Micro-structured rough surfaces by laser etching for heat transfer enhancement on flush mounted heat sinks

Abstract. The aim of this work is to improve heat transfer performances of ush mounted heat sinks used in electronic cooling. To do this we patterned 1.23 cm2 heat sinks surfaces by micro- structured roughnesses built by laser etching manufacturing technique, and experimentally measured the convective heat transfer enhancements due to dierent patterns. Each roughness diers from the others with regards to the number and the size of the micro-ns (e.g. the micro- n length ranges from 200 to 1100 m). Experimental tests were carried out in forced air cooling regime. In particular fully turbulent ows (heating edge based Reynolds number ranging from 3000 to 17000) were explored. Convective heat transfer coecient of the best micro-structured heat sink is found to be roughly two times compared to the smooth heat sinks one. In addition, surface area roughly doubles with regard to smooth heat sinks, due to the presence of micro-ns. Consequently, patterned heat sinks thermal transmittance [W/K] is found to be roughly four times the smooth heat sinks one. We hope this work may open the way for huge boost in the technology of electronic cooling by innovative manufacturing techniques

Notulae to the Italian alien vascular flora: 17

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records and status changes from casual to naturalized for Italy or for Italian administrative regions for taxa in the genera Callianthe, Chamaecyparis, Chamaeiris, Cotoneaster, Erigeron, Freesia, Hemerocallis, Juglans, Kalanchoë, Ludwigia, Nassella, Paulownia, Physocarpus, Pistia, Saccharum, Setaria, and Vachellia. Nomenclatural and distribution updates, published elsewhere, and corrections are provided as supplementary material

Measurement of isotopic separation of argon with the prototype of the cryogenic distillation plant Aria for dark matter searches

The Aria cryogenic distillation plant, located in Sardinia, Italy, is a key component of the DarkSide-20k experimental program for WIMP dark matter searches at the INFN Laboratori Nazionali del Gran Sasso, Italy. Aria is designed to purify the argon, extracted from underground wells in Colorado, USA, and used as the DarkSide-20k target material, to detector-grade quality. In this paper, we report the first measurement of argon isotopic separation by distillation with the 26 m tall Aria prototype. We discuss the measurement of the operating parameters of the column and the observation of the simultaneous separation of the three stable argon isotopes: 36Ar , 38Ar , and 40Ar . We also provide a detailed comparison of the experimental results with commercial process simulation software. This measurement of isotopic separation of argon is a significant achievement for the project, building on the success of the initial demonstration of isotopic separation of nitrogen using the same equipment in 2019

Fabrication of microstructures on glass by imprinting in conventional furnace for lab-on-chip application

Imprinting micro structures on glass in conventional furnace instead of vacuum chamber was carried out using a nickel alloy mold which was fabricated by diode-pumped solid state laser writing. The layout is designed to serve for DNA analysis. In the development of such micro-fluidics structures, the processing frequency, power, scan speed and pass number are found to be key parameter for obtaining good quality surface and enough depth of channels on master. Studies on these parameters were carried out and the optimal combination of them was determined. Both morphological and structural surface modifications of Ni alloy have been investigated by Field Effect Scanning Electron Microscopy, Energy Dispersive X-ray (EDX) and micro profilometer 2D. This study aims to obtain a low cost and high efficient microfluidic chip for lab-on-chip applicatio

Inkjet printing and low power laser annealing of silver nanoparticle traces for the realization of low resistivity lines for flexible electronics

We report on the realization of low resistance silver lines by inkjet printing of a commercial silver-based ink on a flexible kapton substrate and subsequent low energy laser annealing to promote nanoparticle coalescence. Our approach resulted in low resistivity values, yet using a low-silver product, around 22 wt.%. Traditional hot-plate annealing processes were compared also. The approach is of particular interest for the realization of electronic parts such as passive and chipless radio frequency dentification tags with fully inkjet printed inductors and capacitors - that we also demonstrate