Nonlinear modal interactions in clamped-clamped mechanical resonators

A theoretical and experimental investigation is presented on the intermodal coupling between the flexural vibration modes of a single clamped-clamped beam. Nonlinear coupling allows an arbitrary flexural mode to be used as a self-detector for the amplitude of another mode, presenting a method to measure the energy stored in a specific resonance mode. Experimentally observed complex nonlinear dynamics of the coupled modes are quantitatively captured by a model which couples the modes via the beam extension; the same mechanism is responsible for the well-known Duffing nonlinearity in clamped-clamped beams.Comment: 5 pages, 3 figure

Dispersie na het broedseizoen, trek en overwintering van Grote Sterns <i>Thalasseus sandvicensis</i> uit de Voordelta = Post-breeding dispersal, migration and wintering of Sandwich Terns <i>Thalasseus sandvicensis</i> from the southwestern part of the Netherlands

The Sandwich Tern Sterna sandvicensis is a Dutch Red List species with a population of 19,000 pairs in the Dutch coastal zone. It winters off the coasts of Africa and a small populations migrates into the Mediterranean or stays even more north.. In the Netherlands, breeding takes places in a small number of colonies in the Delta area and the Waddensea. In this study, Sandwich Terns from the Delta colony on the Scheelhoek (Natura 2000 SPA ‘Haringvliet’) were investigated which forage during the breeding season in Natura 2000 SPA ‘Voordelta’. In total 30 adult Sandwich Terns were equipped with radio transmitters, a colourring and a plumage colour (picrinic acid or silver nitrate solution). Thanks to these markings birds could be followed in the colonies, from airplanes and from the coast. Several birds used the sand banks off the coast of their breeding colonies to rest after the breeding season. After a short while they dispersed in western and northern direction with sightings in the northern part of the Netherlands (outside and within other colonies). These were always failed breeders, possibly scouting other colonies for future breeding places. Some of these birds even left the Dutch coasts and appeared in Scotland and Denmark. Adults with young probably dispersed into the North Sea after a short stay around the sand banks off the coast near the colonies. They probably head to more nutrient rich areas in the North Sea and adjacent areas where the young birds can practice their fishing techniques before they move south. The adults can build-up here good fat reserves before the start of migration. In September, most of the marked Sandwich Terns were south of their breeding places and during their southward migration birds were seen along the coast of France and on Lanzarote (Canary Islands). Our results showed that using markers on birds could yield good data with a resighting percentage of 20% within only one year. Furthermore, the use of plumage colouring proved to be a good method for obtaining information of individual birds as these colourings attract the attention of observers and are ‘readable’ over large distances

Energieplan Greenportkas II: Verkenning van de besparingsmogelijkheden van het kasconcept

Op basis van de meest actuele stand van zaken in het onderzoek aan energiezuinige tomatenteelt in kassen en de plannen van de ondernemer, is een concept kassysteem Greenportkas II opgesteld. Het Greenportkas II concept is vergeleken met verschillende energiebesparingsprojecten bij tomaat. Onderling vergelijk van deze projecten is bijzonder lastig omdat de uitgangspunten soms zeer sterk verschillen. In dit rapport is geprobeerd de uitgangspunten en resultaten van deze projecten, waaronder ook Greenportkas I, onderling wel vergelijkbaar te maken, door alles terug te rekenen tot inzet van primaire energie

Ontwerp van twee energiezuinige kasconcepten: Iteratief proces van rekenen en discussieren aan de hand van Kaspro

Het Greenportkas II concept zou de volgende stap worden in de energiebesparing in de glastuinbouw, onder meer door gebruik te maken van gecoat diffuus dubbel glas. Dit nieuwe kasconcept, bedoeld voor de teelt van tomaten, is voorafgaande aan de bouw uitgebreid geëvalueerd. De consequenties van combinaties van bepaalde innovaties zijn in een iteratief proces doorgerekend met Kaspro en bediscussieerd met de ondernemer. Dit heeft geleid tot een veel beter uitgedacht systeem. De bouw van dit concept kon echter niet doorgaan. Vervolgens is de ontwikkeling van een ander kasconcept met een vergelijkbare innovatie (de ID kas) ondersteund met het zelfde iteratieve proces. Dit heeft bijgedragen aan het uiteindelijke ontwerp van de kas en de ontwikkeling van een monitoringsplan. Greenportkas II was a new greenhouse concept for further reduction of the energy use in protected tomato cultivation by the use of coated double glazing. This new concept was aimed at the production of tomatoes. It was thoroughly ex ante evaluated through an iterative process with Kaspro calculations and discussions with the grower before the construction of the greenhouse started. This led to a better system lay-out. However, this concept could not be built. Subsequently, another innovative greenhouse concept was ex ante supported with similar calculations and discussions. These activities contributed to the design and building of this new concept: the ID greenhouse. A plan for the monitoring of the energy performance of this new tomato greenhouse was written

Security Applications for Converging Technologies - Impact on the Constitutional State and the Legal order

In this study we investigate the impact of converging technologies on legal practice and criminology in a forward looking study intended for practitioners and policy makers in the field of legislation, crime prevention, and law enforcement. We look at a 15 years timeframe and discuss the scientific and technical progress in various domains as well as the ethical, legal, and policy dilemmas involved.