Void fraction disturbances in a uniform bubbly fluid

The paper is concerned with the flow of dispersions of gas bubbles in liquid, with bubble sizes such that the inertia forces on the bubbles are of importance to the dynamics. One-dimensional conservation equations are derived, which govern the flow when the deviations from the uniform state are small. These are used to describe the features of the propagation of void fraction disturbances, and to investigate the stability of uniform bubbly flows. The results are compared with what has been observed in experiments

Surrogate modeling of RF circuit blocks

Surrogate models are a cost-effective replacement for expensive computer simulations in design space exploration. Literature has already demonstrated the feasibility of accurate surrogate models for single radio frequency (RF) and microwave devices. Within the European Marie Curie project O-MOORE-NICE! (Operational Model Order Reduction for Nanoscale IC Electronics) we aim to investigate the feasibility of the surrogate modeling approach for entire RF circuit blocks. This paper presents an overview about the surrogate model type selection problem for low noise amplifier modeling

Omvang, transport en verwerking van de mestoverschotten voor twee fasen

In 1987 worden als gevolg van de Wet Bodembescherming en de Meststoffenwet beperkingen gesteld aan het bemesten van landbouwgrond met dierlijke mest. In 4 fasen met steeds strengere normen wordt naar een eindnorm gestreefd. Met speciaal ontwikkelde computerprogramma's is de omvang bepaald van de mestoverschotten in Nederland bij de normeringen die gelden in de eerste 2 fasen, en zijn de transport- en verwerkingsstromen van de mestoverschotten tegen minimale kosten berekend. De transportstromen zijn zowel bij hoge als bij lage acceptatie van mest door bedrijven met mesttekorten bepaald en voor 31 regio's weergegeve

The Effect of Answering Questions that Differ in Specificity on Mental Effort and Text Retention

Kester, L., Tabbers, H. K., Gorissen, C., & Kirschner, P. A. (2011, August/September). The effect of answering questions that differ in specificity on mental effort and text retention. Paper presented at the biannual meeting of the European Association for Research on Learning and Instruction, Exeter, Great Britain.Tested information is retained longer than studied information. This, so called, testing effect is thoroughly studied in memory research. Recently, a renewed interest in the testing effect in an educational context can be observed. This study is placed within this line of research and investigates two aspects of the testing effect, namely, effortful retrieval and retrieval induced facilitation. Participants were randomly assigned to one of three experimental conditions that differed in the learning strategy used. Participants either restudied a text that they had received, answered specific questions after studying the text, or answered less specific questions after studying the text. It is assumed that more effort is needed to answer the less specific questions than to answer the specific questions. Therefore, we hypothesize that the less specific questions will produce a stronger testing effect than the specific questions. In addition, we investigate if the benefits of taking an initial test spill over to answering questions that were not initially tested. The results of this study confirm that answering less specific questions requires more effort, however, this does not pay off in a better retention of facts after a week. Nevertheless, a testing was found for the specific questions. No spill over effects were found

Blind Kriging: implementation and performance analysis

When analysing data from computationally expensive simulation codes or process measurements, surrogate modelling methods are firmly established as facilitators for design space exploration, sensitivity analysis, visualisation and optimisation. Kriging is a popular surrogate modelling technique for data based on deterministic computer experiments. There exist several types of Kriging, mostly differing in the type of regression function used. Recently a promising new variable selection technique was proposed to identify a regression function in the Kriging framework. In this paper this type of Kriging, i.e., blind Kriging, has been efficiently implemented in Matlab (R) and has been extended. The implementation is validated and tested on several examples to illustrate the strength and weaknesses of this new, promising modelling technique. It is shown that the performance of blind Kriging is as good as, or better than ordinary Kriging. Though, blind Kriging comes at double the computational cost with respect to ordinary Kriging

Does touch matter? The impact of stroking versus non-stroking maternal touch on cardio-respiratory processes in mothers and infants

The beneficial effects of touch in development were already observed in different types of skin-to-skin care. In the current study, we aimed at studying potential underlying mechanisms of these effects in terms of parasympatho-inhibitory regulation. We examined the specific impact of affective maternal stroking versus non-stroking touch on the cardio-respiration of both mothers and infants in terms of respiratory sinus arrhythmia (RSA). We compared a 3-min TOUCH PERIOD (stroking or non-stroking touch) with a baseline before (PRE-TOUCH) and after (POST-TOUCH) in 45 dyads (24 stroking/21 non-stroking touch) with infants aged 4–16 weeks. We registered mother-infant ECG, respiration and made video-recordings. We calculated RR-interval (RRI), respiration rate (fR) and (respiratory corrected) RSA and analyzed stroking mean velocity rate (MVR) of the mothers. ANOVA-tests showed a significant different impact on infants' respiratory corrected RSA of stroking touch (increase) versus non-stroking touch (decrease). Further, during and after stroking touch, RRI significantly increased whereas fR significantly decreased. Non-stroking touch had no significant impact on infants' RRI and fR. In the mothers, RRI significantly decreased and fR significantly increased during the TOUCH PERIOD. The mothers' MVR occurred within the range of 1–10 cm/s matching with the optimal afferent stimulation range of a particular class of cutaneous unmyelinated, low-threshold mechano-sensitive nerves, named c-tactile (CT) afferents. We suggest CT afferents to be the a potential missing link between the processing of affective touch and the development of physiological and emotional self-regulation. The results are discussed with regard to the potential role of CT afferents within the building of early self-regulation as part of a multisensory intuitive parenting system and the importance to respect this ecological context of an infant in research and clinical applications

Hardware Sequencing of Inflatable Nonlinear Actuators for Autonomous Soft Robots

Soft robots are an interesting alternative for classic rigid robots in appli-cations requiring interaction with organisms or delicate objects. Elastic inflatable actuators are one of the preferred actuation mechanisms for soft robots since they are intrinsically safe and soft. However, these pneumatic actuators each require a dedicated pressure supply and valve to drive and control their actuation sequence. Because of the relatively large size of pres-sure supplies and valves compared to electrical leads and electronic control-lers, tethering pneumatic soft robots with multiple degrees of freedom is bulky and unpractical. Here, a new approach is described to embed hardware intelligence in soft robots where multiple actuators are attached to the same pressure supply, and their actuation sequence is programmed by the inter-action between nonlinear actuators and passive flow restrictions. How to model this hardware sequencing is discussed, and it is demonstrated on an 8-degree-of-freedom walking robot where each limb comprises two actua-tors with a sequence embedded in their hardware. The robot is able to carry pay loads of 800 g in addition to its own weight and is able to walk at travel speeds of 3 body lengths per minute, without the need for complex on-board valves or bulky tethers.ERC starting gran