On the Necessity of Superparametric Geometry Representation for Discontinuous Galerkin Methods on Domains with Curved Boundaries

We provide numerical evidence demonstrating the necessity of employing a superparametric geometry representation in order to obtain optimal convergence orders on two-dimensional domains with curved boundaries when solving the Euler equations using Discontinuous Galerkin methods. However, concerning the obtention of optimal convergence orders for the Navier-Stokes equations, we demonstrate numerically that the use of isoparametric geometry representation is sufficient for the case considered here.Comment: AIAA Aviation 2017 conference pape

Overview geotechnical model tests on dike safety at Deltares

Three on-going dike safety studies (on: macro stability, piping and flow slides) in the Netherlands make use of geotechnical physical models. A short outline of these projects is presented; the physical models chosen are described and discussed. The three studies use different physical models, depending on the research questions at the beginning of the model test series, the heterogeneity that is anticipated in the field, the scaling laws and the knowledge level. The paper describes why a certain model was chosen

Spin filling of valley-orbit states in a silicon quantum dot

We report the demonstration of a low-disorder silicon metal-oxide-semiconductor (Si MOS) quantum dot containing a tunable number of electrons from zero to N=27. The observed evolution of addition energies with parallel magnetic field reveals the spin filling of electrons into valley-orbit states. We find a splitting of 0.10 meV between the ground and first excited states, consistent with theory and placing a lower bound on the valley splitting. Our results provide optimism for the realization in the near future of spin qubits based on silicon quantum dots.Comment: 6 pages, 4 figures, to appear in Nanotechnolog

Electric-field dependent g-factor anisotropy in Ge-Si core-shell nanowire quantum dots

We present angle-dependent measurements of the effective g-factor g* in a Ge-Si core-shell nanowire quantum dot. g* is found to be maximum when the magnetic field is pointing perpendicular to both the nanowire and the electric field induced by local gates. Alignment of the magnetic field with the electric field reduces g* significantly. g* is almost completely quenched when the magnetic field is aligned with the nanowire axis. These findings confirm recent calculations, where the obtained anisotropy is attributed to a Rashba-type spin-orbit interaction induced by heavy-hole light-hole mixing. In principle, this facilitates manipulation of spin-orbit qubits by means of a continuous high-frequency electric field

Stroomdalgraslanden in Nederland : ontwikkeling en beheer in de Vreugderijkerwaard : veldwerkplaats rivierenlandschap Vreugderijkerwaard, 16 mei 2008

Verslag van de veldwerkplaats in de Vreugderijkerwaard, een tweeluik van excursies. Op 28 mei zijn de Millingerwaard en de Erlecomsewaard bezocht. Per gebied werden de beheersstrategieën besproken, de mate van begrazingsintensiteit voor een succesvol beheer, de dynamische verschillen per uiterwaardengebied en de verspreiding en soortensamenstelling van plantengemeenschappen. De Vreugderijkerwaard is een uiterwaard langs de IJssel, waarvan een deel al tientallen jaren in beheer is bij Natuurmonumenten. Op de oeverwal is tijdens de veldexcursie een prachtig ontwikkelde stroomdalvegetatie aangetroffen. Dit zijn de resultaten van een uitgekiend begrazingsbeheer. Ook zijn sinds enkele jaren een aantal voormalige agrarische graslanden bij het reservaat gevoegd en integraal opgenomen in de begrazing. Al na een paar jaar vestigden zich hier (massaal) enkele rode lijst- soorten. De basis voor een geslaagd beheer is de aanwezigheid van gezonde natuurlijke processen

Palladium gates for reproducible quantum dots in silicon

We replace the established aluminium gates for the formation of quantum dots in silicon with gates made from palladium. We study the morphology of both aluminium and palladium gates with transmission electron microscopy. The native aluminium oxide is found to be formed all around the aluminium gates, which could lead to the formation of unintentional dots. Therefore, we report on a novel fabrication route that replaces aluminium and its native oxide by palladium with atomic-layer-deposition-grown aluminium oxide. Using this approach, we show the formation of low-disorder gate-defined quantum dots, which are reproducibly fabricated. Furthermore, palladium enables us to further shrink the gate design, allowing us to perform electron transport measurements in the few-electron regime in devices comprising only two gate layers, a major technological advancement. It remains to be seen, whether the introduction of palladium gates can improve the excellent results on electron and nuclear spin qubits defined with an aluminium gate stack

Entorno Institucional de la Desentralización Estatal en los Países Bajos el papel de las organizaciones de apoyo

A partir de 1998, el IHS se vinculó al SINPA (Programa de apoyo para la implementación de planes nacionales de acción – Support for Implementation of National Plans of Action) financiado por la Dirección general de cooperación al desarrollo de los Países Bajos, junto con la ciudades de Tangail, Santa Cruz y Kitwe y los gobiernos correspondientes de Bangladesh, Bolivia y Zambia. La meta general del Programa SINPA es ayudar a implementar los planes de acción nacionales y la Agenda Hábitat, fortaleciendo la construcción de capacidad local sustentable para la planeación y gestión efectivas del desarrollo urbano. En términos más concretos, el programa busca ayudar al gobierno local y a sus contrapartes a construir capacidad de acción en las áreas más amplias relacionadas con la buena gobernabilidad, la planificación participativa, el alivio de la pobreza, la vivienda y los servicios básicos, y la gestión local ambiental. SINPA se concentra principalmente en la relación entre las organizaciones dedicadas a construir capacidad local (universidades, organizaciones profesionales, organizaciones no gubernamentales u ONG), por una parte, y entre el gobierno local y las organizaciones de la sociedad civil, por otra, con el fin de mejorar sus capacidades de tal forma que sus esfuerzos sean sustentables localmente

Observation of the single-electron regime in a highly tunable silicon quantum dot

We report on low-temperature electronic transport measurements of a silicon metal-oxide-semiconductor quantum dot, with independent gate control of electron densities in the leads and the quantum dot island. This architecture allows the dot energy levels to be probed without affecting the electron density in the leads, and vice versa. Appropriate gate biasing enables the dot occupancy to be reduced to the single-electron level, as evidenced by magnetospectroscopy measurements of the ground state of the first two charge transitions. Independent gate control of the electron reservoirs also enables discrimination between excited states of the dot and density of states modulations in the leads.Comment: 4 pages, 3 figures, accepted for Applied Physics Letter