Sökning: "Parametrization"

Visar resultat 1 - 5 av 59 avhandlingar innehållade ordet Parametrization.

1. 1. Boundary Layer Parametrization in Numerical Weather Prediction Models

   Författare :Jacob Svensson; Gunilla Svensson; Michael Tjernström; Patrick Samuelsson; Stockholms universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Boundary-Layer Meteorology; Numerical Weather Prediction; Turbulence parametrization; COAMPS; IFS; meteorologi; Meteorology;

   Sammanfattning : Numerical weather prediction (NWP) and climate models have shown to have a challenge to correctly simulate stable boundary layers and diurnal cycles. This aim of this study is to evaluate, describe and give suggestions for improvements of the descriptions of stable boundary layers in operational NWP models. Two papers are included. LÄS MER

3. 2. Lithium-ion battery models for performance and aging

   Författare :Jing Ying Ko; Göran Lindbergh; Ulrike Krewer; KTH; []
   Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; Lithium-ion batteries; pseudo two-dimensional model; model extension; parametrization; aging; lifetime; Chemical Engineering; Kemiteknik;

   Sammanfattning : The demand for lithium-ion batteries (LiBs) is increasing at an exponential rate, so is the need to understand their behaviors and properties.In this pursuit, models are useful tools for improving cell design,quality, control system, keeping track of performance, aging andlifetime. LÄS MER

4. 3. Dynamic Security Region Assessment

   Författare :Marina Oluic; Mehrdad Ghandari; Bertil Berggren; Jovica V. Milanovic; KTH; []
   Nyckelord :ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; parametrization; power system transient stability; security boundary; short-term voltage instability; Voltage Impasse Region VIR ; parametrisering; spänningsimpassregion VIR ; spänningsinstabilitet; säkerhetsgräns; transient stabilitet i kraftsystem; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : Among a wide variety of topics that are covered by Dynamic Security Assessment (DSA), maintaining synchronous operation and acceptable voltage profiles stand out. These two stability categories are mostly jeopardized in the seconds after a large contingency occurs. LÄS MER

5. 4. Changes in near-surface winds across Sweden over the past decades - Observations and simulations

   Författare :Lorenzo Minola; Göteborgs universitet; Göteborgs universitet; Gothenburg University; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mean and gust wind speed; stilling-reversal phenomena; regional climate models; climate reanalyses; ERA5; parametrization; NAO; extratropical cyclones; surface roughness; Sweden;

   Sammanfattning : Driven by a combination of anthropogenic activities and climate changes, near- surface terrestrial winds displayed a large decrease in their magnitude in the past decades, named “stilling”, and a recent recovery in their slowdown. Understanding how wind has changed and identifying the factors behind the observed variabilities is crucial so that reasonable future wind scenarios can be constructed. LÄS MER

7. 5. Investigations of Reaction Cross Sections for Protons and 3He

   Författare :Mattias Lantz; Anders Ingemarsson; Livius Trache; Uppsala universitet; []
   Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Nuclear physics; reaction cross section; protons; 3He; experimental method; transmission method; optical model; parametrization; matter distributions; Kärnfysik; Nuclear physics; Kärnfysik;

   Sammanfattning : The reaction cross section gives the probability that a particle will undergo a nonelastic process when passing through a nuclear medium. Therefore reaction cross section data are of importance both for theoretical studies and for applications in such diverse fields as medicine, biology, astrophysics and accelerator-driven transmutation of nuclear waste. LÄS MER