Evaluation of the Mechanical Properties of Electroslag Refined Fe-12Ni Alloys

Three Fe-12Ni alloys, individually alloyed with small amounts of V, Ti, and Al, were manufactured through different melting techniques, with special emphasis on electroslag remelting, in order to achieve different levels of metal purity and associated costs. The relative effectiveness of these melting techniques was evaluated from tensile and slow bend fracture toughness behavior at 25 C and -196 C after tempering the test specimens at various temperatures. The best melting procedure was vacuum induction melting (VIM) with or without electroslag remelting (ESR). VIM+ESR is the recommended procedure since ESR provides increased yield of plate product, a reduction of overall manufacturing costs and, depending on the alloy composition, improved tensile and fracture toughness properties

Experimental on-stream elimination of resonant whirl in a large centrifugal compressor

Resonant whirl condition during operation of a multi-stage centrifugal compressor at higher than anticipated speeds and loads was reported. The condition was diagnosed by a large scale computerized Machinery Condition Monitoring System (MACMOS). This computerized system verified that the predominant subsynchronous whirl frequency locked in on the first resonant frequency of the compressor rotor and did not vary with compressor speed. Compressor stability calculations showed the rotor system had excessive hearing stiffness and inadequate effective damping. An optimum bearing design which was developed to minimize the unbalance response and to maximize the stability threshold is presented

भारत का उज्वल अतीत और अगले सहस्राब्दी की चुनौत्तियां

भारत का उज्वल अतीत और अगले सहस्राब्दी की चुनौत्तिया

The dependence of deep cloud mass flux and area cover on convective and large-scale processes

A framework has been developed that brings together the important physical parameters and processes governing the vertical mass flux in deep convective clouds and their area cover. The main result is a simple relation for the cloud mass flux and area fraction in terms of the large-scale radiative cooling, environmental stratification, and the extent of lateral entrainment of the ambient air by the convective systems. It is shown that the contribution of the moist processes to the total vertical mass flux in deep clouds can become comparable to that of the large-scale radiative component, and thus the neglect of these subsynoptic-scale processes can severely underestimate the convective activity. Further, it is argued that the consideration of moist processes is not merely a question of the inclusion of a correction factor in the relationship, but the uncertainty that needs to be overcome before meaningful predictions of deep cloud area cover can be achieved