure surface happens well before as compared to the flow separation occurring on the stationary vane surface. At the suction surface the flow is more concentrated hence the flow separation is difficult to occur. In this paper theoretical study of boundary layer behavior on the vane pressure surface is done and separation point is computed to find the occurrence of secondary flows from the separation point. The effect of centripetal force using Dean's equation for velocity distribution over the boundary layer, boundary layer thickness, momentum thickness, displacement thickness and Schlichting's form factor is studied and results are plotted to see the variation of these parameters.

Kahn Process Network (KPN) is a popular model of computation for describing streaming applications. In a KPN model, processes communicate through unbounded unidirectional FIFOs. When theoretically unbounded FI-FOs are implemented using finite memory, artificial deadlocks can occur due to one or more FIFOs having insufficient sizes. Generally a system designer must be able to make a design time trade-off between execution time and memory usage, preferably using no more memory than required for obtaining a certain execution time. But it is practically impossible to decide at design time, FIFO sizes that are sufficient to run the application without any artificial deadlocks. Hence there is a need for runtime mechanism for handling the artificial deadlock situations in process networks. Existing mechanisms detect artificial deadlocks only after all KPN processes block. This results in excessive blocking of processes and an application that appears to 'hang'. In this paper we present an improved mechanism for early detection of artificial deadlocks and its implementation on ECLIPSE (Extended CPU Local Irregular Processing ArchitecturE), an application domain specific architecture.

The friction stir welding is a solid state welding in which welding takes place at a temperature below the melting point. This welding is also known as green technology welding as no harmful gases are generated, as well as fluxes are not formed. In this process joining of two dissimilar materials can be achieved. Through this welding one can overcome defects like porosity, solidification, cracks etc by selecting suitable wilding parameters. Present work investigates the effect of different tool pin geometries on mechanical properties of friction stir welded AA6061 and AA7075 alloys keeping the process parameters constant. The welding is carried with process parameters 1000rpm, 50mm/min and 5KN as tool rotational speed, welding speed and axial load respectively, and for four different pin geometries: (a) cylindrical pin, (B) triangular pin, (c) square pin and (d) hexagonal pin. The welded samples are characterized by mechanical properties like tensile strength and micro Vickers hardness test. By considering the both properties the hexagonal pin shown better characteristics under optimum process parameters.