Biosignal and context monitoring: Distributed multimedia applications of body area networks in healthcare

We are investigating the use of Body Area Networks (BANs), wearable sensors and wireless communications for measuring, processing, transmission, interpretation and display of biosignals. The goal is to provide telemonitoring and teletreatment services for patients. The remote health professional can view a multimedia display which includes graphical and numerical representation of patients’ biosignals. Addition of feedback-control enables teletreatment services; teletreatment can be delivered to the patient via multiple modalities including tactile, text, auditory and visual. We describe the health BAN and a generic mobile health service platform and two context aware applications. The epilepsy application illustrates processing and interpretation of multi-source, multimedia BAN data. The chronic pain application illustrates multi-modal feedback and treatment, with patients able to view their own biosignals on their handheld device

Characterization of Metal Sprays Created by a Picosecond Laser-Induced Forward Transfer (LIFT) Process

A new method to analyze and quantify results obtained with the Laser-Induced Forward Transfer (LIFT) process is presented. This experiment based characterization method was designed to investigate the spraying behavior of the LIFT process, that occurs in certain fluence regimes. This method was implemented in MATLAB, and takes 3D data (e.g. obtained from confocal microscopy) as input and subsequently determines an effective radius and the shape of each deposited feature. By using this tool in experiments it was found that, the effective radius of features depends a.o. on the separation between the donor layer and the receiving substrate. In addition, the tool allows statistical investigation of the effective radiu

Linking science and farmers' innovative capacity: diagnostic studies from Ghana and Benin

The article is an introduction to a series of articles about diagnostic studies carried out by eight PhD students in Ghana and Benin. These studies form a prelude to their experimental action research with groups of farmers to develop technologies that work in local conditions and are acceptable to farmers. A last article reports on a comparison of these eight studies by the ninth PhD student in the Convergence of Sciences (CoS) project. In this introductory article, it is argued that the need to ground agricultural research in the needs and circumstances of farmers is as strong as the need to ground research in the international scientific discourse. It explores the reasons why the West African context requires careful diagnostic studies to be able to design agricultural research that is of any use. It introduces preanalytical choice as an overriding concept to explain why choices that reduce the degrees of freedom have to be made explicitly on the basis of criteria. Such criteria are suggested for the quality of preanalytical choices, and the paper ends by examining the way the CoS project made some of its choice

Imaging of the ejection process of nanosecond laser-induced forward transfer of gold

Laser-induced forward transfer is a direct-write process suitable for high precision 3D printing of several materials. However, the driving forces related to the ejection mechanism of the donor ma-terial are still under debate. So far, most of the experimental studies of nanosecond LIFT, are based on post process analysis of either the donor layer and/or the deposits, which were transferred to the receiving substrate. To gain further insights into the ejection dynamics, this article presents results of a series of imaging experiments of the release process of nanosecond LIFT of a 200 nm thick gold donor layer. Images were obtained using a setup which consists of two dual-shutter cameras. Both cameras were combined with a 50× long-distance microscope and used to capture coaxial and side-view images of the ejection process. Bright field illumination of the scene was accomplished by a 6 ns dual-cavity laser source. For laser fluence just above the transfer threshold, the formation of a jet and the subsequent release of a single droplet was observed. The droplet diameter was esti-mated to be about 2 μm. Analysis of the coaxial images indicates the emission of a spectral broad range light which was identified as thermal radiation

Droplet ejection in laser-induced forward transfer: mechanism for droplet fragmentation

Laser-induced forward transfer is a direct-write method suitable for precision printing of various materials. However, occasional defects (i.e. contamination of the receiver due to the impact of multiple small droplets instead of a single droplet) hamper a widespread application of this method. As the ejection mechanism has not been visualized in detail, the cause of these defects is not understood as yet. Therefore, this article presents an experimental study on the ejection process mechanisms of copper-based picosecond laser-induced forward transfer. Images were obtained using bright field illumination by a 6 ns pulsed laser and a 50× long-distance microscope objective. For laser fluences just above the transfer-threshold, the release of a single droplet is frequently (97%) observed. The typical droplet radius in these cases is estimated to be 3 μm. However, images acquired at a later time in time show multiple droplets in the majority (86%) of the observations. The droplet fragments usually follow the main droplet. Two mechanisms to explain these fragments are proposed: i) break-up of “threads” between the donor layer and the ejected droplet; ii) contraction of the ejected droplet. As the phase of the ejected copper is not identified completely, the exact mechanism is not yet known and will be subject of further research

Natuurlijk geventileerde vleesstierenstal met betonroosters

Onderzoek werd verricht naar de ammoniakemissie uit een natuurlijk geventileerde vleesstierenstal met 132 dierplaatsen

Laser-induced periodic surface structures:Fingerprints of light localization

The finite-difference time-domain (FDTD) method is used to study the inhomogeneous absorption of linearly polarized laser radiation below a rough surface. The results are first analyzed in the frequency domain and compared to the efficacy factor theory of Sipe and coworkers. Both approaches show that the absorbed energy shows a periodic nature, not only in the direction orthogonal to the laser polarization, but also in the direction parallel to it. It is shown that the periodicity is not always close to the laser wavelength for the perpendicular direction. In the parallel direction, the periodicity is about lambda/Re((n) over tilde), with (n) over tilde being the complex refractive index of the medium. The space-domain FDTD results show a periodicity in the inhomogeneous energy absorption similar to the periodicity of the low-and high-spatial-frequency laser-induced periodic surface structures depending on the material's excitation