The ComMotion project:Computational methods for moving and deforming objects in extreme waves

Extreme waves and their impact on (fixed and floating) offshore structures have long been subjects that could only be studied with experimental methods; sufficiently accurate existing numerical methods (CFD) are only recently emerging. Phenomena like green water loading and slamming are highly dependent on the relative motion of a ship versus the on- coming wave crests, as influenced by the preceding wave groups. Thus, accurate prediction of the hydrodynamic forces requires methods that can reliably predict the interaction between ex- treme waves and body dynamics. Over the years, the ComFLOW simulation method has been developed to cover this CFD niche. A novel ingredient devceloped in the ComMotion project is an unsteady coupling algorithm that is numerically stable under all circumstances (such as ratio of body mass versus added mass). Also, a new class of absorbing boundary conditions has been extended to include the effects of current. Several applications will be presented, including esperimental validation

The ComMotion project:Computational methods for moving and deforming objects in extreme waves

Extreme waves and their impact on (fixed and floating) offshore structures have long been subjects that could only be studied with experimental methods; sufficiently accurate existing numerical methods (CFD) are only recently emerging. Phenomena like green water loading and slamming are highly dependent on the relative motion of a ship versus the on- coming wave crests, as influenced by the preceding wave groups. Thus, accurate prediction of the hydrodynamic forces requires methods that can reliably predict the interaction between ex- treme waves and body dynamics. Over the years, the ComFLOW simulation method has been developed to cover this CFD niche. A novel ingredient devceloped in the ComMotion project is an unsteady coupling algorithm that is numerically stable under all circumstances (such as ratio of body mass versus added mass). Also, a new class of absorbing boundary conditions has been extended to include the effects of current. Several applications will be presented, including esperimental validation

Oscillating magnetoresistance in diluted magnetic semiconductor barrier structures

Ballistic spin polarized transport through diluted magnetic semiconductor (DMS) single and double barrier structures is investigated theoretically using a two-component model. The tunneling magnetoresistance (TMR) of the system exhibits oscillating behavior when the magnetic field are varied. An interesting beat pattern in the TMR and spin polarization is found for different NMS/DMS double barrier structures which arises from an interplay between the spin-up and spin-down electron channels which are splitted by the s-d exchange interaction.Comment: 4 pages, 6 figures, submitted to Phys. Rev.

Smearing of Observables and Spectral Measures on Quantum Structures

An observable on a quantum structure is any $\sigma$-homomorphism of quantum structures from the Borel $\sigma$-algebra of the real line into the quantum structure which is in our case a monotone $\sigma$-complete effect algebras with the Riesz Decomposition Property. We show that every observable is a smearing of a sharp observable which takes values from a Boolean $\sigma$-subalgebra of the effect algebra, and we prove that for every element of the effect algebra there is its spectral measure