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norskBrowsing Doktorgradsavhandlinger (Fakultet for ingeniørvitenskap og teknologi) by Issue Date
Now showing items 1-20 of 25
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Atmospheric icing on wind turbines : Modeling and consequences for energy production
(Doctoral thesis; Doktorgradsavhandling, 2011) -
Control of rigid bodies : with applications to leader-follower spacecraft formations
(Doctoral thesis; Doktorgradsavhandling, 2012) -
Solutions to some problems related to Diophantine equation, power means and homogenization theory
(Doctoral thesis; Doktorgradsavhandling, 2017-05-19)This Ph.D. thesis consists of an introduction and 7 papers where we investigate the requirements for finding integer or rational solutions to a selection of Diophantine equations leading to problems connected to power means and homogenization. In Paper 1 we present a modern view of classic number theory in a historic context. In Paper 2 we introduce the Crossed Ladders Problem and present a proof ... -
Optimization models and methods for sustainable reverse logistics network design
(Doctoral thesis; Doktorgradsavhandling, 2018-11-29)With the increased focus on sustainable development and circular economy, as never before, the value recovery and re-creation from the End-of-Use and End-of-Life products has been paid considerable attention by the whole society. Reverse logistics is believed as one of the most effective and promising means for the value recovery of the End-of-Use and End-of-Life products, which is the process for ... -
Studies of some Operators of Harmonic Analysis in certain Function Spaces with Applications to PDEs
(Doctoral thesis; Doktorgradsavhandling, 2018-12-05)The study in this PhD thesis aims at development of certain mathematical methods used in applications, in particular, in the study of regularity properties of solutions in various mathematical models described by Partial Differential Equations (PDEs). To this end, we study various operators of harmonic analysis in certain function spaces, since solutions to many PDEs may be expressed in terms of ... -
Representation and application of spline-based finite elements
(Doctoral thesis; Doktorgradsavhandling, 2020-03-31)Isogeometric analysis, as a generalization of the finite element method, employs spline methods to achieve the same representation for both geometric modeling and analysis purpose. Being one of possible tool in application to the isogeometric analysis, blending techniques provide strict locality and smoothness between elements. Motivated by these features, this thesis is devoted to the design and ... -
Some new contributions related to structural problems in engineering
(Doctoral thesis; Doktorgradsavhandling, 2020-06-17)<p>The studies in this PhD thesis are focused on some problems of general interest in applied mathematics and engineering sciences. A very broad view is used from contributions which can be directly used for solving some important structural problems in engineering sciences, to contributions which also are of interest in pure mathematics. The main body of the PhD thesis consists of five papers (papers ... -
Engineering methods for enhancing railway geometry and winter road assessment: A safety and maintenance perspective
(Doctoral thesis; Doktorgradsavhandling, 2020-06-22)In many areas around the world there are limited transportation possibilities when travelling between key cities. If these areas also experience demanding weather conditions or geography, getting from A to B, during difficult conditions, is usually not optimal in regards to accessibility, safety, and comfort. Under challenging conditions, two essential elements in strengthening accessibility, safety, ... -
Geometric Modeling- and Sensor Technology Applications for Engineering Problems
(Doctoral thesis; Doktorgradsavhandling, 2020-10-20)In applications for technical problems, Geometric modeling and sensor technology are key in both scientific and industrial development. Simulations and visualization techniques are the next step after defining geometry models and data types. This thesis attempts to combine different aspects of geometric modeling and sensor technology as well as to facilitate simulation and visualization. It includes ... -
An applied investigation of viscosity–density fluid sensors based on torsional resonators
(Doctoral thesis; Doktorgradsavhandling, 2020-12-04)Real-time viscosity and density measurements give insight into the status of many chemical and biochemical processes and allow for automated controls. In many applications, sensors that enable the real-time measurements of fluid properties use resonant elements. Such sensors measure induced changes in the element’s resonance frequency and damping that can be related to the fluid properties. These ... -
Mathematical modelling of bioenergy systems for stability analysis and parametric sensitivity
