This paper provides an analysis of the main problems encountered during the installation of bitumen-polymer roofing materials. Special attention is paid to typical defects and errors related to insufficient qualifications, as well as problems related to violations of installation technology.

Keywords: bitumen-polymer roofing, installation of a surfaced roof, waterproofing defect, quality management, recommendations for improvement

High purity ultrafine aluminum nitride is produced by gas-phase approach, however there is an issue to divide AlF3 and AlN at the final step of synthesis. Recently, the problem is solved by sublimation of aluminum trifluoride in vacuum, but due to high temperatures aluminum nitride particles agglomerate into chunks with dimension about 8 μm, hence the new alternate methods of separation is in a great interest. Flotation in organic environment is considered to divide aluminum trifluoride and aluminum nitride. The process of AlN and AlF3 interaction with organic and element-organic matters was investigated and the following conclusions were made: there is agglomeration and sedimentation stability of AlN and AlF3 in organic environments and flotation possibility was experimentally proved, hence, flotation after special treatment is a possible approach to divide powders of aluminum trifluoride and nitride.

Keywords: aluminum trifluoride, aluminum nitride, gas-phase synthesis, aglomeration, sedimentation, sublimation