Swedish Defence Research Agency

About: Swedish Defence Research Agency is a government organization based out in Stockholm, Sweden. It is known for research contribution in the topics: Radar & Laser. The organization has 1413 authors who have published 2731 publications receiving 56083 citations. The organization is also known as: Totalförsvarets forskningsinstitut.

Methodology for determination of 89Sr and 90Sr in radiological emergency: II. Method development and evaluation

Abstract: In this work a method for the determination of both 89Sr and 90Sr is presented. The method can potentially be used in radiological emergency and deliver results shortly after an incident. The method development was based on theoretical calculations of potential interferences from other fission products and how these could be discriminated when applying different chemical separation schemes. Validation was done on reactor coolant water containing short-lived fission products, and on a reference material. The results indicate that correct results of 89Sr and 90Sr can be obtained 4 and 9 days, respectively, after an incident.

Scenarios and sustainability: tools for alleviating the gap between municipal means and responsibilities in adaptation planning

Abstract: Adaptation to climate change often involves long-time frames and uncertainties over the consequences of chosen adaptation measures. In this study, two tools designed for assisting local decision-makers in adaptation planning were tested: socio-economic scenarios and sustainability analysis. The objective was to study whether these tools could be of practical relevance to Swedish municipalities and facilitate local-level climate change adaptation. We found that the municipal planners who participated in the testing generally considered the tools useful and of high relevance, but that more time was needed to use the tools than was provided during the test process.

Derivation of the viscous Moore-Greitzer equation for aeroengine flow

Abstract: The viscous Moore-Greitzer equation modeling the airflow through the compression system in turbomachines, such as a jet engine, is derived using a scaled Navier-Stokes equation. The method utilizes a separation of scale argument based on the different spatial scales in the engine and the different time scales in the flow. The pitch and size of the rotor-stator pair of blades provides a small parameter, which is the size of the local cell. The motion of the stator and rotor blades in the compressor produces a very turbulent flow on a fast time scale. The leading order equation, for the fast time and local scales, describes this turbulent flow. The next order equations produce an axisymmetric swirl and a flow pattern analogous to Rayleigh-Benard convection rolls in Rayleigh-Benard convection. On a much larger spatial scale and a slower time scale, there exist modulations of the flow including instabilities called surge and stall. A higher order equation, in the small parameter, describes these global flow modulations, when averaged over the small (local) spatial scales, the fast time scale, and the time scale of the vortex rotations. Thus a more general system of spatially global, slow time equations is obtained. This system can be solved numerically without any approximations. The viscous Moore-Greitzer equation is obtained when small inertial terms are dropped from these slow time, spatially global equations averaged once more in the axial direction. The new equations are simulated with two different simplifying assumptions and the results are compared with simulations of the viscous Moore-Greitzer equations.

Trajectory representation and landmark projection for continuous-time structure from motion

Abstract: This paper revisits the problem of continuous-time structure from motion, and introduces a number of extensions that improve convergence and efficiency. The formulation with a C2-continuous spline ...