Bond Strength Tests Between Silicon Wafers and Duran Tubes (Fusion Bonded Fluidic Interconnects)

The fusion bond strength of glass tubes with standard silicon wafers is presented. Experiments with plain silicon wafers and those coated with silicon oxide and silicon nitride are presented. Results obtained are discussed in terms of homogeneity and strength of fusion bond. High pressure testing shows that the bond strength is large enough for most applications of fluidic interconnects. The bond strength for 525 /spl mu/m thick silicon with glass tubes having outer diameter of 6 mm and with wall thickness 2 mm, is more than 60 bars after annealing at a temperature of 800/spl deg/C

Strategic evaluation study on child-centred community development - Synthesis report

This strategic formative evaluation was carried out by Wageningen International Capacity Development & Institutional Change (CD&IC) programme from May to September 2009. The evaluation aims to obtain insight into the understanding of CCCD within Plan, and to learn more about the factors that favour or obstruct the implementation of Child Centred Community Development (CCCD) in practice. Suggestions on improving CCCD as an approach to development are provided, as well as an analysis of capacity development needs for CCCD implementation. This evaluation report is a product of Phase I of the complete anticipated evaluation trajectory. Phase II will most likely include an international workshop around the findings of Phase I. The findings of Phase I will contribute to the track record for the MFS II application to the Dutch Ministry of Foreign Affairs which Plan Netherlands is currently preparing. The study comprised a desk research stage, which reviewed relevant Plan documentation as well as consultations with key stakeholders within Plan worldwide. During this stage face to face interviews were conducted in Plan IH office in Woking, and at NLNO in Amsterdam. Other interviews with stakeholders in ROs and NOs were done using Skype. Furthermore two field studies were conducted in Kenya and Bangladesh. Given the fact that the topic of the study is broad, it is limited to analysis of the wider issues pertaining to CCCD rather than in-depth detailed analysis of these issues

The influence of the horn effect in tyre/road noise

The horn effect is known as an important amplification mechanism in tyre/road noise. The name is referring to the geometry between tyre and road surface which resembles an exponential horn. The horn effect is a common subject for both experimental and numerical research. Contrary to previous studies which considered point sources, this paper focusses on the horn effect by simulated tyre vibrations. The amplification of acoustic pressure, however, depends largely on the location of the observer. The sound power can be used as a measure for the horn effect which is independent on the point of observation. In this paper, the sound radiation problem is solved using the boundary element method (BEM). First, a case study considering equivalent point sources is used to validate the accuracy of the boundary element model and solver using experimental results. Next, the vibrations of tyres rolling on textured road surfaces are investigated numerically. The computed tyre vibrations are used to study the horn effect using different tyre designs. The amplification by horn effect is determined by the combined tyre/road geometry and the distribution of the noise. The current method may be used to systematically study the influence of the horn effect, for example, during tyre development

An implicit and explicit solver for contact problems

The interaction of rolling tyres with road surfaces is one of the major contributions to road traffic noise. The generation mechanisms of tyre/road noise are usually separated in structure borne and airborne noise. In both mechanisms the contact zone is important. In order to reduce tyre/road noise at the source, accurate (numerical) prediction models are needed. For accurate results, the tyre has to be modelled by a threedimensional finite element model, accounting for complex rubber material behaviour, tread profiles and a detailed tyre construction. A dynamic analysis of a tyre in contact can then be carried out in the time domain. The Structural Dynamics and Acoustics group of the University of Twente has developed an alternative contact solver. The solver, in which the contact condition is always satisfied, is successfully applied to an implicit and explicit three-dimensional finite element model. As a consequence there is no need for contact\ud elements or contact parameters. The finite element model is valid for large translations and rotations, in which different material models and friction models can be added. This paper explains the solver for an implicit and explicit scheme and presents some examples. In one of the examples a deformable rubber ring is modelled, which is rolling on a rigid surface at a slip angle. The results are compared to the finite element package Abaqus. The examples show the robustness and potential of the algorithm

Enhanced sensitivity of postsynaptic serotonin-1A receptors in rats and mice with high trait aggression

Individual differences in aggressive behaviour have been linked to variability in central serotonergic activity, both in humans and animals. A previous experiment in mice, selectively bred for high or low levels of aggression, showed an up-regulation of postsynaptic serotonin-1A (5-HT1A) receptors, both in receptor binding and in mRNA levels, in the aggressive line. The aim of this experiment was to study whether similar differences in 5-HT1A receptors exist in individuals from a random-bred rat strain, varying in aggressiveness. In addition, because little is known about the functional consequences of these receptor differences, a response mediated via postsynaptic 5-HT1A receptors (i.e., hypothermia) was studied both in the selection lines of mice and in the randomly bred rats. The difference in receptor binding, as demonstrated in mice previously, could not be shown in rats. However, both in rats and mice, the hypothermic response to the 5-HT1A agonist alnespirone was larger in aggressive individuals. So, in the rat strain as well as in the mouse lines, there is, to a greater or lesser extent, an enhanced sensitivity of postsynaptic 5-HT1A receptors in aggressive individuals. This could be a compensatory up-regulation induced by a lower basal 5-HT neurotransmission, which is in agreement with the serotonin deficiency hypothesis of aggression.