Phosphate Glasses

This chapter is dedicated to the studies on phosphate glasses, from their fundamental aspects to their most relevant applications of today. P2O5-based glasses have experienced a continuously increasing number of published works in the last decades and still they possess a bright potential. Their sometimes intricate structure has made its study a quite relevant field for the Glass Science community which attracts more and more researchers. And, on the other hand, the associated difficulties in their preparation on a large scale have led to the development of specific methods, such as those used for the melting of Nd-laser glasses. They are particularly known to have a low chemical durability, though the progress in the optimization of their composition demonstrates that can be very competitive and, in this respect, we will also pay attention to the improvement of their properties as a result of their nitridation. The structure and main physico-chemical properties of phosphate glasses will be reviewed, highlighting the most relevant and well-known applications existing nowadays, such as sealing and laser glasses, biomedical, as solid electrolytes or for the storage of wastes.F. Muñoz thanks funding from projects MAT2013-48246-C2-1-P from MINECO of Spain and I-link+0959 from CSIC. I. Ahmed would like to acknowledge the Faculty of Engineering, Advanced Materials Research Group, University of Nottingham, for provision of studentship funds

SEIS: Insight’s Seismic Experiment for Internal Structure of Mars

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼2500 at 1 Hz and ∼200000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of ∼3 at 40∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution