The 79th volume of the journal is dedicated to engineering decisions and research in the synthesis and characterisation of bio-based materials, thermal analysis of technological processes, such as degumming and energy recovery from phosphogypsum desulfurization waste heat, design of a flexible screw conveyor and analysis of the interaction between hydrodynamic lubrication and the main bearing bush in a marine low-speed engine, applied issues of heat transfer and flow kinetics, friction stir welding of polyethylene pipes and analytical study and conservation plan of Akhmerutnisut's tomb in Egypt. The presented results will be useful to a wide range of specialists in chemical production, machinery, energy, construction, and architectural heritage preservation.