6,644 research outputs found

    Hypersonic static stability investigation of a Tomahawk 20-percent-scale model Technical report, 27 May - 2 Jun. 1966

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    Hypersonic static stability investigation of Tomahawk rocket mode

    A model of manufacturer-driven governing mechanisms and distributor performance

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    Drawing from relational exchange, dependence, and agency theories the authors explain that it is not only the type of governing mechanisms but also the proper sequencing of them that improves a manufacturer-distributor relationship and performance. Dependence affected relationship continuity positively. Monitoring affected the second order relational norm construct, comprising information sharing and flexibility, positively. Relational norm positively affected relationship continuity. Dependence, relationship continuity, monitoring, and relational norm affected distributor performance positively

    A comparison of regionalisation methods for catchment model parameters

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    International audienceIn this study we examine the relative performance of a range of methods for transposing catchment model parameters to ungauged catchments. We calibrate 11 parameters of a semi-distributed conceptual rainfall-runoff model to daily runoff and snow cover data of 320 Austrian catchments in the period 1987-1997 and verify the model for the period 1976-1986. We evaluate the predictive accuracy of the regionalisation methods by jack-knife cross-validation against daily runoff and snow cover data. The results indicate that two methods perform best. The first is a kriging approach where the model parameters are regionalised independently from each other based on their spatial correlation. The second is a similarity approach where the complete set of model parameters is transposed from a donor catchment that is most similar in terms of its physiographic attributes (mean catchment elevation, stream network density, lake index, areal proportion of porous aquifers, land use, soils and geology). For the calibration period, the median Nash-Sutcliffe model efficiency ME of daily runoff is 0.67 for both methods as compared to ME=0.72 for the at-site simulations. For the verification period, the corresponding efficiencies are 0.62 and 0.66. All regionalisation methods perform similar in terms of simulating snow cover

    Development of high energy density primary batteries First quarterly report, 22 Jun. - 21 Oct. 1965

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    Electrode and electrolyte studies for lithium- copper fluoride batterie

    Development of high energy density primary batteries Fourth quarterly report, 22 Mar. - 21 Jun. 1966

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    High energy density primary batteries for space flight applications - electrolyte systems, cell systems, and positive electrode constructio

    Development of high energy density primary batteries 200 watt hours per pound total battery weight minimum Final report, 10 Jun. 1964 - 9 Jun. 1965

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    High energy density lithium-anode primary cells developed with energy-to-weight ratios over 200 watt hours per poun

    Методические указания к самостоятельному изучению курса "Университетское образование" студентами-иностранцами

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    Методические указания разработаны в соответствии с программой учебного курса "Университетское образование" и составлена в соответствии с образовательной программой подготовительного отделения факультета международного образования, которая занимает важное место в системе подготовки кадров высших учебных заведений Украины. Методические указания рассчитаны на иностранных студентов подготовительного отделения ЗВО III-IV уровней аккредитации и содержат общие сведения об учебном курсе, тематический план и структуру курса, требования к уровню компетентности студентов, рекомендованную литературу по темам курса, темы практических занятий, образцы вопросов к тестовому и итоговому контролям, систему оценивания учебных достижений студентов

    Flood risk assessment and associated uncertainty

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    International audienceFlood disaster mitigation strategies should be based on a comprehensive assessment of the flood risk combined with a thorough investigation of the uncertainties associated with the risk assessment procedure. Within the "German Research Network of Natural Disasters" (DFNK) the working group "Flood Risk Analysis" investigated the flood process chain from precipitation, runoff generation and concentration in the catchment, flood routing in the river network, possible failure of flood protection measures, inundation to economic damage. The working group represented each of these processes by deterministic, spatially distributed models at different scales. While these models provide the necessary understanding of the flood process chain, they are not suitable for risk and uncertainty analyses due to their complex nature and high CPU-time demand. We have therefore developed a stochastic flood risk model consisting of simplified model components associated with the components of the process chain. We parameterised these model components based on the results of the complex deterministic models and used them for the risk and uncertainty analysis in a Monte Carlo framework. The Monte Carlo framework is hierarchically structured in two layers representing two different sources of uncertainty, aleatory uncertainty (due to natural and anthropogenic variability) and epistemic uncertainty (due to incomplete knowledge of the system). The model allows us to calculate probabilities of occurrence for events of different magnitudes along with the expected economic damage in a target area in the first layer of the Monte Carlo framework, i.e. to assess the economic risks, and to derive uncertainty bounds associated with these risks in the second layer. It is also possible to identify the contributions of individual sources of uncertainty to the overall uncertainty. It could be shown that the uncertainty caused by epistemic sources significantly alters the results obtained with aleatory uncertainty alone. The model was applied to reaches of the river Rhine downstream of Cologne

    Top-kriging - geostatistics on stream networks

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    International audienceWe present Top-kriging, or topological kriging, as a method for estimating streamflow-related variables in ungauged catchments. It takes both the area and the nested nature of catchments into account. The main appeal of the method is that it is a best linear unbiased estimator (BLUE) adapted for the case of stream networks without any additional assumptions. The concept is built on the work of Sauquet et al. (2000) and extends it in a number of ways. We test the method for the case of the specific 100-year flood for two Austrian regions. The method provides more plausible and, indeed, more accurate estimates than Ordinary Kriging. For the variable of interest, Top-kriging also provides estimates of the uncertainty. On the main stream the estimated uncertainties are smallest and they gradually increase as one moves towards the headwaters. The method as presented here is able to exploit the information contained in short records by accounting for the uncertainty of each gauge. We suggest that Top-kriging can be used for spatially interpolating a range of streamflow-related variables including mean annual discharge, flood characteristics, low flow characteristics, concentrations, turbidity and stream temperature
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