Two recent dynamic friction models, the LuGre model and a model by Bliman and Sorine, are investigated and compared. Comparisons are made of captured friction phenomena, behaviour at zero crossings of the velocity and computational issues. Limit cycles in position control of a simple servo with dynamic friction are investigated by means of single input describing function analysis. Both models giv

In this paper we explore the potential of cross-fertilization between research on welfare state reforms and on efforts to green the state in response to ecological challenges. In order to gain a deeper understanding of the conditions for an ecological state to emerge we relate welfare state studies to green political theory, that provide different conceptions of the ecological state and ways to gr

The paper will argue that the centre-periphery dynamics of the modernisation of sexuality is more complex and difficult to grasp than is usually shown in queer studies and gay history. Existing historiography on the emerging of a modern gay and lesbian identity has failed to study the links between different sites for the emergence of a gay and lesbian subculture. The contacts between Greenland

This thesis addresses the interactions and relationships between natural aquatic bacterial communities, environmental parameters, anthropogenic chemicals and the denitrification pathway in the habitat of agricultural constructed wetlands. The main aim was to gain fundamental knowledge of the drivers behind the processes of the denitrification (i.e. nitrogen removal) in constructed wetlands, hence,

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Indonesia came a long way under Suharto but it became very clear in 1997 that the development process was far from finished. In fact, the crisis showed how vulnerable the Indonesian economy still was. A core issue in development policy in Indonesia was the transformation of the agricultural sector and great efforts were put into this in the early Suharto era. With achievement of self sufficiency o

Adding insulation to improve the energy performance of a building with a traditional Swedish wooden construction may increase the risk of mould growth in the wooden construction. There is a need to address this potential problem since the amount of passive houses and low energy buildings are increasing as a means to reduce energy use, energy dependency and greenhouse gas emissions. This paper eva

Fumigation was studied in a 12 L six-cylinder heavy-duty engine. Port-injected ethanol was ignited with a small amount of diesel injected into the cylinder. The setup left much freedom for influencing the combustion process, and the aim of this study was to find operation modes that result in a combustion resembling that of a homogeneous charge compression ignition (HCCI) engine with high efficien

Our previous measurements in the P and D series in 133 Cs have been extended to a number of higher lying levels, populated in a two-step excitation process involving an rf lamp and a CW dye laser. The D states were studied with the level-crossing technique, while the optical-double-resonance method was used for the investigation of the P states. For the magnetic dipole interaction constant a , the

A motion of an object is controlled from a geostationary transit orbit (GTO) of an earth to an orbit of a moon. A first trajectory of the motion of the object is determined from an intermediate orbit of an earth to a neighborhood of a stable manifold of a first Lagrange point (L1). A second trajectory of the motion of the object is determined from the GTO to the intermediate orbit. A third traject