Search for dissertations about: "Reduction technique"

Showing result 1 - 5 of 616 swedish dissertations containing the words Reduction technique.

  2. 1. Investigations of the Kinetics of Reduction and Reduction/Carburization of NiO-WO3 Precursors

    Author : Hesham M. Ahmed; Seshadri Seetharaman; Ricardo Morales Estrella; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Reduction; Reduction-Carburization; Gas-solid Reactions; Kinetics; Hydrogen; Methane; Thermogravimetric analysis; Fluidized bed; Simulation; Thermal diffusivity; Thermal conductivity; Laser flash; Metallurgical process engineering; Metallurgisk processteknik; Process Metallurgy;

    Abstract : Kinetic studies of reduction of the mixtures of NiO and WO3 having different Ni/(Ni+W) molar ratios in flowing hydrogen gas were investigated by means of Thermo Gravimetric Analysis (TGA), Fluidized Bed (FB) technique as well as Thermal diffusivity measurements under isothermal conditions. In the case of TGA, the reaction progress was monitored by mass loss, while evolved gas analysis by a gas chromatograph was the indicator of the reaction progress in the case of FB. READ MORE

  4. 2. Reduction of Aerodynamic Forcing inTransonic Turbomachinery : Numerical Studies on Forcing Reduction Techniques

    Author : Florian Fruth; Torsten Fransson; Damian Vogt; Ronald Mailach; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Forced Response; Aerodynamic Forcing; Efficiency; Blade Count Ratio; Clocking;

    Abstract : Due to more and more aggressive designs in turbomachinery, assuring the structural integrity of its components has become challenging. Also influenced by this trend is blade design, where lighter and slimmer blades, in combination with higher loading, lead to an increased risk of failure, e.g. in the form of blade vibration. READ MORE

  5. 3. Vibrations in Metal Cutting : Measurement, Analysis and Reduction

    Author : Linus Pettersson; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : Vibration and noise in metal cutting are ubiquitous problems in the workshop. The turning operation is one kind of metal cutting that exhibits vibration related problems. Today the industry aims at smaller tolerances in surface finish. Harder regulations in terms of the noise levels in the operator environment are also central. READ MORE

  6. 4. Model Reduction and Parameter Estimation for Diffusion Systems

    Author : Bharath Bhikkaji; Torsten Söderström; Claes Breitholtz; Uppsala universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Diffusion system; Partial differential equations PDEs ; Model reduction; PDE solvers; Finite difference approximation; Chebyshev polynomials; System identification; Parameter estimation; Recursive estimation; Frequency domain estimation; Signal processing; Signalbehandling;

    Abstract : Diffusion is a phenomenon in which particles move from regions of higher density to regions of lower density. Many physical systems, in fields as diverse as plant biology and finance, are known to involve diffusion phenomena. Typically, diffusion systems are modeled by partial differential equations (PDEs), which include certain parameters. READ MORE

  7. 5. NOx Storage and Reduction Catalysts. Reduction with Hydrogen and the Influence of Water and Carbon Dioxide

    Author : Anna Maria Lindholm; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NSR catalyst; Pt Ba Al; H2O; CO2; Pt Al; NOx reduction; H2; NH3 formation; NOx storage; Lean NOx Trap; N2O formation; kinetic modeling; Pt Si;

    Abstract : Environmental concern has increased over the past several years and resulted in stringent emission legislation on NOx, CO, and hydrocarbon emissions from automobile exhausts. Moreover, the demands to improve the fuel efficiency of engines and to lower the CO2 emissions have increased, and a way to meet this is by using lean burn engines which operate with oxygen excess. READ MORE