Search for dissertations about: "zone model"

Showing result 1 - 5 of 514 swedish dissertations containing the words zone model.

  2. 1. Effect of Hyporheic Exchange on Conservative and Reactive Solute Transport in Streams : Model Assessments Based on Tracer Tests

    Author : Karin Jonsson; Anders Wörman; Bernhard H. Schmid; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Earth sciences; conservative; hyporheic exchange; model; reactive; retention; solute; sorption kinetics; stream transport; temporal moments; tracer experiment; Geovetenskap; Earth sciences; Geovetenskap; Sedimentology; sedimentologi;

    Abstract : Understanding of the processes affecting solute transport in flowing water is important for the possibility to predict the evolution with time of polluted stream systems. This thesis presents tracer experiment methodology and model developments for solute transport in streams, with special focus on retention processes and their effect on solute stream transport. READ MORE

  4. 2. The Effective Convectivity Model for Simulation and Analysis of Melt Pool Heat Transfer in a Light Water Reactor Pressure Vessel Lower Head

    Author : Chi Thanh Tran; Tomas Lefvert; Harri Tuomisto; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; light water reactor; hypothetical severe accident; accident progression; accident scenario; core melt pool; heat transfer; turbulent natural convection; heat transfer coefficient; phase change; mushy zone; crust; lower plenum; analytical model; effective convectivity model; CFD simulation; Thermal energy engineering; Termisk energiteknik;

    Abstract : Severe accidents in a Light Water Reactor (LWR) have been a subject of intense research for the last three decades. The research in this area aims to reach understanding of the inherent physical phenomena and reduce the uncertainties in their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors, and to evaluation of the proposed accident management schemes for mitigating the consequences of severe accidents. READ MORE

  5. 3. Development, validation and application of an effective convectivity model for simulation of melt pool heat transfer in a light water reactor lower head

    Author : Chi Thanh Tran; Truc-Nam Dinh; Florian Fichot; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; light water reactor; hypothetical severe accident; accident progression; accident scenario; core melt pool; heat transfer; turbulent natural convection; heat transfer coefficient; phase change; mushy zone; crust; lower plenum; analytical model; effective convectivity model; CFD simulation.; Other physics; Övrig fysik;

    Abstract : Severe accidents in a Light Water Reactor (LWR) have been a subject of the research for the last three decades. The research in this area aims to further understanding of the inherent physical phenomena and reduce the uncertainties surrounding their quantification, with the ultimate goal of developing models that can be applied to safety analysis of nuclear reactors. READ MORE

  6. 4. Differential railway track settlement in a transition zone – Field measurements and numerical simulations

    Author : Kourosh Nasrollahi; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fibre Bragg grating sensors; dynamic vehicle–track interaction; heavy haul traffic; non-linear track model; 3MB slab track; Transition zone; empirical settlement model; condition monitoring;

    Abstract : In a transition zone between two different railway track forms, there is a discontinuity in track structure leading to a gradient in track stiffness. Examples include transitions between different superstructures, e.g., slab track to ballasted track, and/or between different substructures, e. READ MORE

  7. 5. Model Based Optimization of a Complete Diesel Engine/SCR System

    Author : Claes Ericson; Förbränningsmotorer; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MPC; model based optimization; real time models; model based control; SCR; optimization; EGR;

    Abstract : Achieving upcoming emissions legislation (Euro VI) for heavy trucks is a serious challenge for the manufacturers. Apart from the increasingly strict limits on nitrogen oxides (NOx) and particulate emissions (PM), the limited amount of fossil fuels as well as alarming climate changes simultaneously drives the demand for low CO2 emissions. READ MORE