Namita Thomas

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[1] When not laterally confined in valleys, pyroclastic flows create their own channel along the slope by selecting a given flowing width. Furthermore, the lobe-shaped deposits display a very specific morphology with high parallel lateral levees. A numerical model based on Saint Venant equations and the empirical variable friction coefficient proposed by(More)
Recent studies have pointed out the importance of the basal friction on the dynamics of granular flows. We present experimental results on the influence of the roughness of the inclined plane on the dynamics of a monodisperse dry granular flow. We found experimentally that there exists a maximum of the friction for a given relative roughness. This maximum(More)
Experiments were performed to provide insight into the flow behavior and structure of bimodal mixtures of grains in gravity-driven, free-surface flows. Unsteady unconfined flows were produced by releasing instantaneously a dry granular mass, composed of two particle sizes, over a rough inclined plane. As a result of size segregation, the small particles are(More)
The High Resolution Imaging Science Experiment (HiRISE) onboard Mars Reconnaissance Orbiter (MRO) has been used to monitor the seasonal evolution of several regions at high southern latitudes and, in particular, the jet-like activity which may result from the process described by Kieffer (JGR, 112, E08005, doi:10.1029/2006JE002816, 2007) involving(More)
In a half-filled rotating drum, the size segregation of particles of equal density builds a ring pattern of the large particles, whose location continuously varies from the periphery to the center depending on the size ratio between particles [N. Thomas, Phys. Rev. E 62, 961 (2000)]. For small size ratios (typically < 5) position. The existence of circles(More)
To develop an analytical methodology, as non-destructive as possible, suitable for the identification of natural substances from archaeological origin, we studied the potentiality of solid-phase microextraction (SPME) for analysing birch bark tar, an adhesive commonly used during ancient times. First of all, birch bark tars were produced by a controlled(More)
0019-1035/$ see front matter 2009 Elsevier Inc. A doi:10.1016/j.icarus.2009.06.005 * Corresponding author. Address: Universität B Sidlerstasse 5, 3013 Bern, Switzerland. E-mail addresses: alexandra.lefort@space.unibe.c Lefort). The Peneus and Amphitrites Paterae region of Mars displays large areas of smooth, geologically young terrains overlying a rougher(More)
The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission dedicated to search for exoplanet transits by means of ultra-high precision photometry whose launch readiness is expected end 2017. The CHEOPS instrument will be the first space telescope dedicated to search for transits on bright stars already known to host planets. By(More)
The simulation of two-phase flow in bubble columns using commercially available software from Fluent Incorporated is presented here. Data from a bubble column with a ratio of height to the column diameter of 5 : 1 are compared with simulations and experimental results for time-averaged velocity and Reynolds stress profiles are used to validate transient,(More)