The GASMEMS network: Rationale, programme and initial results

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.GASMEMS is an Initial Training Network supported by the European Commission, which aims at training young researchers in the field of rarefied gas flows in MEMS, and at structuring research in Europe in the field of gas microflows in order to improve global fundamental knowledge and enable technological applications to an industrial and commercial level. The partners and the global objectives of this 4 year programme are detailed, and some initial results are presented. First experimental data about the flow of binary gas mixtures through rectangular microchannels are successfully compared with continuum and kinetic models, in the slip flow and early transition regimes. The behaviour of these mixtures has also been simulated in triangular microchannels, for the whole range of the Knudsen number, using a kinetic approach and the McCormack model. Heat transfer in plane microchannels has been numerically investigated, pointing out compressibility and rarefaction effects. The effect of thermal creep has been studied comparing BGK, Smodel and ellipsoidal model with the solution from the full Boltzmann equation. A semi-analytical model of the Knudsen layer has been developed and used to simulate the problem of thermal transpiration in a microchannel. Gaseous flows through rough microchannels have been simulated using kinetic theory and DSMC method, the wall roughness being simulated as a highly porous medium of variable thickness.This study is funded by the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement ITN GASMEMS n° 215504

Fungal Origins of the Bicyclo[2.2.2]diazaoctane Ring System of Prenylated Indole Alkaloids

Over eight different families of natural products, consisting of nearly seventy secondary metabolites, which contain the bicyclo[2.2.2]diazaoctane ring system, have been isolated from various Aspergillus, Penicillium, and Malbranchea species. Since 1968, these secondary metabolites have been the focus of numerous biogenetic, synthetic, taxonomic, and biological studies, and, as such, have made a lasting impact across multiple scientific disciplines. This review covers the isolation, biosynthesis, and biological activity of these unique secondary metabolites containing the bridging bicyclo[2.2.2]diazaoctane ring system. Furthermore, the diverse fungal origin of these natural products is closely examined and, in many cases, updated to reflect the currently accepted fungal taxonomy

Laminar forced convection of liquid flow through silicon microchannels

Many experimental works which appeared in the last decade in the open literature concluded that for channel having a hydraulic diameter less than 1 mm the conventional theory can no longer be considered as able to predict the pressure drop and convective heat transfer coefficients. From a chronological analysis of these experimental results, it is possible to remark that the observed deviations from the prediction of the conventional theory are decreasing. This fact can be explained by considering the dramatic improvement in the microfabrication techniques with the consequent more appropriate control of the channels’ cross-section and the increase in the reliability/accuracy of the recent experimental data. In this paper the conventional theory is used to calculate numerically the Poiseuille numbers and the Nusselt numbers for trapezoidal and rectangular microchannels in which a liquid flows in laminar regime. It is evidenced the role of the cross-section geometry on the pressure drops and the local values of the convective heat transfer coefficients by taking into account the viscous dissipation inside the fluid. The numerical results presented in this paper have evidenced that the conventional theory is able to explain the experimental results obtained for trapezoidal microchannels in terms of friction factors for microchannels with hydraulic diameters greater than 30 µm. It has been demonstrated that for liquid flows, if the microchannel hydraulic diameter becomes less than 50 µm, viscous dissipation effects cannot be ignored for large Reynolds numbers

Exploration of micro-focusing potentialities for microorganism's separation

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A real-time automatic instrument tracking system on cataract surgery videos for dexterity assessment

In this paper we describe the SUITS (Surrey University Instrument Tracking System), an automated video processing system that analyzes videos of cataract surgeries to extract parameters for surgical skill assessment. Through image processing and object tracking techniques the eye is identified, and its movement and direction changes throughout the operation are monitored. Any instrument that moves into or out of the eye is located with its path measured. So far we have developed a prototype real-time system that has demonstrated great potential. The developed system is automatic, with minimal human supervision required throughout the processing time. In addition, the solution is generic, and it can be applied to other tracking problems, possibly other types of surgery videos, with minor modifications