INTRODUCTION Heat and moisture exchangers in combination with a bacterial and viral filter (HMEF) are widely used during general anaesthesia. Excess patient secretions occluding the HMEF have been responsible for previous case reports of airway obstruction. A previous study suggested that differences in HMEF design might contribute to filter obstruction under wet conditions. METHODS We tested...

Heat and moisture exchanging filters (HMEFs) can be blocked by secretions. We have studied HMEF performance under wet conditions to see which particular design features predispose to this complication. Dar Hygrobac-S (composite felt filter and cellulose exchanger), Dar Hygroster (composite pleated ceramic membrane and cellulose exchanger) and Pall BB22-15 (pleated ceramic membrane) HMEFs were t...

the liquid metal flow and the solidification behaviours in a multi-cavity casting mould of two automotive cast parts were simulated in three dimensions. the commercial code, flow-3d® was used because it can track the front of the molten metal by a volume of fluid (vof) method and allows complicated parts to be modeled by the fractional area/volume obstacle representation (favor) method. the gre...

We propose a triplexer in a low temperature co-fired ceramic substrate for ultra-wideband (UWB) and 2.4GHz wireless systems. This triplexer can be applied to the band of 2.4GHz wireless systems (2.4 2.5GHz), the band group 1 (3.168 4.752GHz) of multiband orthogonal frequency-division multiplexing UWB wireless systems, and the band groups 3 and 4 (6.336 9.504GHz) of the same systems. The triplex...

A device was adapted to allow for time-integrated sampling of fluid from the rumen via a cannula. The sampler consisted of a cup-shaped ceramic filter positioned in the ventral rumen of a cannulated cow and attached to a tube through which fluid entering the filter was removed continuously using a peristaltic pump. Rate of ruminal fluid removal using the device was monitored over two 36-h perio...

Multilayer LTCC substrates with screen printed conductors are considered as a key technology for coming RF wireless communication and automotive applications. The direct integration of passive components inside the LTCC environment strongly reduces the costs of a multichip module (MCM). The aim of this paper is to present an efficient way to design a band pass filter for 25GHz with regard to th...