Search for dissertations about: "spherical designs"

Showing result 1 - 5 of 11 swedish dissertations containing the words spherical designs.

2. 1. Some Cases of Kudla’s Modularity Conjecture for Unitary Shimura Varieties

   Author : Jiacheng Xia; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; special cycles; Eisenstein series; spherical designs; central L-values; unitary Shimura varieties; Jacobi forms; rational points; generating functions; the circle method; Kudla s modularity conjecture; theta series; Rankin--Selberg method;

   Abstract : A common theme of the thesis is the interplay of symmetry and rigidity, which is a general phenomenon in mathematics. Symmetry is a notion related to the degree to which an object remains unchanged under transformations, and rigidity is a notion that in terms of physics can be thought of as a lack of freedom, which leads to stronger properties of an object than we normally expect. READ MORE

4. 2. Simulating rolling noise on ballasted and slab tracks: vibration, radiation, and pass-by signals

   Author : Jannik Theyssen; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Railway rolling noise; Numerical modelling; Green s functions; Time domain; Spherical harmonics; Slab track; 2.5D FE BE;

   Abstract : Shifting to rail-bound freight and passenger traffic is key in Europe's strategy towards transport decarbonisation. However, increasing railway traffic can increase environmental noise pollution. Rolling noise is often the dominant noise source. It originates from the interaction of the rough running surfaces of wheel and rail. READ MORE

5. 3. Extremely Large Telescopes Optical Design and Wavefront Correction

   Author : Alexander Gontcharov; Astronomi - Genomgår omorganisation; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Astronomy; akustik; optik; Adaptive Optics; Extremely Large Telescopes; optical design methods; wavefront correction methods.; Electromagnetism; optics; Elektromagnetism; acoustics; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi;

   Abstract : An overview of the state of art within optical design of large astronomical telescopes is given. Recent advances within the field are presented. The importance of new computer-controlled mirror-polishing methods is emphasized. READ MORE

6. 4. Utilization of Low Voltage D-T Neutron Generators in Neutron Physics Studies

   Author : Somsorn Singkarat; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; D-T neutron generator; double-differential cross-section DDX ; n-1H scattering; directional neutron detector; time-of-flight method; natural iron; scintillation fibers; neutron energy converter;

   Abstract : In a small nuclear laboratory of a developing country a low voltage D-T neutron generator can be a very useful scientific apparatus. Such machines have been used successfully for more than 40 years in teaching and scientific research. READ MORE

7. 5. Principles and Models of Solid Fuel Combustion

   Author : Henrik Thunman; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wood; single particle; modelling; fluidized bed; thermochemical conversion; fixed bed; coal; thermal conductivity; fuel loading; measurements; thermochemical properties; biofuels; combustion; grate;

   Abstract : Combustion of solid fuels stands for a substantial part of the heat and power production in the world. In this thesis different aspects related to the thermochemical conversion of solid fuels in fluidized and fixed beds are treated, such as: the combustion temperature of a fuel particle related to the surrounding temperature in a fluidized bed combustor (FBC); the fuel loading in a FBC; a transient description of the conversion of non-spherical fuel particles; the thermochemical properties and composition of volatiles released from wood; the thermal conductivity of wood during different stages of conversion; the modelling of a grate furnace; the general combustion behaviour of a fixed bed on a reciprocating or a travelling grate; and finally, the design and construction of experimental units for investigation of combustion in a fixed bed. READ MORE