520 research outputs found
The determination of the global average OH concentration using a deuteroethane tracer
It is proposed to measure the decreasing global concentration of an OH reactive isotopic tracer, G sub 2 D sub 6, after its introduction into the troposphere in a manner to facilitate uniform global mixing. Analyses at the level of 2 x 10 to the -19th power fraction, corresponding to one kg uniformly distributed globally, should be possible by a combination of cryogenic absorption techniques to separate ethane from air and high sensitivity isotopic analysis of ethane by mass spectrometry. Aliquots of C sub 2 D sub 6 totaling one kg would be introduced to numerous southern and northern latitudes over a 10 day period in order to achieve a uniform global concentration within 3 to 6 months by the normal atmospheric circulation. Then samples of air of 1000 l (STP) would be collected periodically at a tropical and temperate zone location in each hemisphere and spiked with a known amount of another isotopic species of ethane, C-13 sub 2 H sub 6, at the level of 10 to the -11th power mole fraction. After separation of the ethanes from air, the absolute concentration of C sub 2 D sub 6 would be analyzed using the Argonne 100-inch radius mass spectrometer
Langley Full-scale Tunnel Investigation of the Characteristics in Yaw of a Trapezoidal Wing of Aspect Ratio 4 with Circular-arc Airfoil Sections
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Mesh considerations for finite element structural dynamic applications
Three factors relating to a finite element mesh and discretization scheme are discussed: the geometric accuracy of the node locations, the amount of warp of a quadrilateral shell element, and the directional biasing effect of similarly oriented triangular elements. These factors can have a significant effect on the accuracy of a finite element structural dynamic analysis. Two finite element models that illustrate these effects are described
Thoughts and considerations of women with bipolar disorder about family planning and pregnancy : a qualitative study
Keuzevrijheid in de Uitkeringsfase: Internationale Ervaringen
Meer keuzevrijheid in de uitkeringsfase is onderdeel van het maatschappelijke debat over mogelijke aanpassingen van het Nederlandse pensioenstelsel, aldus de Perspectiefnota van SZW (2016). Nederland is een van de weinige landen waarin deelnemers aan de tweede pijler hun pensioen volledig uitgekeerd krijgen in de vorm van een levenslange annuïteit. Wel bestaan er enkele keuzemogelijkheden, onder meer wat betreft de aanvangsleeftijd en het uitkeringsprofiel. Deelnemers aan kapitaalgedekte pensioenregelingen in andere landen hebben veelal meer mogelijkheden om (een deel van) het opgebouwde pensioenvermogen in één keer op te nemen. Nederland kan bij de aanpassing van het pensioenstelsel wellicht lessen trekken uit de ervaringen met keuzevrijheid in de uitkeringsfase van kapitaalgedekte pensioenen in andere landen
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