Dreijen Regeneration Study: Professional Academy 2007

This year the students of the “Professional Academy”, a combined theory and design class in landscape architecture, elaborated on a vision on the campus “de Dreijen” in Wageningen. This campus will be left by the university within the coming decade, university functions mainly moving towards the new campus “de Born” in the North of the city. Their “research by design” study brought about very different visions, but they all reflected the main theories learnt about urban sustainability and ecolog

A Multistory Structure Concept

It is the objective of this thesis to investigate the feasibility of a multistoried structural concept in which the principal structural elements are hollow girders and chambered hollow columns. The scope will be directed towards the general conceptions, assumptions and design procedures for the system. Only such specific design of a particular example will be accomplished as is necessary to provide correlation and justification for the general assumptions. A detailed investigation and design is not intended since this thesis is oriented towards establishing a general concept not merely a particular example

Bifurcation at nonsemisimple 1: - 1 resonance

In this paper a description is given of the bifurcation of periodic solutions occurring when a Hamiltonian system of two degrees of freedom passes through nonsemisimple 1–1 resonance at an equilibrium. A bifurcation like this is found in the planar circular restricted problem of three bodies at the Lagrange equilibriumL 4 when the mass parameter passes through the critical value of Routh. Gegenstand dieses Artikels ist die Verzweigung periodischer Lösungen in Hamilton''schen Systemen mit zwei Freiheitsgraden beim Durchgang durch eine nicht-einfache 1–1-Resonanz an einem Gleichgewicht. Ein Beispiel ist das ebene restringierte Dreikörperproblem am Lagrange-PunktL 4, wenn die Masse durch den kritischen Wert von Routh hindurchgeht

Higher education reform: getting the incentives right

This study is a joint effort by the Netherlands Bureau for Economic Policy Analysis (CPB) and the Center for Higher Education Policy Studies. It analyses a number of `best practices¿ where the design of financial incentives working on the system level of higher education is concerned. In Chapter 1, an overview of some of the characteristics of the Dutch higher education sector is presented. Chapter 2 is a refresher on the economics of higher education. Chapter 3 is about the Australian Higher Education Contribution Scheme (HECS). Chapter 4 is about tuition fees and admission policies in US universities. Chapter 5 looks at the funding of Danish universities through the so-called taximeter-model, that links funding to student performance. Chapter 6 deals with research funding in the UK university system, where research assessments exercises underlie the funding decisions. In Chapter 7 we study the impact of university-industry ties on academic research by examining the US policies on increasing knowledge transfer between universities and the private sector. Finally, Chapter 8 presents food for thought for Dutch policymakers: what lessons can be learned from our international comparison

Splash wave and crown breakup after disc impact on a liquid surface

In this paper we analyze the impact of a circular disc on a free surface using experiments, potential flow numerical simulations and theory. We focus our attention both on the study of the generation and possible breakup of the splash wave created after the impact and on the calculation of the force on the disc. We have experimentally found that drops are only ejected from the rim located at the top part of the splash --giving rise to what is known as the crown splash-- if the impact Weber number exceeds a threshold value \Weber_{crit}\simeq 140. We explain this threshold by defining a local Bond number $Bo_{tip}$ based on the rim deceleration and its radius of curvature, with which we show using both numerical simulations and experiments that a crown splash only occurs when $Bo_{tip}\gtrsim 1$, revealing that the rim disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we show that the flow in the region close to the disc edge possesses a Weber-number-dependent self-similar structure for every Weber number. From this we demonstrate that \Bond_{tip}\propto\Weber, explaining both why the transition to crown splash can be characterized in terms of the impact Weber number and why this transition occurs for $We_{crit}\simeq 140$. Next, including the effect of air, we have developed a theory which predicts the time-varying thickness of the very thin air cushion that is entrapped between the impacting solid and the liquid. Our analysis reveals that gas critically affect the velocity of propagation of the splash wave as well as the time-varying force on the disc, $F_D$. The existence of the air layer also limits the range of times in which the self-similar solution is valid and, accordingly, the maximum deceleration experienced by the liquid rim, what sets the length scale of the splash drops ejected when We>\Weber_{crit}