440 research outputs found

    Alien Registration- Breil, Lydia M. (Scarborough, Cumberland County)

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    https://digitalmaine.com/alien_docs/20122/thumbnail.jp

    Tests with three-dimensional adjustments in the rectangular working section of the French T2 wind tunnel with an AS 07-type swept-back wing model

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    The results obtained on the AS 07 wing and the working section walls for three types of configurations are reported. The first, called non-adapted, corresponds to the divergent upper and lower rectilinear walls which compensate for limit layer thickening. It can serve as a basis for complete flow calculations. The second configuration corresponds to wall shapes determined from calculations which tend to minimize interference at the level of the fuselage. Finally, the third configuration, called two-dimensional adaptation, uses the standard method for T2 profile tests. This case was tested to determine the influence of wall shape and error magnitude. These results are not sufficient to validate the three-dimensional adaptation; they must be coordinated with calculations or with unlimited atmosphere tests

    The response of the regional longwave radiation balance and climate system in Europe to an idealized afforestation experiment

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    Afforestation is an important mitigation strategy for climate change due to its carbon sequestration potential. Besides this favorable biogeochemical effect on global CO2 concentrations, afforestation also affects the regional climate by changing the biogeophysical land surface characteristics. In this study, we investigate the effects of an idealized global CO2 reduction to pre-industrial conditions by a Europe-wide afforestation experiment on the regional longwave radiation balance, starting in the year 1986 on a continent entirely covered with grassland. Results show that the impact of biogeophysical processes on the surface temperatures is much stronger than that of biogeochemical processes. Furthermore, biogeophysically induced changes of the surface temperatures, atmospheric temperatures, and moisture concentrations are as important for the regional longwave radiation balance as the global CO2 reduction. While the outgoing longwave radiation is increased in winter, it is reduced in summer. In terms of annual total, a Europe-wide afforestation has a regional warming effect despite reduced CO2 concentrations. Thus, even for an idealized reduction of the global CO2 concentrations to pre-industrial levels, the European climate response to afforestation would still be dominated by its biogeophysical effects.</p

    Effects of combined sewer overflows on a periurban stream ecosystem: Methodological approach

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    International audienceHere we develop from a long term field experiment an assessment method of interstitial fauna resilience to combined sewer overflows (CSOs) effect. We address the case of small water courses for which the ratio of CSOs to natural flow can be 1 to much more. Biotic material was collected in the benthic and hyporheic layers. Biotic material focussed mainly on oligocheates species whose diversity, species category and abundance are resumed into metrics, called functional traits (FTrs), giving indications on flux dynamics and nutrient bio-assimilation capacity. The biotic resilience is assessed through the analysis of the response time of the biota to CSOs and natural flow characteristics, here called hydrological indices (HIs). In this aim, a series of hydrological indices are defined to reveal varying aspects of the dynamics of CSOs and natural flows. A main result is that CSOs can have both degrading and boosting effects on the biota of a stony stream. Some CSOs characteristics can explain the physical processes supporting these contrasting effects. In particular the geomorphic characteristics of the water course. Management perspectives emerge from the CSOs hydrological indices and resilience of the biota

    Linear and non-linear amplification of high-mode perturbations at the ablation fronts in HIPER targets.

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    The linear and non-linear sensitivity of the 180 kJ baseline HiPER target to high-mode perturbations, i.e. surface roughness, is addressed using two-dimensional simulations and a complementary analysis by linear and non-linear ablative Rayleigh–Taylor models. Simulations provide an assessment of an early non-linear stage leading to a significant deformation of the ablation surface for modes of maximum linear growth factor. A design using a picket prepulse evidences an improvement in the target stability inducing a delay of the non-linear behavior. Perturbation evolution and shape, evidenced by simulations of the non-linear stage, are analyzed with existing self-consistent non-linear theory
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