(Doctoral thesis; Doktorgradsavhandling, 2021-03-19)<p>This thesis presents a research study on bioreactor design and biochemical processes for conversion of biomass into bioenergy and develops mathematical models that can be used for designing better reactors and control systems. Good design of the bioreactors and understanding of the biochemical process is essential to control the process for maximizing the yield. Improving the performance efficiency ... -
Study of the in-cloud dry ice accretion on cylinders for low values of the Stokes number
(Doctoral thesis; Doktorgradsavhandling, 2021-08-31)The study of the atmospheric ice accretion has received some attention from the scientific community in the past, with the available knowledge spanning from the works of the Langmuir and Blodgett (1946) on the Mt. Washington Observatory till the analytical parameterization of the Finstad et al. (1988), with the latter being the current analytical benchmark and the integral part of the ISO 12494 ... -
Study of Atmospheric Ice Accretion on Wind Turbine Blades
(Doctoral thesis; Doktorgradsavhandling, 2021-09-02)<p>This Ph.D. work concerns itself with the atmospheric ice accretion on wind turbine blades. The wind energy has been at the forefront of the renewable energy generation for the last several decades, with the amount and capacity of installed wind turbines steadily increasing. The cold climate (CC) regions around the world like Finland, Germany, Slovak Republic, Norway, Czech Republic, UK, Sweden, ... -
The Impact of Ambient Temperature on Low Carbon Energy Supply - Modelling and optimization studies on the supply of hydrogen energy from northern Norway
(Doctoral thesis; Doktorgradsavhandling, 2021-12-10)To avoid the worst impacts of climate change a rapid green energy transition is required where traditional fossil fuels are replaced by low-carbon alternatives. One attractive route to emissions reduction is blue hydrogen, which has lower CO<sub>2</sub> emissions that traditional hydrogen production. For hydrocarbon exporters, increased blue hydrocarbon production can be achieved in two main ways: ... -
A study of bounded operators on martingale Hardy spaces
(Doctoral thesis; Doktorgradsavhandling, 2021-12-13)<p>The classical Fourier Analysis has been developed in an almost unbelievable way from the first fundamental discoveries by Fourier. Especially a number of wonderful results have been proved and new directions of such research has been developed e.g. concerning Wavelets Theory, Gabor Theory, Time-Frequency Analysis, Fast Fourier Transform, Abstract Harmonic Analysis, etc. One important reason for ... -
Some new mathematical and engineering results connected to structural problems
(Doctoral thesis; Doktorgradsavhandling, 2022-04-08)<p>The research in this PhD thesis is focused on some problems of general interest in both applied mathematics and engineering sciences. It contains new results, which can be directly used for solving some important structural problems in engineering sciences, but which are also of interest in pure mathematics. The main body of this PhD thesis consists of six papers (Papers A – F). <p>In Paper A ... -
Approximation properties of Cesàro means of Vilenkin-Fourier series
(Doctoral thesis; Doktorgradsavhandling, 2022-05-05)<p>This PhD thesis focuses on the investigation of approximation properties of Cesàro means of the Vilenkin-Fourier series. In particular, we obtain some new inequalities related to the rate of <i>L<sup>p</sup></i> approximation by Cesàro means of the Vilenkin-Fourier series of functions from <i>L<sup>p</sup></i>. These inequalities imply sufficient conditions for the convergence of Cesàro means of ... -
Architectures and technologies for increased agility in small-scale manufacturing systems
(Doctoral thesis; Doktorgradsavhandling, 2022-06-16)<p>The rapid booming of industry 4.0 technologies has been boosting further development of industrial manufacturing systems in the recent two decades. An increasing number of disruptive yet enabling technologies are becoming available for industrial applications. However, while the factories becoming more complex, a proliferation of incompatible systems that have been developed by different vendors ... -
A Decision-Support Framework for Smart and Sustainable Reverse Logistics Network Design
(Doctoral thesis; Doktorgradsavhandling, 2022-10-06)The Fourth Industrial Revolution, namely Industry 4.0, has provided opportunities for digitalization and paradigm shifts in many industries and business sectors. Reverse logistics is currently being increasingly focused on by worldwide companies and governments due to the pressure on sustainable development and circular economy. Through the gradual but steady adoption of several disruptive ... -
Some new Contributions to Neural Networks and Wavelets with Applications
(Doctoral thesis; Doktorgradsavhandling, 2023-03-21)<p>In this Ph.D. thesis, we focus on some problems of general interest both in engineering sciences and applied mathematics. The close connection between some problems concerning neural networks, wavelets, structural health monitoring, and modern Fourier analysis is highlighted and applied in various ways. The main body of the Ph.D. thesis consists of six papers, A–F, which are put into a more ...
