If the .zip file contains code or data collection tools, it likely refers to these systems:
: A recent study in Engineering Reports proposes a rope-driven piezoelectric energy harvester (RPEH) . It uses cantilever beams and a proof mass to harvest multidirectional vibration energy, effectively converting motion into electrical power.
Below are the most relevant "solid" papers and research areas that match these descriptions: 1. Energy Harvesting (Piezoelectric & Thermal)
: Research published in Energies details a tube-shaped solid–liquid beam-pumping harvester . It utilizes self-assembled materials and triboelectric nanogenerators to capture energy from water or raindrops.
: A paper titled " Solid design and experiment of forage harvester " outlines an innovative design for silage harvesters, focusing on automatic pneumatic tying and reducing labor intensity.