Rotating Frame Relaxation Times for Off-Resonant MRI Pulses

Magnetic Resonance Imaging (MRI) is an important imaging modality, since it can create high-resolution cross-sectional images of the human body. In MRI scanners, the nuclear spin magnetization is excited using radio-frequency pulses. Images are created based on the time-evolution of this magnetization, which is characterized by relaxation times ...

Degradation study of a reversible solid oxide cell (rSOC) short stack using distribution of relaxation times (DRT) analysis

Reversible solid oxide cells (rSOC) can convert excess electricity to valuable fuels in electrolysis cell mode (SOEC) and reverse the reaction in fuel cell mode (SOFC). In this work, a five – cell rSOC short stack, integrating fuel electrode (Ni-YSZ) supported solid oxide cells (Ni-YSZ || YSZ | CGO || LSC-CGO) with an active area of 100 cm2, is...

Modelling the Last Glacial Ice Sheet on Antarctica with Laterally Varying Relaxation Time

Glacial isostatic adjustment is the viscoelastic response of the earth to ice sheet loading. Ice dynamic models employ glacial isostatic adjustment to accurately simulate bedrock uplift. In previous studies, ice dynamic models use only a constant relaxation time to predict bedrock uplift. In this study, the aim is to improve an ice dynamic model...

The reliability of parameters obtained by fitting of ¹H NMRD profiles and ¹⁷O NMR data of potential Gd³⁺-based MRI contrast agents

Synthetic variable temperature ¹H NMRD profiles and ¹⁷O NMR relaxation and shift data were generated with a model based on the Solomon-Bloembergen-Morgan and Freed theories and then fitted simultaneously or individually. The effects of the fitting procedure and of experimental uncertainties on the resulting best-fit...

The Many Roles of the Relaxation time Parameter in Force based Models of Pedestrian Dynamics

In force based models of pedestrian traffic, the relaxation time, ?, is related to the time it takes a pedestrian to adapt its motion to its preferences. An example of this is linear acceleration, but ? is also connected to how the agent adjusts to spatial variations in its preferred velocity, and affects evasive maneuvers. These many roles of ?...

Nanostructured tracers for laser-based diagnostics in high-speed flows

The potential application of aggregates of nanoparticles for high-speed flow diagnostics is investigated. Aluminum nanoparticles around 10 nm in diameter are produced by spark discharge in argon gas. Through rapid coagulation and oxidation, aggregates of small effective density are formed. They are characterized by microscopy and their...

Evidence of noncascade intracenter electron relaxation in shallow donor centers in silicon

Noncascade relaxation of photoexcited electrons on ionized donor centers has been observed in silicon doped by arsenic (Si:As) at low temperatures. Emission spectra of the Si:As terahertz intracenter laser give evidence of specific channels for the electron relaxation through low-lying donor states. The dominating relaxation channels strongly...

Electron spins in few-electron lateral quantum dots

This thesis describes a series of experiments aimed at understanding and controlling single electron spins confined in semiconductor lateral quantum dots, with the long-term goal of creating of a small-scale quantum computer. The confinement of these electrons results in a quantized energy spectrum, and therefore, the quantum dots can be...

Activated dynamics in a two-dimensional Ising spin glass: Rubidium copper cobalt fluoride (Rb2Cu1-xCoxF4)

Activated dynamics in the two-dimensional Ising spin-glass Rb2Cu1-xCo xF4