Direct contact 1 Dryers (equipment) 1 Drying 1 Drying process 1 Drying technology Energy 1 Energy efficiency 1 Energy utilization 1 Numerical investigations 1 Paper and pulp industry 1 Paper drying 1 Paper industries 1 Paper machine 1 Paper products 1 Papermaking 1 Papermaking machinery 1 Porous materials 1 Total energy 1 Transducers 1 Ultrasonics 1 Ultrasound transducers 1