Early Greek Thought and Perspectives for the Interpretation of Quantum Mechanics: Preliminaries to an Ontological Approach

It will be shown in this article that an ontological approach for some problems related to the interpretation of Quantum Mechanics could emerge from a re-evaluation of the main paradox of early Greek thought: the paradox of Being and non-Being, and the solutions presented to it by Plato and Aristotle. Plato's and Aristotle's systems are argued here to do on the ontological level essentially the same: to introduce stability in the world by introducing the notion of a separable, stable object, for which a principle of contradiction is valid: an object cannot be and not-be at the same place at the same time. After leaving Aristotelian metaphysics, early modern science had to cope with these problems: it did so by introducing ``space'' as the seat of stability, and ``time'' as the theater of motion. But the ontological structure present in this solution remained the same. Therefore the fundamental notion `separable system', related to the notions observation and measurement, themselves related to the modern concepts of space and time, appears to be intrinsically problematic, because it is inextricably connected to classical logic on the ontological level. We see therefore the problems dealt with by quantum logic not as merely formal, and the problem of `non-locality' as related to it, indicating the need to re-think the notions `system', `entity', as well as the implications of the operation `measurement', which is seen here as an application of classical logic (including its ontological consequences) on the material world.Comment: 18 page

Stilling basin optimization for a combined inlet-outlet sluice in the framework of the Sigmaplan

Within the framework of the so-called Actualised Sigmaplan, i.e. the masterplan to create a sustainable Schelde estuary, flood control areas (FCA) are setup in well-chosen polders along the tidal part of the river Scheldeand its tributaries. In some of these FCAs a semi-diurnal, controlled reduced tide (CRT) is introduced, by means of simple inlet and outlet sluices. Nowadays, it is preferred to combine in- let and outlet sluices in one single structure, in which the inlet culverts are situated on top of the outlet culverts. At inflow, energy is dissipated by means of a vertical drop and a stilling basin. In this paper, results are presented of a physical model study (scale 1:8) aiming at the optimization of the inlet configuration, i.e. the stilling basin, starting from the desktop design of the in- and outlet construction for FCACRT Bergenmeersen

On hawser force criteria for navigation lock design: Case study of maritime locks in port of Antwerp

The first part of this paper offers a general reflection upon the issue of mooring line forces and ship behaviour during filling/emptying of (maritime) navigation locks. The philosophy behind the so-called hawser force criterion and the classical approach to deal with it in design studies, is described first. Secondly, some innovations in the definition, verification and validation of the design criteria are highlighted. In the second part of this paper, a case study is presented focusing on two maritime locks in the Port of Antwerp (Belgium): the Zandvliet lock (L x W = 500m x 57m) and the Berendrecht lock (L x W = 500m x 68m). To illustrate and comment upon the hawser force issues, results of scale modelling, in situ measurements and numerical modelling are discussed, in comparison to published hawser force criteria

Optimal Aero-Elastic Design of a Rotor with Bend-Twist Coupling

Passive Bend-Twist Coupling (BTC) can be used in blades to alleviate loads and generate more Annual Energy Production (AEP). However, BTC is inherently aero-elastic, thus difficult to incorporate into the design with sequential design process. Multi-disciplinary Design Optimization (MDO) is an attractive approach for overcoming these challenges. This paper presents the re-design of a 100kW BTC rotor using the MDO rotor design package HAWTOpt2. In the preliminary design phase, MDO was used to assess the differences between elastic BTC (i.e. off-axis fibers) and geometric BTC (i.e. sweep). This work found that aero-elastic design optimization without BTC was able to achieve a 16% improvement, then with sweep a 18% improvement and with material coupling a 17% improvement. Due to the reduced stiffness of off-axis fibers, material coupled designs had more difficulty satisfying the tip deflection constraint. The geometric BTC concept was chosen for the final design. The design optimization was repeated with additional manufacturing constraints. The final design achieved a 12% improvement

Odour nuisance in Scheldt branch Gentbrugge-Melle [POSTER]

The tidal branch of the Sea Scheldt between the lock of Gentbrugge and Melle - part of the complex Ringvaart system around Ghent - has not received any upstream discharge since 1981. Consequently, ebb velocities were reduced, while flood velocities were left unaffected, causing sedimentation in the branch. At some locations along the branch, odour nuisance was regularly reported. In order to address the problem, Division Sea Scheldt of the Flemish Government proposed to dredge the associated muddy material. Flanders Hydraulics Research (FHR) was asked to conduct a study about the necessary upstream discharge at the lock of Gentbrugge needed to ensure the river branch’s self-erosiveness. To answer this question, monitored data were combined with modelling know-how. A 2D numerical morphological model was constructed, for which hydrological and sedimentological parameters, such as discharge, gauge height and sediment concentration, were used as input and for validation. All of these data were provided by FHR. After numerous numerical scenarios, it was concluded that the discharge required, lies between 20 and 25 m3/s. However, as a mean discharge of about 70 m3/s is discharged into the entire water system around Ghent, and as other waterways within this system require sufficient discharges (of which the Canal Ghent-Terneuzen has been determined in a Belgian-Dutch treaty) this discharge is not available in normal circumstances in the tidal branch. Currently, Flanders Hydraulics Research is investigating the possibilities of a lower discharge at the weir of Gentbrugge, that would allow to maintain the branch with a limited dredging