On the Visualization of Thermal Counterflow of He II Past a Circular Cylinder

Thermal counterflow of superfluid ⁴He is investigated experimentally in the proximity of a 3 mm diameter cylinder by analyzing the motions of micrometer-sized solid particles, focusing especially on the occurrence of macroscopic vortices. The influence of heating an opaque brass cylinder by the light source is studied, as thermal counterflow is generated from its surface, and compared with the case of a transparent plexiglass cylinder of the same size. Additionally, we report our preliminary investigation of vertical counterflow around the transparent cylinder. We find that care should be taken when applying conventional visualization techniques—particle image velocimetry and particle tracking velocimetry—as spurious vortical structures might be identified in quantum flows displaying two-fluid behavior.     

Low‐Power Cool Bypass Switch for Hot Spot Prevention in Photovoltaic Panels

With the introduction of high‐current 8‐inch solar cells, conventional Schottky bypass diodes, usually adopted in photovoltaic (PV) panels to prevent the hot spot phenomenon, are becoming ineffective as they cause relatively high voltage drops with associated undue power consumption. In this paper, we present the architecture of an active circuit that reduces the aforementioned power dissipation by profitably replacing the bypass diode through a power MOS switch with its embedded driving circuitry. Experimental prototypes were fabricated and tested, showing that the proposed solution allows a reduction of the power dissipation by more than 70% compared to conventional Schottky diodes. The whole circuit does not require a dedicated DC power and is fully compatible with standard CMOS technologies. This enables its integration, even directly on the panel, thereby opening new scenarios for next generation PV systems.     

Determination of Breakage Parameters in Turbulent Fluid‐Fluid Breakage

Numerous sets of single‐particle breakage experiments are required in order to provide a sufficient database for improving the modeling of fluid particle breakage mechanisms. This work focuses on the interpretation of the physical breakage events captured on video. In order to extract the necessary information required for modeling the mechanisms of the fluid particle breakage events in turbulent flows, a well‐defined image analysis procedure is necessary. Two breakage event definitions are considered, namely, initial breakup and cascade breakup. The reported breakage time, the number of daughter particles created, and the daughter size distribution are significantly affected by the definition used. For each breakage event definition, an image analysis procedure is presented.     

Chemical recycling of glass fibre reinforced composites using subcritical water

A hydrolysis process is applied to degrade an unsaturated polyester resin based on DCPD (dicyclopentadiene) and crosslinked with styrene, as the matrix of a composite material reinforced with long glass fibres. Subcritical conditions of water (200 °C < temperature < 374 °C and pressure < 221bars) were chosen regarding the involved chemistry for the case of simple esters. Several experiments were realised to measure the effects of the process parameters on the efficiency of hydrolysis, on the quality of the recovered fibres and finally on the nature of the recovered organic products. A washing of the fibres is necessary and appears to be an important step of the process realised in batch conditions. The identification of the recovered organic products indicates that monomers of the resin are obtained but also that secondary reactions occur during the hydrolysis process.     

Homogeneous Optical and Electronic Properties of Graphene Due to the Suppression of Multilayer Patches During CVD on Copper Foils

A synthesis method of strictly monolayer and fully homogeneous graphene across tens of centimeter squares, by chemical vapour deposition onto standard copper foils, is presented. The growth technique involves cyclic injection of a carbon precursor separated by idle times with constant hydrogen exposure. The formation of spurious multilayer patches, which accompanies the standard growth techniques based on continuous exposure to methane, is inhibited here, in a broad range of pressure and gas composition, including in two pressure regimes which are known to yield distinctive grain morphologies (dendritic versus hexagonal). Raman spectra confirm the absence of defects within the graphene films. A mechanism for growth/suppression of the multilayer patches based on the carbon storage at defective regions is proposed. The importance of multilayer suppression is highlighted in a comparative study showing the detrimental effect of patches on the performances of graphene transistors and on the optical transparency of stacked layers. The full‐layer graphene sheets are superiorly homogeneous in terms of their optical and electronic properties, and are thus suited for applications for high‐density integration as well as transparent electrodes with spatially continuous optical absorbance. Graphene transistors fabricated by the pulsed CVD method exhibit room‐temperature mobilities with a mean value of 5000 cm² V^?1 s^?1.     

Privacy preserving data sharing and analysis for edge-based architectures

International Journal of Information Security - In this paper, we present a framework for privacy preserving collaborative data analysis among multiple data providers acting as edge of a cloud...     

Molecular Classification and Pharmacogenetics of Primary Plasma Cell Leukemia: An Initial Approach toward Precision Medicine

Primary plasma cell leukemia (pPCL) is a rare and aggressive variant of multiple myeloma (MM) which may represent a valid model for high-risk MM. This disease is associated with a very poor prognosis, and unfortunately, it has not significantly improved during the last three decades. New high-throughput technologies have allowed a better understanding of the molecular basis of this disease and moved toward risk stratification, providing insights for targeted therapy studies. This knowledge, added to the pharmacogenetic profile of new and old agents in the analysis of efficacy and safety, could contribute to help clinical decisions move toward a precision medicine and a better clinical outcome for these patients. In this review, we describe the available literature concerning the genomic characterization and pharmacogenetics of plasma cell leukemia (PCL).