Determination of pseudo-Goldstone boson-photon coupling by the differential time delay of pulsar signals

Pseudo-Goldstone bosons couple with photons through a P and T violating interaction of the form ${\cal {L_I}}=g_{a\gamma \gamma}~ a F\tilde F$. Strong magnetic fields in rotating compact stars induce a non-zero ${\vec E}\cdot{\vec B}$ outside the stellar surface which acts as a source for the pseudo-scalar field. Pulsar signals propagating through this pseudo-scalar `hair' suffer a differential time lag between the left and the right circularly polarised modes because of the P and T violating pseudoscalar boson-photon interaction. Determination of this time lag upto a microsecond accuracy can lead to a measurment of (or rule out) pseudo-Goldstone boson-photon coupling upto $g_{a \gamma \gamma}\leq 4.6 \times 10^{-9}~GeV^{-1}$.Comment: Plain TeX,12 pages,IP/BBSR/92-9

Residual Stresses in Heat Treatment

There are two kinds of stresses that an object may be subjected to: (a) Applied Stresses - which is due to external forces acting on the object. (b) Residual Stress - which remains in the object after all the applied forces have been removed. The basic cause of residual stress is non-uniform plastic flow due to previous operations. Some specific causes are heat treatment, welding, mechanical operations such as cold working, grinding & so on. Residual stresses must form a balanced force system within the object, which implies that a residual compressive stresses in one part of an object must be balanced by residual tensile stress in another part. Residual stresses may be harmful or beneficial. When tensile in nature, it adversely affects the fatigue prop-erties in particular & ductility in general. When it is compressive in nature, as for example, in carburizing or after induction/flame hardening, the fatigue properties improve. Another example of beneficial compressive stress is the steel reinforced prestressed concrete. Residual and applied stresses add algebraically, as long as their sum does not exceed the elastic limit. It is therefore necessary for a designer to know the level and nature of the residual stress so that he could prescribe safe levels of applied stress for an engineering component

Challenge in R&D Management : Tata Steel A Case Study

The purpose of R&D management is to promote innovation as well as wealth creation. The paper traces the history of R&D managementhow it has changed from the first generation when only innovation was the main objective to the fifth generation where IT plays an important role. It is now necessary to understand the needs of market for conducting worthwhile research. The author shares his experience of R&D management at Tata Steel. The experience shows that by adopting judicious R&D strategy it is possible to face the challenges of reconciling innovation with wealth creation is possible by a judicious R&D strategy