Seeds of Life in Space (SOLIS). III. Zooming Into the Methanol Peak of the Prestellar Core L1544

Toward the prestellar core L1544, the methanol (CH3OH) emission forms an asymmetric ring around the core center, where CH3OH is mostly in solid form, with a clear peak at 4000 au to the northeast of the dust continuum peak. As part of the NOEMA Large Project SOLIS (Seeds of Life in Space), the CH3OH peak has been spatially resolved to study its kinematics and physical structure and to investigate the cause behind the local enhancement. We find that methanol emission is distributed in a ridge parallel to the main axis of the dense core. The centroid velocity increases by about 0.2 km s−1 and the velocity dispersion increases from subsonic to transonic toward the central zone of the core, where the velocity field also shows complex structure. This could be an indication of gentle accretion of material onto the core or the interaction of two filaments, producing a slow shock. We measure the rotational temperature and show that methanol is in local thermodynamic equilibrium (LTE) only close to the dust peak, where it is significantly depleted. The CH3OH column density, N tot(CH3OH), profile has been derived with non-LTE radiative transfer modeling and compared with chemical models of a static core. The measured N tot(CH3OH) profile is consistent with model predictions, but the total column densities are one order of magnitude lower than those predicted by models, suggesting that the efficiency of reactive desorption or atomic hydrogen tunneling adopted in the model may be overestimated; or that an evolutionary model is needed to better reproduce methanol abundance

VizieR Online Data Catalog: SOLIS. II. L1157-B1 NH2CHO image (Codella+, 2017)

Datacube in fits format of the NH2CHO(41,4-31,3) towards L1157-B1 using the IRAM-NOEMA interferometer (see Fig. 1). The L1157-B1 shock was observed at 3mm with the IRAM NOEMA seven-element array during several tracks in July, October, and November 2015 using both the C and D configurations. The shortest and longest baselines are 19m and 237m, respectively, allowing us to recover emission at scales up to ~17". (2 data files)

VizieR Online Data Catalog: SOLIS. I. OMC2-FIR4 HC3N and HC5N images (Fontani+, 2017)

IRAM-NOEMA Interferometer, 3mm receiver, Widex and Narrow-band correlators. Observations with the IRAM NOEMA Interferometer of HC3N (9-8) and HC5N (31-30), at rest frequencies 81.881468GHz and 82.539039GHz , respectively, towards OMC-2 FIR4 have been carried out over 5 days between the 5th and the 19th of August, 2015. The HC3N line was observed in the Widex band correlator, providing a resolution in velocity of ~7.15km/s, while the HC5N line was observed also in the Narrow band correlator with a resolution in velocity of ~0.57km/s. (2 data files)

Improvement of heat transfer in joule effect tubular heat exchanger by geometrical modifications. Applications to model (milky dessert) and real (whole egg) fluids

International audienc

Amélioration des performances thermiques d'un échangeur tubulaire à effet Joule (T.P.C.) par modification géométrique. Application sur des fluides modèle et réel

National audienc

Design and performance benchmark of various architectures of a piezoelectric bimetallic strip heat engine

International audienceThis paper deals with an investigation of a thermal energy harvester based on the coupling of a piezoelectric membrane and a bimetallic strip heat engine. The general working principle of the device consists of a double conversion mechanism: the thermal energy is first converted into mechanical energy by means of a bimetallic strip, then the mechanical energy is converted into electricity with a piezoelectric membrane. This paper deals with the study and optimization of the harvester's design. First, the piezoelectric membrane configuration is studied to find the most efficient way to convert mechanical energy into electricity. A benchmark of various piezoelectric materials is then presented to point out the most efficient materials. Finally, our study focuses on the bimetallic strip's properties: the effect of its dimensions of its thermal hysteresis on the harvester's performances are studied and compared. Thanks to these different steps, we were able to point out the best configuration to convert efficiently thermal heat flux into electricit

SPICE modelling of a coupled piezoelectric-bimetal heat engine for autonomous Wireless Sensor Nodes (WSN) power supply

International audienc