Supercritical antisolvent (SAS) method is an emerging technique for particle processing of high energetic materials. The study investigates the recrystallization of high energy material HMX (octahydro- 1,3,5,7-tetranitro-1,3,5,7-tetrazocine) using SAS method. The effect of pressure, solution flow rate, supercritical antisolvent flow rate and temperature on particle size and morphology of HMX crystals has been studied with acetone as solvent and supercritical carbon dioxide as antisolvent. Stable and desirable ��- polymorphic form of HMX could be obtained under certain process conditions and has been confirmed by FTIR spectroscopy. The experimental results show that ��- polymorph of HMX is of rhombohedral morphology with mean particle size of 13.7 μm, as confirmed by SEM and particle size analyzer respectively.

Oxbow lakes occurring in floodplains are those natural elements that are subject to rapid changes, which may lead to their disappearance. These are extremely valuable ecosystems and landscape components, as well as water management units. However, they quickly disappear if they are not periodically fed with river water, which takes place especially when rivers are embanked. Such a situation occurs, among others in Warsaw, in the Vistula valley. There are many opportunities for the reactivation of oxbow lakes, including through technical activities. It is not always possible to restore the naturalvalues of the valley in urbanized areas, however, oxbow lakes can then also play a recreational role and they can fulfill an important task in improving the quality of life, being also an important element of the public space system. The author has carried out research related to land development projects of the new district located in the Vistula River valley in Warsaw (the Siekierkowski Arc). Many different design solutions have been proposed, taking as a leitmotiv the restoration of oxbow lakes, for example: (1) reconstruction of the water channel in the former watercourse with the boulevard along its fragment and with the public park in another part, (2) water supplying of the existing oxbow lake through the green and blue infrastructure system. The author presents few urban designs carried out under her direction for this area and shows that creative reactivation of oxbow lakes can improve water conditions, and be beneficial for the introduction of a new, attractive development.

Professor Piotr Węgleński, who died on January 19, 2024 studied and worked at the University of Warsaw – at the Faculty of Biology and later at the Center for New Technologies. He was a member of the Polish Academy of Sciences and the vice-rector and later the rector of the University of Warsaw. He was responsible for introducing genetic engineering to Poland. He was a great boss – that is what we always called him – and a great academic teacher and was very active in popularizing science.