The role of atmospheric boundary layer-surface interactions on the development of coastal fronts

Frictional convergence and thermal difference between land and sea surface are the two surface conditions that govern the intensity and evolution of a coastal front. By means of the mesoscale model MM5, we investigate the influence of these two processes on wind patterns, temperature and precipitation amounts, associated with a coastal front, observed on the west coast of The Netherlands in the night between 12 and 13 August 2004. The mesoscale model MM5 is further compared with available observations and the results of two operational models (ECMWF and HIRLAM). HIRLAM is not capable to reproduce the coastal front, whereas ECMWF and MM5 both calculate precipitation for the coastal region. The precipitation pattern, calculated by MM5, agrees satisfactorily with the accumulated radar image. The failure of HIRLAM is mainly due to a different stream pattern at the surface and consequently, a different behaviour of the frictional convergence at the coastline. <br><br> The sensitivity analysis of frictional convergence is carried out with the MM5 model, by varying land surface roughness length (<I>z</I><sub>0</sub>). For the sensitivity analysis of thermal difference between sea and land surface, we changed the sea surface temperature (SST). Increasing surface roughness implies stronger convergence near the surface and consequently stronger upward motions and intensification of the development of the coastal front. Setting land surface roughness equal to the sea surface roughness means an elimination of frictional convergence and results in a diminishing coastal front structure of the precipitation pattern. The simulation with a high SST produces much precipitation above the sea, but less precipitation in the coastal area above land. A small increment of the SST results in larger precipitation amounts above the sea; above land increments are calculated for areas near the coast. A decrease of the SST shifts the precipitation maxima inland, although the precipitation amounts diminish. In the situation under study, frictional convergence is the key process that enhances the coastal front intensity. A thermal difference between land and sea equal to zero still yields the development of the coastal front. A lower SST than land surface temperature generates a reversed coastal front. <br><br> This study emphasizes the importance of accurate prescription of surface conditions as input of the numerical weather prediction model to improve coastal front predictability

Cost-effectiveness of recurrence risk guided care versus care as usual in women who suffered from early-onset preeclampsia including HELLP syndrome in their previous pregnancy (the PreCare study)

Contains fulltext : 87321.pdf (publisher's version ) (Open Access

A rapid review of serious games: from healthcare education to dental education

Introduction: Games involving technology have the potential to enhance hand-eye coordination and decision-making skills. As a result, game characteristics have been applied to education and training, where they are known as serious games. There is an increase in the volume of literature on serious games in healthcare education; however, evidence on their impact is still ambiguous. Aims: The aims of this study were (1), to identify high-quality evidence (systematic reviews or meta-analyses) regarding impacts of serious games on healthcare education; and (2), to explore evidence regarding impacts of serious games in dental education. Methods: A rapid review of the literature was undertaken to synthesise available evidence and examine serious games in healthcare education (Stage 1) and dental education (Stage 2). Results: Nine systematic reviews were included in Stage 1, four of which were of high, three of moderate, and two of low quality. For Stage 2, two randomised control trials with moderate quality were included. The findings demonstrated that serious games are potentially effective learning tools in terms of knowledge and skills improvement, although outcomes of serious games over traditional learning approaches were not consistent. In addition, serious games appeared to be more engaging and satisfying for students, which could be considered as the most important positive impact. Conclusion: Serious games provide an option for healthcare and dental education but remain under-utilised and researched. At best, they offer a similar experience to other methods in relation to educational outcome; however, they can provide a supplementary strategy to engage students and improve learner satisfaction

Study of tracking disturbances for high speed Blu-Ray drives

Confidential

Modelling of disturbance forces of a x-y manipulator on a floating platform

Abstract—This paper describes a multi-body model for pre-dicting disturbance forces and torques caused by a multi-stage manipulator (2 DOF) on a floating platform (6 DOF). The manipulator consists of a beam attached to two parallel linear ironless actuators and a rotary arm underneath the beam. The model prediction can be used as a feed-forward in the control of the magnetic bearings of the platform. Lagrange’s equations are used for the analysis, which provide a convenient way for deriving a multi-body model without the need for separating all bodies and calculation of all interacting forces and torques. The model is verified with measurements. The experimental setup consists of a manipulator on an aluminium platform which is connected to the fixed world via a 6 DOF force-torque sensor which is used to verify the model. I

Study of tracking disturbances for high speed Blu-Ray drives

Confidential