In-situ Undisturbed Sand Sampling by Radial Freezing for Liquefaction Analysis

The authors experimented in laboratory that if radial freezing with free drainage is performed under an effective confining pressure of 100 kPa only an increase of the order of 0.5% of volumetric strain takes place going from the unfrozen to the frozen condition. The sample comes back to the original dimension after thawing. The displacements of the sample were measured by radiographs of a lead shot network properly built inside the sample. The technique suggested by Yoshimi and al. (1977) to freeze in situ a column of saturated sands was also verified and optimized in laboratory by simulating in a full scale test the site conditions. Finally 3.10 m length and 55 cm. diameter sample of saturated sand was frozen at a well studied site by radial freezing technique, then pulled out from the ground by a crane, sawed and stored in a freezer for future laboratory tests

The integral field unit for the James Webb space telescope's near-infrared spectrograph

The European Space Agency (ESA) is providing the Near Infrared Spectrograph (NIRSpec) developed by EADS Astrium GmbH to fly on the James Webb Space Telescope (JWST). NIRSpec covers the 0.6-5.0 µm domain. It will be primarily operated as a multi-object spectrograph, using a MEMS micro-shutter array (MSA) provided by NASA to select multiple objects from the field of view at an intermediate image plane formed by the NIRSpec fore-optics. The MSA apertures form multiple entrance slits of the spectrometer section