Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used

The Real Exchange Rate in India: Determinants and Targeting

This paper studies the behaviour of the real exchange rate (RER) in India. The first part investigates the role of important macroeconomic (behaviour and policy) variables in explaining the movement of the RER. It is found that the investment-gdp ratio, the overall fiscal deficit of the public sector and the nominal exchange rates are important explanatory variables. The second part of the paper seeks to determine whether real exchange rate targeting has been used in India as a tool in enhancing the competitiveness of the tradable sector. It is found that this is indeed the case, and moreover, the correlation between inflation and nominal devaluations is found to be small.

A New General Method to Generate Random Modal Formulae for Testing Decision Procedures

The recent emergence of heavily-optimized modal decision procedures has highlighted the key role of empirical testing in this domain. Unfortunately, the introduction of extensive empirical tests for modal logics is recent, and so far none of the proposed test generators is very satisfactory. To cope with this fact, we present a new random generation method that provides benefits over previous methods for generating empirical tests. It fixes and much generalizes one of the best-known methods, the random CNF_[]m test, allowing for generating a much wider variety of problems, covering in principle the whole input space. Our new method produces much more suitable test sets for the current generation of modal decision procedures. We analyze the features of the new method by means of an extensive collection of empirical tests