Ultrasonic Detection of Acoustically Transparent Cracks Using Harmonics

Detection and sizing of closed cracks is challenging as these cracks exhibt a transparent behavior when interacting with ultrasonic waves. To face this challenge, high amplitude ultrasonic waves are used by which harmonics are generated at the crack interface. Exploting this non-linear response, the probability of detection and sizing of such...

Design of Photocatalytic Reactors

Photocatalysis is a photochemical reaction induced by photon–absorption of a solid material, a "photocatalyst", that remains unchanged during the reaction. Photocatalysis has a wide variety of applications, e.g., degrading contaminants in aqueous solutions and in air, oxidizing liquid hydrocarbons, and reducing carbon dioxide into valuable...

Uncertainty quantification in reactor physics using adjoint/perturbation techniques and adaptive spectral methods

This thesis presents the development and the implementation of an uncertainty propagation algorithm based on the concept of spectral expansion. The first part of the thesis is dedicated to the study of uncertainty propagation methodologies and to the analysis of spectral techniques. The concepts introduced within this preliminary analysis are...

Establishing a sea bottom model by applying a multi-sensor acoustic remote sensing approach

Detailed information about the oceanic environment is essential for many applications in the field of marine geology, marine biology, coastal engineering, and marine operations. Especially, knowledge of the properties of the sediment body is often required. Acoustic remote sensing techniques have become highly attractive for classifying the sea...

Cooperative Wideband OFDM Communication

In this thesis, major attention is paid to cooperative diversity as an alternative way to achieve spatial diversity when the multiple antenna structure is not an option. By adopting the cooperative relay nodes to forward information, we can mitigate the fading effects, increase the capacity, lower the bit-error rate, increase the achievable...

LaBr3 gamma?ray spectrometers for space applications

LaBr3 has been developed into large volume scintillator detectors within an ESA and TU Delft programme during this thesis work. The programme, which aimed at the space applications of LaBr3, also led to extensive experiments within a collaborative framework which included representatives for all the development aspects, i.e., from crystal...

Nonproportionality of inorganic scintillators

A scintillator is a transparent material that emits a flash of light when it absorbs a ?-ray photon or an energetic particle. Scintillation crystals are widely used as spectroscopic detectors of ionizing radiation in nuclear science, space exploration, medical imaging, homeland security, etc. This thesis is about nonproportional response of...

Fatigue Crack and Delamination Growth in Fibre Metal Laminates under Variable Amplitude Loading

This thesis presents the investigation into the fatigue propagation and delamination growth of Fibre Metal Laminates under variable amplitude loading. As explained in the first chapter, the motivation of the research is twofold: first, to obtain a clear understanding and detailed characterization of the failure mechanisms in GLARE under variable...

Engineering the electronic structure of lanthanide based materials

Lanthanide based materials are used in everything from phosphors for light bulbs and LEDs, to scintillators for medical imaging purposes to magnets. They also show potential for spintronics and for increasing the efficiency of solar cells. Knowing the energy of the lanthanide 4f and 5d states is important for understanding the electronic...

Feature-based estimation for applications in geosciences

A reservoir simulator mimics the movement of fluids in the presence of each other through a porous medium under some specified conditions. It is a numerical model of a real-life physical process, therefore, subject to uncertainty. Some uncertainties can be lowered by improving model-parameter estimates. This is where data assimilation plays an...

Efficient numerical methods to compute unsteady subsonic flows on unstructured grids

Over the last four decades the increase in computer power and the advances in solver technology has resulted in an estimated reduction of 10 orders in magnitude to compute flow problems. However, to solve the instationairy Reynolds-averaged Navier-Stokes equations, even today, a massive amount of CPU time may be required. For example, to solve...

Molecular simulations in microporous materials: Adsorption and separation

The adsorption of water on hydrophobic zeolites such as silicalite and on hydrophilic MOF (metal-organic framework), Cu-BTC, is completely different, as described in chapters 2 and 4. While in hydrophobic materials water adsorption isotherms are very steep and difficult to measure, both experimentally and by simulation, in hydrophilic materials...