Investigating the effect of energy dissipation on flotation kinetics in an oscillating grid flotation cell

This thesis investigates the effect of energy dissipation on the flotation kinetics of quartz in an oscillating grid flotation cell. Oscillating grids exhibit relatively isotropic and homogeneous turbulence, which cannot be achieved in standard impeller agitated flotation cells. Due to this they provide a potentially ideal environment in which to investigate the effects of energy dissipation on flotation kinetics. Previous work in an oscillating grid flotation cell was limited to energy dissipations of up to 0.6 kW/m³, which is low when compared to 0.6 - 3 kW/m³ commonly used in both flotation literature and industry. The current work uses a new oscillating grid cell which can operate at energy dissipations of up to 5 kW/m³. Quartz (sub 100 μm) has been floated in the new cell at energy dissipations ranging from 0.5 - 5 kW/m³ and using three discrete bubble sizes (0.13 mm, 0.24 mm and 0.82 mm). Characterisation experiments show that the new cell operates in a similar manner to the oscillating grid cell used by Changunda et al. (2008), and produces repeatable results. The effect of changing bubble and particle size on flotation kinetics is in agreement with literature findings, indicating that as a flotation device the oscillating grid cell is operating as expected

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Theia: Faint objects in motion or the new astrometry frontier

In the context of the ESA M5 (medium mission) call we proposed a new satellite mission, Theia, based on relative astrometry and extreme precision to study the motion of very faint objects in the Universe. Theia is primarily designed to study the local dark matter properties, the existence of Earth-like exoplanets in our nearest star systems and the physics of compact objects. Furthermore, about 15 % of the mission time was dedicated to an open observatory for the wider community to propose complementary science cases. With its unique metrology system and "point and stare" strategy, Theia's precision would have reached the sub micro-arcsecond level. This is about 1000 times better than ESA/Gaia's accuracy for the brightest objects and represents a factor 10-30 improvement for the faintest stars (depending on the exact observational program). In the version submitted to ESA, we proposed an optical (350-1000nm) on-axis TMA telescope. Due to ESA Technology readiness level, the camera's focal plane would have been made of CCD detectors but we anticipated an upgrade with CMOS detectors. Photometric measurements would have been performed during slew time and stabilisation phases needed for reaching the required astrometric precision