Strain-cycling fatigue behavior of ten structural metals tested in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K)

Strain-cycling fatigue behavior of 10 different structural alloys and metals was investigated in liquid helium (4 K), in liquid nitrogen (78 K), and in ambient air (300 K). At high cyclic lives, fatigue resistance increased with decreasing temperature for all the materials investigated. At low cyclic lives, fatigue resistance generally decreased with decreasing temperature for the materials investigated. Only for Inconel 718 did fatigue resistance increase with decreasing temperature over the entire life range investigated. Comparison of the experimental fatigue behavior with that predicted by the Manson method of universal slopes showed that the fatigue behavior of these materials can be predicted for cryogenic temperatures by using material tensile properties obtained at those same temperatures

The strainrange partitioning behavior of an advanced gas turbine disk alloy, AF2-1DA

The low-cycle, creep-fatigue characteristics of the advanced gas turbine disk alloy, AF2-1DA have been determined at 1400 F and are presented in terms of the method of strainrange partitioning (SRP). The mean stresses which develop in the PC and CP type SRP cycles at the lowest inelastic strainrange were observed to influence the cyclic lives to a greater extent than the creep effects and hence interfered with a conventional interpretation of the results by SRP. A procedure is proposed for dealing with the mean stress effects on life which is compatible with SRP

Strainrange partitioning behavior of the nickel-base superalloys, Rene' 80 and in 100

A study was made to assess the ability of the method of Strainrange Partitioning (SRP) to both correlate and predict high-temperature, low cycle fatigue lives of nickel base superalloys for gas turbine applications. The partitioned strainrange versus life relationships for uncoated Rene' 80 and cast IN 100 were also determined from the ductility normalized-Strainrange Partitioning equations. These were used to predict the cyclic lives of the baseline tests. The life predictability of the method was verified for cast IN 100 by applying the baseline results to the cyclic life prediction of a series of complex strain cycling tests with multiple hold periods at constant strain. It was concluded that the method of SRP can correlate and predict the cyclic lives of laboratory specimens of the nickel base superalloys evaluated in this program

the implications of phasing out free allowances

The allocation of free allowances for firms belonging to the carbon leakage list of the European Union Emissions Trading Scheme (EU ETS) was found to lead to substantial overcompensation, which is why some stakeholders recently have called for a phasing out of free allowances in the near term. This paper analyzes the consequences of phasing out free allowances in a dynamic two- period model when one group of countries unilaterally implements climate policies such as an emissions trading scheme. A carbon price induces firms to invest in abatement capital, but may also lead to the relocation of some firms. The social planner addresses the relocation problem by offering firms transfers, i.e. free allowances, conditional on maintaining the production in the regulating country. If transfers are unrestricted in both periods, then the social planner can implement the first best by setting the carbon price equal to the marginal environmental damage and using transfers to prevent any relocation. However, if transfers in the future period are restricted, it is optimal to implement a declining carbon price path with the first period price exceeding the marginal environmental damage. A high carbon price triggers investments in abatement capital and thus creates a lock-in effect. With a larger abatement capital stock, firms are less affected by carbon prices in the future and therefore less prone to relocate in the second period where transfers are restricted

Prices versus Quantities: The Impact of Fracking on the Choice of Climate Policy Instruments in the Presence of OPEC

This paper analyzes the impact of declining extraction costs of shale oil producers on the choice of the policy instrument of a climate coalition in the presence of a monopolistic oil supplier such as OPEC. Shale oil producers' extraction costs represent an upper bound for the oil price OPEC can charge. Declining extraction costs ultimately limit OPEC's price setting behavior and thus impacts the optimal climate policy of the climate coalition. A pure cap- and-trade system is weakly welfare-inferior relative to a carbon tax for the climate coalition. While high extraction costs allow OPEC to appropriate the whole climate rent in case of quantity regulation, declining extraction costs imply OPEC to capture only a part of the climate rent. A carbon tax always generates positive revenue and thus is welfare-superior in general. However, low extraction costs prevent OPEC from exerting its market power, leading the climate coalition to implement the Pigouvian tax in the first place. Both market-based instruments are equivalent in this case. Complementing a quota with a base tax cannot outperform a pure carbon tax

Produção de mudas de videira em regiões tropicais e subtropicais do Brasil.

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