Impact of swirl and bluff-body on the transfer function of premixed flames

The frequency response of three lean methane/air flames submitted to flowrate perturbations is analyzed for flames featuring the same equivalence ratio and thermal power, but a different stabilization mechanism. The first flame is stabilized by a central bluff body without swirl, the second one by the same bluff body with the addition of swirl and the last one only by swirl without central insert. In the two last cases, the swirl level is roughly the same. These three flames feature different shapes and heat release distributions, but their Flame Transfer Function (FTF) feature about the same phase lag at low frequencies. The gain of the FTF also shows the same behavior for the flame stabilized by the central insert without swirl and the one fully aerodynamically stabilized by swirl. Shedding of vortical structures from the injector nozzle that grow and rollup the flame tip controls the FTF of these flames. The flame stabilized by the swirler-plus-bluff-body system features a peculiar response with a large drop of the FTF gain around a frequency at which large swirl number oscillations are observed. Velocity measurements in cold flow conditions reveal a strong reduction of the size of the vortical structures shed from the injector lip at this forcing condition. The flame stabilized aerodynamically only by swirl and the one stabilized by the bluff body without swirl do not exhibit any FTF gain drop at low frequencies. In the former case, large swirl number oscillations are still identified, but large vortical structures shed from the nozzle also persist at the same forcing frequency in the cold flow response. These different flame responses are found to be intimately related to the dynamics of the internal recirculation region, which response strongly differs depending upon the injector used to stabilize the flame

“Fibrous nests” in human hepatocellular carcinoma express a Wnt-induced gene signature associated with poor clinical outcome

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Moiré induced organization of size-selected Pt clusters soft landed on epitaxial graphene

International audienceTwo-dimensional hexagonal arrays of Pt nanoparticles (1.5 nm diameter) have been obtained by deposition of preformed and size selected Pt nanoparticles on graphene. This original self-organization is induced, at room temperature, by the 2D periodic undulation (the moiré pattern) of graphene epitaxially grown on the Ir(111) surface. By means of complementary techniques (scanning tunneling microscopy, grazing incidence X ray scattering), the Pt clusters shapes and organization are characterized and the structural evolution during annealing is investigated. The soft-landed clusters remain quasi-spherical and a large proportion appears to be pinned on specific moiré sites. The quantitative determination of the proportion of organized clusters reveals that the obtained hexagonal array of the almost spherical nanoparticles is stable up to 650 K, which is an indication of a strong cluster-surface interaction

Organization and magnetic properties of FePt nanoparticles deposited on graphene/Ir moiré pattern

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Elaboration of nanomagnet arrays: organization and magnetic properties of mass-selected FePt nanoparticles deposited on epitaxially grown graphene on Ir(111)

International audienceThe moiré pattern created by the epitaxy of a graphene sheet on an iridium substrate can be used as a template for the growth of 2D atomic or cluster arrays. We observed for the first time a coherent organization of hard magnetic preformed FePt nanoparticles on the 2D lattice of graphene/Ir(111). Nanoparticles of 2 nm diameter have been mass-selected in gas phase and deposited with a low energy on the hexagonal moiré pattern. Their morphology and organization have been investigated using Grazing Incidence Small Angle X-ray Scattering, while their magnetic properties have been studied by X-ray Magnetic Circular Dichroism, both pointing to a FePt cluster/graphene surface specific interaction. The spatial coherence of the nanoparticles is preserved upon annealing up to 700°C where the hard magnetic phase of FePt is obtained

The Impact of the COVID-19 Lockdown on Weight Loss and Body Composition in Subjects with Overweight and Obesity Participating in a Nationwide Weight-Loss Program: Impact of a Remote Consultation Follow-Up—The CO-RNPC Study

International audienceThe aim of this study was to assess the impact of the nationwide total lockdown (LD) in France on weight loss and body composition modifications in subjects participating in a weight loss program and to evaluate the impact of remote consultations on participants’ adherence to the weight loss program. The CO-RNPC study was a prospective multicentre cohort study including participants undergoing a two to six months program. The rate of weight loss in kg/week was computed before (15 days), during (99 days) and after LD (15 days). In the 1550 completing participants, body weight decreased from 87.1 kg [IQR 77.0; 100.2] to 82.3 kg [72.1; 94.3] resulting in a difference of −4.79 kg [−4.48; −5.10] (p < 0.01), with a corresponding reduction in waist circumference by 4 cm ([0; 9], p < 0.01). The median weight loss was 4.4 kg [0.5; 9.4] in those who used remote consultations, and 1.4 kg [0.8; 5.7] in the no remote consultation group (p < 0.01). In this large prospective cohort, we observed that the rate of weight loss was reduced during LD. This reduction was counterbalanced in participants involved in a remote consultation follow-up with a dose-effect response based on the number of remote consultations

Thin-body ESD protections in 28nm UTBB-FDSOI: From static to transient behavior

International audienceInnovative Ultra-Thin Body and Buried Oxide FDSOI protections (BBC-T and Z2-FET) are characterized and analyzed in order to assess the CDM time domain behavior. In addition to static (leakage and triggering) control, it is found that front and back gate coupling is a very efficient way to improve the transient responses of the proposed devices

Simultaneous Characterization of Metabolic, Cardiac, Vascular and Renal Phenotypes of Lean and Obese SHHF Rats

International audienceIndividuals with metabolic syndrome (MetS) are prone to develop heart failure (HF). However, the deleterious effects of MetS on the continuum of events leading to cardiac remodeling and subsequently to HF are not fully understood. This study characterized simultaneously MetS and cardiac, vascular and renal phenotypes in aging Spontaneously Hypertensive Heart Failure lean (SHHF +/? regrouping +/+ and +/cp rats) and obese (SHHF cp/cp , ''cp'' defective mutant allele of the leptin receptor gene) rats. We aimed to refine the milestones and their onset during the progression from MetS to HF in this experimental model. We found that SHHF cp/cp but not SHHF +/? rats developed dyslipidemia, as early as 1.5 months of age. This early alteration in the lipidic profile was detectable concomitantly to impaired renal function (polyuria, proteinuria but no glycosuria) and reduced carotid distensibility as compared to SHHF +/? rats. By 3 months of age SHHF cp/cp animals developed severe obesity associated with dislipidemia and hypertension defining the onset of MetS. From 6 months of age, SHHF +/? rats developed concentric left ventricular hypertrophy (LVH) while SHHF cp/cp rats developed eccentric LVH apparent from progressive dilation of the LV dimensions. By 14 months of age only SHHF cp/cp rats showed significantly higher central systolic blood pressure and a reduced ejection fraction resulting in systolic dysfunction as compared to SHHF +/?. In summary, the metabolic and hemodynamic mechanisms participating in the faster decline of cardiac functions in SHHF cp/cp rats are established long before their physiological consequences are detectable. Our results suggest that the molecular mechanisms triggered within the first three months after birth of SHHF cp/cp rats should be targeted preferentially by therapeutic interventions in order to mitigate the later HF development