Passive Film Properties of Martensitic Steels in Alkaline Environment: Influence of the Prior Austenite Grain Size

The role of prior austenite grain size (PAGS) on the passive layer properties of martensitic steels is studied. Electron backscatter diffraction analysis shows that PAGS between 5 and 66 µm were obtained after applying different heat treatments. The barrier properties of passive film deteriorate with grain refinement up to 28 µm, attributed to...

Distributed IDA-PBC for Nonholonomic Mechanical Systems

Nonholonomic mechanical systems encompass a large class of practically interesting robotic structures, such as wheeled mobile robots, space manipulators, and multi-fingered robot hands. However, few results exist on the cooperative control of such systems in a generic, distributed approach. In this work we extend a recently developed distributed...

Properties of Passive Films Formed on Ferrite-Martensite and Ferrite-Pearlite Steel Microstructures

The effect of ferrite-pearlite and ferrite-martensite phase combinations on the passive layer properties of low carbon steel is investigated in a 0.1 M NaOH solution. Heat treatments were designed to obtain ferrite-pearlite and ferrite-martensite microstructures with similar ferrite volume fractions. Potentiostatic polarisation and...

The Role of Phase Combinations on the Corrosion and Passivity Behaviour of High Strength Steels

Literature reports a great deal of contradictory results concerning the effect of microstructure on the corrosion and passivity behaviour of advanced high strength steels. The difficulty in identifying the controlling cause of corrosion results from the inability of disentangling the coupled effects of individual microstructural features in a...

Properties and performance of spin-on-glass coatings for the corrosion protection of stainless steels in chloride media

Spin-on-glass deposition was investigated as viable alternative to increase the durability and performance of 316L steel in chloride environment. The buildup of a detrimental interface oxide was prevented by non-oxidative thermal curing of the coatings, which leads to a transformation to an inorganic, SiO₂-like material. The degree...

Control Loop Design for a Helicopter Tactile Cue Trim Actuator

Force feedback in helicopters can improve the performance of the pilot, decrease direct maintenance costs and increase the safety of every flight. Traditional force feedback is done with the use of a force sensor. In this thesis the use of a position based, feedforward control loop to achieve the same purpose is investigated. The limits of...

Manipulator control by energy dissipation

In this research we investigate a class of systems which can only be controlled by dissipating energy. As an example, we investigate the control of a robotic manipulator without motors, but merely dissipative elements such as brakes and dampers. The energy source of the manipulator is the potential (gravitational) energy of the package which it...