128 research outputs found

    Curie Point Pyrolysis Gas Chromatography

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    In Curie Point pyrolysis gas chromatography a ferromagnetic conductor in contact with the sample is heated inside a low volume glass capillary which is inserted into an rf coil with the carrier gas flowing through the capillary. The intrinsic properties of the conductor permit a self-control of the temperature to the Curie Point. The optimum wire diameter for a rapid warm-up is a function of the rf frequency. In order to have a fast temperature drop after cutting the rf field, small wire diameters are preferable. For such conductors relatively high frequencies are inherently necessary for a fast stabilization to the Curie Point. So far no differences in the self-controlled end-temperatures have been detected for wires of different origi

    Controlling the stability transfer between oppositely traveling waves and standing waves by inversion-symmetry-breaking perturbations

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    The effect of an externally applied flow on symmetry degenerated waves propagating into opposite directions and standing waves that exchange stability with the traveling waves via mixed states is analyzed. Wave structures that consist of spiral vortices in the counter rotating Taylor-Couette system are investigated by full numerical simulations and explained quantitatively by amplitude equations containing quintic coupling terms. The latter are appropriate to describe the influence of inversion symmetry breaking perturbations on many oscillatory instabilities with O(2) symmetry.Comment: 4 pages, 4 figure

    Jets opposing turbidity currents and open channel flows

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    Hydraulic jumps at the tail end of spillways are usually induced by baffle blocks or other obstacles. Such jumps can also be induced by jets that oppose the main flow. Another application is to back up turbidity currents in reservoirs by means of opposing jets. This measure can be adopted when transfer tunnels feed water into the reservoir at a higher elevation near the dam. Stopping the turbidity current increases the local sedimentation rate. To reconcile the shallow water equations for turbidity currents with those for open channel flows, massbased scales for the depth and velocity of both types of flows are outlined. The continuity and momentum equation for flows opposed by jets are then stated in terms of these scales and expressed by a single curve for both gravity currents and free surface flows. The corresponding results for free surface flows agree well with those of experiments carried out for this study. An application to turbidity currents is provided as well

    High-resolution measurement of the time-modulated orbital electron capture and of the ÎČ+\beta^+ decay of hydrogen-like 142^{142}Pm60+^{60+} ions

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    The periodic time modulations, found recently in the two-body orbital electron-capture (EC) decay of both, hydrogen-like 140^{140}Pr58+^{58+} and 142^{142}Pm60+^{60+} ions, with periods near to 7s and amplitudes of about 20%, were re-investigated for the case of 142^{142}Pm60+^{60+} by using a 245 MHz resonator cavity with a much improved sensitivity and time resolution. We observed that the exponential EC decay is modulated with a period T=7.11(11)T = 7.11(11)s, in accordance with a modulation period T=7.12(11)T = 7.12(11) s as obtained from simultaneous observations with a capacitive pick-up, employed also in the previous experiments. The modulation amplitudes amount to aR=0.107(24)a_R = 0.107(24) and aP=0.134(27)a_P = 0.134(27) for the 245 MHz resonator and the capacitive pick-up, respectively. These new results corroborate for both detectors {\it exactly} our previous findings of modulation periods near to 7s, though with {\it distinctly smaller} amplitudes. Also the three-body ÎČ+\beta^+ decays have been analyzed. For a supposed modulation period near to 7s we found an amplitude a=0.027(27)a = 0.027(27), compatible with a=0a = 0 and in agreement with the preliminary result a=0.030(30)a = 0.030(30) of our previous experiment. These observations could point at weak interaction as origin of the observed 7s-modulation of the EC decay. Furthermore, the data suggest that interference terms occur in the two-body EC decay, although the neutrinos are not directly observed.Comment: In memoriam of Prof. Paul Kienle, 9 pages, 1 table, 5 figures Phys. Lett. B (2013) onlin

    Religious socialisation and fertility: transition to third birth in the Netherlands

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    Although previous studies have demonstrated that religious people in Europe have larger families, the role played by religious socialisation in the context of contemporary fertility behaviour has not yet been analysed in detail. This contribution specifically looks at the interrelation between religious socialisation and current religiosity and their impact on the transition to the third child for Dutch women. It is based on data of the first wave of the Netherlands Kinship Panel Study (2002–2004) and uses event history analysis. The transitions to first, second and third birth are modelled jointly with a control for unobserved heterogeneity. The findings provide evidence for an impact of women’s current church attendance as well as religious socialisation measured by their fathers’ religious affiliation, when they were teenagers. A religious family background remains influential even when a woman has stopped attending church. The effects of religious indicators strengthen over cohorts. Moreover, the combined religious make-up of the respondent’s parents also significantly determines the progression to the third child.S’il est bien Ă©tabli que les croyants en Europe ont plus d’enfants que les autres, le rĂŽle de la socialisation religieuse dans le contexte de la fĂ©conditĂ© contemporaine n’a pas encore Ă©tĂ© analysĂ© Ă  ce jour. Cette Ă©tude s’intĂ©resse au lien entre la socialisation religieuse et la religiositĂ© actuelle, et Ă  leur impact sur la probabilitĂ© d’agrandissement de deux Ă  trois enfants de la descendance des femmes nĂ©erlandaises. Les donnĂ©es exploitĂ©es sont celles de la premiĂšre vague du Panel NĂ©erlandais d’Etude de la ParentĂ© (the Netherlands Kinship Panel Study, 2002–2004). A l’aide des techniques de l’analyse des biographies, les probabilitĂ©s d’agrandissement de rang 1, rang 2 et rang 3 ont Ă©tĂ© modĂ©lisĂ©es de façon conjointe, en contrĂŽlant l’hĂ©tĂ©rogĂ©nĂ©itĂ© non observĂ©e. Les rĂ©sultats mettent en Ă©vidence l’impact de la frĂ©quentation actuelle de l’église par les femmes et de leur socialisation religieuse, mesurĂ©e par l’appartenance religieuse de leur pĂšre quand elles Ă©taient adolescentes. Il apparaĂźt que la religiositĂ© du contexte familial exerce une influence, mĂȘme quand la femme ne frĂ©quente plus l’église, et que les effets des indicateurs de pratique religieuse se renforcent d’une gĂ©nĂ©ration Ă  l’autre. Enfin, l’appartenance religieuse conjointe des parents de la femme dĂ©termine significativement la probabilitĂ© d’avoir un troisiĂšme enfant

    Curie Point Pyrolysis Gas Chromatography

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    ISSN:0021-9665ISSN:1945-239

    Turbidity currents in an Alpine pumped-storage reservoir

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    Jets Opposing Turbidity Currents and Open Channel Flows

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