Tiltable rotating liquid mirrors: a progress report

Context.We give a progress report on tiltable, nanoengineered, rotating liquid mirrors, which were discussed in previous papers. Aims.We want to develop the technology, improve reflectivities and user-friendliness. The ultimate goal is to demonstrate high-quality liquid mirrors that can be tilted by a few tens of degrees. Methods.We coated hydrophilic liquid substrates that have poor reflectivities with a reflective layer of self-assembling metallic nanoparticles. We analyzed the wavefronts of 1-m diameter mirrors with Ronchi tests, knife-edge tests and point-spread functions (PSFs). Results.There is significant improvement over previous work where the reflecting layer was deposited on hydrophobic oils. While previous work only demonstrated tilted low-reflectivity mirrors, we now test a high-reflectivity 1-m diameter liquid mirror tilted by 45 arcmin. Conclusions.It is considerably easier to coat hydrophilic liquids than hydrophobic ones. We have reached a significant milestone by demonstrating a tilted, highly reflective, liquid mirror. Although this is still an immature technology, it is near the stage where it could be used in astronomy. The remaining technical challenges, for which we propose solutions, are not fundamental and could be overcome with additional work. This will be a worthwhile undertaking, considering the very low cost of liquid mirrors

Strategies for the prediction of acid mine drainage

A comprehensive 1 year study has been carried out to evaluate and compare methods to predict the formation of acid mine drainage (AMD) and to make recommendations on the methods most suitable for laboratory and field use. This paper presents the findings of this study and includes a brief description of methods evaluated, a summary of the test results, and a discussion on the ability of the methods to accurately predict field behaviour. A principal conclusion made from the results of the study is that accurate and confident prediction of AMD is not likely to be achieved in a single test. Factors affecting the choice of test procedures to be used for a given tailing or waste rock are discussed on the basis of simplicity, time, equipment, cost, ease of interpretation, and correlation with field data. In addition, approaches to be used in the selection of AMD prediction methods for site specific applications involving either land-based or sub-aqueous waste deposition are outlined.Applied Science, Faculty ofNon UBCMining Engineering, Keevil Institute ofUnreviewedOthe