Enhancement of flow boiling heat transfer in microchannels by nano- and micro-surface treatments

This work investigates the flow boiling heat transfer in microchannels with the aim of developing compact cooling systems which can be adapted to miniaturized power components. Nano and micro-surface treatments were used as innovative techniques to improve the heat transfer performance as well as to delay the intermittent dryout. It was observed that the micro-structured surfaces show significant enhancements (up to 85%) in heat transfer compared to the smooth surfaces. Especially, using the highly-wetted structured surface, the intermittent dryout is improved

Measurement of the Tau Lepton Polarisation at LEP2

A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation Pτ of tau leptons produced in e + e − annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value Pτ=−0.164±0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV.A first measurement of the average polarisation P_tau of tau leptons produced in e+e- annihilation at energies significantly above the Z resonance is presented. The polarisation is determined from the kinematic spectra of tau hadronic decays. The measured value P_tau = -0.164 +/- 0.125 is consistent with the Standard Model prediction for the mean LEP energy of 197 GeV

The fight against COVID-19 in the age of Connected Medical Sensors and Computational Grids

The dramatic progress in the medical sensor performance and connectivity opens new healthcare perspectives such as home diagnostic of patients, prompt detection of epidemic emergence and in such a case, detailed study of disease properties, statistical monitoring of the evolution from the regional to international levels while providing most relevant field data for validation of epidemiological forecast

Large CPU-Farm Implementation in a HEP experiment with Tight Constraints (June 2005)

The LHCb event filter farm will contain ~ 2000 dual-CPU computers, located in a 80 square meters room underground at the experiment pit. To implement such a large farm in such a small volume, a lot of issues have to be addressed. This paper describes the powering, cooling and packing solutions developed by LHCb for its event filter farm

A new approach to understanding the effects of surface wettability on nucleate boiling

International audienceAlthough boiling process has been a major subject of research for several decades, its physics still remain unclear and require further investigation. This study aims at highlighting the effects of surface wettability on pool boiling heat transfer. Nanocoating techniques were used to vary the water contact angle from 20 to 110 ◦ by modifying nanoscale surface topography and chemistry. The experimental results obtained disagree with the predictions of the classical models. A new approach of nucleation mechanism is established to clarify the nexus between the surface wettability and the nucleate boiling heat transfer. In this approach, we introduce the concept of macro- and micro- contact angles to explain the observed phenomeno

FEDSM-ICNMM2010-30478 FLOW BOILING OF WATER ON NANOCOATED SURFACES IN A MICROCHANNEL

ABSTRACT Experiments were performed to study the effects of surface wettability on flow boiling of water at atmospheric pressure. The test channel is a single rectangular channel 0.5 mm high, 5 mm wide and 180 mm long. The mass flux was set at 100 kg/m² s and the base heat flux varied from 30 to 80 kW/m². Water enters the test channel under subcooled conditions. The samples are silicone oxide (SiOx), titanium (Ti), diamond-like carbon (DLC) and carbon-doped silicon oxide (SiOC) surfaces with static contact angles of 26°, 49°, 63° and 103°, respectively. The results show significant impacts of surface wettability on heat transfer coefficient