Templeton Hendriksen (stitchspot49)

Numerical simulations are increasingly employed in safety assessment of high-field magnetic resonance imaging (MRI) in patients with conductive medical implants such as those with deep brain stimulation (DBS) devices. Performing numerical simulations with realistic patient models and implant geometry is the preferred method as it provides the most accurate results; however, in many cases such an approach is infeasible due to limitation of computational resources. The difficulties in reconstructing realistic patient and device models and obtaining accurate electrical properties of tissue have compelled researchers to adopt compromises, either to exceedingly simplify implant structure and geometry, or the complexity of the body model. This study examines the effect of variations in anatomical details of the human body model and implant geometry on predicted values of specific absorption rate (SAR) values during MRI in a patient with a DBS implant. We used a patient-derived model of a fully implanted DBS implantror introduced by simplifying the implant's geometry could negate the benefit of using a realistic body model, should such model be used at the expense of oversimplifying implant geometry.Four nanostructured active semiconducting materials currently used in electronic inks have been structurally characterised using a combination of small angle scattering techniques and scanning electron microscopy. The percolation theory and scaling laws have been used to obtain quantitative correlations of the network topologies and the local micro-structures with the electronic and electrical properties of the printed, electronic devices. The small angle light scattering has been used to expand the lower q-range of the Ultra Small Angle x-ray Scattering curves of the 2503 metallurgical grade silicon (mSi), silicon dioxide (SiO2), aluminium dioxide (Al2O3) and titanium dioxide (TiO2) materials by close to an order of magnitude, thereby providing valuable clustering properties for each material. Each scattering curve presented a series of multiple structural levels, which are then quantified using the Unified power-law approach to provide valuable clustering characteristics such as the degree of aggregation, polydispersity and geometry standard deviation. Subsequently, a fully screen-printed field effect transistor that uses mSi as the active material is demonstrated. The transistor had an ON/OFF current-ratio of 104; an electron mobility of 0.7 cm2/V s; a leakage current in the order of 5 × 10-9 A, and no current saturation.With the advent of graphene, there has been an interest in utilizing this material and its derivative, graphene oxide (GO) for novel applications in nanodevices such as bio and gas sensors, solid-state supercapacitors and solar cells. Although GO exhibits lower conductivity and structural stability, it possesses an energy band gap that enables fluorescence emission in the visible/near infrared leading to a plethora of optoelectronic applications. In order to allow fine-tuning of its optical properties in the device geometry, new physical techniques are required that, unlike existing chemical approaches, yield substantial alteration of GO structure. Such a desired new technique is one that is electronically controlled and leads to reversible changes in GO optoelectronic properties. In this work, we for the first time investigate the methods to controllably alter the optical response of GO with the electric field and provide theoretical modeling of the electric field-induced changes. Field-dependent GO emission is studied in bulk GO/polyvinylpyrrolidone films with up to 6% reversible decrease under 1.6 V µm-1 electric fields. On an individual flake level, a more substantial over 50% quenching is achieved for select GO flakes in a polymeric matrix between interdigitated microelectrodes subject to two orders of magnitude higher fields. This effect is modeled on a single exciton level by utilizing Wentzel, Kremer, and Bri