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.

Dynamical stabilization of the body centered cubic phase in lanthanum and thorium by phonon-phonon interaction

Abstract: A recently developed self-consistent ab initio lattice dynamical method has been applied to the high temperature body centered cubic (bcc) phase of La and Th, which are dynamically unstable at low temperatures. The bcc phase of these metals is found to be stabilized by phonon-phonon interactions. The calculated high temperature phonon frequencies for La are found to be in good agreement with the corresponding experimental data.

The Use of an Enhanced Eulerian Deposition Model to Investigate Nozzle Clogging During Continuous Casting of Steel

Abstract: Nozzle clogging caused by the build-up of non-metallic inclusions on ceramic walls is a serious industrial problem during continuous casting of steel. The current theoretical study uses the extended Eulerian model to predict the inclusion deposition rate in a submerged entry nozzle (SEN). The model considers Brownian and turbulent diffusion, turbophoresis, and thermophoresis as transportation mechanisms. First, the steel flow in a tundish was simulated using a three-dimensional CFD model. The obtained flow parameter in a SEN was then put into the Eulerian deposition model to predict the deposition rate of non-metallic inclusions. Thereafter, the deposition rates of different-size inclusions in the SEN were predicted and compared. The result shows that the steel flow is non-uniform in the SEN of the tundish. This leads to an uneven distribution of the inclusion deposition rates at different locations of the inner wall of the SEN. In addition, large size inclusions among the size of inclusions considered show a large deposition rate, due to the strong effect of turbophoresis.

Toxicity and Accumulation of Trinitrotoluene (TNT) and its Metabolites in Atlantic Salmon Alevins Exposed to an Industrially Polluted Water

Abstract: A pond in an industrial area in Sweden was selected to study adverse effects on salmon alevins from 2,4,6-trinitrotoluene (TNT)-contaminated water. Chemical screening revealed heavy contamination of TNT and its degradation products, 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT), ranging from 0.05 to 230 g/kg in the sediment (dry weight) within the water system. Pond water contained 3 mg/L TNT. A dilution series of pond water mixed with tap water revealed increased death frequency in alevins down to fivefold dilution (approximate 0.4 mg TNT/L). Uptake was concentration dependent, reaching 7, 9, and 22 μg/g tissue for TNT, 2-ADNT, and 4-ADNT at the highest test concentration. A time-dependent uptake of TNT and its degradation products was found at a water concentration of 0.08 mg TNT/L. Degradation products of TNT showed a more efficient uptake compared to native TNT, and accumulation of 4-ADNT was more pronounced during the late phase of the 40-d exposure study. Bioconcentration factors (BCF) (0.34, 52, and 134 ml/g for TNT, 2-ADNT, and 4-ADNT, respectively) demonstrated a significant uptake of the metabolite 4-ADNT in alevin tissue. Disturbed physiological conditions and delayed development in alevins were not studied, but may not be excluded even at 125-fold diluted pond water (0.016 mg TNT/L). BCF data indicated that bioaccumulation of TNT metabolites need to be considered in TNT chronic toxicity. Fish species and age differences in the accumulation of TNT metabolites need to be further studied.