Essays about: "atmospheric dispersion"

Showing result 1 - 5 of 10 essays containing the words atmospheric dispersion.

1. 1. Inverse Atmospheric Dispersion Modeling in Complex Geometries

   University essay from Umeå universitet/Institutionen för fysik

   Author : Charlie Pelland; [2022]
   Keywords : atmospheric dispersion modeling; dispersion modeling; invers dispersion modeling; atmospheric dispersion; invers atmospheric dispersion; CFD; computational fluid dynamics; radioactive release; openfoam; CRBN; dry deposition; dry deposition velocity; scavenging effect; wet deposition; optimization model; Reynolds Averaged Navier-Stokes; adjoint mode; time-dependent rain simulation; time-dependent rain; time dependent rain simulation; time dependent rain;

   Abstract : In the event of a radioactive release in an urban environment the consequent response mustbe swift and precise. As soon as first responders have correct information, they can make anaccurate risk assessment. However, if the position, release rate and time of the radioactiverelease is unknown it is hard to know how the pollutant will spread. READ MORE

3. 2. Evaluation of a stochastic model of coherent turbulent structures for atmospheric particle deposition applications

   University essay from Uppsala universitet/Luft-, vatten- och landskapslära

   Author : Andreas Eriksson; [2022]
   Keywords : atmospheric dispersion; particle deposition; k-epsilon; RANS; lagrangian particle model; stochastic particle model; OpenFOAM; SIMPLE algorithm; ABL; atmospheric boundary layer; neutral boundary layer; coherent turbulent structures;

   Abstract : In this thesis, we have evaluated a stochastic Lagrangian model for computing particle deposition rates with prospects to use for atmospheric deposition applications.  The model is one-dimensional and models the particle dynamics in the boundary layers near walls and obstacles by simulating the coherent turbulent structures and Brownian motion governing the wall-normal transport. READ MORE

4. 3. Comparison of intensified turbulence events in the Baltic Sea

   University essay from Uppsala universitet/Institutionen för geovetenskaper

   Author : Linnéa Hallgren; [2021]
   Keywords : turbulence; upper ocean; ocean mixing; parameterization;

   Abstract : Turbulence is important since it affects the exchange of momentum, heat, and trace gases between the atmosphere and the ocean. However, measuring oceanic turbulence is not straightforward and that is why parameterizations that describe turbulence events are important. READ MORE

5. 4. Kernel density estimators as a tool for atmospheric dispersion models

   University essay from Umeå universitet/Institutionen för fysik

   Author : Daniel Egelrud; [2021]
   Keywords : Particle model; LPELLO; kernel density estimation; field of concentration; post-processing;

   Abstract : Lagrangian particle models are useful for modelling pollutants in the atmosphere. They simulate the spread of pollutants by modelling trajectories of individual particles. However, to be useful, these models require a density estimate. The standard method to use has been boxcounting, but kernel density estimator (KDE) is an alternative. READ MORE

6. 5. Evaluation of white-light generation as possible seed for a mid-infrared optical parametric chirped pulse amplifier

   University essay from Lunds universitet/Fysiska institutionen; Lunds universitet/Kärnfysik

   Author : Chuang Lu; [2017]
   Keywords : nonlinear linear optics; ultrafast optics; Mid-infrared generation; near-infrared; Optical parametric amplification; Optical Parametric Chirped-pulse Amplification; supercontinuum generation; white-light generation; laser induced filamentation; Dispersion-scan; nonlinear propagation; Physics and Astronomy;

   Abstract : White-light spectra of different crystals, based on 1030-nm intense pump pulses have been investigated in order to derive a near-infrared seed for mid-infrared generation. Among ten crystals, YAG (yttrium aluminium garnet), KGW (potassium gadolinium tungstate) and YVO4 (yttrium orthovanadate) exhibit the most suitable properties for supercontinuum generation with high efficiency for spectral broadening as well as high tolerance to optical damage. READ MORE