GRANDMA is a network of 25 telescopes of different sizes, including both photometric and spectroscopic facilities. The network aims to coordinate follow-up observations of gravitational-wave candidate alerts, especially those with large localisation uncertainties, to reduce the delay between the initial detection and the optical confirmation. In this paper, we detail GRANDMA’s observational performance during Advanced LIGO/Advanced Virgo Observing Run 3 (O3), focusing on the second part of O3; this includes summary statistics pertaining to coverage and possible astrophysical origin of the candidates. To do so, we quantify our observation efficiency in terms of delay between gravitational-wave candidate trigger time, observations, and the total coverage. Using an optimised and robust coordination system, GRANDMA followed-up about 90% of the gravitational-wave candidate alerts, i.e. 49 out of 56 candidates. This led to coverage of over 9000 deg2 during O3. The delay between the gravitational-wave candidate trigger and the first observation was below 1.5 hour for 50% of the alerts. We did not detect any electromagnetic counterparts to the gravitational-wave candidates during O3, likely due to the very large localisation areas (on average thousands of degrees squares) and relatively large distance of the candidates (above 200 Mpc for 60% of BNS candidates). We derive constraints on potential kilonova properties for two potential binary neutron star coalescences (GW190425 and S200213t), assuming that the events’ locations were imaged.

1Particle flocculation with chemical flocculant addition is an essential step in water treatment. 2The performance of flocculation and the property of the flocs formed affect the overall results 3 of the treatment process. In addition to particulate impurities, the presence of organic matter 4 in water, such as natural organic materials (NOM), also influence the effectiveness of 5 chemical flocculation. In this paper, the PIV system was employed to investigate the 6 flocculation dynamics for different flocculants in different model waters. With the PIV and 7 image analysis, the change in particle size distribution could be well recorded. Using the 8 sequence of flocculation, shear breakage and re-flocculation on a jar-test device together with 9 the PIV system, the rate of floc formation, the strength of the flocs, the recovery of broken 10 flocs, and the morphological and structural features of the flocs were characterized. The 11 results indicated that the adsorption of HA on the particle will stabilized the particles, hence 12 hindered the flocculation process. Sweep flocculation using a higher chemical coagulant 13 dosage was an effective means of process enhancement for the removal of particulates and 14 associated organic matter. The dynamics of A-B-R process was characterized by particle size 15 distribution (PSD) measurement with PIV setup. The particle strength and reversibility 16 capability were examined. Strength index showed the HA flocs have comparable strength, 17 while recovery index indicated a less recovery capability with the increasing of HA 18 concentration after exposure to a higher shear, especially for ferric HA flocs. It appears that 19 the bonds holding HA flocs together are not purely physical bonds given the limited regrowth 20 seen. Finally, evolution of floc structure during A-B-R process was analyzed by investigated 21 the fractal dimension D b . The results were generally consistent with previous PSD 22 measurements. It suggested that the structure of flocs in breakage became more compact with 23 little permeability. An increase in floc compaction provides a further explanation for the 24 limited regrowth for most of flocs. According to the performances of alum and ferric, it can 25 3 be noticed that HA flocs have different properties dependent on which chemical coagulant is 26 used. Alum produced larger HA flocs which endured a higher recovery capability after 27 exploring higher shear, hence, compared to ferric, it could be preferred to using in the 28 practical enhanced coagulation unit. 29 30 Keywords: Aggregation-breakage-re-flocculation; humic acid; hydrodynamics; particle image 31 velocimetry (PIV). 32 33The irreversibility of aggregates during cycled shear is most likely the result of 55 particle-flocculant bond breakage during fragmentation, hence the reorganisation and 56 restructuring can both occur. Experimental shear-induced coagulation-fragmentation 57 processes [11][12][13][14] found that the fractal dimension shifts to a larger value compared to the 58 5 initial one...

Abstract. LFEW is a low frequency electromagnetic wave detector mounted on TC-2, which can measure the magnetic fluctuation of low frequency electromagnetic waves. The frequency range is 8 Hz to 10 kHz. LFEW comprises a boommounted, three-axis search coil magnetometer, a preamplifier and an electronics box that houses a Digital Spectrum Analyzer. LFEW was calibrated at Chambon-la-Forêt in France. The ground calibration results show that the performance of LFEW is similar to that of STAFF on TC-1. The first results of LFEW show that it works normally on board, and that the AC magnetic interference of the satellite platform is very small. In the plasmasphere, LFEW observed the ion cyclotron waves. During the geomagnetic storm on 8 November 2004, LFEW observed a wave burst associated with the oxygen ion cyclotron waves. This observation shows that during geomagnetic storms, the oxygen ions are very active in the inner magnetosphere. Outside the plasmasphere,

No abstract